Photoelectrochemical determination of trypsin by using an indium tin oxide electrode modified with a composite prepared from MoS nanosheets and TiO nanorods.

Author(s) Kong, W.; Li, Q.; Xia, L.; Li, X.; Sun, H.; Kong, R.M.; Qu, F.
Journal Mikrochim Acta
Date Published 2019 Jul 02

A photoelectrochemical (PEC) method has been developed for sensitive detection of trypsin. It is based on the use of a composite consisting of MoS nanosheets and TiO nanorods (MoS-TiO). The material has a high specific surface area, superior electrical conductivity, excellent biocompatibility and good band gap matching. The composite was synthesized by a one-pot method using TiO as a template. This results in a uniform distribution of the MoS nanosheets (<5 layers) in the composite. If the composite, placed on an indium tin oxide (ITO) electrode, is coupled to apoferritin, the photocurrent response decreases due to the insulating effect of the protein. Trypsin, in acting as an alkaline protease, decomposes the apoferritin. This results in the recovery of the PEC signal. Attractive features of this PEC method include (a) a superior PEC signal, (b) sensor stability, (c) simple operation, and (d) the lack of any additional modifications of the biosensor. This warrants high sensitivity, reproducibility, repeatability and practicality. The ITO sensor has a linear response in the 1 to 1000 ng·mL trypsin concentration range and a 0.82 ng·mL detection limit. The assay was applied to the determination of trypsin in spiked serum samples and gave satisfactory results. Graphical abstract Schematic presentation of an indium tin oxide (ITO)/MoS-TiO sensor for detecting trypsin. The PEC signal was decreased after immobilization of apoferritin (APO) on the modified ITO. Trypsin catalytically hydrolyzes APO specifically and induces the PEC signal to recover.

DOI 10.1007/s00604-019-3589-0
ISSN 1436-5073
Citation Mikrochim Acta. 2019;186(8):490.

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