Highly efficient photocathodic cascade material for constructing sensitive photoelectrochemical biosensor.

Photocathodic biosensor possesses excellent anti-interference capability in bioanalysis, which however suffers from high electron-hole recombination rate with low photocurrent. Herein, a high-performance inorganic organic PHT@C@ZnO nanosphere with cascade energy band arrangement was synthesized as photoactive signal probe, which inherited the advantages of inorganic strong optical absorptivity and organic high mobility for photo-generated holes. Specifically, the well-matched band gap endowed not only the improved life for light generated carrier and promoted separation of electron-hole pairs, but also the expansion of charge-depletion layer, significantly improving the photoelectric conversion efficiency for acquiring an extremely high photocathodic signal that increased by 30 times compared with individual materials. Accordingly, by integrating with the efficient amplification of DNA nanonet derived from clamped hybrid chain reaction (C-HCR), a sensitive PHT@C@ZnO nanosphere based photocathodic biosensor was proposed for accurate detection of p53. The experimental results showed that the biosensor had a wide detection range from 0.1 fM to 10 nM and a low detection limit of 0.37 fM toward p53, offering a new avenue to construct sensitive PEC platform with superior anti-interference ability and hold a prospective application in early disease diagnosis and biological analysis.