Co-reporter:Rong Zhang;Tao Deng;Jie Wang;Gang Wu;Sirui Li;Yueqing Gu
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 13) pp:5387-5394
Publication Date(Web):2017/06/26
DOI:10.1039/C7NJ00573C
With the growing trials of biocompatible quantum dots (QDs) in biomedical applications, exploring the surface modification of oil-soluble QDs to increase their solubility in water is facing more challenges. Hence, in this report, we describe a new approach to synthesize oil-soluble highly luminescent Zn–Cu–In–Se/ZnS (ZCISe/ZnS) QDs with low cytotoxicity. Their photoluminescence (PL) emission could be tuned from 545 to 850 nm by optimizing a series of parameters, and the typical PL quantum yield (QY) is 40–60%. Then, to transfer these oil-soluble QDs into water, cRGD (c(Arg-Gly-Asp-D-Tyr-Lys) peptide) modified multifunctional multidentate polymer ligands (cRGD-PME) were fabricated. The phase transfer is based on a ligand-exchange process mediated by thioglycerol. The obtained results show that the cRGD-PME polymer can afford the formulation of the oil-soluble ZCISe/ZnS QDs in water, while retaining their initial morphology, crystal structure, and PL properties. Finally, in vitro and in vivo optical imaging experiments were further explored, indicating that the prepared aqueous ZCISe/ZnS QDs via cRGD-PME ligands have potential as a versatile fluorescent probe for evaluating tumor targeting in cells and small animals. This study is also particularly significant for developing new biocompatible QDs-based probes to take the place of previous CdSe or CdTe QDs-based ones.
Co-reporter:Jie Zhang;Jie Wang;Tong Yan;Yanan Peng;Dajun Xu
Journal of Materials Chemistry B 2017 vol. 5(Issue 41) pp:8152-8160
Publication Date(Web):2017/10/25
DOI:10.1039/C7TB02324C
Quantum dots (QDs) exhibit many unique optical properties, and show great promise as fluorescent markers in molecular, cellular and in vivo imaging. In this thematic issue, a major concern is their cytotoxicity. Among various Cd-free alternatives, InP-based QDs without highly toxic heavy metal elements have received the most attention. This article first focuses on the synthetic control of oil-soluble InP/ZnSe/ZnS QDs, exhibiting strong dual emissions, namely, visible excitonic emission and near-infrared (NIR) surface defect emission. Next, the organic-to-aqueous phase transfer of the dual emissive QDs was explored systematically. It was found that the dual emissions are relatively stable against the water transfer strategies used here; among them, aqueous dual emissive QDs obtained by wrapping oil-soluble QDs with a poly(acrylic acid)-octylamine (PAA-based) amphiphilic polymer (or modified with the cRGD peptide) exhibit enhanced NIR emission. Finally, using in vitro cell and in vivo small animal optical imaging techniques, the bioactivities of the cRGD-modified amphiphilic polymer-wrapped QDs were also investigated. The results confirm that single-wavelength excitation with strong dual emissions ranging from 550 to >1000 nm will endow the InP-based QDs with the capability for biomedical optical imaging across different spatial scales, as a promising alternative for Cd- and Pb-based QDs.
Co-reporter:Jie Wang, Tao Deng, Dawei Deng, Rong Zhang, Yueqing Gu and Xiaoming Zha
RSC Advances 2016 vol. 6(Issue 59) pp:53760-53767
Publication Date(Web):26 May 2016
DOI:10.1039/C6RA07407C
Tuning the composition is an efficient strategy to control the photoluminescence (PL) emission of multiplex alloy quantum dots (QDs), just as the size is for binary QDs. Hence, in this paper, a quaternary alloy system was selected as a model. By controlling the composition, the quaternary QDs exhibit favorable, wide ranging composition-tuned PL emissions, while ZnS overcoating may further improve their PL quantum yields (QYs). Specifically, Zn–Ag–In–Se(ZAISe)/ZnS QDs have a tunable PL peak from 550 (green) to 820 (NIR) nm with up to 70% PL QY; the parameters for Zn–Cu–In–Se(ZCISe)/ZnS QDs are almost same as those for ZAISe/ZnS QDs. In addition, these quaternary QDs were proven to be versatile for bioimaging, serving as a promising alternative for Cd- and Pb-based QDs, by using biodegradable RGD-modified N-succinyl-N′-octyl-chitosan (RGD-SOC) micelles as the water transfer agent to fabricate dual-emission nanocomposites.
Co-reporter:Dawei Deng and Junsheng Yu
Crystal Growth & Design 2015 Volume 15(Issue 2) pp:602
Publication Date(Web):December 29, 2014
DOI:10.1021/cg5012007
In this report, nonspherical Se crystals were synthesized from the transformation of CdSe nanoparticles (NPs) under ambient conditions, including nanowires (—), microscale or nanoscale rods (−), crossheads, crosses (+), and other unusual highly anisotropic structures. Here, CdSe NPs are used as the starting point of synthesis; the presence of EDTA triggers the decomposition of primary CdSe NPs, and resultant gradual release of Se2– anions into solution; finally, highly pure well-crystallized nonspherical hexagonal Se (h-Se) crystals are formed via the oxidation of the released Se2– anions in air (this redox reaction will stimulate further the release of Se2– anions) and the subsequent spontaneous crystallization of Se monomers. Some key variables such as the concentrations of EDTA and CdSe NPs, and the ligand of primary NPs, were explored systematically. The experimental results show that the ligand nature of the NP precursor influences the transformation rate of CdSe NPs to Se crystals and dominates the shape and aspect ratio of Se product, while the concentrations of EDTA and CdSe NPs only influence the size of the product. Meanwhile, we also investigated intensively the transformation process of CdSe NP precursors to multiarmed Se crystals, aside from the detailed characterizations on their sizes, shapes, and crystal structures.
Co-reporter:Jie Wang, Rong Zhang, Fangjian Bao, Zhihao Han, Yueqing Gu and Dawei Deng
RSC Advances 2015 vol. 5(Issue 108) pp:88583-88589
Publication Date(Web):13 Oct 2015
DOI:10.1039/C5RA17046J
Quantum dots (QDs), as a new fluorescent reagent, should have potential applications in biomedical optical imaging; however their biological applications are limited by the toxicity of the component elements. Hence, in this work, water-soluble Zn–Ag–In–Se (ZAISe) QDs were synthesized without using highly toxic heavy metal elements. The as-prepared quaternary QDs exhibit bright and widely composition-tunable photoluminescence (PL) emission (namely, maximum PL quantum yield (QY) reaching 30%; PL peak from 450 to 760 nm). MTT assay proved that these QDs have much less cytotoxicity than Cd-based QDs. After being further modified by DHLA–PEG–Suc–RGD ligands, water-soluble ZAISe QDs were explored as a fluorescent probe for tumor cell-targeted optical imaging. In vitro and in vivo results demonstrate that ZAISe QDs prepared here should be a promising substitute for Cd-based QDs in biomedical optical imaging.
Co-reporter:Dawei Deng, Lingzhi Qu and Yueqing Gu
Journal of Materials Chemistry A 2014 vol. 2(Issue 34) pp:7077-7085
Publication Date(Web):27 Jun 2014
DOI:10.1039/C4TC01147C
Highly luminescent AgInSe2/ZnS core/shell quantum dots (AISe/ZnS QDs) have been synthesized via a facile low-temperature solution chemistry route. The as-prepared core/shell QDs have a narrow size distribution, and exhibit composition-tunable photoluminescence (PL) emission in the near-infrared (NIR) range from 700 to 820 nm with a maximum PL quantum yield (QY) of 40%. By using the poly(acrylic acid)–octylamine (PAA-based) amphiphilic polymer, these oil-soluble AISe/ZnS core/shell QDs could be effectively solubilized in water, while retaining their initial morphology, crystal structure and PL properties. Importantly, the results from animal and cell experiments confirm that these highly luminescent, broadly emissive AISe/ZnS QDs are new promising fluorescent probes for biomedical optical imaging (namely, in vivo animal and in vitro cell imaging), as an alternative for Cd-, Hg- and Pb-based QDs and organic dyes.
Co-reporter:Dawei Deng, Lingzhi Qu, Samuel Achilefu and Yueqing Gu
Chemical Communications 2013 vol. 49(Issue 82) pp:9494-9496
Publication Date(Web):14 Aug 2013
DOI:10.1039/C3CC45751F
Highly luminescent oil-soluble quaternary Zn–Ag–In–Se (ZAISe) quantum dots (QDs) with extremely wide emission covering the spectral range from 550 to 1000 nm have been synthesized for the first time. These broadly emissive quaternary QDs are demonstrated to have greater potential in the use of one probe for multi-spatial scale biomedical imaging than binary CdTe and ternary Cu–In–S QDs.
Co-reporter:Dawei Deng, Lingzhi Qu, Jian Zhang, Yuxiang Ma, and Yueqing Gu
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 21) pp:10858
Publication Date(Web):October 1, 2013
DOI:10.1021/am403050s
Exploring the synthesis of new biocompatible quantum dots (QDs) helps in overcoming the intrinsic toxicity of the existing QDs composed of highly toxic heavy metals (e.g., Cd, Hg, Pb, etc.) and is particularly interesting for the future practical application of QDs in biomedical imaging. Hence, in this report, a new one-pot approach to oil-soluble (highly toxic heavy metal-free) highly luminescent quaternary Zn–Ag–In–Se (ZAISe) QDs was designed. Their photoluminescence (PL) emission could be systematically tuned from 660 to 800 nm by controlling the Ag/Zn feed ratio, and their highest PL quantum yield is close to 50% after detailed optimization. Next, by using biodegradable RGD peptide (arginine–glycine–aspartic acid)-modified N-succinyl-N′-octyl-chitosan (RGD-SOC) micelles as a water transfer agent, the versatility of these quaternary ZAISe QDs for multiscale bioimaging of micelles (namely, in vitro and in vivo evaluating the tumor targeting of drug carriers) was further explored, as a promising alternative for Cd- and Pb-based QDs.Keywords: optical imaging; quaternary quantum dots; RGD-modified micelles; targeted delivery; Zn−Ag−In−Se;
Co-reporter:Dawei Deng, Jie Cao, Lingzhi Qu, Samuel Achilefu and Yueqing Gu
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 14) pp:5078-5083
Publication Date(Web):30 Jan 2013
DOI:10.1039/C3CP00046J
Exploring the synthesis and biomedical applications of biocompatible quantum dots (QDs) is currently one of the fastest growing fields of nanotechnology. Hence, in this work, we present a facile approach to produce water-soluble (cadmium-free) quaternary Zn–Ag–In–S (ZAIS) QDs. Their efficient photoluminescence (PL) emissions can be tuned widely in the range of 525–625 nm by controlling the size and composition of the QDs with the PL quantum yields (QYs) of 15–30%. These highly luminescent ZAIS QDs are less toxic due to the absence of highly toxic cadmium, and can be versatilely modified by a DHLA-PEG-based ligand. Importantly, after being modified by tumor cell-specific targeting ligands (e.g., folate and RGD peptide), the PEGylated quaternary QDs show potential applications in tumor cell imaging as a promising alternative for Cd-based QDs.
Co-reporter:Dawei Deng, Lingzhi Qu, Yang Li, and Yueqing Gu
Langmuir 2013 Volume 29(Issue 34) pp:10907-10914
Publication Date(Web):August 1, 2013
DOI:10.1021/la401999r
In this paper, we report on the versatile self-assembly of water-soluble thiol-capped CdTe quantum dots (QDs), nanoparticles (NPs), or nanocrystals induced by l-cysteine (l-Cys). Major efforts are focused on the control of the self-organization of QDs into nanosheets (NSs), for example, by altering the solution pH and the QD size. The as-prepared nanosheets exhibit bright photoluminescence (PL) and retain the size-quantized properties of initial CdTe QDs, since they are actually formed by a 2D network of assembled QDs. By optical techniques, TEM, EDX, powder XRD, etc., it is found that the unique l-Cys-induced external destabilization is responsible for the template-free self-organization process, with the further assistance of the specific NP–NP interactions. And the internal chemical stability of initial CdTe QDs also is proven for the first time to play an important role. These results help to enhance the current understanding about the mechanism for the destabilization of colloidal NPs and their self-assembly behavior.
Co-reporter:Dawei Deng, Yuqi Chen, Jie Cao, Junmei Tian, Zhiyu Qian, Samuel Achilefu, and Yueqing Gu
Chemistry of Materials 2012 Volume 24(Issue 15) pp:3029
Publication Date(Web):July 23, 2012
DOI:10.1021/cm3015594
The exploration of biocompatible quantum dots (QDs) for biomedical imaging is currently one of the fastest growing fields of nanotechnology. This strategy overcomes the intrinsic toxicity of well-developed II–VI and other semiconductor QDs (Cd, Hg, Pb, Se, Te, As, etc.) that remains a major obstacle to their clinical use. In this report, we synthesized high-quality CuInS2/ZnS (CIS/ZnS) QDs without using conventional toxic heavy metals. These QDs exhibited improved photoluminescence (PL) properties, with tunable emission peaks ranging from 550 to 800 nm and a maximum PL quantum yield (QY) up to 80%. Next, we explored the effective loading of the prepared oil-soluble CIS/ZnS QDs using biodegradable folate-modified N-succinyl-N′-octyl chitosan (FA-SOC) micelles. Targeting efficacy of the resulting QDs-loaded micelles to tumors using in vitro and in vivo optical imaging techniques was also investigated. The results show that the micelle platform allowed successful formulation of these oil-soluble QDs in water, while retaining the morphology, crystal structure, and PL of the initial CIS/ZnS QDs. This study demonstrates the versatility of using the biocompatible CIS/ZnS QDs across different spatial scales (in vitro cell imaging and in vivo small animal imaging) for multicolor biological imaging applications.Keywords: CuInS2/ZnS; in vitro imaging; in vivo imaging; micelles; quantum dots;
Co-reporter:Dawei Deng, Lingzhi Qu and Yueqing Gu
RSC Advances 2012 vol. 2(Issue 31) pp:11993-11999
Publication Date(Web):09 Oct 2012
DOI:10.1039/C2RA21980H
The transformation of existing inorganic nanomaterials from one structure into another represents a straightforward, versatile and effective approach for the synthesis of nanomaterials. Hence, in this paper, we focus on the controlled transformation of water-soluble CdTe quantum dots (QDs) → Te-rich CdTe nanaorods (NRs) → second CdTe QDs. It was found that in the presence of L-cysteine (L-cys), aqueous thiolglycolic acid (TGA)-stabilized CdTe QDs might spontaneously assemble and recrystallize into luminescent Te-rich CdTe nanorods under ambient conditions. However, increasing the temperature of the nanorod dispersion to 90 °C or adding a specific amount of TGA into the dispersion of NRs might effectively induce the transformation of Te-rich CdTe NRs → second CdTe QDs. These unique transformation processes that involve simultaneous complicated changes in the chemical compositions, structures and morphologies of nanocrystals were systematically characterized by optical techniques, transmission electron microscopy (TEM) and powder X-ray diffractometry (XRD).
Co-reporter:Jie Cao;Hongyan Zhu;Bing Xue;Liping Tang;Didel Mahounga;Zhiyu Qian;Yueqing Gu
Journal of Biomedical Materials Research Part A 2012 Volume 100A( Issue 4) pp:958-968
Publication Date(Web):
DOI:10.1002/jbm.a.34043
Abstract
In this article, we firstly synthesized oil-soluble PbS quantum dots (QDs) emitting in the near-infrared (NIR) spectral range through a two-phase method, which exhibit a conveniently tunable photoluminescence (PL) emission (from ∼750 to 872 nm) with a narrow PL bandwidth, as well as a high (up to 40%) PL quantum yield (QY). Next, the as-prepared oil-soluble NIR PbS QDs were applied to the in vivo imaging of tumors by entrapping in biodegradable micelles (N-succinyl-N′-octyl nanomicelles, SOC) which had hydrophobic inner cores. Transmission electron microscope results show well dispersed spherical shaped QDs-loaded SOC micelles with 100 nm diameter. The QY of PbS QDs entrapped into SOC has no significant change compared to free QDs. Besides, both in vitro and in vivo acute toxicity results demonstrated that the QDs-loaded micelles have low cytotoxicity. Furthermore, in vivo imaging of PbS QDs-loaded SOC injected intravenously into tumor-bearing nude mice showed the NIR QDs-loaded micelles can accumulate in the tumor tissue due to the enhanced permeability and retention effect of SOC micelles. These results confirm that the as-prepared PbS QDs could be used as fluorescence probes to study the biodistribution of nanocarriers and their intracellular pathways, as well as their passive targeted behavior to tumors in preclinical research. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Co-reporter:Bing Xue;Jie Cao;Junfei Xia
Journal of Materials Science: Materials in Medicine 2012 Volume 23( Issue 3) pp:723-732
Publication Date(Web):2012 March
DOI:10.1007/s10856-012-4548-z
The successful transfer of oil-soluble quantum dots (QDs) into water is critical for many of their bioapplications. In this paper, the impacts of four various strategies (i.e., via micelles, nanohydrogels, amphiphilic polymers and water-soluble thiol small molecules) on the phase transfer of oil-soluble oleic acid-capped NIR-emitting PbS QDs into water were evaluated systematically. It was found that the process of water transfer and the optical property of the resulting water-soluble QDs highly hinge on the type of the phase transfer agents used due to their different interactions with QD surface. Among all these phase transfer agents, SOC micelles and glutathione (thiol) molecules are more favorable for retaining the optical property of the initial oil-soluble PbS QDs. As a result, the obtained water-soluble QDs show strong NIR fluorescence (PL QY > 30% in water). However, in the case of nanohydrogel and amphiphilic polymers, the corresponding water-soluble ones display relatively weak fluorescence emission. These results suggest fully that “correct” phase transfer agents should be selected in order to obtain high-quality water-soluble PbS QDs. The possible reasons for this obvious difference were further analyzed and revealed. Besides, the preliminary results obtained also indicate that the NIR-emitting PbS QDs will be a potential probe in the in vivo biomedical imaging of small animals.
Co-reporter:Jie Wang, Jie Zhang, Dawei Deng
Materials Letters (15 March 2017) Volume 191() pp:
Publication Date(Web):15 March 2017
DOI:10.1016/j.matlet.2017.01.045
•A phosphine-free approach is developed to prepare oil-soluble CdTe quantum dots.•The as-prepared CdTe quantum dots are highly luminescent and monodisperse in size.•The interaction between TeO2-dodecanethiol (Te source) and oleylamine is explored.Currently, the synthesis of CdTe quantum dots (QDs) in organic phase has basically involved costly and air-sensitive reagents such as alkylphosphines, making a more economical approach desirable. Here, a phosphine-free approach has been developed to prepare CdTe QDs, in which TeO2 dissolved in 1-dodecanethiol (DT) was employed as the Te source. The obtained QDs were highly luminescent and exhibited desirable size-tunability and narrow size distribution. More importantly, oleylamine (OLA), the specific solvent in this method, has been found to be crucial for TeO2-DT to provide reactive Te species for the formation of CdTe. These results suggest that the combination of TeO2-DT and OLA should be an efficient Te precursor for the preparation of colloidal tellurides.
Co-reporter:Dawei Deng, Lingzhi Qu and Yueqing Gu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 34) pp:NaN7085-7085
Publication Date(Web):2014/06/27
DOI:10.1039/C4TC01147C
Highly luminescent AgInSe2/ZnS core/shell quantum dots (AISe/ZnS QDs) have been synthesized via a facile low-temperature solution chemistry route. The as-prepared core/shell QDs have a narrow size distribution, and exhibit composition-tunable photoluminescence (PL) emission in the near-infrared (NIR) range from 700 to 820 nm with a maximum PL quantum yield (QY) of 40%. By using the poly(acrylic acid)–octylamine (PAA-based) amphiphilic polymer, these oil-soluble AISe/ZnS core/shell QDs could be effectively solubilized in water, while retaining their initial morphology, crystal structure and PL properties. Importantly, the results from animal and cell experiments confirm that these highly luminescent, broadly emissive AISe/ZnS QDs are new promising fluorescent probes for biomedical optical imaging (namely, in vivo animal and in vitro cell imaging), as an alternative for Cd-, Hg- and Pb-based QDs and organic dyes.
Co-reporter:Dawei Deng, Jie Cao, Lingzhi Qu, Samuel Achilefu and Yueqing Gu
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 14) pp:NaN5083-5083
Publication Date(Web):2013/01/30
DOI:10.1039/C3CP00046J
Exploring the synthesis and biomedical applications of biocompatible quantum dots (QDs) is currently one of the fastest growing fields of nanotechnology. Hence, in this work, we present a facile approach to produce water-soluble (cadmium-free) quaternary Zn–Ag–In–S (ZAIS) QDs. Their efficient photoluminescence (PL) emissions can be tuned widely in the range of 525–625 nm by controlling the size and composition of the QDs with the PL quantum yields (QYs) of 15–30%. These highly luminescent ZAIS QDs are less toxic due to the absence of highly toxic cadmium, and can be versatilely modified by a DHLA-PEG-based ligand. Importantly, after being modified by tumor cell-specific targeting ligands (e.g., folate and RGD peptide), the PEGylated quaternary QDs show potential applications in tumor cell imaging as a promising alternative for Cd-based QDs.
Co-reporter:Dawei Deng, Lingzhi Qu, Samuel Achilefu and Yueqing Gu
Chemical Communications 2013 - vol. 49(Issue 82) pp:NaN9496-9496
Publication Date(Web):2013/08/14
DOI:10.1039/C3CC45751F
Highly luminescent oil-soluble quaternary Zn–Ag–In–Se (ZAISe) quantum dots (QDs) with extremely wide emission covering the spectral range from 550 to 1000 nm have been synthesized for the first time. These broadly emissive quaternary QDs are demonstrated to have greater potential in the use of one probe for multi-spatial scale biomedical imaging than binary CdTe and ternary Cu–In–S QDs.
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