A Cost-Effective Hydrogel-Based Wound Model for Quantitative Evaluation of Topical Treatments in Infected Wounds

Chronic wound infections are frequently associated with bacterial biofilms, which significantly reduce the efficacy of antimicrobial treatments. Conventional in vitro evaluation methods, such as disc diffusion assays and static biofilm models, lack physiological relevance, whereas more advanced wound models are often costly, complex, and difficult to reproduce. In this study, we present a cost-effective and easily applicable in vitro wound model based on gelatin-alginate hydrogels for the evaluation of topical antimicrobial therapies. Hydrogels composed of gelatin type A and sodium alginate were integrated into a transwell system and crosslinked using microbial transglutaminase and calcium ions. This configuration enables passive diffusion of simulated wound fluid from the basolateral compartment, thereby mimicking key aspects of the wound environment. The model supports the growth of Pseudomonas aeruginosa biofilms within a three-dimensional matrix. The hydrogel system supported bacterial growth and microcolony formation during 48 h of incubation at 37 °C. The system was applied in both biofilm inhibition and eradication studies using tobramycin, ε-poly-L-Lysine and the commercially available wound gel Prontosan^®. Viable bacteria were quantitatively recovered through hydrogel dissolution followed by serial dilution and count of colony-forming units. Overall, the developed model provides a simple and accessible platform for quantitative evaluation of antibiofilm treatments. While not intended to fully replicate the complexity of native tissue, this system offers a practical alternative to collagen-based models and helps bridge the gap between conventional in vitro assays and more advanced wound models.