Synergistic Sterilization via Dual-Wavelength LED: Reducing UV Energy and Enhancing Microbial Inactivation through Optimized Irradiation Sequencing

Objective: This study proposes a novel sterilization strategy that integrates ultraviolet (UV) light, blue light (400 nm), and riboflavin-5'-phosphate (FMN) to achieve effective microbial inactivation while reducing UV energy usage and minimizing material degradation caused by prolonged UV exposure. Mechanistic analysis revealed that UV irradiation induces cyclobutane pyrimidine dimer (CPD) formation, resulting in DNA damage, whereas blue light in combination with FMN generates reactive oxygen species (ROS), which disrupt microbial cellular structures. However, blue light also activates CPD photolyase, facilitating CPD repair and thereby potentially diminishing sterilization efficacy. Importantly, the irradiation sequence was found to be critical: applying blue light prior to UV exposure (B→U) led to greater DNA destabilization, promoting higher CPD accumulation and enhanced microbial inactivation. This synergistic effect enabled a significant reduction in the required UV energy, which in turn delayed the aging of sterilized materials. The findings offer valuable insights into the design of advanced sterilization solutions for medical instruments, medical devices, and household products that incorporate materials typically susceptible to UV-induced aging and degradation, providing a balanced approach to sterilization efficacy and material preservation.