A novel HEMA-based copolymer hydrogel film with excellent ultraviolet/high-energy short-wavelength blue light shielding

The human body is susceptible to the adverse effects of exposure to ultraviolet (UV) radiation and high-energy shortwave blue light, which can increase the risk of skin cancer and eye damage. Consequently, light barrier materials have been developed to reduce the radiation hazards of UV and high-energy shortwave blue light. In this study, a novel photobarrier hydrogel was successfully prepared by free radical polymerization using hydroxyethyl methacrylate (HEMA), N-vinylpyrrolidone (NVP) and para-aminoazobenzene (PAAB) as comonomers in aqueous medium. The prepared hydrogels have a surface porous structure and remarkable thermal stability, with decomposition occurring at temperatures above 200 °C. The results of the ultraviolet visible transmission spectrum and light barrier effect experiments show the excellent light barrier rate of the material, with the hydrogel HNP-3 exhibiting a light barrier rate of over 71%. Cytotoxicity assay is performed to identify the favorable biocompatibility of the hydrogel, which can be attributed to the polymerization of PAAB onto polymeric chains. This process effectively inhibits the diffusion of PAAB into cells, thereby preventing adverse effects on cellular function. Based on these findings, it can be concluded that the hydrogel film materials in this study hold great potential for application in a range of applications that require protection of biological tissues such as the eyes and skin from UV or blue light.