A C-reactive protein immunosensor based on platinum nanowire / titania nanotube composite sensitized electrochemiluminescence.

C-reactive protein (CRP) is one of the important indicators of inflammatory response. It plays as an essential role in diseases such as myocardial infarction and atherosclerosis. A simple and effective label-free electrochemiluminescent (ECL) immunosensor for quantitative detection of CRP is reported. The indium tin oxide coated glass was prefunctionalized with the composite of titania nanotubes and platinum nanowires as the sensing matrix. Then the CRP antibody was immobilized on it, hosted the sensing function owing to its specific binding with CRP caused by immune affinity. The characteristics of the fabricated sensor were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and electron microscopes. The sensor has the advantages of high sensitivity, good selectivity, good reproducibility and low cost. Under the optimal experimental conditions, the response of ECL signal on obtained sensor has a good linear regression toward the logarithm of CRP quantity within the range from 0.05 ng to 6.25 ng with a detection limit of 0.011 ng. The immunosensor is small, convenient to use, and provides a feasible way for domestically rapid detection of CRP. It has a promising future in the precaution of cardiovascular and other diseases.

Microemulsion-enhanced electrochemiluminescence of luminol-H2O2 for sensitive flow injection analysis of antioxidant compounds.

A microemulsion enhanced electrochemiluminescence (ECL) of luminol-H(2)O(2) was studied with the flow-injection (FI) technique. The results revealed that the microemulsion composed with cetyltrimethylammonium bromide (CTAB), n-butanol, n-heptane and water greatly enhanced the ECL especially in acidic medium. The ECL emission increased for 20 to 2 times in this microemulsion medium over the pH range of 5.0-8.0 compared to that in aqueous solution. The mechanism of enhancement of surfactant and microemulsion for luminol-H(2)O(2) ECL was discussed. It is mainly based on the electrostatic interaction between luminol anion and the head group of surfactant, which causes the adsorption and promotes the dissociation of luminol on the surfaces of the microemulsion droplets, favors the oxidation of luminol by the yielded reactive oxygen species (ROSs) during electrolysis. This research is very significant for ECL applications because of the extended practicable pH range which was suitable for environmental and biological systems. As an example, this FI-ECL technique can be applied for determination of oligo proanthocyanidin (OPC) because of its antioxidant property and to evaluate the total antioxidant activity of the grape skin using OPC as an index.

Screen-Printing Enzyme Electrode-Immobilizing the Enzyme with Silk Fibroin / 分析化学

This paper reports the technique to develop a disposable screen-printing base carbon electrode for the utilization in the study of enzyme electrode. The silk fibroin was applied to immobilize the mushroom extracted protein, which contained abundant polyphenol oxidase, on the surface of base electrode when it was chemically moldified by ferrocene. The voltammetric current of this enzyme electrode responded to the concentration of substrate such as catechol or dopamine. The linear range is from 2.0× 10-8 mol/L to 2.0× 10-2 mol/L, it reaches to a 95%steady value of current within less than 30 seconds, and the RSD equals to 2.7%. The service life of this enzyme electrode is at least 10 days and it will be preserved for a longer period at a humid and cool condition. All of these performances of the enzyme electrode make clear that its commercial development would be very possible.