A novel signal-on photoelectrochemical sensing platform based on biosynthesis of CdS quantum dots sensitizing ZnO nanorod arrays

New approach for fabrication of photoelectrochemical sensing platform has been demonstrated for sulfate-reducing bacteria (SRB) detection based on biosynthesis of CdS quantum dots (QDs) sensitizing ZnO nanorod arrays. ZnO nanorod arrays were synthesized on the FTO substrate via galvanic-cell-based approach and then silanized by (3-Aminopropyl)triethoxysilane (APTES) with amino groups to introduce Cd2+. By taking advantage of the characteristic bacterial metabolite (H2S) reaction with Cd2+, CdS QDs can be biosynthesized on the surface of ZnO nanorod and significant enhancement of photocurrent due to the formation of CdS/ZnO heterostructures. The fabricated PEC sensing platform showed detection sensitivity of 32 cfu/mL for SRB. The current work can provide new strategies to construct advanced PEC sensing platforms for detections of physiologic messenger molecules (H2S).