Systematic modulation of mesoporous silica particles with avobenzone and benzene-containing organosilica results in remarkable enhancement of UV protection efficiency

Abstract

A new class of mesoporous silica (MPS) based materials (1-4) for application as a protective agent against a broad spectrum of UV radiation was synthesized and characterized. The influence on the UV protection characteristics was investigated when avobenzone-encapsulated MPS surfaces were modified with 1,4-di (triethoxysilyl)benzene (L1) or 4,4'-bis(triethoxysilyl)-1,1'-biphenyl (L2), and their photostability under a sun-simulated lamp was tested. Remarkably, the composition of particles plays a vital role in UV protection performance. For example, the encapsulated avobenzone and the benzene containing organosilica coating enhanced the UV-blocking abilities of materials with the SPF values ranged 4.61-11.81. Furthermore, in vivo protection abilities were investigated against sunburn occurring on the skin of nude mice. By comparing the histological sections of the skin with sunburn-induced damage of the skin tissues at the epidermal and dermal layers, the UV protection capabilities of all materials could be deduced and established. In particular, the skin tissue treated with materials 1-4 exhibited less remarkable changes in the thickness of the epidermis. Strikingly, the skin tissue treated with material 3 did not exhibit thickening of the epidermis, which was 11 times thinner than that of the unprotected skin. Along with high stability against photodegradation, the materials showed a high potential for application as UV protection agents.