Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE The gelatin/ε-polylysine covalent conjugates were prepared through a facile ring-opening addition reaction employing ethylene glycol diglycidyl ether as a cross-linking reagent. The products exhibited significant antibacterial activity. As the amount of ε-polylysine increased, the minimum bactericidal concentration of the samples decreased significantly. This method demonstrates potential as a universal and cost-effective method for preparing antibacterial gelatin derivatives.

ABSTRACT
Gelatin had been widely used in the fields of food, cosmetics, biomedicine, etc. However, bacterial infection remained a critical threat in these fields and had serious risks to human health and life. Unfortunately, gelatin lacked inherent antibacterial properties, which limited its broader applications. Although several strategies had been developed to synthesize modified gelatin with antibacterial properties, it was still a challenge to prepare antibacterial gelatin at low cost. In this work, the gelatin/ε-polylysine covalent conjugates were prepared through a facile ring-opening addition reaction employing ethylene glycol diglycidyl ether (EGDE) as a cross-linking reagent. The Fourier-transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (NMR) spectra, X-ray photoelectron spectroscopy (XPS), primary amino contents, amino acid analysis, molecular weight, zeta potential, viscosity, gel strength, melting/gelling temperatures, and dissolution time of the covalent conjugates were characterized. The products exhibited significant antibacterial activity, as confirmed by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. The cell counting kit-8 (CCK8), live/death staining, and hemolytic properties were studied in detail and the results showed that the gelatin/ε-polylysine covalent conjugates possessed favorable cytocompatibility. This approach avoided the use of expensive cross-linking reagents, thereby maintaining low production costs for the modified gelatin. The ring-opening addition reaction demonstrates potential as a universal and cost-effective method for preparing antibacterial gelatin derivatives.