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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]

Liposomal photoelectrochemical (PEC) bioanalysis holds enormous potential for future sensitive PEC bioanalysis. With tyrosinase (Tyr) and TiO 2 as representative enzyme and electrode, respectively, this communication reports the elegant use of Tyr-loaded liposomes (TLL) toward in situ sensitization of the electrode and thereby the realization of ultrasensitive PEC immunoassay. Specifically, Tyr-encapsulated and detection antibody-functionalized liposomes were first prepared and used as the signal probe. The subsequent sandwich immunobinding could confine the functional liposomes, which were then lysed with surfactant to release the encapsulated Tyr. The free Tyr could then initiate the transformation of tyrosine to dopa, the latter could bind with the undercoordinated Ti sites, forming the stable dopa–Ti charge transfer complex and thus generating enhanced anodic photocurrent under visible light for signaling. Since different semiconductors and enzymes may be adapted into this format, this work is expected to stimulate more interest in the enzyme-induced activation of semiconductors for advanced liposomal PEC bioanalysis. • Tyrosinase-encapsulated liposomes was fabricated and used as labels. • In situ sensitization of the TiO 2 electrode was realized by tyrosinase catalytic chemistry. • The system exhibited good performance for PEC immunoassay application. [ABSTRACT FROM AUTHOR]