Target-Induced Nano-Enzyme Reactor Mediated Hole-Trapping for High-Throughput Immunoassay Based on a Split-Type Photoelectrochemical Detection Strategy

Abstract

Photoelectrochemical (PEC) detection is an emerging and promising analytical tool. However, its actual application still faces some challenges like potential damage of biomolecules (caused by itself system) and intrinsic low-throughput detection. To solve the problems, herein we design a novel split-type photoelectrochemical immunoassay (STPIA) for ultrasensitive detection of prostate specific antigen (PSA). Initially, the immunoreaction was performed on a microplate using a secondary antibody/primer-circular DNA-labeled gold nanoparticle as the detection tag. Then, numerously repeated oligonucleotide sequences with many biotin moieties were in situ synthesized on the nanogold tag via RCA reaction. The formed biotin concatamers acted as a powerful scaffold to bind with avidin-alkaline phosphatase (ALP) conjugates and construct a nanoenzyme reactor. By this means, enzymatic hydrolysate (ascorbic acid) was generated to capture the photogenerated holes in the CdS quantum dot-sensitized TiO2 nanotube arrays, resulting in amplification of the photocurrent signal. To elaborate, the microplate-based immunoassay and the high-throughput detection system, a semiautomatic detection cell (installed with a three-electrode system), was employed. Under optimal conditions, the photocurrent increased with the increasing PSA concentration in a dynamic working range from 0.001 to 3 ng mL(-1), with a low detection limit (LOD) of 0.32 pg mL(-1). Meanwhile, the developed split-type photoelectrochemical immunoassay exhibited high specificity and acceptable accuracy for analysis of human serum specimens in comparison with referenced electrochemiluminescence immunoassay method. Importantly, the system was not only suitable for the sandwich-type immunoassay mode, but also utilized for the detection of small molecules (e.g., aflatoxin B1) with a competitive-type assay format.

Protein detection based on rolling circle amplification sensors

“…AFP could be detected with an LOD of 1.7 pg/ml. [66] Photoelectrochemical detection is a promising analytical tool, however it still faces some challenges with potential damage to bio- Voltammetry Streptavidin Tris-HCl 1 pM to 500 nM 0.4 pM [59] Voltammetry Human epidermal growth factor receptor 2 -1-200 pg/ml 90 fg/ml [60] Chronocoulometry DNA methyltransferase (MTase) Tris-HCl 0.5-60.0 U/ml 0.09 U/ml [61] Voltammetry Vascular endothelial growth factor (VEGF) Tris-HCl 1 aM to 1 pM 0.27 aM [62] Voltammetry PSA PBS 0.05-500 fg/ml 0.020 ± 0.001 fg/ml [63] Voltammetry Alpha-fetoprotein Tris-HCl 0.001-200 ng/ml 0.8 pg/ml [64] Voltammetry GSH Tris-HCl 0.1 pM to 10 nM 0.1 pM [65] Amperometric Alpha-fetoprotein Tris-HCl 0.005-20 ng/ml 1.7 pg/ml [66] Photoelectrochemical Prostate-specific antigen Tris-HCl 0.001-3 ng/ml 0.32 pg/ml [67] Photoelectrochemical Prostate-specific antigen PBS 0.005 ng/ml to 50 ng/ml 1.8 pg/ml [68] F I G U R E 3 Schematic diagram of the amplified detection of lysozyme. (b) Real-time frequency shifts of amplified QCM biosensor to control samples.…”

Dual Signal Amplification Electrochemical Biosensor for Lead Cation

“…Zhuang et al. designed a target‐Induced nano‐enzyme reactor mediated hole‐trapping for high‐throughput immunoassay based on a split‐type photoelectrochemical detection strategy. Thus, electrochemical analysis technology has been widely used.…”

Cadmium Sulfide Nanoparticles Decorated with Au Quantum Dots as Ultrasensitive Photoelectrochemical Sensor for Selective Detection of Copper(II) Ions

“…Therefore, it provides a high-throughput detection system and subsequently prompts in the readout of produced photocurrent signal. Even though a lot of efforts have been reported in the utilization of hybrid structure CdS-Au in detecting biomarkers [26][27] , only a few works have been reported for sensing of heavy metal ions based on label-free method [28][29] . To the best of our knowledge, there is a gap on employing CdS NPs-Au QDs as a PEC sensing electrode material for Cu 2+ The rotational contribution to the overall excited state decay kinetics was removed by depolarizing the pump beam using a depolarizer (DPU-25, Thorlabs).…”