Development of an advanced biopolymer patch for skin tissue regeneration

Traditional passive wound dressings present significant limitations, including poor biocompatibility, inadequate mechanical strength, and uneven material distribution. This study addresses these challenges by enhancing hydrogel strength through UV-induced thiol-ene click chemistry, incorporating biocompatible polymers, chitosan (CS), hyaluronic acid (HA), and polyvinyl alcohol (PVA), and leveraging 3D printing for uniform porous scaffold architecture. Hydrogels composed of CS, HA, and PVA were prepared in various ratios. Chemical cross-linking was achieved using thiolated HA or PVA blended with allyl-modified CS, resulting in OAL-CS/PVA-SH/HA and OAL-CS/PVA/HA-SH formulations. The degree of cross-linking was evaluated through printability parameters (extrudability, uniformity, pore integrity) and physicochemical characterizations, including FTIR, XRD, water sorption, and hydrolytic degradation studies. FTIR analysis confirmed successful UV cross-linking via the disappearance of the alkene (CH₂=CH₂) peak at 1637 cm⁻¹. XRD patterns revealed that UV-cross-linked scaffolds exhibited reduced crystallinity, indicating a more amorphous structure—contributing to enhanced water absorption and permeability. Among all tested formulations, the OAL-CS/PVA-SH/3HA scaffold demonstrated the most favorable properties, including controlled degradation over 30 days, with minimal mass loss and exceptionally high water absorption (2412%), attributed to its amorphous network. Furthermore, 3D printing evaluations showed that this scaffold maintained a stable, uniform porous structure during multilayer deposition, supporting better cell distribution and facilitating uniform tissue formation. In conclusion, the OAL-CS/PVA-SH/3HA scaffold emerges as a promising candidate for tissue engineering, outperforming physically cross-linked variants in terms of mechanical stability, print fidelity, and biocompatibility.