Dai-Wen Pang

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Name: 庞代文; DaiWen Pang
Organization: Wuhan Universi , China
Department: The Institute for Advanced Studies
Title: Professor(PhD)

TOPICS

Co-reporter:En-Ze Sun, An-An Liu, Zhi-Ling Zhang, Shu-Lin Liu, Zhi-Quan Tian, and Dai-Wen Pang
ACS Nano May 23, 2017 Volume 11(Issue 5) pp:4395-4395
Publication Date(Web):March 29, 2017
DOI:10.1021/acsnano.6b07853
Entry is the first critical step for the infection of influenza A virus and of great significance for the research and development of antiflu drugs. Influenza A virus depends on exploitation of cellular endocytosis to enter its host cells, and its entry behaviors in distinct routes still need further investigation. With the aid of a single-virus tracking technique and quantum dots, we have realized real-time and multicolor visualization of the endocytic process of individual viruses and comprehensive dissection of two distinct dynamin-dependent endocytic pathways of influenza A virus, either dependent on clathrin or not. Based on the sequential progression of protein recruitment and viral motility, we have revealed the asynchronization in the recruitments of clathrin and dynamin during clathrin-dependent entry of the virus, with a large population of events for short-lived recruitments of these two proteins being abortive. In addition, the differentiated durations of dynamin recruitment and responses to inhibitors in these two routes have evidenced somewhat different roles of dynamin. Besides promoting membrane fission in both entry routes, dynamin also participates in the maturation of a clathrin-coated pit in the clathrin-dependent route. Collectively, the current study displays a dynamic and precise image of the entry process of influenza A virus and elucidates the mechanisms of distinct entry routes. This quantum dot-based single-virus tracking technique is proven to be well-suited for investigating the choreographed interactions between virus and cellular proteins.Keywords: clathrin; dynamin; endocytosis; influenza A virus; quantum dot; tracking;
Co-reporter:Shu-Lin Liu, Zhi-Gang Wang, Zhi-Ling Zhang and Dai-Wen Pang  
Chemical Society Reviews 2016 vol. 45(Issue 5) pp:1211-1224
Publication Date(Web):23 Dec 2015
DOI:10.1039/C5CS00657K
Single-virus tracking (SVT) technique, which uses microscopy to monitor the behaviors of viruses, is a vital tool to study the real-time and in situ infection dynamics and virus-related interactions in live cells. To make SVT a more versatile tool in biological research, the researchers have developed a quantum dot (QD)-based SVT technique, which can be utilized for long-term and highly sensitive tracking in live cells. In this review, we describe the development of a QD-based SVT technique and its biological applications. We first discuss the advantage of QDs as tags in the SVT field by comparing the conventional tags, and then focus on the implementation of QD-based SVT experiments, including the QD labeling strategy, instrumentation, and image analysis method. Next, we elaborate the recent advances of QD-based SVT in the biological field, and mainly emphasize the representative examples to show how to use this technique to acquire more meaningful biological information.
Co-reporter:Cong-Ying Wen, Hai-Yan Xie, Zhi-Ling Zhang, Ling-Ling Wu, Jiao Hu, Man Tang, Min Wu and Dai-Wen Pang  
Nanoscale 2016 vol. 8(Issue 25) pp:12406-12429
Publication Date(Web):19 Jan 2016
DOI:10.1039/C5NR08534A
The study of cancer is of great significance to human survival and development, due to the fact that cancer has become one of the greatest threats to human health. In recent years, the rapid progress of nanoscience and nanotechnology has brought new and bright opportunities to this field. In particular, the applications of quantum dots (QDs) and magnetic nanoparticles (MNPs) have greatly promoted early diagnosis and effective therapy of cancer. In this review, we focus on fluorescent/magnetic micro/nano-spheres based on QDs and/or MNPs (we may call them “nanoparticle-sphere (NP–sphere) composites”) from their preparation to their bio-application in cancer research. Firstly, we outline and compare the main four kinds of methods for fabricating NP–sphere composites, including their design principles, operation processes, and characteristics (merits and limitations). The NP–sphere composites successfully inherit the unique fluorescence or magnetic properties of QDs or MNPs. Moreover, compared with the nanoparticles (NPs) alone, the NP–sphere composites show superior properties, which are also discussed in this review. Then, we summarize their recent applications in cancer research from three aspects, that is: separation and enrichment of target tumor cells or biomarkers; cancer diagnosis mainly through medical imaging or tumor biomarker detection; and cancer therapy via targeted drug delivery systems. Finally, we provide some perspectives on the future challenges and development trends of the NP–sphere composites.
Co-reporter:Bao-Ping Qi, Lei Bao, Zhi-Ling Zhang, and Dai-Wen Pang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 42) pp:28372
Publication Date(Web):February 24, 2016
DOI:10.1021/acsami.5b11551
With unique and tunable photoluminescence (PL) properties, carbon nanodots (CNDs) as a new class of optical tags have been extensively studied. Because of their merits of controllability and sensitivity to the surface of nanomaterials, electrochemical methods have already been adopted to study the intrinsic electronic structures of CNDs. In this review, we mainly deal with the electrochemical researches of CNDs, including preparation, PL mechanism, and biosensing.Keywords: carbon nanodot; electrochemical; photoluminescence mechanism; preparation; sensing
Co-reporter:Zhi-Gang Wang, Shu-Lin Liu, Yuan-Jun Hu, Zhi-Quan Tian, Bin Hu, Zhi-Ling Zhang, and Dai-Wen Pang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 13) pp:8401
Publication Date(Web):March 21, 2016
DOI:10.1021/acsami.6b01742
Labeling and imaging of live cells with quantum dots (QDs) has attracted great attention in the biomedical field over the past two decades. Maintenance of the fluorescence of QDs in a biological environment is crucial for performing long-term cell tracking to investigate the proliferation and functional evolution of cells. The cell-penetrating peptide transactivator of transcription (TAT) is a well-studied peptide to efficiently enhance the transmembrane delivery. Here, we used TAT peptide-conjugated QDs (TAT–QDs) as a model system to examine the fluorescence stability of QDs in live cells. By confocal microscopy, we found that TAT–QDs were internalized into cells by endocytosis, and transported into the cytoplasm via the mitochondria, Golgi apparatus, and lysosomes. More importantly, the fluorescence of TAT–QDs in live cells was decreased mainly by cell proliferation, and the low pH value in the lysosomes could also lower the fluorescence intensity of intracellular QDs. Quantitative analysis of the amount of QDs in the extracellular region and whole cells indicated that the exocytosis was not the primary cause of fluorescence decay of intracellular QDs. This work facilitates a better understanding of the fluorescence stability of QDs for cell imaging and long-term tracking in live cells. Also, it provides insights into the utility of TAT for transmembrane transportation, and the preparation and modification of QDs for cell imaging and tracking.Keywords: fluorescence stability; influence factors; live cells; quantum dots; transactivator of transcription
Co-reporter:Jiao Hu, Zhi-Ling Zhang, Cong-Ying Wen, Man Tang, Ling-Ling Wu, Cui Liu, Lian Zhu, and Dai-Wen Pang
Analytical Chemistry 2016 Volume 88(Issue 12) pp:6577
Publication Date(Web):June 2, 2016
DOI:10.1021/acs.analchem.6b01427
Sensitive and quantitative detection of protein biomarkers with a point-of-care (POC) assay is significant for early diagnosis, treatment, and prognosis of diseases. In this paper, a quantitative lateral flow assay with high sensitivity for protein biomarkers was established by utilizing fluorescent nanospheres (FNs) as reporters. Each fluorescent nanosphere (FN) contains 332 ± 8 CdSe/ZnS quantum dots (QDs), leading to its superstrong luminescence, 380-fold higher than that of one QD. Then a detection limit of 27.8 pM C-reaction protein (CRP) could be achieved with an immunofluorescent nanosphere (IFN)-based lateral flow test strip. The assay was 257-fold more sensitive than that with a conventional Au-based lateral flow test strip for CRP detection. Besides, the fluorescence intensity of FNs and bioactivity of IFNs were stable during 6 months of storage. Hence, the assay owns good reproducibility (intra-assay variability of 5.3% and interassay variability of 6.6%). Furthermore, other cancer biomarkers (PSA, CEA, AFP) showed negative results by this method, validating the excellent specificity of the method. Then the assay was successfully applied to quantitatively detect CRP in peripheral blood plasma samples from lung cancer and breast cancer patients, and healthy people, facilitating the diagnosis of lung cancer. It holds a good prospect of POC protein biomarker detection.
Co-reporter:Jia-Kai Wu, Zhi-Quan Tian, Zhi-Ling Zhang, An-An Liu, Bo Tang, Li-Juan Zhang, Zhi-Liang Chen, Dai-Wen Pang
Talanta 2016 Volume 159() pp:64-73
Publication Date(Web):1 October 2016
DOI:10.1016/j.talanta.2016.05.078
•First, monodisperse OPA-QDs were obtained by purified with high-performance size exclusion chromatography (HPSEC) to remove excess OPA and aggregated QDs.•Secondly, excess free streptavidin (SA) in fresh prepared QD-labeled SA, and the monodisepese QD-SA were used in tumour maker determination.•Thirdly, monodisperse QD-labeled antibody bioprobes has been obtained by removing away the unbound antibody and suspended agglomerates of QDs at the same time via high-performance size exclusion chromatography (HPSEC).Due to excellent optical properties, quantum dots (QDs) have been widely applied to sensing, labeling, and imaging. For the fabrication of QD-based bioprobes, purification is usually the crucial step. Hydrophilic octylamine grafted polyacrylic acid modified QDs (OPA-QDs) were prepared, and purified by high-performance size exclusion chromatography (HPSEC) to remove excess OPA and aggregated QDs. The percentage of suspended agglomerates of OPA-QDs in the unpurified OPA-QDs increases from 4% to 31% through a year, but the purified OPA-QDs of the same batch possess excellent colloidal stability for at least one year. Subsequently, QD-based bioprobes were fabricated by the conjugation between QDs and streptavidin (SA) or antibody (IgG), generating QD-SA and QD-IgG, respectively, which were purified via HPSEC. Finally, the resulting QD-SA and QD-IgG were adopted to detect tumour markers on slices and showed specific positive signals without nonspecific adsorption, which was contrary to the unpurified QD-IgG. Thus, the HPSEC-coupled system proposed in the current work is potent and universal for the generation of purified and monodisperse QD-based bioprobes, which is promising in the nanobiodetection field.QD-based bioprobes were purified via high-performance size exclusion chromatography to improve the specificity for target imaging.
Co-reporter:Lan Chen, Ling-Ling Wu, Zhi-Ling Zhang, Jiao Hu, Man Tang, Chu-Bo Qi, Na Li, Dai-Wen Pang
Biosensors and Bioelectronics 2016 Volume 85() pp:633-640
Publication Date(Web):15 November 2016
DOI:10.1016/j.bios.2016.05.071
•An efficient cell sorting strategy for HCC CTC isolation was proposed based on IMNs.•ICC identification via biomarkers AFP and GPC3 was applied to HCC CTC detection.•This immunomagnetic cell sorting strategy achieved CTC subtype analyses.Hepatocellular carcinoma (HCC) is an awful threat to human health. Early-stage HCC may be detected by isolation of circulating tumor cells (CTCs) from peripheral blood samples, which is beneficial to the diagnosis and therapy. However, the extreme rarity and high heterogeneity of HCC CTCs have been restricting the relevant research. To achieve an efficient isolation, reliable detection and subtype analyses of heterogeneous HCC CTCs, herein, we present a cell sorting strategy based on anti-CD45 antibody-modified magnetic nanospheres. By this strategy, leukocyte depletion efficiency was up to 99.9% within 30 min in mimic clinical samples, and the purity of the spiked HCC cells was improved 265-317-fold. Besides, the isolated HCC cells remained viable at 92.3% and could be directly recultured. Moreover, coupling the convenient, fast and effective cell sorting strategy with specific ICC identification via biomarkers AFP and GPC3, HCC CTCs were detectable in peripheral blood samples, showing the potential for HCC CTC detection in clinic. Notably, this immunomagnetic cell sorting strategy enabled isolating more heterogeneous HCC cells compared with the established EpCAM-based methods, and further achieved characterization of three different CTC subtypes from one clinical HCC blood sample, which may assist clinical HCC analyses such as prognosis or personalized treatment.
Co-reporter:An-An Liu, Zhenfeng Zhang, En-Ze Sun, Zhenhua Zheng, Zhi-Ling Zhang, Qinxue Hu, Hanzhong Wang, and Dai-Wen Pang
ACS Nano 2016 Volume 10(Issue 1) pp:1147
Publication Date(Web):December 31, 2015
DOI:10.1021/acsnano.5b06438
Real-time, long-term, single-particle tracking (SPT) provides us an opportunity to explore the fate of individual viruses toward understanding the mechanisms underlying virus infection, which in turn could lead to the development of therapeutics against viral diseases. However, the research focusing on the virus assembly and egress by SPT remains a challenge because established labeling strategies could neither specifically label progeny viruses nor make them distinguishable from the parental viruses. Herein, we have established a temporally controllable capsid-specific HaloTag labeling strategy based on reverse genetic technology. VP26, the smallest pseudorabies virus (PrV) capsid protein, was fused with HaloTag protein and labeled with the HaloTag ligand during virus replication. The labeled replication-competent recombinant PrV harvested from medium can be applied directly in SPT experiments without further modification. Thus, virus infectivity, which is critical for the visualization and analysis of viral motion, is retained to the largest extent. Moreover, progeny viruses can be distinguished from parental viruses using diverse HaloTag ligands. Consequently, the entire course of virus infection and replication can be visualized continuously, including virus attachment and capsid entry, transportation of capsids to the nucleus along microtubules, docking of capsids on the nucleus, endonuclear assembly of progeny capsids, and the egress of progeny viruses. In combination with SPT, the established strategy represents a versatile means to reveal the mechanisms and dynamic global picture of the life cycle of a virus.Keywords: capsid; HaloTag; labeling; tracking; virus;
Co-reporter:Lei Bao;Cui Liu;Zhi-Ling Zhang
Advanced Materials 2015 Volume 27( Issue 10) pp:1663-1667
Publication Date(Web):
DOI:10.1002/adma.201405070
Co-reporter:Peng Jiang, Chun-Nan Zhu, Dong-Liang Zhu, Zhi-Ling Zhang, Guo-Jun Zhang and Dai-Wen Pang  
Journal of Materials Chemistry A 2015 vol. 3(Issue 5) pp:964-967
Publication Date(Web):24 Dec 2014
DOI:10.1039/C4TC02437K
A green room-temperature method based on phase transfer and a reaction between Zn2+ and S2− in toluene for coating a ZnS shell on CdSe and Ag2S quantum dots (QDs), respectively, has been developed. In this method, the S2− anions in Na2S aqueous solution were transferred to toluene via electrostatic interactions between the anions and didodecyldimethylammonium bromide (DDAB), which served as an excellent sulfur precursor and thereby reacted with Zn2+ to form a ZnS shell on the surface of semiconductor QDs in the presence of QDs in an organic phase. After the ZnS shell was coated on QDs, the photoluminescence (PL) intensities of the CdSe and Ag2S QDs were found to increase approximately 12 times and 14 times, respectively, while both the emission wavelengths and the peak shapes were well maintained. The proposed method is novel, simple and robust, providing a green solution to the preparation of ZnS shell-coated QDs.
Co-reporter:Peng Jiang, Dong-Liang Zhu, Chun-Nan Zhu, Zhi-Ling Zhang, Guo-Jun Zhang and Dai-Wen Pang  
Nanoscale 2015 vol. 7(Issue 45) pp:19310-19316
Publication Date(Web):22 Oct 2015
DOI:10.1039/C5NR05747G
Metal chalcogenide semiconductor nanocrystals (NCs) are ideal inorganic materials for solar cells and biomedical labeling. In consideration of the hazard and instability of alkylphosphines, the phosphine-free synthetic route has become one of the most important trends in synthesizing selenide QDs. Here we report a novel phase transfer strategy to prepare phosphine-free chalcogenide precursors. The anions in aqueous solution were transferred to toluene via electrostatic interactions between the anions and didodecyldimethylammonium bromide (DDAB). The obtained chalcogenide precursors show high reactivity with metal ions in the organic phase and could be applied to the low-temperature synthesis of various metal chalcogenide NCs based on a simple reaction between metal ions (e.g. Ag+, Pb2+, Cd2+) and chalcogenide anions (e.g. S2−) in toluene. In addition to chalcogenide anions, other anions such as BH4− ions and AuCl4− ions can also be transferred to the organic phase for synthesizing noble metal NCs (such as Ag and Au NCs).
Co-reporter:Bao-Ping Qi, Hui Hu, Lei Bao, Zhi-Ling Zhang, Bo Tang, Ying Peng, Bao-Shan Wang and Dai-Wen Pang  
Nanoscale 2015 vol. 7(Issue 14) pp:5969-5973
Publication Date(Web):06 Mar 2015
DOI:10.1039/C5NR00842E
An efficient edge-functionalization strategy with high specificity was employed to study the effects of conjugated structures on photoluminescence (PL) properties of graphene quantum dots (GQDs). Both the experimental results and density functional theory (DFT)-based calculations suggested the mechanism for conjugated structures in GQDs to tune the band gap of GQDs.
Co-reporter:Jia-Jia Wang, Yong-Zhong Jiang, Yi Lin, Li Wen, Cheng Lv, Zhi-Ling Zhang, Gang Chen, and Dai-Wen Pang
Analytical Chemistry 2015 Volume 87(Issue 21) pp:11105
Publication Date(Web):October 13, 2015
DOI:10.1021/acs.analchem.5b03247
Human enterovirus 71 (EV71) is one of the pathogens that causes hand, foot, and mouth disease (HFMD), which generally leads to neurological diseases and fatal complications among children. Since the early clinical symptoms from EV71 infection are very similar to those from Coxsackievirus B3 (CVB3) infection, a robust and sensitive detection method that can be used to distinguish EV71 and CVB3 is urgently needed for prompting medical treatment of related diseases. Herein, based on immunomagnetic nanobeads and fluorescent semiconductor CdSe quantum dots (QDs), a method for simultaneous point-of-care detection of EV71 and CVB3 is proposed. The synchronous detection of EV71 and CVB3 virions was achieved within 45 min with high specificity and repeatability. The limits of detection are 858 copies/500 μL for EV71 and 809 copies/500 μL for CVB3.This proposed method was further validated with 20 human throat swab samples obtained from EV71 or CVB3 positive cases, with results 93.3% consistent with those by the real-time PCR method, demonstrating the potential of this method for clinical quantification of EV71 and CVB3. The method may also facilitate the prevention and treatment of the diseases.
Co-reporter:Dr. Gang Chen;Jun-Yi Zhu; Zhi-Ling Zhang;Dr. Wei Zhang;Jian-Gang Ren;Min Wu;Zheng-Yuan Hong;Cheng Lv; Dai-Wen Pang; Yi-Fang Zhao
Angewandte Chemie International Edition 2015 Volume 54( Issue 3) pp:1036-1040
Publication Date(Web):
DOI:10.1002/anie.201410223

Abstract

Cell-derived microparticles (MPs) have been recently recognized as critical intercellular information conveyors. However, further understanding of their biological behavior and potential application has been hampered by the limitations of current labeling techniques. Herein, a universal donor-cell-assisted membrane biotinylation strategy was proposed for labeling MPs by skillfully utilizing the natural membrane phospholipid exchange of their donor cells. This innovative strategy conveniently led to specific, efficient, reproducible, and biocompatible quantum dot (QD) labeling of MPs, thereby reliably conferring valuable traceability on MPs. By further loading with small interference RNA, QD-labeled MPs that had inherent cell-targeting and biomolecule-conveying ability were successfully employed for combined bioimaging and tumor-targeted therapy. This study provides the first reliable and biofriendly strategy for transforming biogenic MPs into functionalized nanovectors.

Co-reporter:Dr. Gang Chen;Jun-Yi Zhu; Zhi-Ling Zhang;Dr. Wei Zhang;Jian-Gang Ren;Min Wu;Zheng-Yuan Hong;Cheng Lv; Dai-Wen Pang; Yi-Fang Zhao
Angewandte Chemie 2015 Volume 127( Issue 3) pp:1050-1054
Publication Date(Web):
DOI:10.1002/ange.201410223

Abstract

Cell-derived microparticles (MPs) have been recently recognized as critical intercellular information conveyors. However, further understanding of their biological behavior and potential application has been hampered by the limitations of current labeling techniques. Herein, a universal donor-cell-assisted membrane biotinylation strategy was proposed for labeling MPs by skillfully utilizing the natural membrane phospholipid exchange of their donor cells. This innovative strategy conveniently led to specific, efficient, reproducible, and biocompatible quantum dot (QD) labeling of MPs, thereby reliably conferring valuable traceability on MPs. By further loading with small interference RNA, QD-labeled MPs that had inherent cell-targeting and biomolecule-conveying ability were successfully employed for combined bioimaging and tumor-targeted therapy. This study provides the first reliable and biofriendly strategy for transforming biogenic MPs into functionalized nanovectors.

Co-reporter:Zheng-Yuan Hong, Cheng Lv, An-An Liu, Shu-Lin Liu, En-Ze Sun, Zhi-Ling Zhang, Ai-Wen Lei, and Dai-Wen Pang
ACS Nano 2015 Volume 9(Issue 12) pp:11750
Publication Date(Web):November 7, 2015
DOI:10.1021/acsnano.5b03256
Real-time tracking of fluorophore-tagged viruses in living cells can help uncover virus infection mechanisms. Certainly, the indispensable prerequisite for virus-tracking is to label viruses with some bright and photostable beacons such as quantum dots (QDs) via an appropriate labeling strategy. Herein, we devise a convenient hydrazine-aldehyde based strategy to label viruses with QDs through the conjugation of 4-formylbenzoate (4FB) modified QDs to 6-hydrazinonicotinate acetone hydrazone (HyNic) modified viruses under mild conditions. On the basis of this strategy, viruses can be successfully labeled with QDs with high selectivity, stable conjugation, good reproducibility, high labeling efficiency of 92–93% and maximum retention of both fluorescence properties of QDs and infectivity of viruses, which is very meaningful to tracking and statistical analysis of virus infection processes. By further comparing with the most widely used labeling strategy based on the Biotin-SA system, this new strategy has advantages of both high labeling efficiency and good retention of virus infectivity, thus offering a promising alternative for virus-labeling. Moreover, due to the ubiquitous presence of exposed amino groups on the surface of various viruses, this selective, efficient, reproducible and biofriendly strategy should have good universality for labeling both enveloped and nonenveloped viruses.Keywords: aldehyde; fluorescence imaging; hydrazine; labeling; quantum dot; virus;
Co-reporter:Shu-Lin Liu, Li-Juan Zhang, Zhi-Gang Wang, Zhi-Ling Zhang, Qiu-Mei Wu, En-Ze Sun, Yun-Bo Shi, and Dai-Wen Pang
Analytical Chemistry 2014 Volume 86(Issue 8) pp:3902
Publication Date(Web):March 31, 2014
DOI:10.1021/ac500640u
Understanding the microtubule-dependent behaviors of viruses in live cells is very meaningful for revealing the mechanisms of virus infection and endocytosis. Herein, we used a quantum dots-based single-particle tracking technique to dynamically and globally visualize the microtubule-dependent transport behaviors of influenza virus in live cells. We found that the intersection configuration of microtubules can interfere with the transport behaviors of the virus in live cells, which lead to the changing and long-time pausing of the transport behavior of viruses. Our results revealed that most of the viruses moved along straight microtubules rapidly and unidirectionally from the cell periphery to the microtubule organizing center (MTOC) near the bottom of the cell, and the viruses were confined in the grid of microtubules near the top of the cell and at the MTOC near the bottom of the cell. These results provided deep insights into the influence of entire microtubule geometry on the virus infection.
Co-reporter:Yan-Min Long, Lei Bao, Jing-Ya Zhao, Zhi-Ling Zhang, and Dai-Wen Pang
Analytical Chemistry 2014 Volume 86(Issue 15) pp:7224
Publication Date(Web):July 21, 2014
DOI:10.1021/ac502405p
Recently, research on carbon nanodots (C-dots), a new type of luminescent nanoparticles with superior optical properties, biocompatibility, and low cost, has been focused on exploring novel properties and structure-related mechanisms to extend their scope. Herein, electrochemiluminescence, a surface-sensitive tool, is used to probe the unrevealed property of carbon nanodots which is characterized by surface oxygen-containing groups. Together with chemiluminescence, carbon nanodots as the coreactants for the anodic electrochemiluminescence of Ru(bpy)32+ are demonstrated for the first time. During the anodic scan, the benzylic alcohol units on the C-dots surface are oxidized “homogeneously” by electrogenerated-Ru(bpy)33+ to form reductive radical intermediate, which further reduce Ru(bpy)33+ into Ru(bpy)32+* that produces a strong ECL emission. This work has provided an insight into the ECL mechanism of the C-dots-involved system, which will be beneficial for in-depth understanding of some peculiar phenomena of C-dots, such as photocatalytic activity and redox properties. Moreover, because of the features of C-dots, the ECL system of Ru(bpy)32+/C-dots is more promising in the bioanalysis.
Co-reporter:Qing-Ying Luo, Yi Lin, Jun Peng, Shu-Lin Liu, Zhi-Ling Zhang, Zhi-Quan Tian and Dai-Wen Pang  
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 17) pp:7677-7680
Publication Date(Web):05 Mar 2014
DOI:10.1039/C4CP00572D
A method based on the AFM and colloidal probe techniques was proposed to directly measure nonspecific interactions between QDs and different proteins with respective sizes and isoelectric points. Results indicated that van der Waals forces were the leading force, while electrostatic interactions also played an important role in nonspecific interactions.
Co-reporter:Li Wen, Yi Lin, Zhen-Hua Zheng, Zhi-Ling Zhang, Li-Juan Zhang, Li-Ying Wang, Han-Zhong Wang, Dai-Wen Pang
Biomaterials 2014 35(7) pp: 2295-2301
Publication Date(Web):
DOI:10.1016/j.biomaterials.2013.11.069
Co-reporter:Cong-Ying Wen, Ling-Ling Wu, Zhi-Ling Zhang, Yu-Lin Liu, Shao-Zhong Wei, Jiao Hu, Man Tang, En-Ze Sun, Yi-Ping Gong, Jing Yu, and Dai-Wen Pang
ACS Nano 2014 Volume 8(Issue 1) pp:941
Publication Date(Web):December 6, 2013
DOI:10.1021/nn405744f
The study on circulating tumor cells (CTCs) has great significance for cancer prognosis, treatment monitoring, and metastasis diagnosis, in which isolation and enrichment of CTCs are key steps due to their extremely low concentration in peripheral blood. Herein, magnetic nanospheres (MNs) were fabricated by a convenient and highly controllable layer-by-layer assembly method. The MNs were nanosized with fast magnetic response, and nearly all of the MNs could be captured by 1 min attraction with a commercial magnetic scaffold. In addition, the MNs were very stable without aggregation or precipitation in whole blood and could be re-collected nearly at 100% in a monodisperse state. Modified with anti-epithelial-cell-adhesion-molecule (EpCAM) antibody, the obtained immunomagnetic nanospheres (IMNs) successfully captured extremely rare tumor cells in whole blood with an efficiency of more than 94% via only a 5 min incubation. Moreover, the isolated cells remained viable at 90.5 ± 1.2%, and they could be directly used for culture, reverse transcription–polymerase chain reaction (RT-PCR), and immunocytochemistry (ICC) identification. ICC identification and enumeration of the tumor cells in the same blood samples showed high sensitivity and good reproducibility. Furthermore, the IMNs were successfully applied to the isolation and detection of CTCs in cancer patient peripheral blood samples, and even one CTC in the whole blood sample was able to be detected, which suggested they would be a promising tool for CTC enrichment and detection.Keywords: circulating tumor cells; magnetic nanospheres; rapid and efficient capture; sensitive detection
Co-reporter:Ling-Hong Xiong, Ran Cui, Zhi-Ling Zhang, Xu Yu, Zhixiong Xie, Yun-Bo Shi, and Dai-Wen Pang
ACS Nano 2014 Volume 8(Issue 5) pp:5116
Publication Date(Web):April 29, 2014
DOI:10.1021/nn501174g
Manipulating biochemical reactions in living cells to synthesize nanomaterials is an attractive strategy to realize their synthesis that cannot take place in nature. Yeast cells have been skillfully utilized to produce desired nanoparticles through spatiotemporal coupling of intracellular nonrelated biochemical reaction pathways for formation of fluorescent CdSe quantum dots. Here, we have successfully transformed Staphylococcus aureus cells into cellular beacons (fluorescing cells), all of which are highly fluorescent and photostable with perfect uniformity. Importantly, on the basis of such cells, we efficiently fabricated fluorescent nanobioprobes by a specific interaction between the protein A expressed on the S. aureus surface and the Fc fragment domain of antibodies, avoiding the use of other common methods for cell surface modifications, such as molecular covalent connection or more difficult genetic and metabolic engineering. Coupled with immunomagnetic beads, the resulting fluorescent-biotargeting bifunctional cells, i.e., biotargeting cellular beacons, can be employed as nanobioprobes for detection of viruses, bacteria, and tumor cells. With this method, H9N2 AIV can be detected specifically with a limit of 8.94 ng/mL (based on protein content). Furthermore, diverse probes for detection of different pathogens or for other biomedical applications can be easily obtained by simply changing the antibody conjugated to the cell surface.Keywords: beacon; detection; nanobioprobe; pathogen; quantum dot
Co-reporter:Cong-Ying Wen, Jun Hu, Zhi-Ling Zhang, Zhi-Quan Tian, Guo-Ping Ou, Ya-Long Liao, Yong Li, Min Xie, Zi-Yong Sun, and Dai-Wen Pang
Analytical Chemistry 2013 Volume 85(Issue 2) pp:1223
Publication Date(Web):December 20, 2012
DOI:10.1021/ac303204q
Sensitive, rapid, and reliable detection of bacteria has always been pursued due to the great threat of the bacteria to human health. In this study, a convenient one-step strategy for detecting Salmonella typhimurium was developed. Immunomagnetic nanospheres (IMNS) and immunofluorescent nanospheres (IFNS) were used to specifically capture and recognize S. typhimurium simultaneously. After magnetic separation, the sandwich immune complexes (IMNS–bacteria–IFNS) were detected under a fluorescence microscope with a detection limit as low as ca. 10 CFU/mL. When they were detected by fluorescence spectrometer, a linear range was exhibited at the concentration from 105 to 107 CFU/mL with R2 = 0.9994. Compared with the two-step detection strategy, in which the bacteria were first captured with the IMNS and subsequently identified with the IFNS, this one-step strategy simplified the detection process and improved the sensitivity. Escherichia coli and Shigella flexneri both showed negative results with this method, indicating that this method had excellent selectivity and specificity. Moreover, this method had strong anti-interference ability, and it had been successfully used to detect S. typhimurium in synthetic samples (milk, fetal bovine serum, and urine), showing the potential application in practice.
Co-reporter:Jun Hu, Cong-Ying Wen, Zhi-Ling Zhang, Min Xie, Jiao Hu, Min Wu, and Dai-Wen Pang
Analytical Chemistry 2013 Volume 85(Issue 24) pp:11929
Publication Date(Web):November 6, 2013
DOI:10.1021/ac4027753
In this study, we report a simple method for simultaneous detection of multiplex DNA sequences, including complementary DNA (cDNA) sequences of HIV and HCV, DNA sequence of HBV, with QDs-encoded fluorescent nanospheres and nano-γ-Fe2O3-coated magnetic nanospheres. Detection was achieved on a fluorescence spectrophotometer without additional auxiliary instruments, and the detection limit was about 100 pM. Here, QDs-encoded fluorescent nanospheres (FNS) with different photoluminescent properties, and magnetic nanospheres (MNS) were separately fabricated by stepwise assembly of hydrophobic QDs or nano-γ-Fe2O3 on the surface of branched poly(ethylene imine) (PEI)-coated nanospheres in precisely controlled amounts, finally followed by silica encapsulation. FNS-labeled probe DNAs and MNS-labeled capture DNAs were used to hybridize with the corresponding targets at the same time. After magnetic separation, the sandwich-structured adducts were measured by fluorescence spectrophotometry. The results indicated that the targets could be detected with high sensitivity. This method is convenient, fast enough, and capable of high anti-interference. Therefore, it is expected to be used for simultaneous detection and separation of multiple targets at high levels of purity and throughput.
Co-reporter:Yong Li, Ran Cui, Peng Zhang, Bei-Bei Chen, Zhi-Quan Tian, Li Li, Bin Hu, Dai-Wen Pang, and Zhi-Xiong Xie
ACS Nano 2013 Volume 7(Issue 3) pp:2240
Publication Date(Web):February 9, 2013
DOI:10.1021/nn305346a
Microbial cells have shown a great potential to biosynthesize inorganic nanoparticles within their orderly regulated intracellular environment. However, very little is known about the mechanism of nanoparticle biosynthesis. Therefore, it is difficult to control intracellular synthesis through the manipulation of biological processes. Here, we present a mechanism-oriented strategy for controlling the biosynthesis of fluorescent CdSe quantum dots (QDs) by means of metabolic engineering in yeast cells. Using genetic techniques, we demonstrated that the glutathione metabolic pathway controls the intracellular CdSe QD formation. Inspired from this mechanism, the controllability of CdSe QD yield was realized through engineering the glutathione metabolism in genetically modified yeast cells. The yeast cells were homogeneously transformed into more efficient cell-factories at the single-cell level, providing a specific way to direct the cellular metabolism toward CdSe QD formation. This work could provide the foundation for the future development of nanomaterial biosynthesis.Keywords: biosynthesis; controllability; glutathione metabolic pathway; mechanism; quantum dots; yeast
Co-reporter:Peng Jiang, Zhi-Quan Tian, Chun-Nan Zhu, Zhi-Ling Zhang, and Dai-Wen Pang
Chemistry of Materials 2012 Volume 24(Issue 1) pp:3
Publication Date(Web):December 7, 2011
DOI:10.1021/cm202543m
Co-reporter:Yan-Min Long, Chuan-Hua Zhou, Zhi-Ling Zhang, Zhi-Quan Tian, Lei Bao, Yi Lin and Dai-Wen Pang  
Journal of Materials Chemistry A 2012 vol. 22(Issue 13) pp:5917-5920
Publication Date(Web):14 Feb 2012
DOI:10.1039/C2JM30639E
The shifting and non-shifting fluorescence at varied excitations are observed on carbon nanodots prepared by electro-oxidizing carbon paste electrodes with different compositions. The emissions are proposed to be mainly attributed to the surface states rising from surface oxidation of carbon nanodots.
Co-reporter:Ran Cui, Yi-Ping Gu, Zhi-Ling Zhang, Zhi-Xiong Xie, Zhi-Quan Tian and Dai-Wen Pang  
Journal of Materials Chemistry A 2012 vol. 22(Issue 9) pp:3713-3716
Publication Date(Web):26 Jan 2012
DOI:10.1039/C2JM15691A
By coupling two biochemical processes of reduction of Na2SeO3 with detoxification of Pb2+ in a quasi-biosystem, water-dispersed PbSe nanocubes with good monodispersity were controllably synthesized with different sizes at low temperature (90 °C) under mild conditions. The crystallization mechanism and the nature of bio-molecules influenced on the crystallization process were investigated.
Co-reporter:Wei Zhao, Wan-Po Zhang, Zhi-Ling Zhang, Rui-Li He, Yi Lin, Min Xie, Han-Zhong Wang, and Dai-Wen Pang
Analytical Chemistry 2012 Volume 84(Issue 5) pp:2358-2365
Publication Date(Web):February 1, 2012
DOI:10.1021/ac203102u
In this work, robust approach for a highly sensitive point-of-care virus detection was established based on immunomagnetic nanobeads and fluorescent quantum dots (QDs). Taking advantage of immunomagnetic nanobeads functionalized with the monoclonal antibody (mAb) to the surface protein hemagglutinin (HA) of avian influenza virus (AIV) H9N2 subtype, H9N2 viruses were efficiently captured through antibody affinity binding, without pretreatment of samples. The capture kinetics could be fitted well with a first-order bimolecular reaction with a high capturing rate constant kf of 4.25 × 109 (mol/L)−1 s–1, which suggested that the viruses could be quickly captured by the well-dispersed and comparable-size immunomagnetic nanobeads. In order to improve the sensitivity, high-luminance QDs conjugated with streptavidin (QDs-SA) were introduced to this assay through the high affinity biotin-streptavidin system by using the biotinylated mAb in an immuno sandwich mode. We ensured the selective binding of QDs-SA to the available biotin-sites on biotinylated mAb and optimized the conditions to reduce the nonspecific adsorption of QDs-SA to get a limit of detection low up to 60 copies of viruses in 200 μL. This approach is robust for application at the point-of-care due to its very good specificity, precision, and reproducibility with an intra-assay variability of 1.35% and an interassay variability of 3.0%, as well as its high selectivity also demonstrated by analysis of synthetic biological samples with mashed tissues and feces. Moreover, this method has been validated through a double-blind trial with 30 throat swab samples with a coincidence of 96.7% with the expected results.
Co-reporter:Ran Cui, Yi-Ping Gu, Lei Bao, Jing-Ya Zhao, Bao-Ping Qi, Zhi-Ling Zhang, Zhi-Xiong Xie, and Dai-Wen Pang
Analytical Chemistry 2012 Volume 84(Issue 21) pp:8932
Publication Date(Web):October 9, 2012
DOI:10.1021/ac301835f
The near-infrared (NIR) electrogenerated chemiluminescence (ECL) of water-dispersed Ag2Se quantum dots (QDs) with ultrasmall size was presented for the first time. The Ag2Se QDs have shown a strong and efficient cathodic ECL signal with K2S2O8 as coreactant on the glassy carbon electrode (GCE) in aqueous solution. The ECL spectrum exhibited a peak at 695 nm, consistent with the peak in photoluminescence (PL) spectrum of the Ag2Se QDs solution, indicating that the Ag2Se QDs had no deep surface traps. Dopamine was chosen as a model analyte to study the potential of Ag2Se QDs in the ECL analytical application. The ECL signal of Ag2Se QDs can also be used for the detection of the dopamine concentration in the practical drug (dopamine hydrochloride injection) containing several adjuvants such as edetate disodium, sodium bisulfite, sodium chloride and so on. The Ag2Se QDs could be a promising candidate emitter of ECL biosensors in the future due to their fantastic features, such as ultrasmall size, low toxicity, good water solubility, and near infrared (NIR) fluorescent emission.
Co-reporter:Bi-Hai Huang, Yi Lin, Zhi-Ling Zhang, Fangfang Zhuan, An-An Liu, Min Xie, Zhi-Quan Tian, Zhenfeng Zhang, Hanzhong Wang, and Dai-Wen Pang
ACS Chemical Biology 2012 Volume 7(Issue 4) pp:683
Publication Date(Web):January 17, 2012
DOI:10.1021/cb2001878
Labeling of virus opens new pathways for the understanding of viruses themselves and facilitates the utilization of viruses in modern biology, medicine, and materials. Based on the characteristic that viruses hijack their host cellular machineries to survive and reproduce themselves, a host-cell-assisted strategy is proposed to label enveloped viruses. By simply feeding Vero cells with commercial 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(cap biotinyl) (sodium salt) (Biotin-Cap-PE), we obtained biotinylated Vero cells whose membrane systems were modified with biotin. Subsequently, pseudorabies viruses (PrV) were cultivated in the biotinylated Vero cells, and the PrV progenies were spontaneously labeled with Biotin-Cap-PE during viral natural assembly process. Since the viral natural assembly process was employed for the labeling, potential threats of genetic engineering and difficulties in keeping viral natural bioactivity were avoided. Importantly, this labeling strategy for enveloped virus greatly reduces the technical complexity and allows researchers from different backgrounds to apply it for their specified demands.
Co-reporter:Yan-Min Long, Qiao-Ling Zhao, Zhi-Ling Zhang, Zhi-Quan Tian and Dai-Wen Pang  
Analyst 2012 vol. 137(Issue 4) pp:805-815
Publication Date(Web):21 Dec 2011
DOI:10.1039/C2AN15740C
Fluorescent nanoparticles have attracted much attention over the last two decades. Due to the size- and composition-dependent optical and electrical properties, fluorescent nanoparticles have been emphasized in electronic, optical and biomedical applications. Till now, many kinds of methods have been developed to fabricate diverse fluorescent nanoparticles, which include pyrolysis, template synthesis, hydrothermal synthesis, microemulsion, electrochemical methods and so on. Among them, electrochemical methods are favored for relatively good controllability, ease of operation and mild reaction conditions. By adjusting the applied potential, current, components of the electrolyte and other relevant parameters, the fluorescent nanoparticles could be electrochemically manufactured with tunable sizes, compositions and surface structure, which allows for the modification of electronic and optical properties. Therefore, electrochemical methods are regarded as important means in preparing fluorescent nanoparticles. This review focuses on the recent progress in electrochemical fabrications of fluorescent nanoparticles (together with their optical properties and some applications in optoelectronics and biomedicine).
Co-reporter:Ximei Wu, Binghui Zhu, Lin Lu, Weixiong Huang, Daiwen Pang
Food Chemistry 2012 Volume 133(Issue 2) pp:482-488
Publication Date(Web):15 July 2012
DOI:10.1016/j.foodchem.2012.01.005
Metformin is one of the most common adulterants found in anti-diabetic dietary supplements and herbal medicines. An analytical method based on hydrophilic interaction chromatography (HILIC)/tandem mass spectrometry was developed and validated for the determination of metformin in dietary supplements and herbal medicines. Sample preparation involved solid phase extraction of the analyte using Plexa PCX cartridges, and cleanup by a primary–secondary amine (PSA) adsorbent for minimization of the matrix effect. Chromatographic separation was performed on a HILIC column using a mixture of 0.025 mol/L ammonium formate (pH 3) and acetonitrile (18:82, v/v) as the mobile phase at flow rate of 0.25 mL/min. The method was validated in four matrices (capsules, honeyed pills, tablets and oral solutions). The method had a good linear range (5–500 ng/mL), and the overall precision and accuracy ranged from 2.2% to 9.9% and 4.6% to 11.3%, respectively.Highlights► An analytical method based on HILIC–MS/MS for determination of metformin was developed. ► PCX and PSA were used as extraction/clean-up adsorbent to increase the efficiency of the extraction. ► The two-step extraction process was successfully applied to the clean-up dietary supplements and herbal medicines.
Co-reporter:Xiao-Jing Xing, Xue-Guo Liu, Yue-He, Qing-Ying Luo, Hong-Wu Tang, Dai-Wen Pang
Biosensors and Bioelectronics 2012 Volume 37(Issue 1) pp:61-67
Publication Date(Web):August–September 2012
DOI:10.1016/j.bios.2012.04.037
We present a novel fluorescent aptasensor for simple and accurate detection of adenosine deaminase (ADA) activity and inhibition on the basis of graphene oxide (GO) using adenosine (AD) as the substrate. This aptasensor consists of a dye-labeled single-stranded AD specific aptamer, GO and AD. The fluorescence intensity of the dye-labeled AD specific aptamer is quenched very efficiently by GO as a result of strong π–π stacking interaction and excellent electronic transference of GO. In the presence of AD, the fluorescence of the GO-based probe is recovered since the competitive binding of AD and GO with the dye-labeled aptamer prevents the adsorption of dye-labeled aptamer on GO. When ADA was introduced to this GO-based probe solution, the fluorescence of the probe was quenched owing to ADA can convert AD into inosine which has no affinity to the dye-labeled aptamer, thus allowing quantitative investigation of ADA activity. The as-proposed sensor is highly selective and sensitive for the assay of ADA activity with a detection limit of 0.0129 U/mL in clean buffer, which is more than one order of magnitude lower than the previous reports. Meanwhile, a good linear relationship with the correlation coefficient of R=0.9922 was obtained by testing 5% human serum containing a series of concentrations of ADA. Additionally, the inhibition effect of erythro-9-(2-hydroxy-3-nonyl) adenine on ADA activity was investigated in this design. The GO-based fluorescence aptasensor not only provides a simple, cost-effective and sensitive platform for the detection of ADA and its inhibitor but also shows great potential in the diagnosis of ADA-relevant diseases and drug development.Highlights► A novel fluorescence method for adenosine deaminase (ADA) and its inhibitor assay was developed. ► This approach was based on graphene oxide and adenosine was used as the substrate. ► This assay only requires one labeled DNA probe, making the assay more cost-effective. ► A low detection limit (0.0129 U/mL) was obtained. ► The approach was applied to determine ADA in real human serum sample.
Co-reporter:Chun-Wei Peng, Qian Tian, Gui-Fang Yang, Min Fang, Zhi-Ling Zhang, Jun Peng, Yan Li, Dai-Wen Pang
Biomaterials 2012 33(23) pp: 5742-5752
Publication Date(Web):
DOI:10.1016/j.biomaterials.2012.04.034
Co-reporter:Shu-Lin Liu, Zhi-Quan Tian, Zhi-Ling Zhang, Qiu-Mei Wu, Hai-Su Zhao, Bin Ren, Dai-Wen Pang
Biomaterials 2012 33(31) pp: 7828-7833
Publication Date(Web):
DOI:10.1016/j.biomaterials.2012.07.026
Co-reporter:Shu-Lin Liu, Zhi-Ling Zhang, Zhi-Quan Tian, Hai-Su Zhao, Haibin Liu, En-Ze Sun, Geng Fu Xiao, Wanpo Zhang, Han-Zhong Wang, and Dai-Wen Pang
ACS Nano 2012 Volume 6(Issue 1) pp:141
Publication Date(Web):November 25, 2011
DOI:10.1021/nn2031353
Exploring the virus infection mechanisms is significant for defending against virus infection and providing a basis for studying endocytosis mechanisms. Single-particle tracking technique is a powerful tool to monitor virus infection in real time for obtaining dynamic information. In this study, we reported a quantum-dot-based single-particle tracking technique to efficiently and globally research the virus infection behaviors in individual cells. It was observed that many influenza viruses were moving rapidly, converging to the microtubule organizing center (MTOC), interacting with acidic endosomes, and finally entering the target endosomes for genome release, which provides a vivid portrayal of the five-stage virus infection process. This report settles a long-pending question of how viruses move and interact with acidic endosomes before genome release in the perinuclear region and also finds that influenza virus infection is likely to be a “MTOC rescue” model for genome release. The systemic technique developed in this report is expected to be widely used for studying the mechanisms of virus infection and uncovering the secrets of endocytosis.Keywords: bionanotechnology; endocytosis; infection; influenza virus; quantum dot; single-particle tracking
Co-reporter:Zhi-Gang Wang, Shu-Lin Liu, Zhi-Quan Tian, Zhi-Ling Zhang, Hong-Wu Tang, and Dai-Wen Pang
ACS Nano 2012 Volume 6(Issue 11) pp:10033
Publication Date(Web):October 26, 2012
DOI:10.1021/nn303729r
Membrane nanotubes can facilitate direct intercellular communication between cells and provide a unique channel for intercellular transfer of cellular contents. However, the transport mechanisms of membrane nanotubes remain poorly understood between cancer cells. Also largely unknown is the transport pattern mediated by membrane nanotubes. In this work, wheat germ agglutinin (WGA), a widely used drug carrier and potential antineoplastic drug, was labeled with quantum dots (QDs-WGA) as a model for exploring the intercellular transportation via membrane nanotubes. We found that membrane nanotubes allowed effective transfer of QDs-WGA. Long-term single-particle tracking indicated that the movements of QDs-WGA exhibited a slow and directed motion pattern in nanotubes. Significantly, the transport of QDs-WGA was driven by myosin molecular motors in an active and unidirectional manner. These results contribute to a better understanding of cell-to-cell communication for cancer research.Keywords: membrane nanotubes cancer cells wheat germ agglutinin quantum dots intercellular transportation myosin motors
Co-reporter:Lei Bao;Zhi-Ling Zhang;Zhi-Quan Tian;Li Zhang;Cui Liu;Yi Lin;Baoping Qi
Advanced Materials 2011 Volume 23( Issue 48) pp:5801-5806
Publication Date(Web):
DOI:10.1002/adma.201102866
Co-reporter:Yi-Ping Gu ; Ran Cui ; Zhi-Ling Zhang ; Zhi-Xiong Xie
Journal of the American Chemical Society 2011 Volume 134(Issue 1) pp:79-82
Publication Date(Web):December 8, 2011
DOI:10.1021/ja2089553
A strategy is presented that involes coupling Na2SeO3 reduction with the binding of silver ions and alanine in a quasi-biosystem to obtain ultrasmall, near-infrared Ag2Se quantum dots (QDs) with tunable fluorescence at 90 °C in aqueous solution. This strategy avoids high temperatures, high pressures, and organic solvents so that water-dispersible sub-3 nm Ag2Se QDs can be directly obtained. The photoluminescence of the Ag2Se QDs was size-dependent over a wavelength range from 700 to 820 nm, corresponding to sizes from 1.5 ± 0.4 to 2.4 ± 0.5 nm, with good monodispersity. The Ag2Se QDs are less cytotoxic than other nanomaterials used for similar applications. Furthermore, the NIR fluorescence of the Ag2Se QDs could penetrate through the abdominal cavity of a living nude mouse and could be detected on its back side, demonstrating the potential applications of these less toxic NIR Ag2Se QDs in bioimaging.
Co-reporter:Ming-Xi Zhang, Ran Cui, Jing-Ya Zhao, Zhi-Ling Zhang and Dai-Wen Pang  
Journal of Materials Chemistry A 2011 vol. 21(Issue 43) pp:17080-17082
Publication Date(Web):30 Sep 2011
DOI:10.1039/C1JM13120F
Bio-reducing agent NADPH with relatively weak reducibility and favourable structure simultaneously reduced Au and Ag ions into sub-5 nm alloy nanoparticles in aqueous solution at room temperature.
Co-reporter:Yuhui Wang, Lei Bao, Zhihong Liu, and Dai-Wen Pang
Analytical Chemistry 2011 Volume 83(Issue 21) pp:8130
Publication Date(Web):September 16, 2011
DOI:10.1021/ac201631b
We presented a new aptamer biosensor for thrombin in this work, which was based on fluorescence resonance energy transfer (FRET) from upconverting phosphors (UCPs) to carbon nanoparticles (CNPs). The poly(acrylic acid) (PAA) functionalized UCPs were covalently tagged with a thrombin aptamer (5′-NH2- GGTTGGTGTGGTTGG-3′), which bound to the surface of CNPs through π–π stacking interaction. As a result, the energy donor and acceptor were taken into close proximity, leading to the quenching of fluorescence of UCPs. A maximum fluorescence quenching rate of 89% was acquired under optimized conditions. In the presence of thrombin, which induced the aptamer to form quadruplex structure, the π–π interaction was weakened, and thus, the acceptor was separated from the donor blocking the FRET process. The fluorescence of UCPs was therefore restored in a thrombin concentration-dependent manner, which built the foundation of thrombin quantification. The sensor provided a linear range from 0.5 to 20 nM for thrombin with a detection limit of 0.18 nM in an aqueous buffer. The same linear range was obtained in spiked human serum samples with a slightly higher detection limit (0.25 nM), demonstrating high robustness of the sensor in a complex biological sample matrix. As a practical application, the sensor was used to monitor thrombin level in human plasma with satisfactory results obtained. This is the first time that UCPs and CNPs were employed as a donor–acceptor pair to construct FRET-based biosensors, which utilized both the photophysical merits of UCPs and the superquenching ability of CNPs and thus afforded favorable analytical performances. This work also opened the opportunity to develop biosensors for other targets using this UCPs-CNPs system.
Co-reporter:Shibin He, Bi-Hai Huang, Junjun Tan, Qing-Ying Luo, Yi Lin, Jun Li, Yong Hu, Lu Zhang, Shihan Yan, Qi Zhang, Dai-Wen Pang, Lijia Li
Biomaterials 2011 32(23) pp: 5471-5477
Publication Date(Web):
DOI:10.1016/j.biomaterials.2011.04.013
Co-reporter:Lei Bao ; Liangfeng Sun ; Zhi-Ling Zhang ; Peng Jiang ; Frank W. Wise ; Héctor D. Abruña
The Journal of Physical Chemistry C 2011 Volume 115(Issue 38) pp:18822-18828
Publication Date(Web):August 9, 2011
DOI:10.1021/jp205419z
A strategy for construction of a solid-state electrogenerated chemiluminescence (ECL) sensor based on a self-assembled film of core/shell structural CdSe/ZnS quantum dots (QDs) is presented in this work for the first time. The surface coverage of CdSe/ZnS QDs is about 2.2 × 1012 NPs/cm2, which is on the level of a submonolayer. This self-assembled CdSe/ZnS QD film has shown a strong and efficient cathodic ECL with peroxydisulfate and hydroperoxide as coreactants in aqueous solution. The quenching effect with hydroperoxide as the coreactant reveals an energy-level-related mechanism for the QD ECL processes. The energy levels of QDs and coreactants determine ECL responses. This insight provides a universal guide to select proper coreactants for the QD ECL sensors. In addition, the self-assembled CdSe/ZnS QD ECL sensor has the potential to detect energy-level-related analytes, such as dopamine.
Co-reporter:Jun Hu, Min Xie, Cong-Ying Wen, Zhi-Ling Zhang, Hai-Yan Xie, An-An Liu, Yong-Yong Chen, Shi-Ming Zhou, Dai-Wen Pang
Biomaterials 2011 32(4) pp: 1177-1184
Publication Date(Web):
DOI:10.1016/j.biomaterials.2010.10.015
Co-reporter:Shu-Lin Liu, Zhi-Ling Zhang, En-Ze Sun, Jun Peng, Min Xie, Zhi-Quan Tian, Yi Lin, Dai-Wen Pang
Biomaterials 2011 32(30) pp: 7616-7624
Publication Date(Web):
DOI:10.1016/j.biomaterials.2011.06.046
Co-reporter:Er-Qun Song, Jun Hu, Cong-Ying Wen, Zhi-Quan Tian, Xu Yu, Zhi-Ling Zhang, Yun-Bo Shi, and Dai-Wen Pang
ACS Nano 2011 Volume 5(Issue 2) pp:761
Publication Date(Web):January 20, 2011
DOI:10.1021/nn1011336
Fluorescent-magnetic-biotargeting multifunctional nanobioprobes (FMBMNs) have attracted great attention in recent years due to their increasing, important applications in biomedical research, clinical diagnosis, and biomedicine. We have previously developed such nanobioprobes for the detection and isolation of a single kind of tumor cells. Detection and isolation of multiple tumor markers or tumor cells from complex samples sensitively and with high efficiency is critical for the early diagnosis of tumors, especially malignant tumors or cancers, which will improve clinical diagnosis outcomes and help to select effective treatment approaches. Here, we expanded the application of the monoclonal antibody (mAb)-coupled FMBMNs for multiplexed assays. Multiple types of cancer cells, such as leukemia cells and prostate cancer cells, were detected and collected from mixed samples within 25 min by using a magnet and an ordinary fluorescence microscope. The capture efficiencies of mAb-coupled FMBMNs for the above-mentioned two types of cells were 96% and 97%, respectively. Furthermore, by using the mAb-coupled FMBMNs, specific and sensitive detection and rapid separation of a small number of spiked leukemia cells and prostate cancer cells in a large population of cultured normal cells (about 0.01% were tumor cells) were achieved simply and inexpensively without any sample pretreatment before cell analysis. Therefore, mAb-coupled multicolor FMBMNs may be used for very sensitive detection and rapid isolation of multiple cancer cells in biomedical research and medical diagnostics.Keywords: cancer; magnetic; multifunctional nanobioprobe; multifunctional nanoparticle; multifunctional nanosphere; quantum dot; tumor
Co-reporter:Ming-Xi Zhang;Ran Cui;Zhi-Quan Tian;Zhi-Ling Zhang
Advanced Functional Materials 2010 Volume 20( Issue 21) pp:3673-3677
Publication Date(Web):
DOI:10.1002/adfm.201001185

Abstract

By kinetically controlling a biomimetic reduction in a quasi-biological system (an aqueous solution containing electrolyte, peptide, and coenzyme), water-soluble, glutathione-capped Au clusters with a mean diameter of 1.3 nm are successfully synthesized via a new route. Opportunities that facilitate the control of the reaction are created in such a quasi-biological system. The relatively slow rate of the biomimetic reduction, the pH-dependent reducibility of the reducing agent, and the favorable structure of the capping molecules conspire together for the realization of a kinetics-controlled formation of the Au clusters under mild conditions. Compared to existing methods of synthesizing gold clusters by stoichiometrically controlling the molar ratio of the Au atoms and the ligands, our current method is based on slowing down the reduction of the Au precursors in the initial stage by adjusting the activity of the reducing agent in real time, instead of using a strong reducing agent such as NaBH4. This strategy of rationally utilizing biological or biomimetic processes with unique features to provide a beneficial complement to conventional chemical syntheses could open a new way for the sustainable development of nanotechnology.

Co-reporter:Ran Cui, Ming-Xi Zhang, Zhi-Quan Tian, Zhi-Ling Zhang and Dai-Wen Pang  
Nanoscale 2010 vol. 2(Issue 10) pp:2120-2125
Publication Date(Web):06 Sep 2010
DOI:10.1039/C0NR00193G
A new biomimetic strategy of creating a quasi-biological system (an aqueous solution containing electrolytes, peptide, enzyme and coenzyme) for the preparation of gold nanoparticles with uniform and tunable sizes has been put forward and validated, adopting environmentally-friendly reducing agents and a biocompatible capping ligand in aqueous solution at room temperature. The biomimetic synthetic route has the characteristics for good stability of the resulting AuNPs capped with glutathione via strong Au–S bond in aqueous solution, an appropriate composition of the intermediate with a redox potential favorable for the biomimetic reduction under mild conditions, suitable pH values to adjust the rate of the reduction, and the addition of enzyme catalyzing the reduction. By only adjusting the concentration of the reducing agent NADPH, a series of AuNPs with narrow size-distribution could be controllably synthesized. This method of rational utilization of biological processes could provide a new way for the sustainable development of nanotechnology.
Co-reporter:Min Xie, Kan Luo, Bi-Hai Huang, Shu-Lin Liu, Jun Hu, Di Cui, Zhi-Ling Zhang, Geng-Fu Xiao, Dai-Wen Pang
Biomaterials 2010 31(32) pp: 8362-8370
Publication Date(Web):
DOI:10.1016/j.biomaterials.2010.07.063
Co-reporter:Ming-Xi Zhang, Bi-Hai Huang, Xiao-Yu Sun and Dai-Wen Pang
Langmuir 2010 Volume 26(Issue 12) pp:10171-10176
Publication Date(Web):May 4, 2010
DOI:10.1021/la100315u
A new method of fabricating “clickable” gold nanoparticles that could be used as the building block of nanobioprobes was described. On the basis of a well-developed strategy of encapsulating hydrophobic nanoparticles with a layer of amphiphilic polymers, cheap, easily prepared graft polymer was used as a modifier to prepare monodisperse azide-functionalized gold nanoparticles (AuNPs), which showed good stability in physiological solution. By conjugation with alkyne functional horseradish peroxidase (HRP) via click chemistry under mild conditions, the azide-AuNPs have demonstrated their potential in the fabrication of stable, bioactive nanobioprobes. Some critical problems in the fabrication of nanobioprobes, such as how to detect the number of bound biomolecules on nanoparticles and evaluate the bioactivities of nanobioprobes, are discussed in detail.
Co-reporter:Sheng-Mei Wu, Zhi-Quan Tian, Zhi-Ling Zhang, Bi-Hai Huang, Peng Jiang, Zhi-Xiong Xie, Dai-Wen Pang
Biosensors and Bioelectronics 2010 Volume 26(Issue 2) pp:491-496
Publication Date(Web):15 October 2010
DOI:10.1016/j.bios.2010.07.067
Quantum dots (QDs) are inorganic fluorescent nanocrystals with excellent properties such as tunable emission spectra and photo-bleaching resistance compared with organic dyes, which make them appropriate for applications in molecular beacons. In this work, quantum dot-based molecular beacons (QD-based MBs) were fabricated to specifically detect β-lactamase genes located in pUC18 which were responsible for antibiotic resistance in bacteria Escherichia coli (E. coli) DH5α. QD-based MBs were constructed by conjugating mercaptoacetic acid-quantum dots (MAA-QDs) with black hole quencher 2 (BHQ2) labeled thiol DNA vial metal–thiol bonds. Two types of molecular beacons, double-strands beacons and hairpin beacons, were observed in product characterization by gel electrophoresis. Using QD-based MBs, one-step FISH in tiny bacteria DH5α was realized for the first time. QD-based MBs retained their bioactivity when hybridizing with complementary target DNA, which showed excellent advantages of eliminating background noise caused by adsorption of non-specific bioprobes and achieving clearer focus of genes in plasmids pUC18, and capability of bacterial cell penetration and signal specificity in one-step in situ hybridization.
Co-reporter:Ran Cui;Hui-Hui Liu;Hai-Yan Xie;Zhi-Ling Zhang;Yi-Ran Yang;Zhi-Xiong Xie;Bei-Bei Chen;Bin Hu;Ping Shen
Advanced Functional Materials 2009 Volume 19( Issue 15) pp:2359-2364
Publication Date(Web):
DOI:10.1002/adfm.200801492

Abstract

There are currently some problems in the field of chemical synthesis, such as environmental impact, energy loss, and safety, that need to be tackled urgently. An interdisciplinary approach, based on different backgrounds, may succeed in solving these problems. Organisms can be chosen as potential platforms for materials fabrication, since biosystems are natural and highly efficient. Here, an example of how to solve some of these chemical problems through biology, namely, through a novel biological strategy of coupling intracellular irrelated biochemical reactions for controllable synthesis of multicolor CdSe quantum dots (QDs) using living yeast cells as a biosynthesizer, is demonstrated. The unique fluorescence properties of CdSe QDs can be utilized to directly and visually judge the biosynthesis phase to fully demonstrate this strategy. By such a method, CdSe QDs, emitting at a variety of single fluorescence wavelengths, can be intracellularly, controllably synthesized at just 30°C instead of at 300°C with combustible, explosive, and toxic organic reagents. This green biosynthetic route is a novel strategy of coupling, with biochemical reactions taking place irrelatedly, both in time and space. It involves a remarkable decrease in reaction temperature, from around 300 °C to 30 °C and excellent color controllability of CdSe photoluminescence. It is well known that to control the size of nanocrystals is a mojor challenge in the biosynthesis of high-quality nanomaterials. The present work demonstrates clearly that biological systems can be creatively utilized to realize controllable unnatural biosynthesis that normally does not exist, offering new insights for sustainable chemistry.

Co-reporter:Zhi-Quan Tian, Zhi-Ling Zhang, Peng Jiang, Ming-Xi Zhang, Hai-Yan Xie and Dai-Wen Pang
Chemistry of Materials 2009 Volume 21(Issue 14) pp:3039
Publication Date(Web):June 25, 2009
DOI:10.1021/cm900867j
Co-reporter:Zhi-Quan Tian, Zhi-Ling Zhang, Jinhao Gao, Bi-Hai Huang, Hai-Yan Xie, Min Xie, Héctor D. Abruña and Dai-Wen Pang  
Chemical Communications 2009 (Issue 27) pp:4025-4027
Publication Date(Web):10 Jun 2009
DOI:10.1039/B906149E
We have developed a convenient strategy for preparing color-tunable fluorescent–magnetic core/shell multifunctional nanocrystals, which exhibit excellent photoluminescence (PL) properties (fluorescing tunably from 550 nm to 630 nm by modifying the shell thickness) and ferromagnetic material properties (a magnetization of 4.4 emu g−1 and a coercivity of 95 Oe).
Co-reporter:Min Xie, Jun Hu, Yan-Min Long, Zhi-Ling Zhang, Hai-Yan Xie, Dai-Wen Pang
Biosensors and Bioelectronics 2009 Volume 24(Issue 5) pp:1311-1317
Publication Date(Web):1 January 2009
DOI:10.1016/j.bios.2008.07.058
Nanomaterial-based nanobiosensors (nanobiodevices or nanobioprobes) are increasingly emphasized. Here, quantum dots and γ-Fe2O3 magnetic nanoparticles were co-embedded into single swelling poly(styrene/acrylamide) copolymer nanospheres to fabricate fluorescent-magnetic bifunctional nanospheres. Subsequently, fluorescent-magnetic-biotargeting trifunctional nanobiosensors (TFNS) modified with wheat germ agglutinin (WGA), peanut agglutinin (PNA) or Dolichos biflorus agglutinin (DBA) were conveniently produced so as to bind with A549 cells which are surface-expressed with N-acetylglucosamine, d-galactosamine and N-acetylgalactosamine residues. The values of WGA, PNA and DBA on each nanobiosensor were calculated to be 40, 14 and 60, respectively. These three kinds of lectin-modified trifunctional nanobiosensors (lectin-TFNS) can be used for qualitative and quantitative analysis of the glycoconjugates on A549 cell surface. The fluorescence intensity of WGA-modified nanobiosensors related to N-acetylglucosamine on A549 cell surface was much higher than that of PNA-modified nanobiosensors corresponding to d-galactosamine and that of N-acetylgalactosamine-related DBA-modified nanobiosensors, which is consistent with the results detected by flow cytometry. Lectin-modified trifunctional nanobiosensors not only can quantify the different glycoconjugates on A549 cell surface, but also can recognize and isolate A549 cells. 0.5 mg of WGA-modified fluorescent-magnetic trifunctional nanobiosensors could capture 7.0 × 104 A549 cells. Therefore, the lectin-modified trifunctional nanobiosensors may be applied in mapping the glycoconjugates on cell surfaces and for recognition and isolation of targeted cells.
Co-reporter:Sheng-Mei Wu, Zhi-Ling Zhang, Xiao-Dan Wang, Ming-Xi Zhang, Jun Peng, Zhi-Xiong Xie and Dai-Wen Pang
The Journal of Physical Chemistry C 2009 Volume 113(Issue 21) pp:9169-9174
Publication Date(Web):2017-2-22
DOI:10.1021/jp901221h
Ferrichrome is a kind of high-affinity iron(III) chelators and its complex with Fe3+ can be specifically recognized by the corresponding receptors located on the outer membrane of some bacterial cells. Quantum dots as a type of semiconductor nanocrystals have high luminance and good resistance to photobleaching. Herein, ferrichrome was conjugated with polyethylene glycol- phosphoethanolamine-coated quantum dots to produce a new type of quantum dot-ferrichrome bioprobes. The quantum dot-ferrichrome bioprobes were used for recognizing Pseudomonas fluorescens (P. fluorescens) isolated from Dong-Hu Lake in China. P. fluorescens could be recognized quickly and sensitively with quantum dot-ferrichrome bioprobes by forming cell clusters through reaction between ferrichrome-ferric complex and its receptors. It was multiple ligands on a quantum dot and multiple receptors on a P. fluorescens cell that made the bacteria cluster. Single cells can also be realized with superfluous quantum dot-ferrichrome bioprobes to occupy the receptors on bacterial outer membrane. The biosensitive quantum dot-ferrichrome kept excellent fluorescent property of quantum dot and might be a promising bioprobes for fluorescent Pseudomonads targeting.
Co-reporter:Qiao-Ling Zhao, Zhi-Ling Zhang, Bi-Hai Huang, Jun Peng, Min Zhang and Dai-Wen Pang  
Chemical Communications 2008 (Issue 41) pp:5116-5118
Publication Date(Web):24 Sep 2008
DOI:10.1039/B812420E
A simple and facile method was developed to prepare fluorescent carbon nanocrystals (CNCs) with low cytotoxicity and no photobleaching, by electrooxidation of graphite in aqueous solution.
Co-reporter:Xin-Cheng Shen, Zhi-Ling Zhang, Bo Zhou, Jun Peng, Min Xie, Min Zhang and Dai-Wen Pang
Environmental Science & Technology 2008 Volume 42(Issue 14) pp:5049-5054
Publication Date(Web):June 11, 2008
DOI:10.1021/es800668g
Visible light-induced photocatalytic degradation of environmental pollutants with improved TiO2 has attracted much attention in pollution control and management. The degradation of nucleic acids is of great significance for biological contaminants such as viruses. In the present work, visible light-induced plasmid DNA damage catalyzed by a CdSe/ZnS-photosensitized nano-TiO2 film (QDs-TiO2 film) was investigated by atomic force microscopy (AFM) and agarose gel electrophoresis. Illuminated by visible light, the supercoiled pUC18 DNA could be damaged into nicked-circle and linear conformations by the QDs-TiO2 film. The percentage of different conformations of damaged DNA changed with illumination time. A statistical rule for calculating the quantity of supercoiled DNA has been established to evaluate the photocatalytic activity of the QDs-TiO2 film based on AFM results. Visible light-induced plasmid DNA damage catalyzed by the QDs-TiO2 film is characteristic of zero-order kinetics and the rate constant (k) is 3.5 × 10−11 M·s−1. Given an illumination time, the quantity of damaged supercoiled DNA catalyzed by the QDs-TiO2 film is constant.
Co-reporter:Lu Ma;Sheng-Mei Wu;Jing Huang;Yi Ding;Lijia Li
Chromosoma 2008 Volume 117( Issue 2) pp:181-187
Publication Date(Web):2008 April
DOI:10.1007/s00412-007-0136-2
Semiconductor nanocrystals, also called quantum dots (QDs), are novel inorganic fluorophores which are brighter and more photostable than organic fluorophores. In the present study, highly dispersive QD-labeled oligonucleotide (TAG)8 (QD-deoxyribonucleic acid [DNA]) conjugates were constructed via the metal-thiol bond, which can be used as fluorescence in situ hybridization (FISH) probes. FISH analysis of maize metaphase chromosomes using the QD-DNA probes showed that the probes could penetrate maize chromosomes and nuclei and solely hybridized to complementary target DNAs. Compared with the conventional organic dyes such as Cy3 and fluorescein isothiocyanate, this class of luminescent labels bound with oligonucleotides is brighter and more stable against photobleaching on the chromosomes after FISH. These results suggest that QD fluorophores may be a more stable and useful fluorescent label for FISH applications in plant chromosome mapping considering their size-tunable luminescence spectra.
Co-reporter:Hai-Yan Xie, Min Xie, Zhi-Ling Zhang, Yan-Min Long, Xin Liu, Ming-Liang Tang, Dai-Wen Pang, Zheng Tan, Calum Dickinson and Wuzong Zhou
Bioconjugate Chemistry 2007 Volume 18(Issue 6) pp:1749
Publication Date(Web):September 26, 2007
DOI:10.1021/bc060387g
A simple and convenient strategy has been put forward to fabricate smart fluorescent magnetic wheat germ agglutinin-modified trifunctional nanospheres (WGA-TFNS) for recognition of human prostate carcinoma DU-145 cells which are surface-expressed with sialic acid and N-acetylglucosamine. These TFNS can be easily manipulated, tracked, and conveniently used to capture and separate target cells. The presence of wheat germ agglutinin on the surface of WGA-TFNS was confirmed by FTIR, biorecognition of carboxymethyl chitin-modified quantum dots (CM-CT-QDs), and bacterium Staphylococcus aureus. The success in recognizing DU-145 cells by the WGA-TFNS indicates that WGA-TFNS could be applicable.
Co-reporter:Sheng-Fu Wang, Ting Chen, Zhi-Ling Zhang, Dai-Wen Pang, Kwok-Yin Wong
Electrochemistry Communications 2007 Volume 9(Issue 7) pp:1709-1714
Publication Date(Web):July 2007
DOI:10.1016/j.elecom.2007.03.018
The effects of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) on direct electrochemistry and bioelectrocatalysis of hemoglobin (Hb), myoglobin (Mb), and catalase (Cat) entrapped in agarose hydrogel films were investigated. A small amount of water in [bmim][BF4] is necessary to maintain the electrochemical activities of these heme proteins. The direct electron transfer between heme proteins and glassy carbon electrode (GC) is a surface-confined quasi-reversible process, corresponding to heme Fe(III) + e → heme Fe(II). Several electrochemical parameters of these processes, such as the charge-transfer coefficient (a) and the apparent electron transfer rate constant (ks), were calculated by nonlinear regression analysis of square wave voltammetry (SWV) experimental data. Furthermore, highly electrocatalytic activities of the heme protein–agarose films toward hydrogen peroxide (H2O2) were observed, indicating that heme proteins entrapped in agarose films retained their bioelectrocatalytic activities in [bmim][BF4] solution. The apparent Michaelis-Menten constant (Kmapp) of Mb for H2O2 was evaluated to be 5.93 × 10−4 mol L−1. The catalytic reduction peak current is directly proportional to the concentration of H2O2 between 1.28 × 10−6 mol L−1 and 7.08 × 10−4 mol L−1. Experiments for Hb and Cat received similar results.
Co-reporter:Sheng-Fu Wang, Ting Chen, Zhi-Ling Zhang, Dai-Wen Pang
Electrochemistry Communications 2007 Volume 9(Issue 6) pp:1337-1342
Publication Date(Web):June 2007
DOI:10.1016/j.elecom.2007.01.042
The activity and stability of horseradish peroxidase (HRP) were investigated in a hydrophilic room temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluroborate ([bmim][BF4]) by electrochemical methods. Although no detectable activity exhibited in anhydrous [bmim][BF4], HRP was active in the presence of a small amount of water (4.53%, v/v). And its activity can be improved by immobilization in agarose hydrogel. The immobilized HRP possesses excellent activity at 65 °C. It remained 80.2% of its initial activity after being immersed for 10.5 h in an aqueous mixture of [bmim][BF4] with some hydrogen peroxide (H2O2) under room temperature, implying extremely high stability. Moreover, the immobilized HRP was found to be very sensitive and stable in H2O-containing [bmim][BF4] for the detection of H2O2, with a wide linear range of 6.10 × 10−7 to 1.32 × 10−4 mol l−1 and low detection limit of 1.0 × 10−7 mol l−1.
Co-reporter:Yi Lin;XinCheng Shen;JingJing Wang;Lei Bao;ZhiLing Zhang
Science Bulletin 2007 Volume 52( Issue 23) pp:3189-3192
Publication Date(Web):2007 December
DOI:10.1007/s11434-007-0475-7
Based on tapping mode AFM imaging, a method was demonstrated to evaluate compression elasticity of single double-stranded DNA (dsDNA) molecules in the force region. With images under ambient conditions, Young’s moduli of dsDNA in compression were calculated. Results demonstrated that Young’s moduli of dsDNA can be simply deduced according to the proposed model. The method can also be used to evaluate the compression elasticity of similar soft nanomaterials.
Co-reporter:Xiang Zhao;Sheng-Mei Wu;Zhi-Ling Zhang Dr.;Hai-Yan Xie Dr.;Zhi-Quan Tian;Jun Peng;Zhe-Xue Lu Dr.;Zhi-Xiong Xie Dr.
ChemPhysChem 2006 Volume 7(Issue 5) pp:1062-1067
Publication Date(Web):20 APR 2006
DOI:10.1002/cphc.200500608

Semiconductor quantum dots (QDs) as a kind of nonisotopic biological labeling material have many unique fluorescent properties relative to conventional organic dyes and fluorescent proteins, such as composition- and size-dependent absorption and emission, a broad absorption spectrum, photostability, and single-dot sensitivity. These properties make them a promising stable and sensitive label, which can be used for long-term fluorescent tracking and subcellular location of genes and proteins. Here, a simple approach for the construction of QD-labeled DNA probes was developed by attaching thiol-ssDNA to QDs via a metal–thiol bond. The as-prepared QD-labeled DNA probes had high dispersivity, bioactivity, and specificity for hybridization. Based on such a kind of probe with a sequence complementary to multiple clone sites in plasmid pUC18, fluorescence in situ hybridization of the tiny bacterium Escherichia coli has been realized for the first time.

Co-reporter:Guo-Ping Wang, Er-Qun Song, Hai-Yan Xie, Zhi-Ling Zhang, Zhi-Quan Tian, Chao Zuo, Dai-Wen Pang, Dao-Cheng Wu and Yun-Bo Shi  
Chemical Communications 2005 (Issue 34) pp:4276-4278
Publication Date(Web):08 Aug 2005
DOI:10.1039/B508075D
Hydrazide-containing bifunctional nanospheres were covalently coupled on the surface with IgG, avidin, and biotin, to generate novel fluorescent-magnetic-biotargeting trifunctional nanospheres, which can be used in a number of biomedical applications, including visual sorting and manipulation of apoptotic cells as demonstrated here.
Co-reporter:Yuan-Hai Zhu, Zhi-Ling Zhang, Dai-Wen Pang
Journal of Electroanalytical Chemistry 2005 Volume 581(Issue 2) pp:303-309
Publication Date(Web):1 August 2005
DOI:10.1016/j.jelechem.2005.05.004
Carboxylic multi-wall carbon nanotubes (MWCNT) were directly cast onto the glassy carbon electrode to fabricate the MWCNT modified electrode, which showed good stability and reproducibility. The modified electrode exhibited good promotion to the electrochemical reaction of theophylline (TP) and greatly enhanced the peak currents. The possible mechanism of the catalytic oxidation of TP was investigated by means of cyclic voltammetry and UV–Vis spectroscopy. Under optimal conditions there was a good linear relationship between anodic peak current and TP concentration in the range from 3 × 10−7 to 1 × 10−5 mol L−1, and a detection limit of 5 × 10−8 mol L−1 (S/N = 3) was achieved after 2 min of open-circuit accumulation. The MWCNT modified electrode can be applied to determination of TP in drug.
Co-reporter:Ji-Wen Luo, Min Zhang, Dai-Wen Pang
Sensors and Actuators B: Chemical 2005 Volume 106(Issue 1) pp:358-362
Publication Date(Web):29 April 2005
DOI:10.1016/j.snb.2004.08.020
DNA-modified graphite powder microelectrodes (DNA/GPMEs) were used for selective and sensitive detection of uric acid (UA) in urine samples by differential pulse voltammetry (DPV). Under optimal conditions the powder microelectrode technique combined with DNA immobilization on the surface of graphite powder can effectively eliminate the interference of ascorbic acid (AA) and greatly improve the detection sensitivity. In a citrate-phosphate buffer solution (pH 5.5) the difference in oxidation peak potentials (ΔEp) between UA and AA reached to 360 mV, and the linear response range for detection of UA was 1.0 × 10−7–5.0 × 10−5 mol/L, with a detection limit of 5.0 × 10−8 mol/L. UA in real human urine can be determined using DNA/GPMEs without any pretreatment of samples, giving satisfactory results.
Co-reporter:Ye-Mei Li, Hui-Hong Liu, Dai-Wen Pang
Journal of Electroanalytical Chemistry 2004 Volume 574(Issue 1) pp:23-31
Publication Date(Web):15 December 2004
DOI:10.1016/j.jelechem.2004.07.011
Myoglobin and hemoglobin was immobilized on edge-plane pyrolytic graphite (EPG) electrodes by methyl cellulose (MC). Both the proteins entrapped in the MC film underwent fast direct transfer-electron reactions, corresponding to hemeFeIII + e− → hemeFeII. The formal potential (E0′), the apparent coverage (Γ), the electron transfer coefficient (α) and the apparent electron transfer rate constant (ks) were calculated by performing non-linear regression analysis of SWV experimental data. E0′ was linearly dependent on the solution pH (redox Bohr effect), indicating the electron transfer of the FeIII/FeII redox couple accompanied by the transfer of proton. UV–Vis absorption (UV–Vis) and reflection–absorption infrared (RAIR) spectra suggested that the proteins keep their original conformation in the MC film. The conformation changed reversibly in the range of pH values investigated (3.0–9.0). Atomic force microscopy (AFM) images suggested a strong interaction between the heme proteins and MC. The processes of catalytic reduction of oxygen, hydrogen peroxide and nitric oxide by Mb and Hb entrapped in MC film were also explored.
Co-reporter:Hu-Zhi Zheng, Dai-Wen Pang, Zhe-Xue Lu, Zhi-Ling Zhang, Zhi-Xiong Xie
Biophysical Chemistry 2004 Volume 112(Issue 1) pp:27-33
Publication Date(Web):1 December 2004
DOI:10.1016/j.bpc.2004.06.011
A fluorescence microscope (FM) coupled with an intensified charge-coupled device (ICCD) camera was used to investigate the combing of DNA on cetyltrimethyl ammonium bromide (CTAB)-coated glass surfaces. DNA molecules can be combed uniform and straight on CTAB-coated surfaces. Different combing characteristics at different pH values were found. At lower pH (ca. 5.5), DNA molecules were stretched 30% longer than the unextended and DNA extremities bound with CTAB-coated surfaces via hydrophobic interaction. At high pH values (e.g., 6.4 and 6.5), DNA molecules were extended about 10% longer and DNA extremities bound with CTAB-coated surfaces via electrostatic attraction. At pH 6.0, DNA molecules could be extended 30% longer on 0.2-mM CTAB-coated surfaces. CTAB cationic surfactant has both a hydrophobic motif and a positively charged group. So, CTAB-coated surfaces can bind DNA extremities via hydrophobic effect or electrostatic attraction at different pH values. It was also found that combing of DNA on CTAB-coated surfaces is reversible. The number of DNA base pairs binding to CTAB-coated surfaces was calculated.
Co-reporter:Hui-Hong Liu, Zhi-Quan Tian, Zhe-Xue Lu, Zhi-Ling Zhang, Min Zhang, Dai-Wen Pang
Biosensors and Bioelectronics 2004 Volume 20(Issue 2) pp:294-304
Publication Date(Web):15 September 2004
DOI:10.1016/j.bios.2004.01.015
Three heme-proteins, including myoglobin (Mb), hemoglobin (Hb) and horseradish peroxidase (HRP), were immobilized on edge-plane pyrolytic graphite (EPG) electrodes by agarose hydrogel. The proteins entrapped in the agarose film undergo fast direct electron transfer reactions, corresponding to FeIII+e−→FeII. The formal potential (E°′), the apparent coverage (Γ), the electron transfer coefficient (α) and the apparent electron transfer rate constant (ks) were calculated by integrating cyclic voltammograms or performing nonlinear regression analysis of square wave voltammetric (SWV) experimental data. The E°′s are linearly dependent on solution pH (redox Bohr effect), indicating that the electron transfer was proton-coupled. Ultraviolet visible (UV-Vis) and reflection–absorption infrared (RAIR) spectra suggest that the conformation of proteins in the agarose film are little different from that proteins alone, and the conformation changes reversibly in the range of pH 3.0–10.0. Atomic force microscopy (AFM) images of the agarose film indicate a stable and crystal-like structure formed possibly due to the synergistic interaction of hydrogen bonding between N,N-dimethylformamide (DMF), agarose hydrogel and heme-proteins. This suggests a strong interaction between the heme-proteins and the agarose hydrogel. DMF plays an important role in immobilizing proteins and enhancing electron transfer between proteins and electrodes. The mechanisms for catalytic reduction of hydrogen peroxide and nitric oxide (NO) by proteins entrapped in agarose hydrogel were also explored.
Co-reporter:Hui-Hong Liu, Ji-Lin Lu, Min Zhang, Dai-Wen Pang, Héctor D Abruña
Journal of Electroanalytical Chemistry 2003 Volume 544() pp:93-100
Publication Date(Web):13 March 2003
DOI:10.1016/S0022-0728(03)00080-9
The direct electron transfer of surface-confined horse heart cytochrome c (Cyt c) was achieved using single- or double-stranded (ss- or ds-) calf-thymus DNA immobilized on gold electrodes. The formal potential (E°′) for Cyt c in a 10 mM PBS (pH7.0) buffer at a scan rate of 20 mV s−1 was −0.027 V with dsDNA and −0.016 V with ssDNA, respectively. The interaction between Cyt c and DNA makes the formal potential shift negatively when compared to that of Cyt c in solution (+0.258 V vs. SHE, i.e. +0.017 vs. SCE). Both UV–visible and reflection-absorption infrared spectroscopy indicate that the surface-confined Cyt c existed in its native form. The fractional coverage of bound Cyt c was 0.51 (with dsDNA) and 0.46 (with ssDNA) a single monolayer. The binding site sizes were determined to be 13 base pairs per Cyt c molecule with dsDNA and 26 nucleotides binding 1 Cyt c molecule with ssDNA. At a dsDNA/Au electrode, reduction and oxidation electron-transfer rate constant values of ks,Red=21 s−1 and ks,Ox=15 s−1 were obtained. At the ssDNA/Au electrode, the values were ks,Red=24 s−1 and ks,Ox=19 s−1, respectively. The incorporated Cyt c was strongly affected by variations in both the ionic strength and pH of the solution. The quantitative determination of Cyt c by differential pulse voltammetry (DPV) using DNA-modified electrodes was also explored.
Co-reporter:Yuan-Di Zhao, Dai-Wen Pang, Shen Hu, Zong-Li Wang, Jie-Ke Cheng, Hong-Ping Dai
Talanta 1999 Volume 49(Issue 4) pp:751-756
Publication Date(Web):12 July 1999
DOI:10.1016/S0039-9140(99)00078-8
The covalent immobilization of DNA onto self-assembled monolayer (SAM) modified gold electrodes (SAM/Au) was studied by X-ray photoelectron spectrometry and electrochemical method so as to optimize its covalent immobilization on SAMs. Three types of SAMs with hydroxyl, amino, and carboxyl terminal groups, respectively, were examined. Results obtained by both X-ray photoelectron spectrometry and cyclic voltammetry show that the largest covalent immobilization amount of dsDNA could be gained on hydroxyl-terminated SAM/Au. The ratio of amount of dsDNA immobilized on hydroxyl-terminated SAMs to that on carboxyl-terminated SAMs and to that on amino-terminated SAMs is (3–3.5): (1–1.5): 1. The dsDNA immobilized covalently on hydroxyl-terminated SAMs accounts for 82.8–87.6% of its total surface amount (including small amount of dsDNA adsorbed). So the hydroxyl-terminated SAM is a good substrate for the covalent immobilization of dsDNA on gold surfaces.
Co-reporter:Cheng Lv, Yi Lin, An-An Liu, Zheng-Yuan Hong, Li Wen, Zhenfeng Zhang, Zhi-Ling Zhang, Hanzhong Wang, Dai-Wen Pang
Biomaterials (November 2016) Volume 106() pp:69-77
Publication Date(Web):November 2016
DOI:10.1016/j.biomaterials.2016.08.013
Highly efficient labeling of viruses with quantum dots (QDs) is the prerequisite for the long-term tracking of virus invasion at the single virus level to reveal mechanisms of virus infection. As one of the structural components of viruses, viral envelope lipids are hard to be labeled with QDs due to the lack of efficient methods to modify viral envelope lipids. Moreover, it is still a challenge to maintain the intactness and infectivity of labeled viruses. Herein, a mild method has been developed to label viral envelope lipids with QDs by harnessing the biotinylated lipid-self-inserted cellular membrane. Biotinylated lipids can spontaneously insert in cellular membranes of host cells during culture and then be naturally assembled on progeny Pseudorabies virus (PrV) via propagation. The biotinylated PrV can be labeled with streptavidin-conjugated QDs, with a labeling efficiency of ∼90%. Such a strategy to label lipids with QDs can retain the intactness and infectivity of labeled viruses to the largest extent, facilitating the study of mechanisms of virus infection at the single virus level.
Co-reporter:Cheng Lv, Yi Lin, An-An Liu, Zheng-Yuan Hong, Li Wen, Zhenfeng Zhang, Zhi-Ling Zhang, Hanzhong Wang, Dai-Wen Pang
Biomaterials (November 2016) Volume 106() pp:69-77
Publication Date(Web):November 2016
DOI:10.1016/j.biomaterials.2016.08.013
Co-reporter:Li Wen, Yi Lin, Zhi-Ling Zhang, Wen Lu, Cheng Lv, Zhi-Liang Chen, Han-Zhong Wang, Dai-Wen Pang
Biomaterials (August 2016) Volume 99() pp:24-33
Publication Date(Web):August 2016
DOI:10.1016/j.biomaterials.2016.04.038
Co-reporter:Li Wen, Yi Lin, Zhi-Ling Zhang, Wen Lu, Cheng Lv, Zhi-Liang Chen, Han-Zhong Wang, Dai-Wen Pang
Biomaterials (August 2016) Volume 99() pp:24-33
Publication Date(Web):August 2016
DOI:10.1016/j.biomaterials.2016.04.038
Envelope, capsid and nucleic acids are key viral components that are all involved in crucial events during virus infection. Thus simultaneous labeling of these key components is an indispensable prerequisite for monitoring comprehensive virus infection process and dissecting virus infection mechanism. Baculovirus was genetically tagged with biotin on its envelope protein GP64 and enhanced green fluorescent protein (EGFP) on its capsid protein VP39. Spodoptera frugiperda 9 (Sf9) cells were infected by the recombinant baculovirus and subsequently fed with streptavidin-conjugated quantum dots (SA-QDs) and cell-permeable nucleic acids dye SYTO 82. Just by genetic engineering and virus propagation, multi-labeling of envelope, capsid and nucleic acids was spontaneously accomplished during virus inherent self-assembly process, significantly simplifying the labeling process while maintaining virus infectivity. Intracellular dissociation and transportation of all the key viral components, which was barely reported previously, was real-time monitored based on the multi-labeling approach, offering opportunities for deeply understanding virus infection and developing anti-virus treatment.
Co-reporter:Jun Hu, Cong-Ying Wen, Zhi-Ling Zhang, Min Xie, Hai-Yan Xie, Dai-Wen Pang
Biophysical Journal (1 July 2014) Volume 107(Issue 1) pp:
Publication Date(Web):1 July 2014
DOI:10.1016/j.bpj.2014.05.005
Bead-based assay is widely used in many bioanalytical applications involving the attachment of proteins and other biomolecules to the surface. For further understanding of the formation of a sphere-biomolecule complex and easily optimizing the use of spheres in targeted biological applications, it is necessary to know the kinetics of the binding reaction at sphere/solution interface. In our presented work, a simple fluorescence analysis method was employed to measure the kinetics for the binding of biotin to sphere surface-bound FITC-SA, based on the fact that the fluorescence intensity of FITC was proportionally enhanced by increasing the binding amount of biotin. By monitoring the time-dependent changes of FITC fluorescence, it was found that the binding rate constant of biotin to sphere surface-immobilized FITC-SA was much smaller than that of biotin to freely diffusing FITC-SA. This can be attributed to the decreased encounter frequency of the reaction pair, restricted motion of the attached biomolecule, and the weakened steric accessibility of the binding site. These factors would become more obvious when increasing the size of the sphere upon which the FITC-SA was immobilized. Additionally, the effect of nanoparticles on the diffusion-controlled bimolecular binding reaction was more evident than that on the chemical recognition-controlled binding reaction.
Co-reporter:Jing-Ya Zhao; Gang Chen; Yi-Ping Gu; Ran Cui; Zhi-Ling Zhang; Zi-Li Yu; Bo Tang; Yi-Fang Zhao
Journal of the American Chemical Society () pp:
Publication Date(Web):2017-2-22
DOI:10.1021/jacs.5b10340
Cell-derived microvesicles (MVs) are natural carriers that can transport biological molecules between cells, which are expected to be promising delivery vehicles for therapeutic purposes. Strategies to label MVs are very important for investigation and application of MVs. Herein, ultrasmall Mn-magnetofunctionalized Ag2Se quantum dots (Ag2Se@Mn QDs) integrated with excellent near-infrared (NIR) fluorescence and magnetic resonance (MR) imaging capabilities have been developed for instant efficient labeling of MVs for their in vivo high-resolution dual-mode tracking. The Ag2Se@Mn QDs were fabricated by controlling the reaction of Mn2+ with the Ag2Se nanocrystals having been pretreated in 80 °C NaOH solution, with an ultrasmall size of ca. 1.8 nm, water dispersibility, high NIR fluorescence quantum yield of 13.2%, and high longitudinal relaxivity of 12.87 mM–1 s–1 (almost four times that of the commercial contrast agent Gd-DTPA). The ultrasmall size of the Ag2Se@Mn QDs enables them to be directly and efficiently loaded into MVs by electroporation, instantly and reliably conferring both NIR fluorescence and MR traceability on MVs. Our method for labeling MVs of different origins is universal and free of unfavorable influence on intrinsic behaviors of MVs. The complementary imaging capabilities of the Ag2Se@Mn QDs have made the long-term noninvasive whole-body high-resolution dual-mode tracking of MVs in vivo realized, by which the dynamic biodistribution of MVs has been revealed in a real-time and in situ quantitative manner. This work not only opens a new window for labeling with QDs, but also facilitates greatly the investigation and application of MVs.
Co-reporter:Zhi-Quan Tian, Zhi-Ling Zhang, Jinhao Gao, Bi-Hai Huang, Hai-Yan Xie, Min Xie, Héctor D. Abruña and Dai-Wen Pang
Chemical Communications 2009(Issue 27) pp:NaN4027-4027
Publication Date(Web):2009/06/10
DOI:10.1039/B906149E
We have developed a convenient strategy for preparing color-tunable fluorescent–magnetic core/shell multifunctional nanocrystals, which exhibit excellent photoluminescence (PL) properties (fluorescing tunably from 550 nm to 630 nm by modifying the shell thickness) and ferromagnetic material properties (a magnetization of 4.4 emu g−1 and a coercivity of 95 Oe).
Co-reporter:Shu-Lin Liu, Zhi-Gang Wang, Zhi-Ling Zhang and Dai-Wen Pang
Chemical Society Reviews 2016 - vol. 45(Issue 5) pp:NaN1224-1224
Publication Date(Web):2015/12/23
DOI:10.1039/C5CS00657K
Single-virus tracking (SVT) technique, which uses microscopy to monitor the behaviors of viruses, is a vital tool to study the real-time and in situ infection dynamics and virus-related interactions in live cells. To make SVT a more versatile tool in biological research, the researchers have developed a quantum dot (QD)-based SVT technique, which can be utilized for long-term and highly sensitive tracking in live cells. In this review, we describe the development of a QD-based SVT technique and its biological applications. We first discuss the advantage of QDs as tags in the SVT field by comparing the conventional tags, and then focus on the implementation of QD-based SVT experiments, including the QD labeling strategy, instrumentation, and image analysis method. Next, we elaborate the recent advances of QD-based SVT in the biological field, and mainly emphasize the representative examples to show how to use this technique to acquire more meaningful biological information.
Co-reporter:Yan-Min Long;Chuan-Hua Zhou;Zhi-Ling Zhang;Zhi-Quan Tian;Lei Bao;Yi Lin
Journal of Materials Chemistry A 2012 - vol. 22(Issue 13) pp:
Publication Date(Web):2012/03/06
DOI:10.1039/C2JM30639E
The shifting and non-shifting fluorescence at varied excitations are observed on carbon nanodots prepared by electro-oxidizing carbon paste electrodes with different compositions. The emissions are proposed to be mainly attributed to the surface states rising from surface oxidation of carbon nanodots.
Co-reporter:Ming-Xi Zhang, Ran Cui, Jing-Ya Zhao, Zhi-Ling Zhang and Dai-Wen Pang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 43) pp:NaN17082-17082
Publication Date(Web):2011/09/30
DOI:10.1039/C1JM13120F
Bio-reducing agent NADPH with relatively weak reducibility and favourable structure simultaneously reduced Au and Ag ions into sub-5 nm alloy nanoparticles in aqueous solution at room temperature.
Co-reporter:Qing-Ying Luo, Yi Lin, Jun Peng, Shu-Lin Liu, Zhi-Ling Zhang, Zhi-Quan Tian and Dai-Wen Pang
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 17) pp:NaN7680-7680
Publication Date(Web):2014/03/05
DOI:10.1039/C4CP00572D
A method based on the AFM and colloidal probe techniques was proposed to directly measure nonspecific interactions between QDs and different proteins with respective sizes and isoelectric points. Results indicated that van der Waals forces were the leading force, while electrostatic interactions also played an important role in nonspecific interactions.
Co-reporter:Ran Cui, Yi-Ping Gu, Zhi-Ling Zhang, Zhi-Xiong Xie, Zhi-Quan Tian and Dai-Wen Pang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 9) pp:
Publication Date(Web):
DOI:10.1039/C2JM15691A
Co-reporter:Peng Jiang, Chun-Nan Zhu, Dong-Liang Zhu, Zhi-Ling Zhang, Guo-Jun Zhang and Dai-Wen Pang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 5) pp:NaN967-967
Publication Date(Web):2014/12/24
DOI:10.1039/C4TC02437K
A green room-temperature method based on phase transfer and a reaction between Zn2+ and S2− in toluene for coating a ZnS shell on CdSe and Ag2S quantum dots (QDs), respectively, has been developed. In this method, the S2− anions in Na2S aqueous solution were transferred to toluene via electrostatic interactions between the anions and didodecyldimethylammonium bromide (DDAB), which served as an excellent sulfur precursor and thereby reacted with Zn2+ to form a ZnS shell on the surface of semiconductor QDs in the presence of QDs in an organic phase. After the ZnS shell was coated on QDs, the photoluminescence (PL) intensities of the CdSe and Ag2S QDs were found to increase approximately 12 times and 14 times, respectively, while both the emission wavelengths and the peak shapes were well maintained. The proposed method is novel, simple and robust, providing a green solution to the preparation of ZnS shell-coated QDs.
Co-reporter:Qiao-Ling Zhao, Zhi-Ling Zhang, Bi-Hai Huang, Jun Peng, Min Zhang and Dai-Wen Pang
Chemical Communications 2008(Issue 41) pp:NaN5118-5118
Publication Date(Web):2008/09/24
DOI:10.1039/B812420E
A simple and facile method was developed to prepare fluorescent carbon nanocrystals (CNCs) with low cytotoxicity and no photobleaching, by electrooxidation of graphite in aqueous solution.
Alanine, 3,3'-diselenodi-, L-
(2S)-2-amino-4-ethylselanyl-butanoic acid