Liposome-Mediated In Situ Formation of Ag₃PO₄/AgBr/Br-CN Ternary Nanostructures on Photoanodes for Photoelectrochemical Immunoassay

Abstract

A dual-photoelectrode self-powered photoelectrochemical (PEC) biosensing system for protein was proposed based on the liposome-assisted signal amplification strategy. The dual-photoelectrode self-powered device was constructed by integrating Ag 3 PO 4 with bromine-doped g-C 3 N 4 (Ag 3 PO 4 /Br-CN) as a photoanode and CuInS 2 as a photocathode synchronously. Ag nanoparticle (AgNP)encapsulated liposomes as tags were labeled on the target protein through a sandwich immunoreaction implemented in a 96-well plate. The AgNP-encapsulated liposomes were used to generate the signal regulator Ag + for PEC detection. In the presence of Ag + , the reaction between Ag + and Ag 3 PO 4 /Br-CN occurred to form Ag 3 PO 4 /AgBr/Br-CN ternary heterostructures. The compact contact and the matchable band-edge levels of Ag 3 PO 4 , AgBr, and Br-CN in the ternary heterostructures broaden the light absorption range and efficiently restrain the electron−hole recombination of the photoanode, producing an enhanced photocurrent response. The large loading capacity of liposomes, the fine performance of the formed ternary heterostructures, and the well-designed dual-photoelectrode selfpowered PEC device endows the biosensing system with high sensitivity for protein detection. Using prostate-specific antigens as model proteins, the biosensing system exhibited a low detection limit of 3.4 × 10 −13 g mL −1 with a linear range of 1.0 × 10 −12 g mL −1 to 5.0 × 10 −8 g mL −1 . The marriage of the self-powered system with the liposome-assisted strategy not only represented a generic method for protein detection but also provided a path to fulfill the requirement of high sensitivity in PEC analysis.

In Situ Growth Reaction on Photoelectrodes of Single-Atom Fe Incorporated Bi4O5I2: A General Photoelectrochemical Immunoassay Toward Sensitive Protein Analysis

“…For the anti-Myo-Ag NPs that were applied as the probe, Ag NPs were also characterized by TEM and UV–vis absorption spectra. An absorption peak centered at 400 nm can be observed in Figure S3A, indicating the successful preparation of Ag NPs . According to the TEM image and the size distribution of Ag NPs in Figure S3B, Ag NPs displayed a spherical structure and exhibited a normal distribution from 7 to 17 nm with a diameter of about 11 nm.…”

“…Ag NPs were synthesized referring to our previous work . Briefly, Ag NPs colloids were first prepared by mixing 10 mL of AgNO 3 (0.001 M) with 10 mL of cold NaBH 4 (0.003 M) solution under stirring.…”

“…For example, Gao’s group fabricated a PEC immunosensor for heart-type fatty acid binding protein detection based on the in situ formation of ZnInS nanosheets (ZIS NSs)/SnS 2 type-Ι heterojunction on the FTO/ZIS NSS-Sn (IV) electrode. Our group constructed a PEC biosensing system for prostate-specific antigens by reacting Ag + and Ag 3 PO 4 /Br-CN to generate Ag 3 PO 4 /AgBr/Br-CN ternary heterojunction in situ on the ITO electrode. It can be deduced that the ingenious combination of the single-atom-based photoactive materials and in situ growth reaction sensing strategy would greatly improve the performance of the PEC sensor.…”

Split-type photoelectrochemical immunoassay for sensitive quantification of carcinoembryonic antigen based on target-induced in situ formation of Z-type heterojunction

“…19,20 Xiao et al proposed a PEC biosensor based on Ag 3 PO 4 /bromine-doped g-C 3 N 4 and Ag nanoparticle-encapsulated liposomes, in which the photocurrent could be enhanced by the formation of a new heterostructure. 21 Wu's group loaded Na 2 S solution into mesoporous silica nanospheres to construct a signal-off PEC protocol based on BiOBr/BiOI for the sensitive detection of prostate-specific antigen. The photocurrent decreased due to the in situ generation of Bi 2 S 3 , which hindered the reaction between dissolved oxygen and photogenerated electrons.…”

Dual Engine Boosts Organic Photoelectrochemical Transistor for Enhanced Modulation and Bioanalysis

“…With the integration of both the photoanode and photocathode, dual-photoelectrode systems have proved superiority over single-photoelectrode system across diverse sectors, such as photocatalysis, electrochemiluminescence, and photovoltaic. − In biosensors, dual-photoelectrode systems have exhibited enhanced photoelectric response due to the dual responses and the so-called “self-biasing” effect, which has been increasingly applied for detecting various targets. , Further endeavors have been made to enhance photoelectric conversion efficiency through exploring new materials or constructing heterojunctions upon one or two photoelectrodes. For example, Yan et al employed WO 3 @CdS photoanode and Co-CuInS 2 photocathode for the analysis of carcinoembryonic antigen .…”