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In this report, enhanced organic−inorganic heterojunction of polypyrrole@Bi 2 WO 6 was fabricated and applied for sensitive photoelectrochemical (PEC) immunoassay of creatine kinase-MB (CK-MB). Specifically, heterostructured polypyrrole@Bi 2 WO 6 photoelectrode was prepared and sandwich immunorecognition were integrated for the CK-MB immunoassay. In the detection, with the aid of alkaline phosphate (ALP)-induced biocatalytic precipitation (BCP), the precipitation-dependent suppression of the photocurrent can be recorded due to the impediment of the interfacial mass and electron transfer. On the basis of target-controlled BCP formation, a novel PEC immunoassay could be developed for the sensitive and specific CK-MB detection. This work manifested the great potential of polypyrrole@Bi 2 WO 6 heterojunction as a novel platform for PEC bioanalysis development and also a PEC method for CK-MB detection. This work is expected to stimulate more interest in the design and implementation of numerous other organic−inorganic heterojunction for advanced PEC bioanalysis development. • Organic−inorganic heterojunction of polypyrrole@Bi 2 WO 6 was fabricated. • Sandwich immunorecognition was directed on the heterojunction electrode. • Photoelectrochemical immunoassay of creatine kinase-MB was realized. [ABSTRACT FROM AUTHOR]

Liposome-assisted photoelectrochemical (PEC) bioanalysis represents one of the latest frontiers in the arena of PEC bioanalysis. This work reports a general enzyme-amplified liposomal PEC bioanalysis protocol via the use of enzyme-loaded liposomes to boost the biocatalytic precipitation (BCP) effect. In the representative system, the horseradish peroxidase (HRP)-loaded liposome (HRPLL) and the Au nanoclusters (NCs)/Au nanoparticles (NPs)/TiO 2 nanotubes (NTs) framework (AATF) were used as liposomal label and photoelectrode, respectively. In the detection, the sandwich immunocomplex reaction was accomplished in a 96-well plate to confine the HRPLL label, which was then lysed to release the HRP molecules to initiate the BCP process. Due to the amplified formation of HRP-induced BCP on the AATF scaffold, the photo-current response correlated closely with the immunorecognition process and the analyte could be detected very sensitively. This work features the first integration of enzyme-loaded liposomes and the BCP for sensitive PEC bioanalysis, which to our knowledge has not been reported. With the use of various other enzymes, this work could serve as a general basis for the PEC bioanalysis of numerous other target of interest. Image 1 • Peroxidase (HRP)-loaded liposomes were prepared. • The released HRP could induce enhanced biocatalytic precipitation. • The as-derived photoelectrochemical immunoassay has good performance. [ABSTRACT FROM AUTHOR]