Co-reporter:Hongyu Chen, Aijin Fang, Youyu Zhang, Shouzhuo Yao
Talanta 2017 Volume 174(Volume 174) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.talanta.2017.06.006
•Monodispersed and water stable silver triangular nanoplates (STNPs) were synthesized.•STNPs as a high efficient fluorescence quenching reagent of UCNPs were used to constract a novel nanosensor.•The nanosensor was fabricated for the simultaneous detection of protamine and trypsin.•The proposed nanosensor has low detection limit, high sensitivity and selectivity.•The nanosensor was used to detect protamine and trypsin in real sample.Silver triangular nanoplates (STNPs) as a high efficient fluorescence quenching reagent of upconversion nanoparticles (UCNPs) was used to constract a novel label-free fluorescence nanosensor for ultrasensitive detection of protamine and trypsin based on fluorescence resonance energy transfer (FRET) between STNPs and UCNPs. In this assay, the negatively charged STNPs can bind with positively charged UCNPs through electrostatic interaction, and then quenched the fluorescence of UCNPs. When protamine was added to the mixture of UCNPs-STNPs, the STNPs interacted with protamine and then detached from the surface of UCNPs and aggregated, which result in the recovery of the fluorescence of UCNPs. Trypsin could catalyze the hydrolysis of protamine and effectively quench the fluorescence recovered by protamine. By measuring the changes of the fluorescence of UCNPs, the concentrations of protamine and trypsin were determined. Under the optimized conditions, the linear response range was obtained from 10 to 500 ng/mL, 5–80 ng/mL and with the low detection limit of 3.1 ng/mL and 1.8 ng/mL for protamine and trypsin, respectively. Meanwhile, the nanosensor shows good selectivity, sensitivity and can be successfully applied to detection of protamine and trypsin in serum samples.Download high-res image (224KB)Download full-size image
Co-reporter:Youming Shen, Xiangyang Zhang, Youyu Zhang, Chunxiang Zhang, Junling Jin, Haitao Li
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 Volume 185(Volume 185) pp:
Publication Date(Web):5 October 2017
DOI:10.1016/j.saa.2017.05.041
•A novel and simple fluorescent probe was designed and synthesized.•The probe has the advantages of high sensitivity, excellent selectivity and a large Stokes shift towards cysteine.•Based on the result of NMR and MS, a possible mode of the probe with cysteine was proposed.A new turn-on phthalimide fluorescent probe has designed and synthesized for sensing cysteine (Cys) based on excited state intramolecular proton transfer (ESIPT) process. It is consisted of a 3-hydroxyphthalimide derivative moiety as the fluorophore and an acrylic ester group as a recognition receptor. The acrylic ester acts as an ESIPT blocking agent. Upon addition of cystein, intermolecular nucleophilic attack of cysteine on acrylic ester releases the fluorescent 3-hydroxyphthalimide derivative, thereby enabling the ESIPT process and leading to enhancement of fluorescence. The probe displays high sensitivity, excellent selectivity and with large Stokes shift toward cysteine. The linear interval range of the fluorescence titration ranged from 0 to 1.0 × 10− 5 M and detection limit is low (6 × 10− 8 M). In addition, the probe could be used for bio-imaging in living cells.Download high-res image (51KB)Download full-size image
Co-reporter:Haiyan Wang, Qiujun Lu, Yalan Liu, Huan Li, Youyu Zhang, Shouzhuo Yao
Sensors and Actuators B: Chemical 2017 Volume 250(Volume 250) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.snb.2017.04.117
•A dual-signal readout sensor for highly sensitive detection of iodide ions was developed.•N-doped C-dots with high FLQY of 29.9% were prepared by a facile one-pot hydrothermal approach.•The proposed sensor had dual-signal response, low environmental interference, low detection limit and high selectivity.•The sensor was successfully used to detect iodide ions in urine.In this work, a novel colorimetric and ratiometric fluorescence detection method for iodide ions (I−) was developed. In the presence of I−, the color of N-doped C-dots/H2O2/OPD system aqueous solution varied from colorless to yellow due to 2,3-diaminophenazine (OPDox) produced from I−-catalyzed H2O2-o-phenylenediamine (OPD) reaction. At the same time, the OPDox had an excellent fluorescence (FL) property. Under the excitation wavelength at 390 nm, a novel FL emission ascribed to OPDox was clearly observed at 565 nm. In addition, the FL at 565 nm gradually increased, while the FL of emission peak at 450 nm attributed to N-doped C-dots gradually decreased with the increasing concentration of I− due to the FL resonance energy transfer (FRET) between N-doped C-dots and OPDox. Therefore, a dual-signal optical sensor was developed for detection of I−. Under the optimized conditions, the linear response to I− was in the range of 0.09–50 μM and the limit of detection was 0.06 μM. Moreover, this proposed assay was successfully applied for the detection of I− in urine. These results indicate that the colorimetric and ratiometric fluorescence dual-readout assay method has great potential for applications in physiological and pathological diagnosis.Download high-res image (89KB)Download full-size image
Co-reporter:Qian Long;Yanqing Wen;Haitao Li;Shouzhuo Yao
Journal of Fluorescence 2017 Volume 27( Issue 1) pp:205-211
Publication Date(Web):2017 January
DOI:10.1007/s10895-016-1947-4
In this paper, we report a simple and sensitive fluorescent biosensor for the quantitative analysis of silver ions (Ag+) by using NaYF4:Yb3+, Tm3+ upconversion nanoparticles (UCNPs). Ag+ could oxidize o-phenylenediamine (OPD) to the oxidized OPD (oxOPD) directly. The fluorescence of UCNPs can be significantly quenched by oxOPD through inner filter effects (IFE). Under the optimized conditions, the Ag+ concentration is proportional to the changes of the fluorescence intensity of UCNPs. The proposed method shows high selectivity and Ag+ could be quantitatively detected in the range of 0 to 0.5 mM with a low detection limit of 33 nM for Ag+. The selectivity and sensitivity of the detection can also be satisfactory. More importantly, this method has potential in practical application to detect Ag+ in real samples without interference.
Co-reporter:Xiangyang Zhang, Youming Shen, Youyu Zhang, Guangyu Shen, Haiyan Xiang, Xiaofeng Long
Talanta 2017 Volume 164() pp:483-489
Publication Date(Web):1 March 2017
DOI:10.1016/j.talanta.2016.12.016
•A new polymer containing aldehyde and ferrocene groups can be easily obtained from linear poly (vinylbenzyl chloride).•Antibodies can be directly immobilized on the surface of designed film.•The fabrication of a label-free electrochemical immunosensor based on the new polymer film is convenient.•The proposed electrochemical immunosensor had a good specificity, stability and repeatability.In this work, a novel and convenient strategy for synthesis of a well-defined polymer containing both aldehyde and ferrocene functional groups by grafting 4-hydroxybenzaldehyde and ferrocenecarboxylhydrazide onto linear poly (vinylbenzyl chloride) was developed. The designed polymer film (polymer CAF) could be used as a new support matrix for fabrication of a label-free electrochemical immunosensor with high sensitivity, good stability and repeatability. With human IgG as an analyte model, the proposed electrochemical immunosensor showed a linear concentration range from 0.1 to 20 ng mL−1 with a detection limit of 0.07 ng mL−1 (S/N=3). Moreover, interfering proteins including HSA, IgM, and IgE were added into the analyte, the developed immnnosensor can detect human IgG with high specificity.
Co-reporter:Hongyu Chen, Aijin Fang, Li He, Youyu Zhang, Shouzhuo Yao
Talanta 2017 Volume 164() pp:580-587
Publication Date(Web):1 March 2017
DOI:10.1016/j.talanta.2016.10.008
•Upconversion nanosensor for sensitive fluorescence detection of H2O2 and glucose based on inner filter effect between upconversion nanoparticles (UCNPs) and SQA-iron(III).•The proposed nanosensor had low detection limit, high sensitivity and selectivity.•The nanosensor was used to detect glucose in real sample.Diabetes mellitus is an epidemic disease that it has became a worldwide public health problem. Thus, blood glucose monitoring has attracted extensive attention. Here, we report a nanosensor based on inner filter effect (IFE) between upconversion nanoparticles (UCNPs) and squaric acid (SQA)-iron(III) for the highly sensitive and selective detection of glucose levels in human serum. In this assay, GOx-catalyzed oxidization of glucose produces gluconic acid and hydrogen peroxide (H2O2). The latter can catalytically oxidize iron(II) to iron(III) which can rapidly (<1 min) coordinate with the SQA to produce (SQA)-iron(III). The absorption band of (SQA)-iron(III) largely covered the emission band of UCNPs, resulting the fluorescence emission of UCNPs was effectively quenched. Therefore, the glucose can be monitored based on the formation of SQA-iron(III). Under the optimal condition, the fluorescence quenching efficiency shows a good linear response to glucose concentration in the ranges of 7–340 μmol/L with a detection limit of 2.3 μmol/L. The developed method has been further applied to monitor glucose levels in human serum with satisfactory results. Compared with other fluorescence methods, current method displayed high sensitivity and signal-to-noise ratio. Meanwhile, this nanosystem is also generalizable and can be easily expanded to the detection of various H2O2-involved analytes.
Co-reporter:Lijun Zhu, Xue Peng, Haitao Li, Youyu Zhang, Shouzhuo Yao
Sensors and Actuators B: Chemical 2017 Volume 238() pp:196-203
Publication Date(Web):January 2017
DOI:10.1016/j.snb.2016.07.029
•A novel fluorescent nanosensor was developed for dual detection and quantification of chromium(VI) and hydrogen sulfide based on silicon nanoparticles via inner filter effect.•The proposed nanosensor had several advantages, such as low cost, ease of operation, low detection limit, high sensitivity and selectivity.•The nanosensor was successfully applied in the determination of chromium(VI) and hydrogen sulfide in real sample.A highly sensitive and selective fluorescence sensor for detection of chromium(VI) and hydrogen sulfide was developed by using silicon nanoparticles (SiNPs) as probe. The fluorescence of SiNPs was effectively quenched by Cr(VI) via the inner filter effect. Upon addition of hydrogen sulfide, the fluorescence of SiNPs was recovered due to the oxidation-reduction between Cr(VI) and H2S. Under optimal conditions, the wide linear response ranges were obtained over the range of 0.1–200 μM and 0.1–200 μM with the low detection limits of 28 nM and 22 nM for Cr(VI) and H2S, respectively. The sensing platform was successfully applied to determination of Cr(VI) and H2S in real samples.
Co-reporter:Qiujun Lu, Haiyan Wang, Yalan Liu, Yuxin Hou, Haitao Li, Youyu Zhang
Biosensors and Bioelectronics 2017 Volume 89(Part 1) pp:411-416
Publication Date(Web):15 March 2017
DOI:10.1016/j.bios.2016.05.064
•g-C3N4-dots were synthesized by electrochemical “tailoring” process from bulk graphitic carbon nitride for the first time. .•The novel g-C3N4-dots show the reducibility for the reduction of Ag+ to AgNPs.•An optical sensor is developed for the detection of biothiols based on the measuring the absorption peak change of the AgNPs.•The present study has opened a way for synthesis of g-C3N4-dots and expand the potential application of g-C3N4.The graphitic carbon nitride nanodots (g-C3N4-dots) were synthesized by a simple electrochemical “tailoring” process from bulk graphitic carbon nitride (g-C3N4) under alkaline solution for the first time. Compared with the bulk g-C3N4, the novel g-C3N4-dots not only exhibit enhanced fluorescence and excellent dispersion stability in water but also show the reducibility for the reduction of Ag+ to AgNPs at 60 °C. The biothiols can bound with Ag+ through formation of biothiol-Ag+ complex to consume the Ag+ and act as capping agent to prevent the growth of AgNPs, which cause the decrease of the absorption peak of the AgNPs. Therefore, an optical sensor was developed for the detection of biothiols based on the change of the plasmon resonance absorption peak of the AgNPs. The proposed method exhibits excellent sensitivity and selectivity to biothiols with low detection limit for cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) with 11.5, 16.1, and 15.5 nM, respectively. This method also has been successfully applied for the detection of biothiols in human serum with satisfactory results.
Co-reporter:Aijin Fang, Hongyu Chen, Haitao Li, Meiling Liu, Youyu Zhang, Shouzhuo Yao
Biosensors and Bioelectronics 2017 Volume 87() pp:545-551
Publication Date(Web):15 January 2017
DOI:10.1016/j.bios.2016.08.111
•A dual-functional platform for AChE activity and Cd2+ was designed.•The dual-functional platform was based on glutathione regulation of AuNPs-UCNPs.•The AChE activity and Cd2+ detection limits reached 0.015 mU/mL and 0.2 μM, respectively.•The method has been applied to the analysis of AChE in serum and Cd2+ in water samples.•It demonstrates a general strategy for design of small molecules regulated platform.A dual-functional platform for the sensing of acetylcholinesterase (AChE) activity and cadmium ions (Cd2+) was developed based on the fluorescence resonance energy transfer (FRET) between NaYF4:Yb,Er upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs) via glutathione regulation. The detection mechanism is based on the fact that AuNPs can quench the fluorescence of UCNPs. AChE catalyzes the hydrolysis of acetylthiocholine (ATC) into thiocholine which reacts with AuNPs by S-Au conjunction and results the aggregation of AuNPs and change in fluorescence of UCNPs. Therefore, the AChE activity can be detected through the changes of the color of solution and fluorescence recovery of UCNPs. However, the presence of glutathione (GSH) can protect AuNPs from aggregation and enlarge the inter-particle distance between AuNPs and UCNPs. When Cd2+ is added into the stable mixture of AuNPs, GSH and AChE/ATC, Cd2+ could interact with GSH to form a spherical shaped (GSH)4Cd complex, which decreases the free GSH on the surface of AuNPs to weaken the stability of AuNPs and lead to the easily aggregation of them in the system. The aggregated-AuNPs are released from the surface of UCNPs, which results in the fluorescence of UCNPs gradually recovered. Under the optimized conditions, the detection limits of AChE activity and Cd2+ are estimated to be 0.015 mU/mL and 0.2 µM, respectively. The small molecules regulated dual-functional platform based on UCNPs/AuNPs is a simple, label-free method and can be applied for the turn-on fluorescence detection of AChE activity in human serum and Cd2+ in real water samples. The present work demonstrates a general strategy for the design of small molecules regulated multifunctional platform and will be expanded for different areas in the future.
Co-reporter:Yalan Liu;Qiujun Lu;Xiaojun Hu;Haiyan Wang;Haitao Li
Journal of Fluorescence 2017 Volume 27( Issue 5) pp:1847-1853
Publication Date(Web):20 June 2017
DOI:10.1007/s10895-017-2122-2
Clenbuterol (CLB), a member of β-agonist family, has now been a serious threat to human health due to its illegal usage in the animal feed. In this paper, we designed a fluorescence resonance energy transfer (FRET) system consisting of carbon dots (C-dots) and gold nanoparticles (AuNPs) for recovered fluorescence detecting of CLB. In the presence of CLB, CLB molecules can interact with AuNPs via Au-N bonds, preventing the interaction of C-dots and AuNPs, which induced the recover of the fluorescent intensity. Under the optimal conditions, the limit of detection for CLB was 3 nM, with a wide concentration linear range of 8–200 nM (S/N = 3). Meanwhile, the proposed method was successfully applied to detect CLB in pork samples, illustrating it could be used as a reliable, rapid, and cost-effective method for the determination of CLB residues in pork samples.
Co-reporter:Youming Shen, Xiangyang Zhang, Youyu Zhang, Chunxiang Zhang, Junling Jin, Haitao Li and Shouzhuo Yao
Analytical Methods 2016 vol. 8(Issue 11) pp:2420-2426
Publication Date(Web):16 Feb 2016
DOI:10.1039/C5AY02884A
A novel and simple turn-on fluorescent probe bearing 7-nitrobenz-2-oxa-1,3-diazole and benzaldehyde fragments for the rapid optical sensing of cysteine and homocysteine has been designed and synthesized. The probe has almost no background fluorescence (Φf < 0.0001) in aqueous solutions; however, it displayed fluorescence turn-on response to cysteine and homocysteine and exhibited a large bathochromic-shift (106 nm) in absorption wavelength accompanied by color changes which could be distinguished by the naked-eye. There is a good linearity with cysteine in the range of 0 to 1.37 × 10−4 M, with a detection limit of 98 nM (S/N = 3). In addition, the optical responses of the probe were investigated by density function theory (DFT) calculations. Moreover, it can be used to detect biological thiols in living cells.
Co-reporter:Yuxin Hou, Qiujun Lu, Haiyan Wang, Haitao Li, Youyu Zhang, Shiying Zhang
Materials Letters 2016 Volume 173() pp:13-17
Publication Date(Web):15 June 2016
DOI:10.1016/j.matlet.2016.03.003
•The carbon dots/TiO2 (CDs/TiO2) nanocomposites are synthesized by One-pot electrochemical method.•The CDs/TiO2 exhibit good visible photocatalytic activity to degrade methylene blue.•Compared with expensive Xenon lamp source, we only need a 50 W halogen tungsten lamp.We propose a novel electrochemical method to one-pot synthesize carbon dots/titanium dioxide (CDs/TiO2) nanocomposites for the first time. The as-prepared CDs/TiO2 nanocomposites exhibit excellent visible photocatalytic activity for degradation of methylene blue (MB) under a 50 W halogen tungsten lamp irradiation.
Co-reporter:Aijin Fang, Qian Long, Qiongqiong Wu, Haitao Li, Youyu Zhang, Shouzhuo Yao
Talanta 2016 Volume 148() pp:129-134
Publication Date(Web):1 February 2016
DOI:10.1016/j.talanta.2015.10.048
•Upconversion nanosensor was developed for detection of Sudan I–IV based on inner filter effect.•The proposed nanosensor had low detection limit, high sensitivity and selectivity.•The nanosensor can be used to detect Sudan dyes in real sample.Sudan dyes are banned as food additives due to the carcinogenicity of their metabolites in the human body. Therefore, it is of great significance for sensitive detection of Sudan dyes. This paper reports a novel nanosensor for Sudan dyes detection based on fluorescence (FL) quenching of hexadecyl trimethyl ammonium bromide (CTAB) stabilized upconversion nanoparticles (UCNPs) through the inner filter effect (IFE). In the presence of Sudan I–IV, the fluorescence emission of UCNPs was effectively quenched due to the absorption bands of Sudan I–IV largely covered the emission bands of UCNPs. Under the optimized conditions, the FL was quenched with Sudan concentration over the range of 0.05–40, 0.01–20, 0.01–40 and 0.05–40 μg/mL for Sudan I–IV, respectively. The corresponding limit of detection is 15.1, 2.83, 3.52 and 16.7 ng/mL (at 3σ/slope) respectively. Meanwhile, the nanosensor shows good selectivity, sensitivity and can be successfully applied to detection of Sudan in chili powder samples.
Co-reporter:Qian Long, Aijin Fang, Yanqing Wen, Haitao Li, Youyu Zhang, Shouzhuo Yao
Biosensors and Bioelectronics 2016 Volume 86() pp:109-114
Publication Date(Web):15 December 2016
DOI:10.1016/j.bios.2016.06.017
•A novel fluorescent nanosensor for detection of uric acid (UA) is developed.•This sensor is based on enzymatic catalysis-induced upconversion inner filter effect.•The new biosensor was successfully applied to human serum samples.In this work, a novel and simple fluorescence method for detection of uric acid (UA) based on NaYF4:Yb3+, Tm3+ upconversion nanoparticles (UCNPs) is developed. The proposed method is based on the fact that uricase can oxidize uric acid to allantoin and hydrogen peroxide, which, on its turn, can oxidize o-phenylenediamine (OPD) to the oxidized OPD (oxOPD). The fluorescence of UCNPs can be significantly quenched by oxOPD through inner filter effects (IFE). Under the optimized conditions, the UA concentration was proportional to the changes in fluorescence intensity of UCNPs. A linear response was obtained over the concentration range from 20 to 850 μΜ with the low detection limit of 6.7 μΜ for uric acid. More importantly, this method has the potential to detect uric acid in human serum samples, suggesting the nanosensor can be used in a complex biological sample matrix.
Co-reporter:Aijin Fang, Qiongqiong Wu, Qiujun Lu, Hongyu Chen, Haitao Li, Meiling Liu, Youyu Zhang, Shouzhuo Yao
Biosensors and Bioelectronics 2016 Volume 86() pp:664-670
Publication Date(Web):15 December 2016
DOI:10.1016/j.bios.2016.07.055
•A upconversion ratiometric fluorescence and colorimetric method for UA was designed.•The platform to UA was based on upconversion UCNPs and ZnFe2O4 magnetic beads.•The FL and UV detection limits reached 2.86 μM and 5.79 μM, respectively.•The proposed method has been successfully applied to the analysis of UA in serum.A new upconversion colorimetric and ratiometric fluorescence detection method for uric acid (UA) has been designed. Yb3+, Er3+ and Tm3+ co-doped NaYF4 nanoparticles (UCNPs) was synthesized. The co-doped NaYF4 nanoparticles, emit upconversion fluorescence with four typical emission peaks centered at 490 nm, 557 nm, 670 nm and 705 nm under the 980 nm near-infrared (NIR) irradiation. The ZnFe2O4 magnetic nanoparticles (MNPs) possessing excellent peroxidase-like activity was prepared and used to catalyze oxidation the coupling of N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt (TOPS) and 4-amino-antipyrine (4-AAP) in the presence of H2O2 to form purple products (compound 1) which has a characteristic absorption peak located at 550 nm. The upconversion fluorescence at 557 nm was quenched by the compound 1 while the upconversion emission at 705 nm was essentially unchanged, the fluorescence ratio ((I557/I705)0/(I557/I705)) is positively proportional to UA concentration in existence of uricase. More importantly, colorimetric signal can be easily observed and applied to directly distinguish the concentration of UA by the naked eye. Under the optimized conditions, the linear range of colorimetric and ratiometric fluorescence sensing towards UA was 0.01–1 mM, the detection limits were as low as 5.79 μM and 2.86 μM (S/N=3), respectively. The proposed method has been successfully applied to the analysis of UA in human serum. These results indicate that the colorimetric and ratiometric fluorescence dual-readout assay method has great potential for applications in physiological and pathological diagnosis.
Co-reporter:Haiyan Wang, Qiujun Lu, Yuxin Hou, Yalan Liu, Youyu Zhang
Talanta 2016 Volume 155() pp:62-69
Publication Date(Web):1 August 2016
DOI:10.1016/j.talanta.2016.04.020
•The S, N co-doped C-dots with high FLQY of 73.1% were prepared by hydrothermal method.•Nanosensor for detection of uric acid based on S, N co-doped C-dots was developed.•The proposed nanosensor had low detection limit, high sensitivity and selectivity.•The nanosensor was used to detect uric acid in human serum samples.Sulfur, nitrogen co-doped carbon dots (S, N co-doped C-dots) as highly selective fluorescent probe for uric acid (UA) detection were designed. The S, N co-doped C-dots with high quantum yield of 73.1% were prepared by hydrothermal method. It was found that the fluorescence of S, N co-doped C-dots was quenched apparently by hydroxyl radicals from Fenton reaction between H2O2 and Fe2+. The production of H2O2 originated from the oxidization of UA by uricase. Therefore, an optical biosensor was developed for the detection of UA based on Fenton reaction and enzymatic reaction. Under the optimized conditions, two linear relationships between the ratio of fluorescence quenching of the C-dots and UA concentration were found in the range of 0.08–10 µM and 10–50 µM, respectively. The detection limit was down to 0.07 µM. Moreover, the proposed biosensor was successfully applied to the detection of uric acid in human serum samples.
Co-reporter:Na Huang, Si Zhang, Liuqing Yang, Meiling Liu, Haitao Li, Youyu Zhang, and Shouzhuo Yao
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 32) pp:17935
Publication Date(Web):July 29, 2015
DOI:10.1021/acsami.5b04597
In this paper, a new strategy for the construction of multifunctional electrochemical detection platforms based on the Michael addition/Schiff base reaction of polydopamine modified reduced graphene oxide was first proposed. Inspired by the mussel adhesion proteins, 3,4-dihydroxyphenylalanine (DA) was selected as a reducing agent to simultaneously reduce graphene oxide and self-polymerize to obtain the polydopamine-reduced graphene oxide (PDA-rGO). The PDA-rGO was then functionalized with thiols and amines by the reaction of thiol/amino groups with quinine groups of PDA-rGO via the Michael addition/Schiff base reaction. Several typical compounds containing thiol and/or amino groups such as 1-[(4-amino)phenylethynyl] ferrocene (Fc-NH2), cysteine (cys), and glucose oxidase (GOx) were selected as the model molecules to anchor on the surface of PDA-rGO using the strategy for construction of multifunctional electrochemical platforms. The experiments revealed that the composite grafted with ferrocene derivative shows excellent catalysis activity toward many electroactive molecules and could be used for individual or simultaneous detection of dopamine hydrochloride (DA) and uric acid (UA), or hydroquinone (HQ) and catechol (CC), while, after grafting of cysteine on PDA-rGO, simultaneous discrimination detection of Pb2+ and Cd2+ was realized on the composite modified electrode. In addition, direct electron transfer of GOx can be observed when GOx-PDA-rGO was immobilized on glassy carbon electrode (GCE). When glucose was added into the system, the modified electrode showed excellent electric current response toward glucose. These results inferred that the proposed multifunctional electrochemical platforms could be simply, conveniently, and effectively regulated through changing the anchored recognition or reaction groups. This study would provide a versatile method to design more detection or biosensing platforms through a chemical reaction strategy in the future.Keywords: catalysis; detection; Michael addition reaction/Schiff base reaction; multifunctional electrochemical platforms; polydopamine-reduced graphene oxide (PDA-rGO)
Co-reporter:Qiujun Lu, Jianhui Deng, Yuxin Hou, Haiyan Wang, Haitao Li and Youyu Zhang
Chemical Communications 2015 vol. 51(Issue 61) pp:12251-12253
Publication Date(Web):19 Jun 2015
DOI:10.1039/C5CC04231C
Ultrathin graphitic carbon nitride nanosheets (g-C3N4) with a thickness of about 2 nm were synthesized by a one-step electrochemical method for the first time. The possible mechanism of the electrochemical synthesis was discussed. This as-synthesized g-C3N4 showed intrinsic peroxidase-like activity and was successfully applied for the detection of uric acid.
Co-reporter:Qiujun Lu, Jianhui Deng, Yuxin Hou, Haiyan Wang, Haitao Li, Youyu Zhang and Shouzhuo Yao
Chemical Communications 2015 vol. 51(Issue 33) pp:7164-7167
Publication Date(Web):17 Mar 2015
DOI:10.1039/C5CC01771H
Hydroxyl-rich C-dots were used as both the reducing and stabilizing agent in the preparation of noble metal nanoparticles (AuNPs, AgNPs and Au@AgNPs) for the detection of glucose.
Co-reporter:Jianhui Deng, Qiujun Lu, Yuxin Hou, Meiling Liu, Haitao Li, Youyu Zhang, and Shouzhuo Yao
Analytical Chemistry 2015 Volume 87(Issue 4) pp:2195
Publication Date(Web):January 16, 2015
DOI:10.1021/ac503595y
Biological thiols play a critical role in biological processes and are involved in a variety of diseases. The discrimination detection of biological thiols is of increasing importance in clinical diagnosis. In this paper, a novel nanosensor was developed to discriminate cysteine (Cys) from homocysteine (Hcy) and glutathione (GSH) with multiple signals: colorimetric, photoluminescence (PL), and up-conversional photoluminescence (UCP). The nanosensor (NC-dots/AuNPs) was constructed by nitrogen-doped carbon dots (NC-dots) and gold nanoparticles (AuNPs) through assembling NC-dots “shell” on AuNPs and showed the obvious different response to Cys, Hcy, and GSH with colorimetric, PL, and UCP signals. The discrimination effect for Cys is originated from conformations and interaction difference of the thiols groups in Cys and Hcy and/or GSH with AuNPs. Among them, only Cys can quickly penetrate into the NC-dots “shell” of the composite and induce the dispersing of the aggregated NC-dots/AuNPs, which lead to the color change from purple to red and the recovery of PL and UCP of NC-dots. This assay was successfully applied for the detection of Cys in human serum with the detection limit of 4 nM.
Co-reporter:Yuxin Hou, Qiujun Lu, Jianhui Deng, Haitao Li, Youyu Zhang
Analytica Chimica Acta 2015 Volume 866() pp:69-74
Publication Date(Web):25 March 2015
DOI:10.1016/j.aca.2015.01.039
•One-pot electrochemical synthesis of functionalized carbon dots (C-Dots).•The C-Dots can serve as a fluorescent probe for sensitive detection of Hg2+.•The detection limit for Hg2+ is 3.3 nM.•The sensor is successfully applied to Hg2+ determination in real samples.We propose a simple, economical, and one-pot method to synthesize water-soluble functionalized fluorescent carbon dots (C-Dots) through electrochemical carbonization of sodium citrate and urea. The as-prepared C-Dots have good photostability and exhibit a high quantum yield of 11.9%. The sizes of the C-Dots are mainly distributed in the range of 1.0–3.5 nm with an average size of 2.4 nm. It has been further used as a novel label-free sensing probe for selective detection of Hg2+ ions with detection limit as low as 3.3 nM. The detection linear range is 0.01–10 μM. The as-prepared C-Dots are also successfully applied for the determination of Hg2+ in real water samples.
Co-reporter:Qiujun Lu, Yalan Liu, Yuxin Hou, Haiyan Wang, Youyu Zhang and Shouzhuo Yao
Analyst 2015 vol. 140(Issue 22) pp:7645-7649
Publication Date(Web):18 Sep 2015
DOI:10.1039/C5AN01605C
We have found that hydroxyl-rich carbon dots (C-dots) have the ability to reduce Au3+ to form gold nanoparticles (AuNPs). Thiocyanate (SCN−) can be absorbed on the surface of the AuNPs due to its high affinity toward the AuNPs, which inhibits the growth of the AuNPs. Meanwhile, SCN− has the ability to etch the as-synthesized big AuNPs to small AuNPs, which can also cause the absorption peak of the AuNPs to decrease. Therefore, an optical sensor is developed for the detection of SCN− based on measuring the plasmon resonance absorption peak change of the AuNPs. Under optimal conditions, this method yields excellent sensitivity (the limit of detection is 0.16 μM) and selectivity toward SCN−. This method can detect SCN− in raw milk with satisfactory results. This work gives new insight into monitoring the quality of milk.
Co-reporter:Biao Gu, Liyan Huang, Naxiu Mi, Peng Yin, Youyu Zhang, Xinman Tu, Xubiao Luo, Shenlian Luo and Shouzhuo Yao
Analyst 2015 vol. 140(Issue 8) pp:2778-2784
Publication Date(Web):16 Feb 2015
DOI:10.1039/C5AN00273G
A novel ratiometric fluorescent Hg2+ detecting system was rationally developed based on the typical excited state intramolecular proton transfer (ESIPT) characteristic of the latent fluorophore, 2-(1-(p-tolyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenol (Pol) and the Hg2+-mediated cleavage of the vinyl group. The probe responds selectively to Hg2+ over various other metal ions with a larger bathochromic shift (∼100 nm). The sensing mechanism was investigated in detail by fluorescence spectroscopy, NMR spectra and mass spectrometry. Taking advantage of the enhancement effect of dichloromethane on the ESIPT efficiency, a facile dichloromethane extraction was introduced in the process of detection of Hg2+, which affords a high sensitivity for the probe with a detection limit of 7.8 × 10−9 M for Hg2+. By using the new strategy, the novel probe can be used for the detection of Hg2+ in practical water samples with good recovery. Moreover, the probe was successfully applied to the fluorescence image of Hg2+ in living cells. These results indicated that the probe and the proposed method have promising applications for Hg2+ sensing in biological and environmental sciences.
Co-reporter:Qiujun Lu, Jiangna Zhao, Shanyan Xue, Peng Yin, Youyu Zhang and Shouzhuo Yao
Analyst 2015 vol. 140(Issue 4) pp:1155-1160
Publication Date(Web):05 Dec 2014
DOI:10.1039/C4AN01847H
In this study, we synthesized a new fluorescence probe which was used to detect melamine by coupling with gold nanoparticles (AuNPs). The new fluorescence probe has good optical stability and high fluorescence intensity, which can greatly improve the detection sensitivity. Compared to the traditional fluorophore, it is less dependent on the pH value. It has a very strong fluorescence emission peak at 550 nm, which has larger overlap with the absorption peak of AuNPs. When the probe incubates with the AuNPs, the fluorescence of the probe can be effectively quenched by AuNPs. Adding melamine into a probe–AuNPs mixture caused aggregation of AuNPs and released the adsorbed probe; the fluorescence intensity of the probe was recovered. By measuring the changes of the fluorescence intensity of the probe, the detection of melamine can be realized. Under optimized conditions, the linear response to melamine is in the range of 1.0 × 10−8–4.0 × 10−6 mol L−1 and lowers the detection limit down to 3.0 nmol L−1 with the sensor. This method can detect melamine in milk and milk-based productions.
Co-reporter:Youming Shen, Xiangyang Zhang, Xi Huang, Siyu Wen, Mingdi Liu, Yan Deng, Youyu Zhang, Chunxiang Zhang, Junling Jin, Haitao Li and Shouzhuo Yao
RSC Advances 2015 vol. 5(Issue 97) pp:79519-79524
Publication Date(Web):14 Sep 2015
DOI:10.1039/C5RA15373E
A simple and reversible fluorescent probe bearing 7-nitrobenz-2-oxa-1,3-diazole and a selenomorpholine fragment was designed and synthesized. The probe showed highly selective, sensitive and fast (<10 s) recognition to hypochlorite in aqueous solutions. The relative results demonstrated that the linear response range of the probe was between 5.0 × 10−8 M and 1.2 × 10−4 M, with a low detection limit of 3.3 nM (S/N = 3). The probe was capable of monitoring hypochlorite reversibly in the presence of glutathione. In addition, the biological applications in living cells have been described.
Co-reporter:Youming Shen, Xiangyang Zhang, Xi Huang, Youyu Zhang, Chunxiang Zhang, Junling Jin, Xuewen Liu, Haitao Li and Shouzhuo Yao
RSC Advances 2015 vol. 5(Issue 78) pp:63226-63232
Publication Date(Web):16 Jul 2015
DOI:10.1039/C5RA11116A
A new naphthalimide derivative containing hexanoic acid and boronate groups was designed and synthesized. The compound displays off/on ratio singles, highly selective and sensitive towards glucose based on a naphthalimide derivative reacting with enzyme generated H2O2 in 100% water. The fluorescence intensity is proportional to the concentration of glucose over a range of 0–120 μM (R2 = 0.9912), with a limit of detection of 0.3 μM (S/N = 3). Moreover, the fluorescent sensor has been used for determination of glucose in serum with satisfactory results, which further demonstrates its value in practical applications.
Co-reporter:Jianhui Deng, Qiujun Lu, Haitao Li, Youyu Zhang and Shouzuo Yao
RSC Advances 2015 vol. 5(Issue 38) pp:29704-29707
Publication Date(Web):23 Mar 2015
DOI:10.1039/C4RA16805D
A novel electrochemical synthesis for graphene quantum dots (GQD) with a large scale from graphite oxide (GO) in pure water has been proposed. GQDs with different sizes and different emission colors were obtained with a yield of 65.5% in weight, which exhibited intrinsic peroxidase-like activity in glucose detection.
Co-reporter:Qian Long, Jiangna Zhao, Bangda Yin, Haitao Li, Youyu Zhang, Shouzhuo Yao
Analytical Biochemistry 2015 Volume 477() pp:28-34
Publication Date(Web):15 May 2015
DOI:10.1016/j.ab.2015.02.017
Abstract
A novel label-free fluorescence nanosensor was developed for ultrasensitive detection of protamine and heparin based on fluorescence resonance energy transfer (FRET) between NaYF4:Yb,Er upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs). The FRET system was formed by the electrostatic adsorption of AuNPs on UCNPs, and the fluorescence of UCNPs was significantly quenched. When protamine was added to the mixture of UCNPs–AuNPs, the AuNPs interacted with protamine and then desorbed from the surface of UCNPs and aggregated, resulting in the recovery of the fluorescence of UCNPs. On the addition of both protamine and heparin, the FRET system formed owing to the stronger interaction between heparin and protamine than that with AuNPs, leading to a marked fluorescence quenching of UCNPs. The concentrations of protamine and heparin were proportional to the changes of the fluorescence of UCNPs. The linear response range was obtained over the concentration ranges of 0.02 to 1.2 μg/ml and 0.002 to 2.0 μg/ml with low detection limits of 6.7 and 0.7 ng/ml for protamine and heparin, respectively. Simultaneous measurement of protamine and heparin in human serum can be achieved, suggesting that the nanosensor can be used in a complex biological sample matrix.
Co-reporter:Youming Shen, Chang Liu, Youyu Zhang, Xiangyang Zhang, Chunxiang Zhang, Junling Jin, Xuewen Liu, Haitao Li and Shouzhuo Yao
Analytical Methods 2015 vol. 7(Issue 15) pp:6419-6425
Publication Date(Web):02 Jul 2015
DOI:10.1039/C5AY00732A
A simple and new fluorescent and colorimetric probe bearing 7-nitrobenz-2-oxa-1,3-diazole and 4-maleimidophenol fragments for biothiols was designed and synthesized. The probe itself showed almost no background fluorescence (ΦF < 1 × 10−4) and displayed fluorescence turn-on response with selectivity for thiols over other relevant biological species in aqueous solutions. In addition, the probe exhibited 110 nm red-shifted absorption spectra accompanied by color changes which could be obviously distinguished by the naked eye. Furthermore, the probe showed high sensitivity towards thiols with a detection limit of 1.2 × 10−7 M (S/N = 3) and the mechanism regarding the optical responses of the probe to thiols was explained by density function theory (DFT) calculations. Finally, the probe has been successfully used to image thiols in HeLa cells.
Co-reporter:Youming Shen, Youyu Zhang, Meiling Liu, Xiaoyin Liu, Huan Guo, Xiangyang Zhang, Chunxiang Zhang, Haitao Li, Shouzhuo Yao
Talanta 2015 Volume 141() pp:288-292
Publication Date(Web):15 August 2015
DOI:10.1016/j.talanta.2015.04.004
•The thiol aromatic aldehyde (TAA) can be synthesized in one-step with (±)-Lipoic acid and 4-hydroxybenzaldehyde.•The thiol aromatic aldehyde (TAA) is used to not only modify electrode but also immobilize antibody directly.•No additional chemical cross-linker is required for the electrochemical immunosensor.•The proposed electrochemical immunosensor had a good selectivity, reproducibility and sensitivity.In this work, a novel sulfur-containing compound with aldehyde groups was synthesized, which was used to immobilize antibodies through the covalent bonding of the aldehyde groups with amino groups, in which no additional chemical cross-linker is required. Human IgG was used as a model analyte to fabricate the electrochemical immunosensor. Using the proposed immunosensor, IgG was detected within the range from 0.01 to 25 ng mL−1 with a detection limit of 0.003 ng mL−1 obtained by 3 S/N. The simple electrochemical immunosensor had a good specificity, stability and reproducibility.
Co-reporter:Qiongqiong Wu, Qian Long, Haitao Li, Youyu Zhang, Shouzhuo Yao
Talanta 2015 Volume 136() pp:47-53
Publication Date(Web):1 May 2015
DOI:10.1016/j.talanta.2015.01.005
•A nanosensor was developed based on upconversion nanoparticles and gold nanoparticles.•The sensor linearly responses to melamine within 32.0-500 nM with a detection limit of 18.0 nM.•The fluorescent sensor was used to detect melamine in raw milk sample.Here we report a nanosensor based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs) for melamine detection. The positively charged UCNPs as donor and the negatively charged AuNPs as acceptor bound together through electrostatic interaction, which caused the fluorescence quenching of UCNPs. Upon addition of melamine, AuNPs were released from the surface of UCNPs and aggregation due to the N-Au interaction between melamine and AuNPs, which results in the fluorescence of UCNPs gradually recovered. Under the optimal conditions including media pH (7.0), the concentration of AuNPs (1.23 nM) and incubation time (12 min), the fluorescence enhanced efficiency shows a linear response to the melamine concentration ranging from 32.0 to 500 nM with a detection limit of 18.0 nM. Compared with other fluorescence methods, the fluorimetric nanosensor shows high sensitivity of 0.968, ease of operation and can be used for the determination of melamine in raw milk samples.
Co-reporter:Qian Long, Haitao Li, Youyu Zhang, Shouzhuo Yao
Biosensors and Bioelectronics 2015 Volume 68() pp:168-174
Publication Date(Web):15 June 2015
DOI:10.1016/j.bios.2014.12.046
•A novel organophosphorus pesticides sensor was developed through fluorescence resonance energy transfer between upconversion nanoparticles (UCNPs) and gold nanoparticles.•The as-prepared UCNPs could eliminate the interference from background fluorescence and complex matrixes.•Detection limits of parathion-methyl, monocrotophos and dimethoate reached 0.67, 23, and 67 ng/L, respectively.•The performance of the biosensor has been validated using food sample.This paper reports a novel nanosensor for organophosphorus pesticides based on the fluorescence resonance energy transfer (FRET) between NaYF4:Yb,Er upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs). The detection mechanism is based on the facts that AuNPs quench the fluorescence of UCNPs and organophosphorus pesticides (OPs) inhibit the activity of acetylcholinesterase (AChE) which catalyzes the hydrolysis of acetylthiocholine (ATC) into thiocholine. Under the optimized conditions, the logarithm of the pesticides concentration was proportional to the inhibition efficiency. The detection limits of parathion-methyl, monocrotophos and dimethoate reached 0.67, 23, and 67 ng/L, respectively. Meanwhile, the biosensor shows good sensitivity, stability, and could be successfully applied to detection of OPs in real food samples, suggesting the biosensor has potentially extensive application clinic diagnoses assays.
Co-reporter:Xue Peng, Qian Long, Haitao Li, Youyu Zhang, Shouzhuo Yao
Sensors and Actuators B: Chemical 2015 213() pp: 131-138
Publication Date(Web):
DOI:10.1016/j.snb.2015.02.070
Co-reporter:Qiong Chen, Meiling Liu, Jiangna Zhao, Xue Peng, Xiaojiao Chen, Naxiu Mi, Bangda Yin, Haitao Li, Youyu Zhang and Shouzhuo Yao
Chemical Communications 2014 vol. 50(Issue 51) pp:6771-6774
Publication Date(Web):03 Apr 2014
DOI:10.1039/C4CC01703J
We demonstrate that photoluminescent Si-dots exhibit intrinsic peroxidase-like activity, and can catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2, and produce a color change. This strategy can be used to detect glucose with high sensitivity and selectivity.
Co-reporter:Xiaojiao Chen, Yangzhong Wang, Youyu Zhang, Zhuhai Chen, Yang Liu, Zhaolong Li, and Jinghong Li
Analytical Chemistry 2014 Volume 86(Issue 9) pp:4278
Publication Date(Web):March 31, 2014
DOI:10.1021/ac404070m
We demonstrate a multivalent recognition and highly selective aptamer signal amplification strategy for electrochemical cytosensing and dynamic cell surface N-glycan expression evaluation by the combination of concanavalin A (Con A), a mannose binding protein, as a model, conjugated poly(amidoamine) dendrimer on a chemically reduced graphene oxide (rGO–DEN) interface, and aptamer- and horseradish peroxidase-modified gold nanoparticles (HRP–aptamer–AuNPs) as nanoprobes. In this strategy, the rGO–DEN can not only enhance the electron transfer ability but also provide a multivalent recognition interface for the conjugation of Con A that avoids the weak carbohydrate–protein interaction and dramatically improves the cell capture efficiency and the sensitivity of the biosensor for cell surface glycan. The high-affinity aptamer- and HRP-modified gold nanoparticles provide an ultrasensitive electrochemical probe with excellent specificity. As proof-of-concept, the detection of CCRF-CEM cell (human acute lymphoblastic leukemia) and its surface N-glycan was developed. It has demonstrated that the as-designed biosensor can be used for highly sensitive and selective cell detection and dynamic evaluation of cell surface N-glycan expression. A detection limit as low as 10 cells mL–1 was obtained with excellent selectivity. Moreover, this strategy was also successfully applied for N-glycan expression inhibitor screening. These results imply that this biosensor has potential in clinical diagnostic and drug screening applications and endows a feasibility tool for insight into the N-glycan function in biological processes and related diseases.
Co-reporter:Meiling Liu, Linping Wang, Yue Meng, Qiong Chen, Haitao Li, Youyu Zhang, Shouzhuo Yao
Electrochimica Acta 2014 Volume 116() pp:504-511
Publication Date(Web):10 January 2014
DOI:10.1016/j.electacta.2013.11.060
In this paper, a new electron mediator modified graphene oxide (GO) was firstly prepared by covalently grafted (4-ferrocenylethyne) phenylamine (FEPA) onto the surface of GO. The successful attachment of FEPA onto GO sheets was demonstrated by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis spectroscopy, thermogravimetric analysis (TGA) and electrochemical experiments. The as prepared FEPA modified GO (FEPA-GO) proved to be a novel hybrid composite with highly enhanced conductivity and compatibility. Combined the FEPA-GO with chitosan (CS) to fabricate the modified glassy carbon electrode (GCE), a highly sensitive amperometric nitrite sensor was successfully constructed. The electrochemical oxidation current of nitrite on the CS/FEPA-GO/GCE was largely enhanced, which may result from the catalysis effect of the FEPA-GO. With this novel sensor, the oxidation peak currents were linearly dependent on the nitrite concentrations in the range of 0.3-3100 μmol L−1 with the detection limit of 0.1 μmol L−1. Modification of FEPA on GO held great promise to enhance the electrochemical performance of GO and will pay a new way for fabricating newly ferrocene functionalized graphene-based electrochemical biosensors.
Co-reporter:Bangda Yin, Wenli Zhou, Qian Long, Chengzhi Li, Youyu Zhang and Shouzhuo Yao
CrystEngComm 2014 vol. 16(Issue 36) pp:8348-8355
Publication Date(Web):29 May 2014
DOI:10.1039/C4CE00650J
High-quality hexagonal upconversion nanocrystals of β-NaYF4:Yb3+,Er3+ were prepared through a one-pot mild solvothermal synthesis. The crystal structure of NaYF4:Yb3+,Er3+ can rapidly transform from cubic (α-) to hexagonal (β-)phase in the presence of salts, such as sodium hydrogen phosphate (Na2HPO4). It was found that the size and structure of as-prepared NaYF4:Yb3+,Er3+ can be controlled by changing the molar ratio of phosphate to Ln3+ (Ln3+ represents the total amount of Y3+ and the doped rare earth elements such as Yb3+, Er3+). A possible formation mechanism was proposed on the basis of XRD analyses and TEM observations of the products under different reaction conditions. The upconversion fluorescence at 550 nm of β-NaYF4:Yb3+,Er3+ nanocrystals with hexagonal structure and narrow size distribution was enhanced up to 22.5-fold compared to the cubic nanocrystals (α-NaYF4:Yb3+,Er3+). This study is also expected to provide a new synthetic strategy for the exploration of other complexes with controllable structures and optical properties.
Co-reporter:Youming Shen, Youyu Zhang, Xiangyang Zhang, Chunxiang Zhang, Linli Zhang, Junling Jin, Haitao Li and Shouzhuo Yao
Analytical Methods 2014 vol. 6(Issue 13) pp:4797-4802
Publication Date(Web):29 Apr 2014
DOI:10.1039/C4AY00729H
A new and simple fluorescent probe bearing 7-nitrobenz-2-oxa-1,3-diazole and N,N-bis(thiophen-2-ylmethyl)ethane-1,2-diamine was developed as a fluorescent chemosensor with high selectivity and sensitivity toward Hg2+ over other cations tested. The signaling is due to the coordination of S and N atoms of N,N-bis(thiophen-2-ylmethyl)ethane-1,2-diamine to Hg2+. Upon addition of 30 equivalents of Hg2+, a 45-fold increase in fluorescence emission intensity was observed. Moreover, the probe is further successfully used to image Hg2+ in MCF-7 cells.
Co-reporter:Jiangna Zhao, Jianhui Deng, Yinhui Yi, Haitai Li, Youyu Zhang, Shouzhuo Yao
Talanta 2014 Volume 125() pp:372-377
Publication Date(Web):1 July 2014
DOI:10.1016/j.talanta.2014.03.031
•A novel label free and environmentally friendly fluorescence SiQDs-based probe was developed.•Cu2+ was detected based on fluorescence quenching of SiQDs by using the Fenton reaction.•The proposed method is of high sensitivity and selectivity for Cu2+.In this work, label-free silicon quantum dots (SiQDs) were used as a novel fluorescence probe for the sensitive and selective detection of Cu2+. The fluorescence of the SiQDs was effectively quenched by H2O2 from the reaction of ascorbic acid with O2, and hydroxyl radicals from Fenton reaction between H2O2 and Cu+. The fluorescence intensity of SiQDs was quenched about 25% in 15 min after the addition of H2O2 (1 mM). While the SiQDs was incubated with AA (1 mM) and Cu2+ (1 µM) under the same conditions, the fluorescence intensity of SiQDs decreased about 55%. Obviously, the recycling of Cu2+ in the test system may lead to a dramatical decrease in the fluorescence of SiQDs. Under the optimized experimental conditions, the rate of fluorescence quenching of SiQDs was linearly dependent on the Cu2+ concentration ranging from 25 to 600 nM with the limit of detection as low as 8 nM, which was much lower than that of existing methods. Moreover, the probe was successfully applied to the determination of Cu2+ in different environmental water samples and human hair.
Co-reporter:Jianhui Deng;Qiujun Lu;Naxiu Mi; Haitao Li;Meiling Liu; Mancai Xu; Liang Tan; Qingji Xie; Youyu Zhang; Shouzhuo Yao
Chemistry - A European Journal 2014 Volume 20( Issue 17) pp:4993-4999
Publication Date(Web):
DOI:10.1002/chem.201304869
Abstract
Carbon nanodots (C-dots) show great potential as an important material for biochemical sensing, energy conversion, photocatalysis, and optoelectronics because of their water solubility, chemical inertness, low toxicity, and photo- and electronic properties. Numerous methods have been proposed for the preparation of C-dots. However, complex procedures and strong acid treatments are often required, and the as-prepared C-dots tend to be of low quality, and in particular, have a low efficiency for photoluminescence. Herein, a facile and general strategy involving the electrochemical carbonization of low-molecular-weight alcohols is proposed. As precursors, the alcohols transited into carbon-containing particles after electrochemical carbonization under basic conditions. The resultant C-dots exhibit excellent excitation- and size-dependent fluorescence without the need for complicated purification and passivation procedures. The sizes of the as-prepared C-dots can be adjusted by varying the applied potential. High-quality C-dots are prepared successfully from different small molecular alcohols, suggesting that this research provides a new, highly universal method for the preparation of fluorescent C-dots. In addition, luminescence microscopy of the C-dots is demonstrated in human cancer cells. The results indicate that the as-prepared C-dots have low toxicity and can be used in imaging applications.
Co-reporter:Yinhui Yi, Jianhui Deng, Youyu Zhang, Haitao Li and Shouzhuo Yao
Chemical Communications 2013 vol. 49(Issue 6) pp:612-614
Publication Date(Web):23 Nov 2012
DOI:10.1039/C2CC36282A
Si quantum dots have been demonstrated to be environmentally friendly photoluminescence probes and their fluorescence was quenched by H2O2 that was produced from the glucose oxidase-catalyzed oxidation of glucose. This strategy could be used to detect glucose with high sensitivity and selectivity.
Co-reporter:Mingjie Wei, Peng Yin, Youming Shen, Lingli Zhang, Jianhui Deng, Shanyan Xue, Haitao Li, Bin Guo, Youyu Zhang and Shouzhuo Yao
Chemical Communications 2013 vol. 49(Issue 41) pp:4640-4642
Publication Date(Web):28 Mar 2013
DOI:10.1039/C3CC39045D
A fluorescent probe (N-(4-methyl-2-oxo-2H-chromen-7-yl)-2,4-dinitrobenzenesulfonamide), which exhibits high selectivity to glutathione and cysteine among amino acids including sulphur-containing methionine and metal ions, was synthesized. The experiments demonstrate that the fluorescent probe is a reliable and specific probe for glutathione and cysteine in living cells.
Co-reporter:Yinhui Yi, Gangbing Zhu, Chang Liu, Yan Huang, Youyu Zhang, Haitao Li, Jiangna Zhao, and Shouzhuo Yao
Analytical Chemistry 2013 Volume 85(Issue 23) pp:11464
Publication Date(Web):October 28, 2013
DOI:10.1021/ac403257p
Sensitive, rapid, and simple detection methods for the screening of extensively used organophosphorus pesticides and highly toxic nerve agents are in urgent demand. A novel label-free silicon quantum dots (SiQDs)-based sensor was designed for ultrasensitive detection of pesticides. This sensing strategy involves the reaction of acetylcholine chloride (ACh) with acetylcholinesterase (AChE) to form choline that is in turn catalytically oxidized by choline oxidase (ChOx) to produce betaine and H2O2 which can quench the photoluminescence (PL) of SiQDs. Upon the addition of pesticides, the activity of AChE is inhibited, leading to the decrease of the generated H2O2, and hence the PL of SiQDs increases. By measuring the increase in SiQDs PL, the inhibition efficiency of pesticide to AChE activity was evaluated. It was found that the inhibition efficiency was linearly dependent on the logarithm of the pesticides concentration. Consequently, pesticides, such as carbaryl, parathion, diazinon, and phorate, were determined with the SiQDs PL sensing method. The lowest detectable concentrations for carbaryl, parathion, diazinon, and phorate reached 7.25 × 10–9, 3.25 × 10–8, 6.76 × 10–8, and 1.9 × 10–7 g/L, respectively, which were much lower than those previously reported. The detecting results of pesticide residues in food samples via this method agree well with those from high-performance liquid chromatography. The simple strategy reported here should be suitable for on-site pesticides detection, especially in combination with other portable platforms.
Co-reporter:Linping Wang, Yue Meng, Qiong Chen, Jianhui Deng, Youyu Zhang, Haitao Li, Shouzhuo Yao
Electrochimica Acta 2013 Volume 92() pp:216-225
Publication Date(Web):1 March 2013
DOI:10.1016/j.electacta.2013.01.003
A dual sensitized graphene composite decorated with carbon nanoparticles (CNP) and a new ferrocene-derivative redox mediator, (4-ferrocenylethyne) phenylamine (FEPA), is prepared by a facile and rapid one-step method. The as-prepared (4-ferrocenylethyne) phenylamine–carbon nanoparticles–graphene (FEPA–CNP–GR) composite coupling with Nafion was used to construct an ultrasensitive electrochemical sensor (Nafion-FEPA–CNP–GR) for simultaneous detection of dihydroxybenzene isomers. It was found that the well-dispersed hydrophilic-type CNP in the composite could improve the water-solubility and the surface area of GR, and exhibit an excellent catalytic activity toward resorcinol (RC) oxidation. Meanwhile, synthesized FEPA served as a good electron-transfer mediator, improved the sensitivity of the sensor, permitted favorable oxidation peak separations between isomers, and reduced the interferences between isomers. FEPA steadily adsorbed on the surface of GR through the π-stacking interaction between the conjugate chain of FEPA and GR, which effectively prevented FEPA mediator leaking from electrode surface. In addition, Nafion used as an immobilization film for eliminate the main interferences in relatively high concentrations, which led to an excellent selectivity. Thus, the proposed method exhibited good stability, sensitivity and selectivity for the simultaneous determination of dihydroxybenzene isomers due to the synergistic effect of CNP, FEPA and GR. Under the optimum conditions, the calibration curves for hydroquinone (HQ), catechol (CC), and RC were obtained in the range of 0.3–90 μmol L−1, 0.6–100 μmol L−1 and 4–300 μmol L−1, respectively. The detection limits were found to be 0.1 μmol L−1 for HQ, 0.2 μmol L−1 for CC and 0.7 μmol L−1 for RC based on S/N of 3. The developed method was successfully applied to the simultaneous determination of dihydroxybenzene isomers in synthetic and real samples, and the results are satisfactory.
Co-reporter:Jianhui Deng, Meilin Liu, Fanbo Lin, Youyu Zhang, Yang Liu, Shouzhuo Yao
Analytica Chimica Acta 2013 Volume 767() pp:59-65
Publication Date(Web):12 March 2013
DOI:10.1016/j.aca.2012.12.051
In this work, a novel 1,4-bis (4- aminophenylethynyl)benzene (OPE-NH2, a symmetric linear conjugated oligo(phenylene ethynylene)s derive) and chemically-reduced graphene oxide (rGO) nanocomposite (OPE-NH2/rGO) was synthesized by a simple self-assembly method. The OPE-NH2/rGO nanocomposite was stable and water soluble. The formation of OPE-NH2/rGO nanocomposite was ascribed to the π–π stacking interaction between the conjugated structure of OPE-NH2 and rGO as well as the electrostatic force between the amino group of OPE-NH2 and the carboxyl group on rGO, which was characterized by FT-IR, UV–vis spectra and fluorescence spectra. The OPE-NH2/rGO nanocomposite exhibited significantly improved electrocatalytic activity to the oxidization of dopamine (DA) than that of rGO or OPE-NH2. The electrochemical performances of OPE-NH2/rGO were dependent on the OPE-NH2 contents, and OPE-NH2 content of 5 wt% exhibited the highest activity. Compared with that of rGO, the nanocomposite presented superior high sensitivity with detection limit of 5 nM, excellent selectivity, wide linear range (0.01–60 μM) and good stability on the determination of DA. The practical application of the developed OPE-NH2/rGO nanocomposite modified electrode was successfully demonstrated for DA determination in human serum samples.Graphical abstractHighlights► A novel oligo (phenylene ethynylene)s/graphene nanocomposite (OPE-NH2/rGO) was synthesized. ► The OPE-NH2/rGO modified electrode exhibited improved electroactivity to dopamine oxidation. ► The sensor showed good performances for DA detection and can be used for human serum samples.
Co-reporter:Jie Zhao, Meiling Liu, Youyu Zhang, Haitao Li, Yuehe Lin, Shouzhuo Yao
Analytica Chimica Acta 2013 Volume 759() pp:53-60
Publication Date(Web):8 January 2013
DOI:10.1016/j.aca.2012.10.041
A novel and ultrasensitive sandwich-type electrochemical aptasensor has been developed for the detection of thrombin, based on dual signal-amplification using HRP and apoferritin. Core/shell Fe3O4/Au magnetic nanoparticles (AuMNPs) loading aptamer1 (Apt1) was used as recognition elements, and apoferritin dually labeled with Aptamer2 (Apt2) and HRP was used as a detection probe. Sandwich-type complex, Apt1/thrombin/Apt2–apoferritin NPs–HRP was formed by the affinity reactions between AuMNPs–Apt1, thrombin, and Apt2–apoferritin–HRP. The complex was anchored on a screen-printed carbon electrode (SPCE). Differential pulse voltammetry (DPV) was used to monitor the electrode response. The proposed aptasensor yielded a linear current response to thrombin concentrations over a broad range of 0.5–100 pM with a detection limit of 0.07 pM (S/N = 3). The detection signal was amplified by using apoferritin and HRP. This nanoparticle-based aptasensor offers a new method for rapid, sensitive, selective, and inexpensive quantification of thrombin, and offers a promising potential in protein detection and disease diagnosis.Graphical abstractHighlights► A novel apoferritin nanoparticles modified with HRP and aptamer was synthesized. ► Signal dual amplification was carried out by using the resulted nanoparticles as detection probe. ► Ultrasensitive and high specific thrombin detection was achieved.
Co-reporter:Bangda Yin, Jianhui Deng, Xue Peng, Qian Long, Jiangna Zhao, Qiujun Lu, Qiong Chen, Haitao Li, Hao Tang, Youyu Zhang and Shouzhuo Yao
Analyst 2013 vol. 138(Issue 21) pp:6551-6557
Publication Date(Web):05 Aug 2013
DOI:10.1039/C3AN01003A
High quality carbon dots (C-dots) with down- and up-conversion fluorescence have been synthesized through low-temperature carbonization using sweet pepper as the carbon source. The C-dots with a quantum yield (QY) of 19.3% exhibit superior photophysical properties, for example, narrow and symmetric emission spectra, large stock shifts, resistance to photobleaching, and excitation-dependent fluorescence behavior. The excellent C-dots serve as useful fluorescent probes for hypochlorite (ClO−) detection by both down- and up-conversion fluorescence. Two consecutive linear ranges allow a wide determination of ClO− concentrations with a low detection limit of 0.05 μmol L−1 and 0.06 μmol L−1 (S/N = 3) for down- and up-conversion fluorescence measurements, respectively. The proposed detection method is advantageous because it is simple, sensitive, dual-signalling model and low-cost and has potential extensive applications in environmental and biological assays.
Co-reporter:Lingli Zhang, Youyu Zhang, Mingjie Wei, Yinhui Yi, Haitao Li and Shouzhuo Yao
New Journal of Chemistry 2013 vol. 37(Issue 4) pp:1252-1257
Publication Date(Web):06 Feb 2013
DOI:10.1039/C3NJ41103F
A label-free fluorescent sensor for the detection of Cu2+ was constructed based on internal DNA cleavage and DNA intercalator SYBR Green I. The DNAzyme complex formed by the hybridization of the enzyme strand and substrate strand has two base-pairing regions including a DNA duplex and a DNA triplex. The copper ion-induced catalytic reaction makes the substrate strand irreversibly break at the cleavage site, which disturbs the formation of DNA strands. The weakly fluorescent dye SYBR Green I served as a fluorescence indicator that intercalated into the base-pairing regions of DNAzyme, resulting in a strong fluorescence emission. In the presence of Cu2+ in the test system, the complementary regions were reduced due to the fracture of the DNA strand. The fluorescence intensity was decreased because SYBR Green I was released from the cleaved regions. Other metal ions had no notable “on-off” phenomenon even at 50 times Cu2+ concentration. Under the optimal conditions, a linear response with Cu2+ concentration ranging from 4 × 10−8 to 120 × 10−8 M was obtained. The detection limit reached as low as 10 nM. Moreover, the cost-effective sensor was successfully applied to the determination of Cu2+ in drinking water.
Co-reporter:Lingli Zhang, Naxiu Mi, Youyu Zhang, Mingjie Wei, Haitao Li and Shouzhuo Yao
Analytical Methods 2013 vol. 5(Issue 21) pp:6100-6105
Publication Date(Web):29 Aug 2013
DOI:10.1039/C3AY41032C
A simple label-free Pb2+ fluorescent aptasensor was proposed in this work. It is known that SYBR Green1 can embed into double-stranded DNA resulting in fluorescence enhancement, but it cannot bind to the G-quadruplex formed by Pb2+ and PS2.M. In the absence of Pb2+, SYBR Green1 intercalated into the double-stranded DNA hybridized between PS2.M and its complementary strand and the fluorescence was greatly enhanced. In the presence of Pb2+, a compact G-quadruplex structure was formed and the double-stranded structure was destroyed, releasing SYBR Green1 and causing the fluorescence intensity to significantly decrease. The detection limit of the sensor was as low as 3 nM. This proposed assay strategy was a low-cost detection method for Pb2+ with high sensitivity and good selectivity.
Co-reporter:Yinhui Yi, Yan Huang, Gangbing Zhu, Fanbo Lin, Lingli Zhang, Haitao Li, Youyu Zhang and Shouzhuo Yao
Analytical Methods 2013 vol. 5(Issue 10) pp:2477-2484
Publication Date(Web):2013/03/18
DOI:10.1039/C3AY40087E
We developed a highly specific sensing platform for the sequential detection of two analytes in a homogenous solution by using colorimetric and fluorescence methods. This design used aptamer units [thiolated aptamer I (Apt I) for platelet-derived growth factor BB (PDGF-BB); fluorescein amidite (FAM)-labeled aptamer II (Apt II) for adenosine]. A bifunctional aptasensor was prepared by the self-assembly of thiolated Apt I on gold nanoparticles (AuNPs) and partial hybridization between Apt I and Apt II. The fabricated bifunctional aptasensor was used to detect two targets (PDGF-BB and adenosine) sequentially and selectively in a homogenous solution. In the presence of target molecules PDGF-BB, the color and absorbance of the aptamer-modified AuNPs changed because of AuNP aggregation. The increase of fluorescence intensity of FAM at 520 nm was used to analyze adenosine in the test system. The proposed aptasensor had low detection limit, high sensitivity, and bifunctional recognition and was successfully used for real serum samples. It also highlights promising applications for other aptamers and a broad range of other analytes.
Co-reporter:Fanbo Lin, Bangda Yin, Chengzhi li, Jianhui Deng, Xiaoyu Fan, Yinhui Yi, Chang Liu, Haitao Li, Youyu Zhang and Shouzhuo Yao
Analytical Methods 2013 vol. 5(Issue 3) pp:699-704
Publication Date(Web):28 Nov 2012
DOI:10.1039/C2AY25519G
Au nanoparticles (AuNPs) have good absorption properties in the visible region, while upconversion nanoparticles (UCNPs) have an emission at 547 nm upon excitation with a 980 nm laser, which could avoid most interfering signals of biomolecules in serum. In this paper, we developed an aptasensor for platelet-derived growth factor (PDGF–BB) detection in 30% blood serum based on fluorescence resonance energy transfer between AuNPs and UCNPs. With the proposed aptasensor, PDGF–BB in 30% blood serum was detected. Two consecutive linear ranges allow a wide determination of PDGF–BB concentrations with a low detection limit of 10 nM (S/N = 3). Importantly, the fluorescence biosensor can directly detect PDGF–BB in blood serum of lymphoma patient. This detection approach can also exhibit good stability and selectivity.
Co-reporter:Linping Wang;Meiling Liu;Yue Meng;Haitao Li;Shouzhuo Yao
Chinese Journal of Chemistry 2013 Volume 31( Issue 6) pp:845-854
Publication Date(Web):
DOI:10.1002/cjoc.201201229
Abstract
A novel (4-ferrocenylethyne) phenylamine functionalized graphene sheets (FEPA-GR), coupling with chitosan (CS) were used as a signal amplification platform for simultaneous and sensitive determination of dopamine (DA) and acetaminophen (AC). In this work, FEPA used as electron transfer mediator can be immobilized on GR surface via strong π-π stacking interaction between the conjugate chain of FEPA and GR, which effectively prevents FEPA electron mediator leaking from the electrode surface and amplified the signal. Transmission electron microscopy, FT-IR spectroscopy, UV-vis spectroscopy and electrochemical experiments results are all demonstrated the strong π-π stacking interaction between FEPA and GR. The resulted biosensor exhibited a fast response, remarkable electrocatalytic activity, perfect anti-interference ability and good stability for simultaneous detection of DA and AC. Under the optimum conditions, the oxidation peak currents of DA and AC were linearly correlated to their concentrations in the range of 2.0–135.0 µmol·L−1 and 0.3–80.0 µmol·L−1, respectively. The lower detection limits for DA and AC were 0.30 and 0.05 µmol·L−1, respectively. The feasibility of the proposed method was validated by successfully applied to the simultaneous determination of DA and AC in serum samples with the standard addition method.
Co-reporter:Meiling Liu, Jianhui Deng, Qiong Chen, Yan Huang, Linping Wang, Yan Zhao, Youyu Zhang, Haitao Li, Shouzhuo Yao
Biosensors and Bioelectronics 2013 Volume 41() pp:275-281
Publication Date(Web):15 March 2013
DOI:10.1016/j.bios.2012.08.040
A new ferrocene benzyne derivative (Fc-SAc) that contained oligo-(phenylene-ethynylene) skeleton, ferrocene and thiolate terminal groups was firstly synthesized. The hydrolysis product of Fc-SAc (Fc-SH) was immobilized onto gold nanoparticles (AuNPs) modified glass carbon electrode (GCE) as sensing element for rutin detection with high sensitivity. The new sensing strategy was proposed by using two Fc-SH modified electrodes: Fc-S/AuNPs/GCE (Electrode1) and Fc-S/AuNPs/graphene-chitosan/GCE (Electrode2). The electrochemical oxidation of rutin on Electrode2 was a diffusion-controlled process, which was different from a mass-controlled process on Electrode1. Under the optimal conditions, the peak currents of the sensors were linearly related to the concentrations of rutin. The linear responses ranges were 0.05–30 μM and 0.04–100 μM with the regression coefficients of 0.998 and 0.997 on Electrode1 and Electrode2, respectively. Electrode2 presented wider linear range, superior high sensitivity, lower detection limit and better stability on determination of rutin.Highlights► A new ferrocene benzyne derivative (Fc-SAc) was firstly synthesized. ► Fc-SH was immobilized onto AuNPs modified electrodes for rutin detection. ► Sensitive detection of rutin resulted from synergy signal enhancement of nanomaterial and Fc-SAc. ► Two Fc-SAc modified electrodes showed excellent performance in rutin detection.
Co-reporter:Jie Zhao, Fanbo Lin, Yinhui Yi, Yan Huang, Haitao Li, Youyu Zhang and Shouzhuo Yao
Analyst 2012 vol. 137(Issue 15) pp:3488-3495
Publication Date(Web):11 May 2012
DOI:10.1039/C2AN35340G
A highly sensitive and selective electrochemical aptasensor for thrombin was developed. By introducing chitosan–gold nanoparticles and horseradish peroxidase (CS–AuNPs–HRP) conjugates to the sensitive union, the thrombin detection signal was dual amplified. The capture probe was prepared by immobilizing an anti-thrombin aptamer on core–shell Fe3O4–Au magnetic nanoparticles (AuMNPs) and which was served as magnetic separation material as well. The detection probe was prepared from another anti-thrombin aptamer, horseradish peroxidase (HRP), thiolated CS nanoparticle and gold nanoparticle (CS–AuNPs–HRP–Apt2). In the presence of thrombin, the sandwich structure of AuMNPs–Apt1/thrombin/Apt2–CS–AuNPs–HRP was formed and abundant HRP was captured in it. The resultant conjugates are of magnetic characters and were captured onto the surface of a screen printed carbon electrode (SPCE) to prepare the modified electrode by a magnet located on the outer flank of the SPCE. It was demonstrated that the oxidation of hydroquinone (HQ) with H2O2 was dramatically accelerated by the captured HRP. The electrochemical signal, which correlated to the reduction of BQ (the oxidation product of HQ), was amplified by the catalysis of HRP toward the reaction and the enrichment of HRP on the electrode surface. Under optimized conditions, ultrasensitive and high specific detection for thrombin was realized with the proposed assay strategy. The signal current was linearly correlated to the thrombin concentration in the range of 0.01–10 pM with a detection limit of 5.5 fM (S/N = 3). These results promise extensive applications of this newly proposed signal amplification strategy in protein detection and disease diagnosis.
Co-reporter:Xiaoyu Fan, Haitao Li, Jie Zhao, Fanbo Lin, Lingli Zhang, Youyu Zhang, Shouzhuo Yao
Talanta 2012 Volume 89() pp:57-62
Publication Date(Web):30 January 2012
DOI:10.1016/j.talanta.2011.11.056
A novel label-free and sensitive fluorescent aptasensor for the detection of potassium ion (K+) was developed based on the horseradish peroxidase–mimicking DNAzyme (HRP–DNAzyme). In this work, we selected a K+-stabilized single stranded DNA (ssDNA) with G-rich sequence as the recognition element. In the presence of K+, the G-rich DNA folded into the G-quadruplex structure, and then hemin can bind to the G-quadruplex structure as a co-factor and form HRP–DNAzyme. 3-(p-Hydroxyphenyl)-propanoic acid (HPPA) can be oxidized by H2O2 into a fluorescent product in the presence of DNAzyme. The fluorescence intensity of the HPPA oxidative product increased with the K+ concentration. Under the optimal conditions, the fluorescence intensity was linearly related to the logarithm of K+ concentration in the range of 2.5 μM to 5 mM. Other metal ions, such as Na+, Li+, NH4+, Mg2+ and Ca2+ caused no notable interference on the detection of K+.Highlights► A novel label-free potassium ions (K+) fluorescent aptasensor was developed. ► A single stranded G-rich DNA (ssDNA) was used as the recognition element for K+. ► The employed DNA specifically interacts with K+ and hemin to form a DNAzyme. ► H2O2-mediated oxidation of 3-(p-Hydroxyphenyl)-propanoic is accelerated by the DNAzyme. ► The proposed aptasensor is of high selectivity and sensitivity for K+ detection.
Co-reporter:Jiao Luo, Mingnan Dong, Fanbo Lin, Meiling Liu, Hao Tang, Haitao Li, Youyu Zhang and Shouzhuo Yao
Analyst 2011 vol. 136(Issue 21) pp:4500-4506
Publication Date(Web):12 Sep 2011
DOI:10.1039/C1AN15515F
A three-dimensional network PAMAM-Au nanocomposite (3D-PAMAM-Au NC) was prepared by using the first generation polyamidoamine dendrimer (G1 PAMAM) as the dispersant agent. The resultant 3D-PAMAM-Au NC was successfully used as an immobilization matrix for the construction of a reagentless mediator-free horseradish peroxidase (HRP)-based H2O2 biosensor on a multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode. With the advantages of the three-dimensional network, the organic–inorganic hybrid materials dramatically facilitate the direct electron transfer of HRP, and good bioelectrocatalytic activity towards H2O2 was demonstrated. Under optimum conditions, the current response of the enzyme modified electrode at −0.30 V was detected. The current response is linearly correlated to H2O2 concentration within the range of 18.00 μM to 20.80 mM with a correlation coefficient of 0.9992 and a sensitivity of 377.78 μA mM−1 cm−2. The detection limit was down to 6.72 μM (S/N = 3). Furthermore, the biosensor exhibits some other excellent characteristics, such as high selectivity, short response time, and long-term stability. The 3D-PAMAM-Au NC has proved to be a promising biosensing platform for the construction of mediator-free biosensors, and may find wide potential applications in biosensors, biocatalysis, bioelectronics and biofuel cells.
Co-reporter:Jiao Luo, Meiling Liu, Qiangqin Zhao, Jie Zhao, Youyu Zhang, Liang Tan, Hao Tang, Qingji Xie, Haitao Li, Shouzhuo Yao
Electrochimica Acta 2010 Volume 56(Issue 1) pp:454-462
Publication Date(Web):15 December 2010
DOI:10.1016/j.electacta.2010.09.026
A novel symmetric conjugated oligo(phenylene-ethynylene) (OPE) linear molecule (1,4-bis(4-aminophenylethynyl)benzene); BAB) was synthesized by Sonogashira cross-coupling reactions. The structure and purity of the compound were confirmed by 1H NMR, 13C NMR and infrared (IR) and mass spectrometry (MS). The electrochemical oxidation process and mechanism of BAB were investigated via in situ Fourier transform infrared (FTIR) spectroelectrochemistry and electrochemical quartz crystal microbalance (EQCM). The electrochemical oxidation mechanism of BAB was proposed. The studies revealed that the BAB concentration and oxidation potential had a significant influence on the growth of the polymer film. A densely packed polymer film, which exhibited nonelectroactivity, was formed when a high monomer concentration and a high oxidation potential were used. When the electropolymerization of BAB was conducted at a lower concentration, a new pair of redox peaks appeared, and the resultant thin film had better electroactivity. The in situ FTIR studies confirmed that BAB could be electro-oxidized into radical cations and then electropolymerized via para (N-N) and/or ortho (N-C) coupling reactions to form polymers with a larger conjugated π-electron system. The surface morphology of the poly-BAB was also investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM).
Co-reporter:Min Ye, Youyu Zhang, Haitao Li, Yuqin Zhang, Ping Tan, Hao Tang, Shouzhuo Yao
Biosensors and Bioelectronics 2009 Volume 24(Issue 8) pp:2339-2345
Publication Date(Web):15 April 2009
DOI:10.1016/j.bios.2008.12.002
A novel method for DNA point mutation detection using single-base-coded CdS nanoparticle probes is proposed. Target DNA was immobilized on core/shell Fe3O4/Au magnetic nanoparticles. Single-base-coded CdS nanoparticles, such as guanosine coded CdS (G-CdS), cytidine coded CdS (C-CdS), thymidine coded CdS (T-CdS) and adenosine coded CdS (A-CdS) were used as the probes to identify the mutation sites in DNA strand. The hybridization process of single-base-coded CdS nanoparticle probes with the mutation sites in DNA was monitored using piezoelectric quartz crystal microbalance (QCM). The hybridization of the mutation base in DNA with its complementary base-coded CdS nanoprobes specifically caused significant changes in the resonance frequency of the QCM. Thus the base types of the mutation sites in DNA strand could be identified. The results were further confirmed by fluorescence measurement of CdS. Owing to its operation convenience and cost-effective, this DNA point mutation detection method is expected to hold a great promise in the detection of DNA point mutation and genetic assays.
Co-reporter:Meiling Liu, Youyu Zhang, Yuandao Chen, Qingji Xie, Shouzhuo Yao
Journal of Electroanalytical Chemistry 2008 Volume 622(Issue 2) pp:184-192
Publication Date(Web):15 October 2008
DOI:10.1016/j.jelechem.2008.06.002
In situ piezoelectric FTIR (Fourier transform infrared) spectroelectrochemistry, a combination technique of in situ FTIR and electrochemical quartz crystal microbalance (EQCM), was used to study the electrochemical oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and the effect of some large-sized anions on the oxidation process. A V-shaped frequency response curve was observed during the electrochemical oxidation of TMB. The formation of TMB cation free radical and charge transfer complex (CTC) were experimentally found in the process of TMB electro-oxidation. In cyclic voltammetric test, the deposition of CTC onto the electrode surface from TMB solution was observed after several scanning cycles, even though the CTC is dissolvable in the solution. Further investigations suggested that the CTC was formed by TMB and TMB2+. Some representative large-sized anions, such as heparin, alizarin red and DNA, can affect the electro-oxidation of TMB.
Co-reporter:Youyu Zhang, Meiling Wang, Qingji Xie, Xianhui Wen, Shouzhuo Yao
Sensors and Actuators B: Chemical 2005 Volume 105(Issue 2) pp:454-463
Publication Date(Web):28 March 2005
DOI:10.1016/j.snb.2004.07.002
The interaction process of tannin with bovine serum albumin (BSA) was studied by the electrochemical quartz-crystal impedance system (EQCIS) and fluorescence spectrophotometry. The equivalent circuit parameters and resonant frequencies of the piezoelectric quartz-crystal (PQC) resonance, the value of half-peak width of the electroacoustic conductance spectrum (ΔfG1/2) as well as the electrical double-layer capacitance were obtained and analyzed. The results showed that the frequency curve and the double-layer capacitance curve due to BSA adsorption exhibited a character of a sum of exponential functions. Both piezoelectric impedance and fluorescence measurements revealed that the molar ratio of tannin to BSA in the tannin-BSA binding was 2:1. The combining constant (3.6 × 1011 L2 mol−2) was calculated out from the concentration and relative fluorescence intensity based on the Stern–Volmer equation.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 13) pp:
Publication Date(Web):
DOI:10.1039/C4AY00729H
A new and simple fluorescent probe bearing 7-nitrobenz-2-oxa-1,3-diazole and N,N-bis(thiophen-2-ylmethyl)ethane-1,2-diamine was developed as a fluorescent chemosensor with high selectivity and sensitivity toward Hg2+ over other cations tested. The signaling is due to the coordination of S and N atoms of N,N-bis(thiophen-2-ylmethyl)ethane-1,2-diamine to Hg2+. Upon addition of 30 equivalents of Hg2+, a 45-fold increase in fluorescence emission intensity was observed. Moreover, the probe is further successfully used to image Hg2+ in MCF-7 cells.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 21) pp:NaN6105-6105
Publication Date(Web):2013/08/29
DOI:10.1039/C3AY41032C
A simple label-free Pb2+ fluorescent aptasensor was proposed in this work. It is known that SYBR Green1 can embed into double-stranded DNA resulting in fluorescence enhancement, but it cannot bind to the G-quadruplex formed by Pb2+ and PS2.M. In the absence of Pb2+, SYBR Green1 intercalated into the double-stranded DNA hybridized between PS2.M and its complementary strand and the fluorescence was greatly enhanced. In the presence of Pb2+, a compact G-quadruplex structure was formed and the double-stranded structure was destroyed, releasing SYBR Green1 and causing the fluorescence intensity to significantly decrease. The detection limit of the sensor was as low as 3 nM. This proposed assay strategy was a low-cost detection method for Pb2+ with high sensitivity and good selectivity.
Co-reporter:Mingjie Wei, Peng Yin, Youming Shen, Lingli Zhang, Jianhui Deng, Shanyan Xue, Haitao Li, Bin Guo, Youyu Zhang and Shouzhuo Yao
Chemical Communications 2013 - vol. 49(Issue 41) pp:NaN4642-4642
Publication Date(Web):2013/03/28
DOI:10.1039/C3CC39045D
A fluorescent probe (N-(4-methyl-2-oxo-2H-chromen-7-yl)-2,4-dinitrobenzenesulfonamide), which exhibits high selectivity to glutathione and cysteine among amino acids including sulphur-containing methionine and metal ions, was synthesized. The experiments demonstrate that the fluorescent probe is a reliable and specific probe for glutathione and cysteine in living cells.
Co-reporter:Qiujun Lu, Jianhui Deng, Yuxin Hou, Haiyan Wang, Haitao Li and Youyu Zhang
Chemical Communications 2015 - vol. 51(Issue 61) pp:NaN12253-12253
Publication Date(Web):2015/06/19
DOI:10.1039/C5CC04231C
Ultrathin graphitic carbon nitride nanosheets (g-C3N4) with a thickness of about 2 nm were synthesized by a one-step electrochemical method for the first time. The possible mechanism of the electrochemical synthesis was discussed. This as-synthesized g-C3N4 showed intrinsic peroxidase-like activity and was successfully applied for the detection of uric acid.
Co-reporter:Qiong Chen, Meiling Liu, Jiangna Zhao, Xue Peng, Xiaojiao Chen, Naxiu Mi, Bangda Yin, Haitao Li, Youyu Zhang and Shouzhuo Yao
Chemical Communications 2014 - vol. 50(Issue 51) pp:NaN6774-6774
Publication Date(Web):2014/04/03
DOI:10.1039/C4CC01703J
We demonstrate that photoluminescent Si-dots exhibit intrinsic peroxidase-like activity, and can catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2, and produce a color change. This strategy can be used to detect glucose with high sensitivity and selectivity.
Co-reporter:Yinhui Yi, Jianhui Deng, Youyu Zhang, Haitao Li and Shouzhuo Yao
Chemical Communications 2013 - vol. 49(Issue 6) pp:NaN614-614
Publication Date(Web):2012/11/23
DOI:10.1039/C2CC36282A
Si quantum dots have been demonstrated to be environmentally friendly photoluminescence probes and their fluorescence was quenched by H2O2 that was produced from the glucose oxidase-catalyzed oxidation of glucose. This strategy could be used to detect glucose with high sensitivity and selectivity.
Co-reporter:Qiujun Lu, Jianhui Deng, Yuxin Hou, Haiyan Wang, Haitao Li, Youyu Zhang and Shouzhuo Yao
Chemical Communications 2015 - vol. 51(Issue 33) pp:NaN7167-7167
Publication Date(Web):2015/03/17
DOI:10.1039/C5CC01771H
Hydroxyl-rich C-dots were used as both the reducing and stabilizing agent in the preparation of noble metal nanoparticles (AuNPs, AgNPs and Au@AgNPs) for the detection of glucose.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 10) pp:NaN2484-2484
Publication Date(Web):2013/03/18
DOI:10.1039/C3AY40087E
We developed a highly specific sensing platform for the sequential detection of two analytes in a homogenous solution by using colorimetric and fluorescence methods. This design used aptamer units [thiolated aptamer I (Apt I) for platelet-derived growth factor BB (PDGF-BB); fluorescein amidite (FAM)-labeled aptamer II (Apt II) for adenosine]. A bifunctional aptasensor was prepared by the self-assembly of thiolated Apt I on gold nanoparticles (AuNPs) and partial hybridization between Apt I and Apt II. The fabricated bifunctional aptasensor was used to detect two targets (PDGF-BB and adenosine) sequentially and selectively in a homogenous solution. In the presence of target molecules PDGF-BB, the color and absorbance of the aptamer-modified AuNPs changed because of AuNP aggregation. The increase of fluorescence intensity of FAM at 520 nm was used to analyze adenosine in the test system. The proposed aptasensor had low detection limit, high sensitivity, and bifunctional recognition and was successfully used for real serum samples. It also highlights promising applications for other aptamers and a broad range of other analytes.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 3) pp:NaN704-704
Publication Date(Web):2012/11/28
DOI:10.1039/C2AY25519G
Au nanoparticles (AuNPs) have good absorption properties in the visible region, while upconversion nanoparticles (UCNPs) have an emission at 547 nm upon excitation with a 980 nm laser, which could avoid most interfering signals of biomolecules in serum. In this paper, we developed an aptasensor for platelet-derived growth factor (PDGF–BB) detection in 30% blood serum based on fluorescence resonance energy transfer between AuNPs and UCNPs. With the proposed aptasensor, PDGF–BB in 30% blood serum was detected. Two consecutive linear ranges allow a wide determination of PDGF–BB concentrations with a low detection limit of 10 nM (S/N = 3). Importantly, the fluorescence biosensor can directly detect PDGF–BB in blood serum of lymphoma patient. This detection approach can also exhibit good stability and selectivity.
Co-reporter:
Analytical Methods (2009-Present) 2015 - vol. 7(Issue 15) pp:NaN6425-6425
Publication Date(Web):2015/07/02
DOI:10.1039/C5AY00732A
A simple and new fluorescent and colorimetric probe bearing 7-nitrobenz-2-oxa-1,3-diazole and 4-maleimidophenol fragments for biothiols was designed and synthesized. The probe itself showed almost no background fluorescence (ΦF < 1 × 10−4) and displayed fluorescence turn-on response with selectivity for thiols over other relevant biological species in aqueous solutions. In addition, the probe exhibited 110 nm red-shifted absorption spectra accompanied by color changes which could be obviously distinguished by the naked eye. Furthermore, the probe showed high sensitivity towards thiols with a detection limit of 1.2 × 10−7 M (S/N = 3) and the mechanism regarding the optical responses of the probe to thiols was explained by density function theory (DFT) calculations. Finally, the probe has been successfully used to image thiols in HeLa cells.
![Ferrocene, [2-[4-(acetylthio)phenyl]ethynyl]-](/data/chemimg/124400/169231-41-8.png)
![Ferrocene, [2-[4-(acetylthio)phenyl]ethynyl]-](/data/chemimg/124400/169231-41-8_b.png)
![Glycine,N-[N-(N-benzoylglycyl)glycyl]- (8CI,9CI)](http://img.cochemist.com/ccimg/31400/31384-90-4.png)
![Glycine,N-[N-(N-benzoylglycyl)glycyl]- (8CI,9CI)](http://img.cochemist.com/ccimg/31400/31384-90-4_b.png)
![1H-BENZ[DE]ISOQUINOLINE-1,3(2H)-DIONE, 2-BUTYL-6-HYDROXY-](/data/chemimg/2344700/791-80-0.png)
![1H-BENZ[DE]ISOQUINOLINE-1,3(2H)-DIONE, 2-BUTYL-6-HYDROXY-](/data/chemimg/2344700/791-80-0_b.png)
