Bacterial nanocellulose membranes loaded with vitamin B-based ionic liquids for dermal care applications

Abstract

The development of innovative bio-based skin care products has received an increased attention in the latter years. In the present work, the synthesis of original active principle ingredients based on ionic liquids (ILs) with cholinium cation and vitamins B anions, followed by their incorporation in bacterial nanocellulose (BC) membranes for topical applications, is reported. Three ILs, namely cholinium nicotinate [Ch][B3], cholinium pantothenate [Ch][B5] and cholinium pyridoxylate [Ch][B6], were synthesized through a metathesis reaction and their structure characterized in detail. Thermal analysis confirmed their denomination as ILs and their high thermal resistance. The solubility of these ILs was higher than their vitamin precursors, especially in the case of [Ch][B3] whose solubility increased 30.6-fold enhancing the bioavailability of this vitamin. The incorporation of ILs in BC led to translucent and homogeneous membranes stable up to 190 °C. ILs acted as plasticizers reducing BC brittleness that facilitated their application on irregular skin regions. Moreover, the re-hydration ability of BC-ILs membranes was improved 2.9 to 4.8-fold in comparison to BC, ensuring adequate hydration for ILs release, while the release of ILs in buffer solutions was more complete and faster than the release of vitamins. Finally, BC-ILs were proven not cytotoxic to skin epithelial cells and thus are suitable materials for skin care applications.