Development of Gelatin-Alginate Conjugate Bioink for Skin Wound Healing Applications

Abstract

Skin serves as a crucial physiological barrier; however, deep or chronic wounds frequently exhibit impaired healing due to limited vascularization and insufficient structural support. Although conventional treatments, such as wound dressings and grafts, are widely utilized, they often fail to recapitulate the complex microenvironment and spatial organization required for functional tissue regeneration. Three-dimensional (3D) bioprinting presents a promising solution by enabling the precise, layer-by-layer fabrication of cell-laden constructs that mimic native skin architecture. However, successful printing is critically dependent on the development of bioinks that possess both mechanical printability and prolonged biological activity. Although alginate and gelatin are frequently combined due to their complementary properties, physical mixtures of these polymers demonstrate significant limitations. Gelatin is thermodynamically unstable at physiological temperatures and rapidly leaches from the hydrogel network. This uncontrolled loss compromises the structural stability of the scaffold and depletes the bioactive properties essential for sustained cellular function. To address these challenges, we developed chemically conjugated Gelatin-Alginate (Gel-Alg) bioinks synthesized via EDC/NHS-mediated amide bond formation to enhance structural stability and biological functionality. The physicochemical properties, printability, and physiological stability of the Gel-Alg bioinks were evaluated in comparison with pure alginate and physical mixture bioinks. Results demonstrated that the Gel-Alg bioinks exhibited superior printability compared to the alginate bioinks. Furthermore, Gel-Alg scaffolds maintained structural integrity and minimal gelatin release over a period of two weeks, demonstrating prolonged stability and bioactivity. Biologically, the Gel-Alg group exhibited enhanced cell viability and proliferation. These findings suggest that the Gel-Alg conjugates effectively combines the printability of alginate with the biocompatibility of gelatin, offering robust and biologically active platforms for skin tissue regeneration.