Ultrasensitive ratiometric photoelectrochemical immunoassay for prostate specific antigen based on nanoscale heterojunction

Key Words:REDUCED GRAPHENE OXIDE; GOLD NANOPARTICLES; SENSITIVE DETECTION; IMMUNOSENSOR; AMPLIFICATION; PLATFORM; SUPERCAPACITOR; PHOTOCATALYST; PHOTOCURRENT; COMPOSITE

Abstract:A new photoelectrochemical (PEC) immunosensor is fabricated for the ultrasensitive detection of prostatespecific antigen (PSA). Nanoscale poly(indole-5-carboxylic acid) (P5ICA)/WO3 p-n type heterojunction is firstly used as the photoactive material with good photoelectric activity and chemical stability. The energy level matching effect between P5ICA and WO3 is conducive to the generation of stronger photocurrent signals. The sensitization effect of this heterojunction can also increase the absorption range of visible light and improve the utilization of light. This ratiometric device includes detection section (DS) and reference section (RS), which are equipped on a single FTO electrode. DS incubates with different concentrations of PSA, and RS incubates with a constant concentration of PSA. Thus, the ultrasensitive ratiometric detection of PSA is achieved by the ratio value of photocurrents (DS/RS), reducing the impact of external factors on detection results effectively. This sensor exhibits a dynamic working range between 0.0005-50 ng mL(-1) with a limit of detection (LOD) of 0.00012 ng mL(-1) and a limit of quantification (LOQ) of 0.0004 ng mL(-1). In addition, this sensor has high selectivity, good portability and acceptable detection accuracy in actual samples, which indicates potential applications for detection of disease-related biomarkers.

Volume:326

Translation or Not:no