Cell culture media

All cell-culture media and reagents were purchased from Biological Industries (Beit-HaEmek, Israel). The skin samples were obtained from healthy women (between 30 and 65 years old) who were undergoing aesthetic abdominal surgery and had signed an informed consent form. The experiments were conducted with the approval of the IRB (Helsinki Committee) of Soroka Medical Center, Beer Sheva, Israel. Human skin culture preparation and treatments were performed under aseptic conditions. A mechanical skin-press apparatus was used to section the skin into 0.64 cm² pieces, as previously described (Scheme 2; left).^{45 (link)} The skin explants were maintained in an air–liquid interface, with the dermal side submerged in the liquid. The biopolymers were applied topically (3 μL). After 48 h, the spent media were discarded and IL-1α was evaluated by ELISA (Biolegend, CA, US). In addition, the epidermis was separated and viability was determined by MTT, as previously reported after 48 h (Scheme 2; right).^{46 (link)} For morphological evaluation, the samples were fixed with 4% formaldehyde for 1 h at room temperature. Then, the tissues were washed with PBS and kept in 70% ethanol at 2–8 °C until use. Following dehydration, paraffin sections (10 μm) were prepared, and slides were stained with hematoxylin-eosin solution.