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
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
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.
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.
