Liposome-Assisted Enzymatic Modulation of Plasmonic Photoelectrochemistry for Immunoassay

Recently emerged liposomal photoelectrochemical (PEC) bioanalysis has brought new opportunities for biosensor development. This work presents the new concept of liposome-assisted enzymatic modulation of plasmonic photoelectrochemistry for PEC bioanalysis, which was exemplified by an Au nanoclusters (NCs)-sensitized nanoporous TiO₂ nanotubes (Au NC@TiO₂ NT) photoelectrode and an alkaline phosphatase (ALP)-loaded liposomal immunoassay of heart-type fatty acid binding protein in a 96-well plate. After sandwich immunorecognition and subsequent lysis treatment, enzymatically generated ascorbic acid by the released ALP was directed to reduce Au³⁺ into Au nanoparticles using the Au NCs as seeds, leading to the in situ change of the photoelectrochemistry of the electrode and corresponding reduction of the photocurrent. The depressed signal could be correlated with the target concentration with good analytical performance in terms of sensitivity and selectivity. This work features the liposome-assisted enzymatic modulation of plasmonic photoelectrochemistry, which provides a new protocol for general PEC bioanalysis development.