Hydrolyzed bacterial cellulose as a UV radiation barrier

This study investigates the potential of hydrolyzed bacterial cellulose (hBC) for UV radiation protection. BC membranes are produced under static conditions by Komagataeibacter sucrofermentans, purified, mechanically shredded, and hydrolyzed. As a result, hBC exhibits colloidal properties at various concentrations (0.34 - 11 mg ml(-1)). With a water-holding capacity of 89.1% +/- 0.341, hBC forms a 3.65 mu m thick transparent film with an approximate density of 7 mu g per mm(2). In Scanning Electron Microscopy (SEM) analysis, the lengths of filamentous BC particles were between 50 and 300 nm, while the lengths of rod-like nanocrystalline cellulose were between 400 and 1500 mu m. According to dynamic light scattering (DLS) result, 88% of the particles were approximately 1 mu m long. The zeta potential was -25.13 +/- 0.65 mV, hBC showed thixotropic behaviour, and its crystallinity was 92. hBC and its films exhibited barrier properties to UV radiation (190-400 nm). The highest UV absorbance (almost 100%) for all UV regions (UV-A, UV-B and UV-C) of hBC in colloidal form is at a concentration of 11 mg ml(-1). At most, the UV transmittance of all UV regions of the hBC films was 16%. Sun protective factor (SPF) values of colloidal and film forms of the hBC at a concentration of 11 mg ml(-1) and 212 mu g/mm(2) were 29 and 12, respectively. hBC was not cytotoxic on mouse fibroblast L929 and human keratinocyte (HaCaT) cells. In conclusion, hBC can be an alternative UV radiation protector and thickening agent. This study represents the first report on the UV barrier property of hBC for aqueous formulations.