Isolation and characterization of Chitosan from shrimp shell waste and the sustainable preparation of salicylic acid-loaded Chitosan nanoparticles for antibiofilm applications

Microbial biofilms present a significant global health challenge, as they are associated with severe chronic infections and the emergence of antibiotic resistance. Currently, only a limited number of clinically available drugs effectively target microbial biofilms. This underscores the urgent need for the development of new sustainable therapeutic strategies to address biofilm-associated infections. Developing a sustainable and biodegradable preparation for eradicating microbial biofilms is critically important. In this study, chitosan was extracted from shrimp shell waste and utilized to prepare salicylic acid-loaded chitosan nanoparticles (NPs) using various synthesis methods. The particle size of the prepared nanoparticles ranged from 287.4 to 226.3 nm, with zeta potential values between + 36.6 and + 41.3 mV, indicating good stability. The nanoparticles demonstrated safety, with half maximal inhibitory concentration (IC₅₀) values ranging from 1009 to 1346 µg/mL. The combination of chitosan and salicylic acid exhibited significant antibiofilm activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Candida albicans, with particularly high efficacy against Candida albicans, achieving up to 85% biofilm inhibition. While the particle size and antibiofilm activity of the nanoforms showed minimal differences, formulation M4, using sodium alginate, stands out as the most eco-friendly option. This study highlights the potential of bio-sustainable chitosan-based formulations for combating biofilm formation and addressing antimicrobial resistance.