Bacterial cellulose (BC) has become of great interest in recent years, as a delivery system in several areas of application, including food, drugs, and cosmetics, thanks to its exclusive advantages, such as high biocompatibility, water holding capacity, and good gas permeability. The novel approach of the authors has led to a protocol for checking the quality and safety of bacterial cellulose matrices in the manufacture of cosmetic masks. Two non-destructive techniques, near-infrared spectroscopy (NIR) and multiple light scattering (MLS), were used to verify different parameters affecting the quality of BC sheets, allowing cellulose masks to be checked over time. NIR spectroscopy allowed for discovering changes in the water content, depending on filling/packaging procedures, like flat-folding. Multiple light scattering was used to ascertain the stability of solutions in contact with masks. From a clinical standpoint, the cutaneous tolerability of biocellulose masks, and their effect on skin parameters, were evaluated through some specific “in vivo” tests. Also, a safety evaluation during application was conducted through different studies: a short-term one after single application, and a long-term one upon continued use.
Resonance effects in multiple light scattering from statistically rough metallic surfaces
