Ch3 ch2 11so4na

Fresh porcine skin was obtained from a local abattoir. After cleaning the cadaver, removing the subdermal fat tissue and hair, the tissues were rinsed thrice with sterile water and subjected to freeze–thaw (–80 to 37°C) cycles for three consecutive times. At 120 rpm and constant temperature (25°C), the tissues were treated with 1% Triton X-100 solution (Sinopharm Chemical Reagent Co., Ltd., China) for 12 h and 1% CH₃(CH₂)₁₁SO₄Na (Sinopharm Chemical Reagent Co., Ltd., China) for 6 h. The resulting acellular dermal matrix (ADM) tissues were washed by phosphate-buffered saline (PBS) for several times and freeze-dried overnight. Then those samples were milled to a powder (i.e. ADM) and digested by high-quality pepsin powder in a dilute HCL solution (pH 2–3) containing different concentrations of vancomycin for 6 h. The osmotic pressure was adjusted by dropping 40X PBS buffer, and the pH was adjusted to 7.2–7.4 by gradual dropwise addition of 10-M sodium hydroxide (NaOH) cooled beforehand. These steps were performed aseptically. Five samples of the skin were separately prepared in the following compositions: (1). Porcine ADM hydrogel; (2). Porcine ADM hydrogel containing 1 mg/mL vancomycin (represented as VADM1); (3). VADM2; (4). VADM4; and, (5). VADM6. The pH-adjusted formative gel can be stored at 4°C for up to 1 week.

Vancomycin was purchased from Aladdin (Shanghai, China), Triton X100 and CH₃(CH₂)₁₁SO₄Na from Sinopharm Chemical Reagent Co., Ltd. (China), Pig glycosaminoglycan (GAG) ELISA Kit from Jianglai Biotechnology Co., Ltd (Shanghai China), Hyp assay kit from Beijing solarbio science & technology Co., Ltd. (China). Agar from Sangon Biotech Co., Ltd. (Shanghai, China), TRYPTONE from OXOID (Shanghai, China), and soya peptone from Sinopharm Chemical Reagent Co., Ltd. (China). DNA kit from CW Biotech (Beijing, China), Live/dead cell staining dye was purchased from BioVision (USA), and Cell Counting Kit-8 (CCK8) from APExBIO Technology LLC (USA).