Quasi-BIC metasurfaces enable rapid, localized singlet-oxygen generation

concentration compared with conventional approaches. Tuning structural asymmetry and excitation wavelength enables wavelength- and position-selective cytotoxicity without additional molecular sensitizers. By decoupling strong absorption from nobel-metal usage while extending hot-carrier persistence in a single platform, BIC-engineered metasurfaces offer a general way to achieve efficient photon-to-chemical conversion at solid-liquid interfaces. This approach is of significant value to rapid-acting photodynamic therapy, selective oxidation, and flow microreactors where low dose and geometric precision are critical.