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The direct electron transfer of surface-confined horse heart cytochrome c (Cyt c) was achieved using COOH-terminated alkanethiolate-modified gold electrode. Later DNA was immobilized on the two-layer modified electrode. The quantitative determination of DNA was explored and the interaction between cytochrome c and DNA was studied. The binding site sizes were determined to be 15 bp per Cyt c molecule with double-stranded (ds) DNA and 30 nucleotides binding one Cyt c molecule with single-stranded (ss) DNA. At the dsDNA/Cyt c/MUA/Au electrode, the rate constant of oxidation electron transfer k(s,ox)=1.59x10(-3)cms-1 was obtained, at the ssDNA/Cyt c/MUA/Au electrode, the value was 2.43x10(-3)ms-1 when the scan rate was 1.0V/s. The different electrodes were characterized with electrochemical quartz crystal microbalance and atomic force microscope.

A new type of gold nanoparticles-attached indium tin oxide electrode was made. By SEM and EDS, the as-prepared gold nanoparticles-modified ITO electrode was characterized. This modified electrode has been used for the determination of pirarubicin (THP) in urine by cyclic voltammetry. Compared to a bare ITO electrode, the modified electrode exhibited a marked enhancement in the current response. Liner calibration curves are obtained in the range 5×10-9mol/L∼1.5×10-6 mol/L with a detection limit of 1×10-9 mol/L. The percentage of the recoveries ranged from 99.3% to 106.3%. The practical analytic utility of the method is illustrated by quantitative determination of THP in urine. [ABSTRACT FROM AUTHOR]

Abstract: Cytochrome c (Cyt. c) was immobilized on the 11-mercaptohendecanoic acid (MUA)-modified gold electrode. The electrode was stable and sensitive to Cyt. c. Later, DNA was also immobilized on the two-layer modified electrode. Cyclic voltammetry studies show that Cyt. c can interact with dsDNA and ssDNA. The binding site sizes were determined to be 15 base pairs per Cyt. c molecule with dsDNA and 30 nucleotides binding 1 Cyt. c molecule with ssDNA. The modified electrodes were characterized by quartz crystal microbalance (QCM), impedance spectroscopy and atomic force microscope (AFM). The modified electrode can be used for determining DNA. [Copyright &y& Elsevier]

Abstract: NH2 + ions implantation was performed at energy of 80keV with the ion dose of 5.0×1015 ionscm−2 for indium tin oxide (ITO) electrode, which formed a new electrode NH2/ITO. And then the electrode was immersed into the platinum nanoparticles (PtNPs) solution, in which PtNPs were successfully attached to the surface of NH2/ITO electrode through the strong electrostatic attraction formed between PtNPs and the NH2/ITO surface, resulting platinum nanoparticles-attached NH2 + ions implantation-modified ITO (PtNPs/NH2/ITO) electrode. Results of X-ray photoelectron spectra (XPS) and the water contact angle (WCA) measurements showed that the implanted NH2 + ions existed on the NH2/ITO surface. Scanning electron microscopy (SEM) analysis indicated that the attachment of PtNPs to ITO surface was improved after NH2 + ions implantation. Cyclic voltammetric measurements were carried out to investigate the electrochemical performance of the PtNPs/NH2/ITO electrode. It was found that the PtNPs/NH2/ITO electrode showed high electrochemical activities and displayed good electrocatalytic oxidation response to methanol. Therefore, the modified electrode could be applicable to be the sensor for detecting methanol. [Copyright &y& Elsevier]

Abstract: A COOH+ ion implantation-modified indium tin oxide (COOH/ITO) electrode was prepared and the existence of carboxyl group on the electrode was verified by X-ray photoelectron spectroscopy analysis. The field emission-scanning electron microscope result showed that the ion implantation formed many active centers on the ITO surface. The COOH/ITO electrode was applied for cytochrome c (cyt c) immobilization and the electrochemical behaviors of cyt c were evaluated by cyclic voltammetric techniques. The results demonstrated that the immobilized cyt c retained its electrocatalytic activity to the reduction of H2O2. This ion implantation-modified electrode might be used in development of new biosensors and biofuel cells. [Copyright &y& Elsevier]

Abstract: NH2 + ion implantation was performed at the energy of 80keV with fluence of 2×1016 ions·cm−2 for indium tin oxide (ITO) film coated glass, and the existence of amino group on the ITO surface was verified by Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS) analysis. The gold nanoparticles (AuNPs) have been fabricated on the surface of the obtained NH2 + ions implantation-modified ITO (NH2/ITO) film, resulting gold nanoparticles-attached NH2 + ions implantation-modified ITO (AuNPs/NH2/ITO) substrate. This ion implantation approach provides a useful strategy to attach AuNPs on the ITO surface with higher density without using certain organic binding molecules. Cyclic voltammtric results indicate that the AuNPs/NH2/ITO electrode shows excellent electrochemical properties, and thus this material is expected to have widely potential applications in electrochemical analysis and biosensors. [Copyright &y& Elsevier]

Abstract: A ions implantation-modified indium tin oxide (NH2/ITO) electrode was prepared and the existence of amino group on the electrode was verified by FT-IR spectra and X-ray photoelectron spectroscopy analysis (XPS). The gold nanoparticles (AuNPs) have been fabricated on the surface of NH2/ITO electrode, resulting novel gold nanoparticles-attached ions implantation-modified ITO (AuNPs/NH2/ITO) electrode, which could provide a biocompatible surface for the adsorption of cytochrome c (Cyt c). The Ultraviolet–visible (UV–vis) spectra indicated that Cyt c adsorbed on the AuNPs interface retained the native structure. Electrochemical impedance spectra (EIS) and cyclic voltammetric techniques were employed to evaluate the electrochemical behaviors of Cyt c. The surface of the AuNPs/NH2/ITO electrode was exhibited using the scanning electron microscopy (SEM) comparing with the surface of the gold nanoparticles-attached ITO electrode (AuNPs/ITO). We found that the functional surface of the NH2/ITO electrode resulted in a high AuNPs loading. The obtained Cyt c/AuNPs/NH2/ITO electrode gave an excellent electrocatalytic activity towards the reduction of H2O2, and the catalysis currents were proportional to the H2O2 concentration in the range of 2.0–300.0μM with a detection limit of 0.5μM (S/N =3). [Copyright &y& Elsevier]