Optimization of Citrus aurantifolia peel extract encapsulation in alginate-gelatin hydrogel microbeads for antibacterial wound dressing applications
Euis Julaeha, Winda Rian Puspita, Nandang Permadi, Asep Harja, Sarifah Nurjanah, Tatang Wahyudi, Jamaludin Al Anshori
Abstract
The extract of Citrus aurantifolia peel has been encapsulated into alginate-gelatin-based microbeads using an external ionotropic gelation method to apply antibacterial wound dressings. Such variables, like the alginate-gelatin ratio, extract quantity, and CaCl2 cross-linkers, were optimized to produce a good yield, well-distributed size, and encapsulation efficiency. Antibacterial efficacy was tested against both S. aureus and E. coli. Optimal microbead characteristics were obtained at alginate:gelatin concentration ratio of 1.75%:0.25% (w/v), with 15 mg of extract and a 2% CaCl2 cross-linker. These conditions resulted in the microbeads with 82.94 ± 1.056% yield, particle sizes between 1.080-1.244 µm, and encapsulation efficiency of 79.127 ± 0.186%. The microbeads exhibited an almost spherical morphology with a slightly rough surface. The extract release mechanism out of the microbeads was governed by both diffusion and erosion of the shells following the Korsmeyer-Peppas kinetic model (k=1.014 ± 0.007/min). Upon immobilizing the microbeads on gauze, an add-on percentage of 73.98% was observed. Moreover, the gauze-immobilized microbeads inhibited S. aureus and E. coli growth with inhibition zones of 11±1.48 and 12.56±4.89 mm, respectively. In conclusion, the antibacterial alginate-gelatin-based microbeads have demonstrated optimal characteristics and exhibited effective inhibition against S. aureus and E. coli, showcasing their potential as antibacterial wound dressings.