Synthesis of phenylalanine and leucine dipeptide functionalized silica-based nanoporous material as a safe UV filter for sunscreen

To allay concerns that sunscreen ingredients are harmful to skin health, we have developed phenylalanine (Phe) and leucine (Leu) dipeptide functionalized silica-based nanoporous material (Phe-Leu-OMe-Meso) as a safe ultraviolet filter for skin protection from UVA/UVB sun irradiation. The selected peptide-based functional molecules are composed of natural amino acids, which have obvious advantages compared with other biological molecules and organic molecules, such as low toxicity and high stability. Octyl salicylate (OS) is adopted as the drug molecule to observe the adsorption behavior of the nanoporous materials. The results confirm that Phe groups effectively improve the OS loaded capacity of Phe-Leu-OMe-Meso by aromatic π–π stacking interaction, and the experimental data obey the pseudo-second-order kinetic model and the Langmuir, Freundlich, Temkin isotherm model. Moreover, in vitro evaluation of the spectrophotometric sun protection factor indicates that Leu groups make Phe-Leu-OMe-Meso possess an excellent sunscreen efficacy close to that of mesoporous TiO₂ and exhibit a synergistic effect with OS on sun protection. In summary, the dipeptide functionalization of silica-based nanoporous material has an excellent prospect in the application of sunscreen.