Target-induced nano-enzyme reactor mediated hole-trapping for high-throughput immunoassay based on a split-type photoelectrochemical detection strategy.
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.
Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE and Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou 350108, People's Republic of China.
Junyang
J
Zhuang
Chongqing Key Laboratory of Environmental Materials and Remediation Technologies, Chongqing University of Arts and Sciences , Chongqing 402160, People's Republic of China.
Dianyong
D
Tang
Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE and Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou 350108, People's Republic of China.
Wenqiang
W
Lai
Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE and Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou 350108, People's Republic of China.
Mingdi
M
Xu
Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE and Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou 350108, People's Republic of China.
Dianping
D
Tang
D000469:Alkaline Phosphatase / Q000378:metabolism*; D001360:Avidin / Q000378:metabolism; D001483:Base Sequence; D019187:Cadmium Compounds / Q000737:chemistry; D004247:DNA / Q000737:chemistry / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004563:Electrochemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D008958:Models, Molecular; D043942:Nanotubes / Q000737:chemistry; D009690:Nucleic Acid Conformation; D055668:Photochemical Processes; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000097:blood; D045663:Quantum Dots / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
D019187:Cadmium Compounds; D017931:DNA Primers; D013440:Sulfides; C034939:cadmium sulfide; D001360:Avidin; C009495:titanium dioxide; D004247:DNA; D014025:Titanium; D000469:Alkaline Phosphatase; D017430:Prostate-Specific Antigen