Photoelectrochemical aptasensing for thrombin based on exonuclease III-assisted recycling signal amplification and nanoceria enzymatic strategy.

In the present work, a capture DNA (c-DNA) was immobilized on the TNA/g-CN to develop a sensitive and selective TNA/g-CN/c-DNA photoelectrochemical aptasensor for determining thrombin. With the aid of the specific recognition of anti-thrombin aptamer towards thrombin, ingenious design of hairpin DNA, and exonuclease III-assisted recycling signal amplification, more nanoceria could be assembled on the TNA/g-CN/c-DNA to form TNA/g-CN/nanoceria in the presence of thrombin. Due to the oxidase-mimic catalytic efficiency of nanoceria and the oxygen consumption for glucose oxidation, the photoexcited electrons at the conduction band of g-CN could be well transferred to that of TNA under visible light irradiation, resulting in the increase of the photocurrent of TNA/g-CN/nanoceria, and the increase value of photocurrent had a linear relationship with the concentration of thrombin under the optimal conditions.

Self-powered aptasensing for prostate specific antigen based on a membraneless photoelectrochemical fuel cell.

A self-powered aptasensor for prostate specific antigen (PSA) based on a membraneless photoelectrochemical fuel cell (PEFC) with double photoelectrodes was constructed, in which, PSA-binding aptamer was electrostatically immobilized on the KOH-doped g-CN modified TiO nanotube arrays (TNA/A-g-CN/aptamer), which was used as a photoanode, and Fe-doped CuBiO modified indium doped tin oxide (ITO) substrate (ITO/CBFeO) was used as a photocathode. Under visible light irradiation, glucose was photocatalytically oxidized by A-g-CN and generated HO in situ, which was used as the electron acceptor for ITO/CBFeO photocathode, thus producing a high cell output response with a maximum output power of 133.5 μW cm and an open circuit potential of 0.

Photoelectrochemically driven bioconversion and determination of nifedipine based on a double photoelectrode system.

In the present work, a double photoelectrode system has been constructed for photoelectrochemically driven enzymatic bioconversion and determination of nifedipine. In which, the TiO nanotube arrays in-situ assembled with g-CN (TNA/g-CN) was used as a photoanode, and a cytochrome P450 3A4 (CYP3A4) enzyme was immobilized in the porous ITO/CuO films to fabricate an ITO/CuO/CYP3A4 photocathode. The constructed double photoelectrode system had a significant photocurrent response compared to the single ITO/CuO/CYP3A4 or TNA/g-CN under visible light irradiation.

Photoelectrochemical determination of alkaline phosphatase activity based on a photo-excited electron transfer strategy.

A sensitive photoelectrochemical (PEC) biosensor for determination of alkaline phosphatase (ALP) activity was constructed based on a photo-excited electron transfer strategy. Immobilization of CdTe quantum dots (QDs) on TiO nanotube arrays (TNAs), addition of iron (III) and adenosine triphosphate (ATP) in turn can effectively adjust the photocurrent response of TNAs under visible light irradiation due to a photo-excited electron transfer process, and alkaline phosphatase (ALP) activity can be determined for its catalysis toward dephosphorylation of ATP. The preparation of CdTe QDs, construction of TNA/QD PEC biosensor and the mechanism of photo-excited electron transfer are investigated in the present work.

Photoelectrochemical TiO nanotube arrays biosensor for asulam determination based on in-situ generation of quantum dots.

Inspired by the photoelectrochemical (PEC) properties of TiO nanotubes arrays (TNA) and their application as a super vessel for immobilizing biomolecules, we constructed an inhibition-effect PEC biosensor for determination of asulam based on the in-situ generation of CdS quantum dots (QDs) on TNA using an enzymatic reaction. Horseradish peroxidase (HRP) enzyme was covalently assembled on the inner-wall of TNAs, which exhibited good electrochemical and catalytic properties. In the mixture solution containing HO, CdY and SO, HRP enzyme in TNAs catalyzed HO reduce SO to S.