Optimization of lysozyme-modified ion exchange nanofiber membrane for efficient capture of Escherichia coli: Antibacterial and cytotoxic studies

Background: Lysozyme, a natural antibacterial agent, is widely used across various fields but faces limitations such as reduced effectiveness against Gram-negative bacteria, high costs, and a limited lifespan. Methods: To address these challenges, chemical immobilization techniques on PAN nanofiber membranes were employed, optimizing critical factors like alkaline hydrolysis time, pH, and initial lysozyme concentration to ensure efficient immobilization with strong antibacterial efficacy and sustainability. The resulting nanofiber membrane, named P-COOH-LYZ, was characterized theoretically and experimentally, with cytotoxicity also investigated. Significant findings: The study found that the maximum efficacy was achieved under optimal chemical immobilization conditions, resulting in a notable two-fold enhancement of antibacterial activity against Gram-negative E. coli, with free lysozyme exhibiting 45.30 % efficacy compared to 95.61 % for P-COOH-LYZ. The novel material also demonstrated remarkable reusability and stability, retaining 94.22 % and 75.64 % activities after five cycles of reuse and five weeks of storage at room temperature, respectively. Furthermore, the material showed no cytotoxicity, establishing it as a safe option for various body-related applications.