Recent advances in microfluidic-based photoelectrochemical (PEC) sensing platforms for biomedical applications.

Photoelectrochemical (PEC) techniques seamlessly combine electrochemical and spectroscopic principles, offering a powerful platform for the detection of biomarkers and biological molecules in clinical and biomedical settings. This review provides a comprehensive overview of microfluidic PEC probes, emphasizing their potential for ultrasensitive detection through enhanced light absorption and charge transfer processes. Key advantages of microfluidic PEC include real-time monitoring of biological processes, non-invasive detection, and the possibility of multiplexing when integrated with various quantification modalities. However, the practical implementation of PEC faces challenges such as bulky setup, matrix interference, and stability of PEC-active materials. Also, this paper discusses the intricate mechanisms of PEC sensing, highlighting the roles of nanomaterials in enhancing microfluidic PEC systems. Additionally, the limitations inherent in PEC material selection, including stability and bandgap engineering, are critically discussed. Solutions such as doping and the development of composite materials are proposed to address these issues. Through presented examples of PEC applications in biomedical fields, this review elucidates the future potential of PEC-based methods as reliable and effective tools for diagnostic applications. Additionally, this review proposes the most effective probes for future investigations to develop commercial devices.