Semiautomated Support Photoelectrochemical Immunosensing Platform for Portable and High-Throughput Immunoassay Based on Au Nanocrystal Decorated Specific Crystal Facets BiVO₄ Photoanode

Abstract

Photoelectrochemical (PEC) measurement has been developed rapidly for bioanalysis in recent years. However, the actual application for most existed PEC bioanalytical systems is still a challenge because the perfect solutions for sensing surface design, high-throughput detection, and portability are lacked. To successfully overcome these limitations and realize accurate, continuous screening and assessing on prognostic indicator of early stage cancer on the spot, an innovative and portable semiautomated support power-free photoelectrochemical (SP-PEC) immunosensing platform consisted with a miniature semiautomatic injection system and digital multimeter (DMM) readout is designed (prostate specific antigen, PSA, was used as the proof-of-concept analyte). Decahedral BiVO that decorated with Au nanocrystal on {010} facets (Au-BiVO) by photodeposition is used as the photoanode materials to produce photocurrent signal under irradiation of micro laser light (5.0 w, λ ≥ 380 nm). The monoclonal anti-PSA capture antibody (mAb)-functionalized FeO magnetic nanobeads (mAb-MN) and glucose oxidase (GOx)/monoclonal detection antibody (mAb)-conjugated gold nanoparticle (GOx-AuNP-mAb) are employed as immunosensing probe and signal probe, respectively. The HO as an excellent holes scavenger that in suit generated from GOx oxidization glucose substrate significantly amplifies the photocurrent. The variation of instantaneous current value that registered as the signal of the immunoassay increases linearly with the logarithm of target PSA concentration increasing in a wide range from 10 pg mL to 100 ng mL with a low detection limit (LOD) of 4.0 pg mL. The SP-PEC immunosensing platform not only simplifies the assay process, but also improves detecting efficiency. The semiautomatic and portable SP-PEC analysis device allows analysis on spot and high-throughput continuous detection. Additional, we also gain deep insight into the relations between the specific shape as well as Au nanocrystal decoration and PEC activity and speculate the possible enhancement mechanisms of Au-BiVO. Therefore, the present work not only develops a flexible SP-PEC biosensor platform for rapid and continuous detection, but also provides a possible route for designing high performance photoelectric materials.

Selective Deposition of Ag3PO4 on Specific Facet of BiVO4 Nanoplate for Enhanced Photoelectrochemical Performance

“…In theory, the maximum OER photocurrent density can reach 7.6 mA cm −2 approximately under AM 1.5G solar illumination . However, some defects limit the achievable actual photocurrent intensity, such as short holes lifetime, poor carriers transport property, unsatisfactory electron‐hole separation yield, and low utilization efficiency of surface‐reaching holes . Therefore, various attempts have been made to eliminate the above‐mentioned drawbacks …”

NiFe‐layered Double Hydroxide/Vertical Bi2WO6 Nanoplate Arrays with Oriented {001} Facets Supported on ITO Glass: Improved Photoelectrocatalytic Activity and Mechanism Insight

“…Taking this into account, Bi 2 WO 6 with exposed lattice plane parallel to the [Bi 2 O 2 ] 2+ layers and exposing more Bi and O atoms would exhibit excellent photocatalytic activity. The {001} facets were found to satisfy these two criteria, therefore, Bi 2 WO 6 with a large proportion of {001} facets would exhibit excellent photocatalytic activity [12–15] . Many efforts have been devoted to the synthesis of {001}‐oriented Bi 2 WO 6 [12,16] .…”

Semimetal Bismuth‐Enhanced Light Adsorption and Interface Charge Transfer in Bi@BiVO4

“…However, the photoactivity still remains unsatisfactory for the practical applications due to a low electric conductivity and a low charge separate efficiency . To date, many strategies are developed to enhance its photoactivity . Among them, that noble‐metal‐based Schottky junctions are demonstrated to be one of the most efficient methods.…”

“…Among them, that noble‐metal‐based Schottky junctions are demonstrated to be one of the most efficient methods. Typically, Au decoration has greatly improved photoelectric propensities of BiVO 4 photoanode . However, its high cost and rare resource severely limit the wide application.…”