Bilayer Wound Dressing Composed of Allograft Collagen-Glycosaminoglycan and Silicone: Synthesis, Characterization and Biological Behavior

Restoring the physiological function of the damaged skin is crucial due to its undeniable protective role as well as its aesthetic aspects. Herein, a novel bilayer freeze-dried scaffold comprised of allograft collagen and glycosaminoglycan (Col-GAG; the biocompatible inner layer) adhered to silicone (mechanically reinforcing component) utilizing gelatin as the bio-glue was prepared to benefit from each origin (human-derived and synthetic) advantages. The structural characterizations of the scaffolds were analyzed by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), tensile stress test, water uptake behavior, and Water Vapor Permeability (WVP). Also, the scaffolds' cytocompatibility was assessed by culturing human dermal fibroblasts (HDF) on the samples. Furthermore, the in vivo functionality was performed by implanting the scaffolds in male mice and observing the cellularization as well as neovascularization by Hematoxylin and Eosin (H&E) staining and CD31 marker. Based on the results, the potentially amorphous scaffolds were three-dimensional (3D) porous with randomly oriented interconnected pores suitable for cellular ingrowth. The application of the silicone layer resulted in resisting the extra osmotic pressure of water molecules by decreasing the water uptake ratio to 59.2 ± 0.33%, maintaining the WVP at an approximate rate of 0.1–10 mg/cm 2 hr, and boosting the tensile strength to 1.66 ± 0.12 MPa. The grafts provided an optimum environment for cell attachment and presented cellular viability upper than 70% after 72h. In vivo assessment exhibited improved perivascular localization, with the cell migration rate approximating 64%. The outcomes indicated that the achieved scaffold holds promise as an ideal wound dressing.