Metal-organic framework(MOF)nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors.The rational design of bimetallic MOF-functionalized microelectrode is of importa...Metal-organic framework(MOF)nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors.The rational design of bimetallic MOF-functionalized microelectrode is of importance for improv-ing the electrochemical performance but still in great challenge.In this work,the bimetallic FeCo-MOF nanostructures were assembled onto a gold disk ultramicroelectrode(Au UME,5.2μm in diameter)via an in-situ electrodeposition method,which enhanced the sensitive detection of epinephrine(EP).The in-situ electrodeposited FeCo-MOF exhibited a character-istic nanoflower-like morphology and was uniformly dispersed on the Au UME.The FeCo-MOF/Au UME demonstrated excellent electrochemical performance on the detection of EP with a high sensitivity of 36.93μA·μmol^(-1)·L·cm^(-2)and a low detection limit of 1.28μmol·L^(-1).It can be attributed to the nonlinear diffusion of EP onto the ultra-micro working substrate,coupled with synergistical catalytic activity of the bimetallic Fe,Co within MOF structure.Furthermore,the FeCo-MOF/Au UME has been successful applied to the analysis of EP in human serum samples,yielding high recovery rates.These results not only contribute to the expansion of the research area of electrochemical sensors,but also provide novel insights and directions into the development of high-performance MOF-based electrochemical sensors.展开更多
An in-situ reflection ultramicroelectrode microscopic FTIR spectroelectrochemical cell was constructed and demonstrated by using hexacyanoferrate redox couple in aqueous sulphate solution.An excellent microscopic SNIF...An in-situ reflection ultramicroelectrode microscopic FTIR spectroelectrochemical cell was constructed and demonstrated by using hexacyanoferrate redox couple in aqueous sulphate solution.An excellent microscopic SNIFTIRS reflection spectra had been obtained with no difficulty of IR beam focusing.The cell is simple in construction and convenient for use,And it will have most of all advantages of micro-/ultramicroelectrode.展开更多
Described here are the fabrication and characterization of carbon fiber cylinder ultramicroelectrodes with cylinder length of less than 100 am, total tip diameter of several hundreds nanometers. The electrodes have be...Described here are the fabrication and characterization of carbon fiber cylinder ultramicroelectrodes with cylinder length of less than 100 am, total tip diameter of several hundreds nanometers. The electrodes have been fabricated by direct etching of carbon fiber using an ion beam thinner. Optical microscopy, scanning electron microscopy (SEM), cyclic voltammetry have been employed to characterize those electrodes. The experimental results obtained indicate the electrodes can be used for in vivo detection of neurotransmitters such as dopamine, 5—hydroxytryptamine in a single cell.展开更多
Precise and long-term electroanalysis at the single-cell level is crucial for the accurate diagnosis and monitoring of brain diseases.The reliable protection in areas outside the signal acquisition points at sharp ult...Precise and long-term electroanalysis at the single-cell level is crucial for the accurate diagnosis and monitoring of brain diseases.The reliable protection in areas outside the signal acquisition points at sharp ultramicroelectrode(UME)tips has a significant impact on the sensitivity,fidelity,and stability of intracellular neural signal recording.However,it is difficult for existing UMEs to achieve controllable exposure of the tip functional structure,which affects their ability to resist environmental interference and shield noise,resulting in unsatisfactory signal-to-noise ratio and signal fidelity of intracellular recordings.To address this issue,we chose a dense and electrochemically stable diamond-like carbon(DLC)film as the UME protection coating and developed a method to precisely control the exposed degree of the functional structure by directly fixed-point processing of the UME tip by the strong site-selectivity and good controllability of the atmospheric microplasma jet.By analyzing the interaction between the microplasma jet and the UME tip,as well as the changes in the removal length and microstructure of UME tips with processing time,the exposed tip length was precisely controlled down to the submicron scale.Biocompatibility experiments,electrochemical aging tests and real-time intracellular pH recording experiments have demonstrated that the DLC-UME with effective tip protection processed by microplasma jet has the potential to enable long-term detection of intracellular high-fidelity signals.展开更多
A highly sensitive electrochemiluminescence(ECL) biosensing method was developed for monitoring casein kinase Ⅱ(CK2) at subcellular level via bio-bar-code assay.A bio-bar-code probe(h-DNA/AuNPs/pDNA) prepared by conj...A highly sensitive electrochemiluminescence(ECL) biosensing method was developed for monitoring casein kinase Ⅱ(CK2) at subcellular level via bio-bar-code assay.A bio-bar-code probe(h-DNA/AuNPs/pDNA) prepared by conjugating phosphorylated DNA(p-DNA) and hairpin DNA(h-DNA) onto gold nanoparticles(AuNPs) was used as a carrier for ECL signal reagent(Ru(phen)32+) while a specific peptide was used as a recognition substance.A gold ultramicroelectrode with a diameter of 400 nm was fabricated and then modified with the specific peptide via self-assembly technique to obtain peptide modified gold ultramicroelectrode.The peptide on gold ultramicroelectrode was phosphorylated in the presence of CK2 and adenosine 5’-triphosphate,and then the phosphorylated peptide was integrated with the h-DNA/AuNPs/p-DNA through a process mediated by zirconium cations(Zr4+),and finally Ru(phen)32+ was intercalated into h-DNA.A "signal on" ECL method was developed for the detection of CK2 in the range of 0.005-0.2 U/mL with a detection limit of 0.001 U/mL.Additionally,combined efficient subcellular phosphorylation in vivo with bio-bar-code-based ECL biosensing method,the ECL method was further applied to monitor CK2 at subcellular level without tedious subcellular fractionation.It was found that the concentration of CK2 by inserting the peptide modified gold ultramicroelectrode into the nucleus was higher than that into cytoplasm of HeLa cells.A distinct heterogeneity among CK2 concentrations in single cells was observed for cellular heterogeneity assessment.展开更多
A circuit based on the current feedback operational amplifier was constructed to accomplish on-line ohmic drop compensation in ultrafast cyclic voltammetry. Firstly, its characteristics were confirmed experimentally o...A circuit based on the current feedback operational amplifier was constructed to accomplish on-line ohmic drop compensation in ultrafast cyclic voltammetry. Firstly, its characteristics were confirmed experimentally on dummy cells. Then the reduction of anthracene in acetonitrile, a classical test example with very fast electron-transfer kinet-ics, was examined to prove them too. The results showed that this circuit could afford excellent ohmic drop com-pensation so that the undistorted voltammograms up to 2.2 MVs-1 scan rate can be recorded, and 2.5 MVs-1 if 5% error is tolerated.展开更多
The development of the instrumentation of a scanning electrochemical microscopy (SECM) is presented. The core of the SECM sensing system is constructed based on piezo-bimorph scanners, a mechanical micropositioner of ...The development of the instrumentation of a scanning electrochemical microscopy (SECM) is presented. The core of the SECM sensing system is constructed based on piezo-bimorph scanners, a mechanical micropositioner of multi-dimensional adjustment and ultramicroelectrodes. The control of the electrochemical cell and the SECM system is realized by a battery powered bipoteniostat and analog control circuits respectively with the control of a microcomputer work station. The demonstrations of SECM experiments are given on both a standard IDA sample and a silver electrode. Discussions on the resolution and quality of SECM image are made.展开更多
基金support from the National Key Research and Development Program of China(2021YFB3201400,2021YFB3201401,2020YFC1908602)the National Natural Science Foundation of China(21904001 and 61774159)+1 种基金the Anhui Provincial Natural Science Foundation(2008085QF288)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Anhui Province(2020LCX032).
文摘Metal-organic framework(MOF)nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors.The rational design of bimetallic MOF-functionalized microelectrode is of importance for improv-ing the electrochemical performance but still in great challenge.In this work,the bimetallic FeCo-MOF nanostructures were assembled onto a gold disk ultramicroelectrode(Au UME,5.2μm in diameter)via an in-situ electrodeposition method,which enhanced the sensitive detection of epinephrine(EP).The in-situ electrodeposited FeCo-MOF exhibited a character-istic nanoflower-like morphology and was uniformly dispersed on the Au UME.The FeCo-MOF/Au UME demonstrated excellent electrochemical performance on the detection of EP with a high sensitivity of 36.93μA·μmol^(-1)·L·cm^(-2)and a low detection limit of 1.28μmol·L^(-1).It can be attributed to the nonlinear diffusion of EP onto the ultra-micro working substrate,coupled with synergistical catalytic activity of the bimetallic Fe,Co within MOF structure.Furthermore,the FeCo-MOF/Au UME has been successful applied to the analysis of EP in human serum samples,yielding high recovery rates.These results not only contribute to the expansion of the research area of electrochemical sensors,but also provide novel insights and directions into the development of high-performance MOF-based electrochemical sensors.
文摘An in-situ reflection ultramicroelectrode microscopic FTIR spectroelectrochemical cell was constructed and demonstrated by using hexacyanoferrate redox couple in aqueous sulphate solution.An excellent microscopic SNIFTIRS reflection spectra had been obtained with no difficulty of IR beam focusing.The cell is simple in construction and convenient for use,And it will have most of all advantages of micro-/ultramicroelectrode.
基金This project was supported by the National Science Foundation of China and Doctoral Programme from State Education Commission Foundation of China
文摘Described here are the fabrication and characterization of carbon fiber cylinder ultramicroelectrodes with cylinder length of less than 100 am, total tip diameter of several hundreds nanometers. The electrodes have been fabricated by direct etching of carbon fiber using an ion beam thinner. Optical microscopy, scanning electron microscopy (SEM), cyclic voltammetry have been employed to characterize those electrodes. The experimental results obtained indicate the electrodes can be used for in vivo detection of neurotransmitters such as dopamine, 5—hydroxytryptamine in a single cell.
基金supported by the National Key R&D Program of China under grant 2022YFF120301the Fundamental Research Funds for the Central Universities,the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA25040100,XDA25040200 and XDA25040300)+4 种基金the National Natural Science Foundation of China(No.42127807-03)Project supported by Shanghai Municipal Science and Technology Major Project(2021SHZDZX)Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong University(No.21TQ1400203)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.SL2023ZD205)SJTU Trans-med Award(No.21X010301627).
文摘Precise and long-term electroanalysis at the single-cell level is crucial for the accurate diagnosis and monitoring of brain diseases.The reliable protection in areas outside the signal acquisition points at sharp ultramicroelectrode(UME)tips has a significant impact on the sensitivity,fidelity,and stability of intracellular neural signal recording.However,it is difficult for existing UMEs to achieve controllable exposure of the tip functional structure,which affects their ability to resist environmental interference and shield noise,resulting in unsatisfactory signal-to-noise ratio and signal fidelity of intracellular recordings.To address this issue,we chose a dense and electrochemically stable diamond-like carbon(DLC)film as the UME protection coating and developed a method to precisely control the exposed degree of the functional structure by directly fixed-point processing of the UME tip by the strong site-selectivity and good controllability of the atmospheric microplasma jet.By analyzing the interaction between the microplasma jet and the UME tip,as well as the changes in the removal length and microstructure of UME tips with processing time,the exposed tip length was precisely controlled down to the submicron scale.Biocompatibility experiments,electrochemical aging tests and real-time intracellular pH recording experiments have demonstrated that the DLC-UME with effective tip protection processed by microplasma jet has the potential to enable long-term detection of intracellular high-fidelity signals.
基金supported by the National Natural Science Foundation of China(Nos.21775097 and 21775098)the Fundamental Research Funds for the Central Universities(No.GK201801006)。
文摘A highly sensitive electrochemiluminescence(ECL) biosensing method was developed for monitoring casein kinase Ⅱ(CK2) at subcellular level via bio-bar-code assay.A bio-bar-code probe(h-DNA/AuNPs/pDNA) prepared by conjugating phosphorylated DNA(p-DNA) and hairpin DNA(h-DNA) onto gold nanoparticles(AuNPs) was used as a carrier for ECL signal reagent(Ru(phen)32+) while a specific peptide was used as a recognition substance.A gold ultramicroelectrode with a diameter of 400 nm was fabricated and then modified with the specific peptide via self-assembly technique to obtain peptide modified gold ultramicroelectrode.The peptide on gold ultramicroelectrode was phosphorylated in the presence of CK2 and adenosine 5’-triphosphate,and then the phosphorylated peptide was integrated with the h-DNA/AuNPs/p-DNA through a process mediated by zirconium cations(Zr4+),and finally Ru(phen)32+ was intercalated into h-DNA.A "signal on" ECL method was developed for the detection of CK2 in the range of 0.005-0.2 U/mL with a detection limit of 0.001 U/mL.Additionally,combined efficient subcellular phosphorylation in vivo with bio-bar-code-based ECL biosensing method,the ECL method was further applied to monitor CK2 at subcellular level without tedious subcellular fractionation.It was found that the concentration of CK2 by inserting the peptide modified gold ultramicroelectrode into the nucleus was higher than that into cytoplasm of HeLa cells.A distinct heterogeneity among CK2 concentrations in single cells was observed for cellular heterogeneity assessment.
基金the National Natural Science Foundation of China (No. 20173054).
文摘A circuit based on the current feedback operational amplifier was constructed to accomplish on-line ohmic drop compensation in ultrafast cyclic voltammetry. Firstly, its characteristics were confirmed experimentally on dummy cells. Then the reduction of anthracene in acetonitrile, a classical test example with very fast electron-transfer kinet-ics, was examined to prove them too. The results showed that this circuit could afford excellent ohmic drop com-pensation so that the undistorted voltammograms up to 2.2 MVs-1 scan rate can be recorded, and 2.5 MVs-1 if 5% error is tolerated.
基金supported by the National Natural Science Foundation of China.
文摘The development of the instrumentation of a scanning electrochemical microscopy (SECM) is presented. The core of the SECM sensing system is constructed based on piezo-bimorph scanners, a mechanical micropositioner of multi-dimensional adjustment and ultramicroelectrodes. The control of the electrochemical cell and the SECM system is realized by a battery powered bipoteniostat and analog control circuits respectively with the control of a microcomputer work station. The demonstrations of SECM experiments are given on both a standard IDA sample and a silver electrode. Discussions on the resolution and quality of SECM image are made.
