Development of Chitosan Membranes Loaded with 18-beta-Glycyrrhetic Acid for Skin Regeneration and Repair

The development of biodegradable nano-structured membranes that provide physical support, mechanical stimuli and biochemical cues able to modulate the cell fate, represents a major challenge for the creation of skin tissues. Flat nanoporous chitosan (CHT) membranes were developed and tested as promising biomaterials for skin reconstruction, since they allow the formation of specific epidermal strata and complete dermal/epidermal constructs [1, 2]. A further strategy is represented by the membrane loading with a bioactive molecule constantly released in the time that facilitate the biological processes needed for skin reconstruction and repair. In this work, microporous membranes of chitosan loaded with a natural compound with therapeutic and healing properties were developed. 18-beta-Glycyrrhetic Acid (GA) is a natural derivative of Licorice (Glycyrrhiza) extract, with a wide range of pharmacological activities, including anti-allergic, anti-oxidant, anti-carcinogenic, anti-inflammatory, immune-modulatory, wound healing, and protective of aging- and UV-induced skin damages. The biomolecule was incorporated in the microporous structure of the chitosan membrane as a water-soluble inclusion complex with beta-cyclodextrin (beta-CD). Cyclodextrins are recognized as promising pharmaceutical excipients in several formulation and biomaterials for controlled drug delivery and release of hydrophobic molecules, and as versatile cues to study cellular behaviour [3]. Composite CHT membranes, with different ratio of betaCD-GA inclusion complex, were realized by phase inversion process. Membranes were characterized to evaluate structural, physico-chemical and biodegradation properties, and the GA incorporation and release were assessed in the time. Successively, the developed membranes were used for the formation of epidermal constructs by using human keratinocytes that were maintained for 21 days of culture. The morphological behaviour, proliferation, metabolic functions, and the expression of specific cytokeratins involved in the keratinocytes differentiation, were expressed at different levels by cells cultured on native chitosan membrane, and on chitosan/betaCD-GA composite membranes highlighting the pivotal role played by GA. These results represent a starting point for the development of new membranes that incorporate bioactive molecules useful in the tissue regeneration processes of the epidermis, and that could be used as a patch for topical drug delivery, wound healing and skin repair. References[1] S. Salerno, A. Messina, F. Giordano, A. Bader, E. Drioli, L. De Bartolo. Dermal-epidermal membrane systems by using human keratinocytes and mesenchymal stem cells isolated from dermis. Mater Sci Eng C-Mater Biol Appl, 71 (2017), 943-53.[2] S. Salerno, S. Morelli, F. Giordano, A. Gordano, L. De Bartolo. Polymeric membranes modulate human keratinocyte differentiation in specific epidermal layers. Colloid Surface B-Biointerfaces, 146 (2016), 352-62.[3] F. Valle, S. Tortorella, A. Scala, A. Cordaro, M. Barbalinardo, F. Biscarini and A. Mazzaglia. Amphiphilic cationic cyclodextrin nanovesicles: a versatile cue for guiding cell adhesion. Nanoscale Adv. (in press) DOI: 10.1039/d0na00623h.