Light as a master switch: a critical review of photonanozymes from design to applications.

Despite the widespread industrial applications of nanozymes, their usage is often limited by mechanistic factors. They lack reaction control with catalyst fouling, which limits catalytic turnover and makes nanozyme recovery an energy-intensive process at large scale. These mechanistic challenges have been addressed by the evolution of photoresponsiveness into nanozymes called as photonanozymes (PNZs). This research is focused to critically assess the architecure of photonanozymes leading to photoresponsivness. A three domain framework deconstructing photoresponsive mechanism with research road map to guided subsequent investigation constitutes the distinctive contribution of this review. The photoresponsive architechture elucidates the mechanism of light gated catalysis governed by wavelength selectivity and spatiotemporal precison. Thereby, expanding the enzyme mimicking catalysis and its applciations in environmental remediation, theragnostics, cancer therapy, biosensing and biofuel synthesis. Rather than merely describing the operating principles of photonanozymes, rational foundation is build up which determines future design. Challenges impeding photocatalytic mechanisms are critically examined including limited wavelength selectivity, insufficient opertional stability and difficulty of achieving reproducible and scalable synthesis. Presented review strategizes a forward-looking roadmap centered around robust PNZ design, standardized performance, and translation of light-programmable catalysis from laboratory proof-of-concept to practical technology. Through a rigorous and comprehensive examination of inherent complexities, it frames PNZs as a transformative step towards programmable, self-healing nanomaterials with controlled implications, serving as an invaluable resource for those seeking orientation within photocatalysis. Furthermore, it reaches beyond its immediate boundaries, presenting new ideas, evidence-based conclusions, and prospective directions intended to influence the course of future investigations.