Photoelectrochemical signal polarity transition mediated by quercetin for the detection of neuron specific enolase

Abstract

A photoelectrochemical (PEC) biosensor with a wide detection linear range was developed for neuron-specific enolase (NSE) sensitive detection, which realized by a photocurrent polarity transition strategy mediated by quercetin. The coupling reaction between Cr(Ⅵ) and quercetin drive the signal polarity from anodic to cathodic. When quercetin in the test solution only, the photogenerated electrons transferred to the electrode to generate anodic photocurrent. When the target was detected, the signal probe was treated and released Cr(Ⅵ), which interact with quercetin and the electrons transfer direction was changed to achieve signal polarity conversion. Meanwhile, protoporphyrin-sensitized Bi: SrTiO3 nanocubes were used as the matrix photoactive materials to provide basic photocurrent. The doping of Bi element would prefer the bandgap of SrTiO3, and the organic-inorganic composite material has good photostability and chemical stability, that can maintain stable photoelectric properties over a long period of time. Such a novelty signal polarity transition strategy greatly broadened the sensor detection range of 0.00007 ~170 ng/mL and obtained a relative low detection limit (25 fg/mL), which greatly improved the detection sensitivity and accuracy of the biosensor