Cathodic “signal-on” photoelectrochemical aptasensor for chloramphenicol detection using hierarchical porous flower-like Bi-BiOI@C composite

• Published in: Biosensors & bioelectronics 2019-04, Vol.131, p.79-87
• Main Authors: Zhu, Yuhan, Yan, Kai, Xu, Zuwei, Wu, Jinnan, Zhang, Jingdong
• Format: Article
• Language: English
• Subjects: Aptasensor; aptasensors; Bi-BiOI@C; bismuth; carbon; cathodes; Cathodic photocurrent; Chloramphenicol; detection limit; electric current; glucose; oligonucleotides; reducing agents; Surface plasmon resonance
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2019.02.008

A novel p-type semiconductor-based cathodic “signal-on” photoelectrochemical (PEC) aptasensor was proposed for highly sensitive and selective detection of chloramphenicol (CAP). The photocathode was fabricated with hierarchical porous flower-like Bi-BiOI@C composite synthesized via a one-pot solvothermal method using glucose as both green reductant and carbon precursor. Due to the surface plasmon resonance (SPR) effect of Bi and high-conductivity of carbon, the composite exhibited an enhanced cathodic photocurrent as compared with pure BiOI or Bi-BiOI. When CAP-binding aptamer was immobilized as recognition element on Bi-BiOI@C modified electrode, a cathodic PEC aptasensor showing specific “signal-on” response to CAP was constructed. Some influencing factors such as coating amount of Bi-BiOI@C suspension, applied bias potential, and aptamer concentration were studied. Under the optimum conditions, the cathodic photocurrent of the constructed PEC aptasensor increased linearly with CAP concentration from 2 to 250 nM, with a detection limit (3S/N) of 0.79 nΜ. The proposed sensor was successfully applied to the determination of CAP in pharmaceutical tablet, eye drop and lake water samples. •Cathodic “signal-on” photoelectrochemical (PEC) aptasensing strategy is developed.•Flower-like Bi-BiOI@C composite is synthesized via a one-pot solvothermal process.•Glucose is used as both green reductant and carbon precursor for composite synthesis.•Bi-BiOI@C composite exhibits an improved performance for cathodic PEC sensing.•Bi-BiOI@C is utilized to construct cathodic PEC aptasensor for CAP detection.