Hai-Chen Wu

Pillararene-Based Aggregation-Induced-Emission-Active Supramolecular System for Simultaneous Detection and Removal of Mercury(II) in Water

Co-reporter:Hong-Bo Cheng, Ziyan Li, Yao-Dong Huang, Lei Liu, and Hai-Chen Wu

ACS Applied Materials & Interfaces April 5, 2017 Volume 9(Issue 13) pp:11889-11889

Publication Date(Web):March 20, 2017

DOI:10.1021/acsami.7b00363

Supramolecular polymers are polymers based on monomeric units held together with directional and reversible noncovalent interactions. Compared with traditional polymers, they possess better processability and better recycling properties, owing to their reversible monomer-to-polymer transition. Herein, we report the construction of a new supramolecular system through self-assembly of a thymine-substituted copillar[5]arene 1 and a tetraphenylethylene (TPE) derivative 2 in the presence of Hg2+. Copillar[5]arene 1 can coordinate with Hg2+ tightly through T–Hg2+–T pairings. On the other hand, 1 can bind with guest molecule 2 through host–guest interactions between the pillararene cavity and the nitrile moiety of 2. These joint interactions generate crisscrossed networks composed of 1, 2, and Hg2+, which eventually wrap into spherical nanoparticles. Due to the aggregation-induced emission (AIE) properties of 2, the formed supramolecular polymer exhibits strong fluorescence which renders convenient the detection of the Hg2+-containing nanoparticles and the subsequent removal procedure. Furthermore, the polymer precipitate can be readily isolated by simple treatment, and the pseudorotaxane 2 ⊂ 1 can be recycled and reused. Our study has demonstrated a practical strategy for the sensing and removal of heavy metal ions in water by the construction of supramolecular polymers.Keywords: aggregation-induced emission; mercury(II); pillararene; self-assembly; supramolecular polymer;

Rapid and visual detection of heparin based on the disassembly of polyelectrolyte-induced pyrene excimers

Co-reporter:Yadong Qiao;Zhiyi Yao;Wenqi Ge;Li Zhang

Organic & Biomolecular Chemistry 2017 vol. 15(Issue 12) pp:2569-2574

Publication Date(Web):2017/03/22

DOI:10.1039/C7OB00115K

We have developed a ratiometric sensor based on polyelectrolyte-induced pyrene excimers for the rapid and visual detection of heparin in aqueous media. This sensor has a simple preparation method, fast response, low cost, and high sensitivity and selectivity. As a complementary strategy for the detection of heparin based on the formation of pyrene excimers, this approach could identify heparin specifically over chondroitin sulphate, which is the major interferent in most sensing systems for the detection of heparin. The detection limit of this approach can be as low as 0.14 μM using fluorescence measurements. To the best of our knowledge, this is among the lowest LOD for the detection of heparin reported in the literature. It enables the rapid and visual detection of heparin both in buffered solution and serum samples.

Revealing different aggregational states of a conjugated polymer in solution by a nanopore sensor

Co-reporter:Bingyuan Guo, Zhiyi Yao, Lei Liu and Hai-Chen Wu

Chemical Science 2016 vol. 7(Issue 8) pp:5287-5293

Publication Date(Web):05 May 2016

DOI:10.1039/C6SC00296J

The functionalities of conjugated polymers are determined not only by local molecular structure, but also by the mesoscale conformational and morphological states of the polymer chains. Simulation studies have successfully established the connections between molecular structure and conformational states of certain conjugated polymers. However, experimental tools that can accurately discriminate between different conformational and morphological states of conjugated polymers are still scarce. Here, we use a nanopore sensor to analyze different aggregational states of a polythiophene derivative by threading the polymer through the pore under applied potentials. When the fluorescence of the polythiophene is quenched by pH tuning or the presence of Dy3+, the UV-vis and fluorescence spectra of the two solutions appear indistinguishable. However, threading the polymer molecules of these two solutions through an α-hemolysin nanopore affords entirely different translocation profiles owing to their different aggregational states. We further substantiate the results by conducting aggregational interconversion experiments and TEM measurements. This work has clearly indicated that nanopores are promising tools for the analysis of aggregational changes of conjugated polymers and may open new avenues for the investigation of aggregational states of biomacromolecules in the context of early disease diagnosis and prognosis.

Approach Based on Polyelectrolyte-Induced Nanoassemblies for Enhancing Sensitivity of Pyrenyl Probes

Co-reporter:Zhiyi Yao, Yadong Qiao, Haiqin Liang, Wenqi Ge, Li Zhang, Zhong Cao, and Hai-Chen Wu

Analytical Chemistry 2016 Volume 88(Issue 21) pp:10605

Publication Date(Web):October 5, 2016

DOI:10.1021/acs.analchem.6b02809

We have developed a unique approach for enhancing the sensitivity of pyrenyl probes based on polyelectrolyte-induced nanoassemblies and explored its sensing application toward 2,4,6-trinitrophenol (TNP). The key issue of the method is the formation of the nanoassemblies which possess high-density charges, specific surface area, and inner hydrophobic regions. These properties would help increase the loading of analytes and promote probe–analyte interactions, thereby leading to the prominent enhancement of the sensitivity. In the course of TNP detection, pyrene nanoassemblies can bind TNP efficiently through cooperative noncovalent interactions including electrostatic, π–π stacking, and charge-transfer interactions, resulting in the distinct fluorescent responses of pyrene moieties. This system has excellent selectivity and sensitivity for TNP detection. The detection limit is as low as 5 nM. It may be used for monitoring the TNP concentrations in real-world samples.

Selective Detection of 8-Oxo-2′-deoxyguanosine in Single-Stranded DNA via Nanopore Sensing Approach

Co-reporter:Lei Liu, Yuru Li, Ting Li, Jiani Xie, Chaofei Chen, Quansheng Liu, Shouwen Zhang, and Hai-Chen Wu

Analytical Chemistry 2016 Volume 88(Issue 2) pp:1073

Publication Date(Web):December 24, 2015

DOI:10.1021/acs.analchem.5b04102

We have developed a nanopore sensing approach for the selective detection of 8-oxo-2′-deoxyguanosine (8-oxoG) in single-stranded DNA. First, 1,12-dodecanediamine is coupled with 8-oxoG-containing DNA molecules in high yield which leaves a free amine group for subsequent attaching of an adamantane moiety. After incubation with cucurbit[7]uril, the host–guest complex-modified DNA hybrid is translocated through an α-hemolysin nanopore. Highly characteristic events can be recorded and used to quantify the 8-oxoG-DNA content in a DNA mixture. Compared with the existing methods, this study provides a reliable, quick, and low-cost approach for the detection of 8-oxoG site in single-stranded DNA at the single-molecule level, particularly suitable for high-throughput screening of a massive number of samples.

Photocontrolled Reversible Luminescent Lanthanide Molecular Switch Based on a Diarylethene–Europium Dyad

Co-reporter:Hong-Bo Cheng, Guo-Fei Hu, Zhan-Hui Zhang, Liang Gao, Xingfa Gao, and Hai-Chen Wu

Inorganic Chemistry 2016 Volume 55(Issue 16) pp:7962

Publication Date(Web):July 22, 2016

DOI:10.1021/acs.inorgchem.6b01009

A new europium complex coordinated between a Eu(III) ion and an unsymmetrical diarylperfluorocyclopentene yields a light-controlled diarylethene–europium dyad, DAE@TpyEu(tta)3, whose photophysical properties can be reversibly switched by optical stimuli. When DAE@TpyEu(tta)3 is exposed to 365 nm UV light, an efficient intramolecular photochromic fluorescence resonance energy transfer (pc-FRET) occurs between the emission of the Eu3+ donor (D) and the absorption of the diarylethene acceptor (A) in closed-form DAE@TpyEu(tta)3 accompanied by luminescence quenching. However, the pc-FRET process could be effectively inhibited by visible light (λ > 600 nm) irradiation, and the lanthanide emission of DAE@TpyEu(tta)3 is rapidly recovered. Furthermore, this luminescent lanthanide molecular switch could serve as a highly reliable and sensitive “turn on” fluorescent marker in living cells irradiated by red light without any optical interference.

Selective detection of mercury(II) and methylmercury(II) via coordination-induced emission of a small-molecule probe

Co-reporter:Yan Yang;Zhiyi Yao;Wei Li;Kui Chen;Lei Liu

Science China Chemistry 2016 Volume 59( Issue 12) pp:1651-1657

Publication Date(Web):2016 December

DOI:10.1007/s11426-016-0137-y

Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion (Hg2+) and organic methylmercury (CH3Hg+). Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg2+ and CH3Hg+. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg2+ or CH3Hg+, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg2+ or CH3Hg+, leading to significantly enhanced fluorescent emission. The response induced by Hg2+ is much stronger than CH3Hg+; but for specific detection of CH3Hg+, we introduced a T-rich DNA fragment which could completely mask Hg2+ in solution. Furthermore, we have employed the sensor for confocal imaging of Hg2+ and CH3Hg+in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.

Detection of 5-methylcytosine and 5-hydroxymethylcytosine in DNA via host–guest interactions inside α-hemolysin nanopores

Co-reporter:Tao Zeng, Lei Liu, Ting Li, Yuru Li, Juan Gao, Yuliang Zhao and Hai-Chen Wu

Chemical Science 2015 vol. 6(Issue 10) pp:5628-5634

Publication Date(Web):24 Jun 2015

DOI:10.1039/C5SC01436K

Cytosine methylation and hydroxymethylation are both important epigenetic modifications of DNA in mammalian cells. Therefore, profiling DNA (hydroxy)methylation across the genome is vital for understanding their roles in gene regulation. Here, we report a nanopore-based approach for quick and reliable detection of 5-methylcytosine and 5-hydroxymethylcytosine in DNA at the single-molecule level. The single-stranded DNA containing 5-methylcytosine or 5-hydroxymethylcytosine was first selectively modified on the epigenetic base to attach a host–guest complex. Threading of the modified DNA molecules through α-hemolysin nanopores causes unbinding of the host–guest complex and generates highly characteristic current signatures. Statistical analysis of the signature events affords quantitative information about 5-methylcytosine and 5-hydroxymethylcytosine in DNA. Our results suggest that other DNA modifications could also be detected with the developed method. Furthermore, we anticipate our nanopore sensing strategy to be generally useful in biochemical analysis and to find applications in the early diagnosis of diseases.

A prominent bathochromic shift effect of indole-containing diarylethene derivatives

Co-reporter:Hong-Bo Cheng, Yao-Dong Huang, Lina Zhao, Xu Li and Hai-Chen Wu

Organic & Biomolecular Chemistry 2015 vol. 13(Issue 11) pp:3470-3475

Publication Date(Web):29 Jan 2015

DOI:10.1039/C4OB02619E

The potential implication of photochromic materials with absorption and reactivity in the near-infrared region is far-reaching. In this work, three novel bisindole-containing diarylethene derivatives 1o–3o have been successfully synthesized and their photochromic behaviour exhibits a strong bathochromic shift effect compared with bisbenzothiophene diarylethene 4o. These new bisindole-diarylethene compounds 1o–3o are highly sensitive to photo-stimuli both in solution and in poly(methyl methacrylate) films. Besides, 1o–3o exhibit an excellent reversible fluorescence switching behavior modulated by optical stimuli.

A simple fluorescent probe based on a pyrene derivative for rapid detection of protamine and monitoring of trypsin activity

Co-reporter:Baiyang Tang, Yan Yang, Gefu Wang, Zhiyi Yao, Li Zhang and Hai-Chen Wu

Organic & Biomolecular Chemistry 2015 vol. 13(Issue 32) pp:8708-8712

Publication Date(Web):09 Jul 2015

DOI:10.1039/C5OB01034A

We report the synthesis of a simple pyrene derivative and its application in protamine detection and monitoring of trypsin activity. This assay can be conducted in aqueous solution and features rapid response, visual detection, high sensitivity and selectivity. The limit of detection of protamine was 0.5 μg mL−1. The IC50 value of a soybean trypsin inhibitor was estimated to be 0.51 U mL−1.

A Universal Strategy for Aptamer-Based Nanopore Sensing through HostGuest Interactions inside -Hemolysin

Co-reporter:Ting Li;Dr. Lei Liu;Yuru Li;Jiani Xie ;Dr. Hai-Chen Wu

Angewandte Chemie 2015 Volume 127( Issue 26) pp:7678-7681

Publication Date(Web):

DOI:10.1002/ange.201502047

Abstract

Nanopore emerged as a powerful single-molecule technique over the past two decades, and has shown applications in the stochastic sensing and biophysical studies of individual molecules. Here, we report a versatile strategy for nanopore sensing by employing the combination of aptamers and host–guest interactions. An aptamer is first hybridized with a DNA probe which is modified with a ferrocene⊂cucurbit[7]uril complex. The presence of analytes causes the aptamer–probe duplex to unwind and release the DNA probe which can quantitatively produce signature current events when translocated through an α-hemolysin nanopore. The integrated use of magnetic beads can further lower the detection limit by approximately two to three orders of magnitude. Because aptamers have shown robust binding affinities with a wide variety of target molecules, our proposed strategy should be universally applicable for sensing different types of analytes with nanopore sensors.

A Universal Strategy for Aptamer-Based Nanopore Sensing through HostGuest Interactions inside -Hemolysin

Co-reporter:Ting Li;Dr. Lei Liu;Yuru Li;Jiani Xie ;Dr. Hai-Chen Wu

Angewandte Chemie International Edition 2015 Volume 54( Issue 26) pp:7568-7571

Publication Date(Web):

DOI:10.1002/anie.201502047

Abstract

Nanopore emerged as a powerful single-molecule technique over the past two decades, and has shown applications in the stochastic sensing and biophysical studies of individual molecules. Here, we report a versatile strategy for nanopore sensing by employing the combination of aptamers and host–guest interactions. An aptamer is first hybridized with a DNA probe which is modified with a ferrocene⊂cucurbit[7]uril complex. The presence of analytes causes the aptamer–probe duplex to unwind and release the DNA probe which can quantitatively produce signature current events when translocated through an α-hemolysin nanopore. The integrated use of magnetic beads can further lower the detection limit by approximately two to three orders of magnitude. Because aptamers have shown robust binding affinities with a wide variety of target molecules, our proposed strategy should be universally applicable for sensing different types of analytes with nanopore sensors.

Recent advances of DNA sequencing via nanopore-based technologies

Co-reporter:Bing-Yuan Guo;Tao Zeng

Science Bulletin 2015 Volume 60( Issue 3) pp:287-295

Publication Date(Web):2015 February

DOI:10.1007/s11434-014-0707-6

This review briefly summarizes recent progress in nanopore DNA sequencing from the beginning of 2012 to July 2014. Although partial successes have been achieved in different types of nanopores, biological pores such as α-hemolysin and MspA afford most promising results.

Regioselective alkyl transfer from phosphonium ylides to functionalized polyfluoroarenes

Co-reporter:Wei Lu, Juan Gao, Jing-Kui Yang, Lei Liu, Yuliang Zhao and Hai-Chen Wu

Chemical Science 2014 vol. 5(Issue 5) pp:1934-1939

Publication Date(Web):28 Jan 2014

DOI:10.1039/C4SC00221K

We report an unprecedented alkyl transfer from phosphonium ylides to polyfluoroarenes in a highly regioselective manner. This reaction allows the introduction of a variety of alkyl groups to the para position of functionalized polyfluoroarenes under mild conditions. The process is found to be compatible with several electrophilic functional groups such as carboxyl, ester, amide and cyano groups. NMR spectroscopy studies and deuterated labeling experiments reveal that the reaction proceeds via an SNAr mechanism and the proton that is transferred to the α-carbon of the alkyl group during the last C–P bond breaking step is from water.

Visual detection of Cu(II) ions based on a simple pyrene derivative using click chemistry

Co-reporter:Yanbo Yang, Zhiyi Yao, Baiyang Tang, Junhua Yu, Xiaolin Bi, Yuliang Zhao and Hai-Chen Wu

Analytical Methods 2014 vol. 6(Issue 14) pp:4977-4981

Publication Date(Web):15 May 2014

DOI:10.1039/C4AY00880D

A ratiometric fluorescent probe for the visual detection of Cu2+ in aqueous media has been developed based on a “click” reaction between a pyrene azide and a positively charged terminal alkyne. The probe has a quick response and excellent selectivity towards Cu2+, with a detection limit as low as 50 nM.

Halochromism of a Polythiophene Derivative Induced by Conformational Changes and Its Sensing Application of Carbon Dioxide

Co-reporter:Zhiyi Yao, Xianping Hu, Binghuan Huang, Li Zhang, Lei Liu, Yuliang Zhao, and Hai-Chen Wu

ACS Applied Materials & Interfaces 2013 Volume 5(Issue 12) pp:5783

Publication Date(Web):May 24, 2013

DOI:10.1021/am401761n

We report the design and synthesis of a halochromic polythiophene derivative, whose conformation can be alternated between random coil and rodlike phase by adjusting the pH of the solution. Distinct solution color changes associated with the pH-induced conformational transitions can be used to construct a colorimetric probe for sensing carbon dioxide. This probe can be recovered by bubbling nitrogen gas into carbon dioxide-treated solutions for over 20 cycles.Keywords: carbon dioxide; conformation; halochromism; polythiophene; sensor;

Highly Sensitive Simultaneous Detection of Lead(II) and Barium(II) with G-Quadruplex DNA in α-Hemolysin Nanopore

Co-reporter:Chun Yang, Lei Liu, Tao Zeng, Daowu Yang, Zhiyi Yao, Yuliang Zhao, and Hai-Chen Wu

Analytical Chemistry 2013 Volume 85(Issue 15) pp:7302

Publication Date(Web):July 16, 2013

DOI:10.1021/ac401198d

Both Pb2+ and Ba2+ can bind with high affinity to some specific DNA sequences, inducing the formation of unimolecular G-quadruplex structures. Translocation of a DNA probe containing such sequences through an α-hemolysin nanopore in the presence of Pb2+ or Ba2+ would result in much prolonged DNA translocation events. Quantification of these events can reveal the concentrations of Pb2+ or Ba2+ at as low as 0.8 nM. Besides, Pb2+ and Ba2+ in the solution can be simultaneously detected and individually identified. Furthermore, the probe is highly selective for Pb2+ and Ba2+ detection without interference from other metal ions. This sensing strategy can be extended to many other analytes which can bind to DNA molecules with high affinity.

Visual Detection of Copper(II) Ions Based on an Anionic Polythiophene Derivative Using Click Chemistry

Co-reporter:Zhiyi Yao, Yanbo Yang, Xueliang Chen, Xianping Hu, Li Zhang, Lei Liu, Yuliang Zhao, and Hai-Chen Wu

Analytical Chemistry 2013 Volume 85(Issue 12) pp:5650

Publication Date(Web):June 6, 2013

DOI:10.1021/ac401386v

We have developed a novel approach for the rapid visual detection of Cu2+ based on an anionic polythiophene derivative (sodium poly(2-(4-methyl-3-thienyloxy)propanesulfonate, PMTPS) using click chemistry. The method relies on the disassembly of PMTPS aggregates in the presence of cationic surfactant through electrostatic and hydrophobic interactions. In the assay of Cu2+ detection, a cationic surfactant was formed via a click reaction catalyzed by copper(I), which was derived in situ from copper(II) and promoted the disassembly of PMTPS aggregates leading to the distinct solution color change from purple to yellow. This polymer probe has excellent sensitivity and selectivity for Cu2+ with a detectable range in the micromolar regime by naked eyes and can be used for monitoring Cu2+ concentrations below the safety limit in real-world samples.

Effects of different metal ions on the fluorescence of CdSe/ZnS quantum dots capped with various thiolate ligands

Co-reporter:Tao Zeng, Yanxi Hu, Na Wang, Chuanqin Xia, Shoujian Li, Yan Zu, Lei Liu, Zhiyi Yao, Yuliang Zhao and Hai-Chen Wu

Physical Chemistry Chemical Physics 2013 vol. 15(Issue 42) pp:18710-18715

Publication Date(Web):11 Sep 2013

DOI:10.1039/C3CP52666F

In this report, we systematically studied the effects of different metal ions on the fluorescence of common thiolate ligand capped quantum dots. Generally, heavy metal ions exhibited much more significant fluorescence quenching. Also, the coordination capability and steric hindrance of the ligand jointly affect the quenching efficiency.

Colorimetric and fluorescent detection of protamines with an anionic polythiophene derivative

Co-reporter:Zhiyi Yao, Wenjuan Ma, Yan Yang, Xueliang Chen, Li Zhang, Chen Lin and Hai-Chen Wu

Organic & Biomolecular Chemistry 2013 vol. 11(Issue 38) pp:6466-6469

Publication Date(Web):01 Aug 2013

DOI:10.1039/C3OB41407H

We have developed a novel approach for the colorimetric and fluorescent detection of protamines based on an anionic polythiophene derivative. This probe has high sensitivity and selectivity toward protamines with a linear detectable range from 0.1 to 30 μg mL−1, and can be used for protamine detection in serum samples.

Colorimetric and fluorescent dual detection of paraquat and diquat based on an anionic polythiophene derivative

Co-reporter:Zhiyi Yao, Xianping Hu, Wenjuan Ma, Xueliang Chen, Li Zhang, Junhua Yu, Yuliang Zhao and Hai-Chen Wu

Analyst 2013 vol. 138(Issue 19) pp:5572-5575

Publication Date(Web):23 Jul 2013

DOI:10.1039/C3AN01205K

We have developed a colorimetric and fluorescent dual-response probe for the detection of paraquat and diquat in aqueous solutions based on an anionic polythiophene derivative. The detection limit of this approach can be as low as 10−9 M by fluorescence measurements.

Colorimetric detection of copper ions based on a supramolecular complex of water-soluble polythiophene and ATP

Co-reporter:Zhiyi Yao, Binghuan Huang, Xianping Hu, Li Zhang, Depeng Li, Ming Guo, Xiaohui Zhang, Hui Yuan and Hai-Chen Wu

Analyst 2013 vol. 138(Issue 6) pp:1649-1652

Publication Date(Web):29 Jan 2013

DOI:10.1039/C3AN00151B

A colorimetric probe for the detection of copper(II) ions in aqueous media by the naked eye has been developed based on a supramolecular complex comprised of a cationic polythiophene derivative and ATP with a detection limit as low as 0.05 mM.

Highly Sensitive and Selective DNA-Based Detection of Mercury(II) with α-Hemolysin Nanopore

Co-reporter:Shuang Wen ; Tao Zeng ; Lei Liu ; Kai Zhao ; Yuliang Zhao ; Xianjin Liu

Journal of the American Chemical Society 2011 Volume 133(Issue 45) pp:18312-18317

Publication Date(Web):October 13, 2011

DOI:10.1021/ja206983z

The duplex formation mediated by Hg2+ in a properly designed ssDNA generates a stable hairpin structure, which greatly alters the translocation profile of the ssDNA through α-hemolysin nanopore. From the 2D-events contour plot, the presence of Hg2+ can be confirmed in as little as 30 min at ∼7 nM or higher. The sensor is highly selective to Hg2+, without interference from other metal ions. It can be fabricated from readily available materials, without the processes of synthesis, purification, probe-making, and so forth. This sensing strategy opens new possibilities for detecting many types of analytes which have specific interactions with DNA molecules.

Improved Syntheses of Phosphine Ligands by Direct Coupling of Diarylbromophosphine with Organometallic Reagents

Co-reporter:Dr. Lei Liu;Dr. Hai-Chen Wu;Dr. Jin-Quan Yu

Chemistry - A European Journal 2011 Volume 17( Issue 39) pp:10828-10831

Publication Date(Web):

DOI:10.1002/chem.201101467

Rapid and visual detection of heparin based on the disassembly of polyelectrolyte-induced pyrene excimers

Co-reporter:Yadong Qiao, Zhiyi Yao, Wenqi Ge, Li Zhang and Hai-Chen Wu

Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 12) pp:NaN2574-2574

Publication Date(Web):2017/03/07

DOI:10.1039/C7OB00115K

We have developed a ratiometric sensor based on polyelectrolyte-induced pyrene excimers for the rapid and visual detection of heparin in aqueous media. This sensor has a simple preparation method, fast response, low cost, and high sensitivity and selectivity. As a complementary strategy for the detection of heparin based on the formation of pyrene excimers, this approach could identify heparin specifically over chondroitin sulphate, which is the major interferent in most sensing systems for the detection of heparin. The detection limit of this approach can be as low as 0.14 μM using fluorescence measurements. To the best of our knowledge, this is among the lowest LOD for the detection of heparin reported in the literature. It enables the rapid and visual detection of heparin both in buffered solution and serum samples.

Visual detection of Cu(II) ions based on a simple pyrene derivative using click chemistry

Co-reporter:

Analytical Methods (2009-Present) 2014 - vol. 6(Issue 14) pp:

Publication Date(Web):

DOI:10.1039/C4AY00880D

A ratiometric fluorescent probe for the visual detection of Cu2+ in aqueous media has been developed based on a “click” reaction between a pyrene azide and a positively charged terminal alkyne. The probe has a quick response and excellent selectivity towards Cu2+, with a detection limit as low as 50 nM.

Revealing different aggregational states of a conjugated polymer in solution by a nanopore sensor

Co-reporter:Bingyuan Guo, Zhiyi Yao, Lei Liu and Hai-Chen Wu

Chemical Science (2010-Present) 2016 - vol. 7(Issue 8) pp:NaN5293-5293

Publication Date(Web):2016/05/05

DOI:10.1039/C6SC00296J

The functionalities of conjugated polymers are determined not only by local molecular structure, but also by the mesoscale conformational and morphological states of the polymer chains. Simulation studies have successfully established the connections between molecular structure and conformational states of certain conjugated polymers. However, experimental tools that can accurately discriminate between different conformational and morphological states of conjugated polymers are still scarce. Here, we use a nanopore sensor to analyze different aggregational states of a polythiophene derivative by threading the polymer through the pore under applied potentials. When the fluorescence of the polythiophene is quenched by pH tuning or the presence of Dy3+, the UV-vis and fluorescence spectra of the two solutions appear indistinguishable. However, threading the polymer molecules of these two solutions through an α-hemolysin nanopore affords entirely different translocation profiles owing to their different aggregational states. We further substantiate the results by conducting aggregational interconversion experiments and TEM measurements. This work has clearly indicated that nanopores are promising tools for the analysis of aggregational changes of conjugated polymers and may open new avenues for the investigation of aggregational states of biomacromolecules in the context of early disease diagnosis and prognosis.

Detection of 5-methylcytosine and 5-hydroxymethylcytosine in DNA via host–guest interactions inside α-hemolysin nanopores

Co-reporter:Tao Zeng, Lei Liu, Ting Li, Yuru Li, Juan Gao, Yuliang Zhao and Hai-Chen Wu

Chemical Science (2010-Present) 2015 - vol. 6(Issue 10) pp:NaN5634-5634

Publication Date(Web):2015/06/24

DOI:10.1039/C5SC01436K

Cytosine methylation and hydroxymethylation are both important epigenetic modifications of DNA in mammalian cells. Therefore, profiling DNA (hydroxy)methylation across the genome is vital for understanding their roles in gene regulation. Here, we report a nanopore-based approach for quick and reliable detection of 5-methylcytosine and 5-hydroxymethylcytosine in DNA at the single-molecule level. The single-stranded DNA containing 5-methylcytosine or 5-hydroxymethylcytosine was first selectively modified on the epigenetic base to attach a host–guest complex. Threading of the modified DNA molecules through α-hemolysin nanopores causes unbinding of the host–guest complex and generates highly characteristic current signatures. Statistical analysis of the signature events affords quantitative information about 5-methylcytosine and 5-hydroxymethylcytosine in DNA. Our results suggest that other DNA modifications could also be detected with the developed method. Furthermore, we anticipate our nanopore sensing strategy to be generally useful in biochemical analysis and to find applications in the early diagnosis of diseases.

Regioselective alkyl transfer from phosphonium ylides to functionalized polyfluoroarenes

Co-reporter:Wei Lu, Juan Gao, Jing-Kui Yang, Lei Liu, Yuliang Zhao and Hai-Chen Wu

Chemical Science (2010-Present) 2014 - vol. 5(Issue 5) pp:NaN1939-1939

Publication Date(Web):2014/01/28

DOI:10.1039/C4SC00221K

We report an unprecedented alkyl transfer from phosphonium ylides to polyfluoroarenes in a highly regioselective manner. This reaction allows the introduction of a variety of alkyl groups to the para position of functionalized polyfluoroarenes under mild conditions. The process is found to be compatible with several electrophilic functional groups such as carboxyl, ester, amide and cyano groups. NMR spectroscopy studies and deuterated labeling experiments reveal that the reaction proceeds via an SNAr mechanism and the proton that is transferred to the α-carbon of the alkyl group during the last C–P bond breaking step is from water.

A simple fluorescent probe based on a pyrene derivative for rapid detection of protamine and monitoring of trypsin activity

Co-reporter:Baiyang Tang, Yan Yang, Gefu Wang, Zhiyi Yao, Li Zhang and Hai-Chen Wu

Organic & Biomolecular Chemistry 2015 - vol. 13(Issue 32) pp:NaN8712-8712

Publication Date(Web):2015/07/09

DOI:10.1039/C5OB01034A

We report the synthesis of a simple pyrene derivative and its application in protamine detection and monitoring of trypsin activity. This assay can be conducted in aqueous solution and features rapid response, visual detection, high sensitivity and selectivity. The limit of detection of protamine was 0.5 μg mL−1. The IC50 value of a soybean trypsin inhibitor was estimated to be 0.51 U mL−1.

A prominent bathochromic shift effect of indole-containing diarylethene derivatives

Co-reporter:Hong-Bo Cheng, Yao-Dong Huang, Lina Zhao, Xu Li and Hai-Chen Wu

Organic & Biomolecular Chemistry 2015 - vol. 13(Issue 11) pp:NaN3475-3475

Publication Date(Web):2015/01/29

DOI:10.1039/C4OB02619E

The potential implication of photochromic materials with absorption and reactivity in the near-infrared region is far-reaching. In this work, three novel bisindole-containing diarylethene derivatives 1o–3o have been successfully synthesized and their photochromic behaviour exhibits a strong bathochromic shift effect compared with bisbenzothiophene diarylethene 4o. These new bisindole-diarylethene compounds 1o–3o are highly sensitive to photo-stimuli both in solution and in poly(methyl methacrylate) films. Besides, 1o–3o exhibit an excellent reversible fluorescence switching behavior modulated by optical stimuli.

Colorimetric and fluorescent detection of protamines with an anionic polythiophene derivative

Co-reporter:Zhiyi Yao, Wenjuan Ma, Yan Yang, Xueliang Chen, Li Zhang, Chen Lin and Hai-Chen Wu

Organic & Biomolecular Chemistry 2013 - vol. 11(Issue 38) pp:NaN6469-6469

Publication Date(Web):2013/08/01

DOI:10.1039/C3OB41407H

We have developed a novel approach for the colorimetric and fluorescent detection of protamines based on an anionic polythiophene derivative. This probe has high sensitivity and selectivity toward protamines with a linear detectable range from 0.1 to 30 μg mL−1, and can be used for protamine detection in serum samples.

Effects of different metal ions on the fluorescence of CdSe/ZnS quantum dots capped with various thiolate ligands

Co-reporter:Tao Zeng, Yanxi Hu, Na Wang, Chuanqin Xia, Shoujian Li, Yan Zu, Lei Liu, Zhiyi Yao, Yuliang Zhao and Hai-Chen Wu

Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 42) pp:NaN18715-18715

Publication Date(Web):2013/09/11

DOI:10.1039/C3CP52666F

In this report, we systematically studied the effects of different metal ions on the fluorescence of common thiolate ligand capped quantum dots. Generally, heavy metal ions exhibited much more significant fluorescence quenching. Also, the coordination capability and steric hindrance of the ligand jointly affect the quenching efficiency.

TOPICS

Abstract

Abstract