Facile and highly sensitive photoelectrochemical biosensing platform based on hierarchical architectured...

The fabrication of photosensitive interface and molecular recognition layer at the biosensing surface are of vital importance in photoelectrochemical (PEC) biosensor construction. Developing facial methods with favorable biomolecule immobilization as well as excellent photoelectric activity still need to be explored. In this work, by integration of the merits of tungsten oxide (WO₃) semiconductor nanomaterial and polydopamine (PDA) polymer, a novel biofunctional PDA/WO₃ nanocomposites (PDA/WO₃ NCs) modified ITO hierarchical architecture was fabricated by simple thermal annealing and self-polymerization methods. The proposed PEC biosensor platform based on PDA/WO₃/ITO not only have preponderances in simple preparation, but also possesses excellent PEC activity, high specific surface area and good microenvironment for biomolecule immobilization. Utilizing CYFRA 21-1 as a model target, label-free PEC immunosensor was developed successfully, which exhibited great sensitivity and broad dynamic range with four orders of magnitude (10 pg mL^-1 to 100 ng mL^-1), and the limit of detection was as low as 2.5 pg mL^-1. Moreover, owing to the great sensitivity and selectivity of the proposed platform, this convenient sensor also performed well in real serum sample analysis. It is worth noting that our work not only helps in gaining a better understanding of the applicability of the PEC properties of PDA/WO₃ NCs, but also sheds novel light on the design and development of PEC biosensing platform based on PDA/WO₃ NCs.