Bacterial Cellulose As a UVB Filter to Protect the Skin Microbiota

Certain aerobic bacteria produce bacterial cellulose (BC) to protect themselves from UV radiation. Inspired by this natural function, the UV-filtering capacity of wet BC film (BC) and dried BC (BC-Dried) is evaluated and it is concluded that both samples hardly filter UVA, but filter UVB to some extent, especially BC-Dried. Moreover, this filtering capacity does not diminish but significantly increases with time, with efficiencies in the 145-160 min time range equal to or greater than most UV filters of the market. This increase in efficiency is due to the fact that the BC structure is modified by prolonged exposure to UVB radiation. Specifically, UVB causes sintering of the cellulose fibers, making the structure denser and increasing its reflection and scattering of UVB radiation. Remarkably, this UVB filtering ability of BC allows it to protect key skin probiotics, Lactobacillus fermentum (L. fermentum) and Cutibacterium acnes (C. acnes), against UVB damage. While the protection of healthy skin microbiota is not currently a regulatory requirement for sunscreens with UV filters, it may become a key differentiator for future UV filters given the increasing evidence on the role of skin microbiota in health. Bacterial cellulose (BC), a biomaterial produced by certain bacteria to protect themselves from UV represents an alternative to commercial UV filters. BC filters UVB radiation with high efficiency, especially at longer times, and protects the probiotics Lactobacillus fermentum and Cutibacterium acnes from UVB damage, which is relevant given the increasing evidence of the role of skin microbiota in health. image