Nisin-loaded chitosan/sodium alginate microspheres enhance the antimicrobial efficacy of nisin against Staphylococcus aureus

• Published in: Journal of applied microbiology 2024-11, Vol.135 (11)
• Main Authors: Tang, Taya, Chen, Yinzhu, Zhao, Zhongling, Bai, Qianyu, Leisner, Jørgen J, Liu, Tianlong
• Format: Article
• Language: English
• Subjects: Alginates - chemistry; Anti-Bacterial Agents - pharmacology; Chitosan - chemistry; Chitosan - pharmacology; Glucuronic Acid - chemistry; Glucuronic Acid - pharmacology; Hexuronic Acids - chemistry; Hexuronic Acids - pharmacology; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Microspheres; Nisin - pharmacology; Particle Size; Staphylococcus aureus - drug effects; Staphylococcus aureus - growth & development
• ISSN: 1365-2672; 1365-2672
• DOI: 10.1093/jambio/lxae259

To develop and evaluate nisin-loaded chitosan/sodium alginate (CS/SA) microspheres as an improved antimicrobial delivery system targeting Staphylococcus aureus strains. The microspheres were prepared using a modified water-in-oil emulsion cross-linking method, resulting in spherical particles sized 1-8 µm with a surface charge of -7.92 ± 5.09 mV, confirmed by scanning electron microscopy (SEM) and Zetasizer analysis. Encapsulation efficiency (EE) and loading capacity (LC) of nisin were 87.60% ± 0.43% and 1.99% ± 0.01%, respectively. In vitro release studies over 48 h indicated a controlled release pattern of nisin, described by the Korsmeyer-Peppas model, with higher release rates at 37°C and alkaline pH. Antimicrobial assays showed an enhanced efficacy of nisin-loaded CS/SA microspheres compared to free nisin, with minimum inhibitory concentration values reduced by 50%. Confocal laser scanning microscopy (CLSM), SEM, and transmission electron microscopy showed significant bacterial membrane damage and cellular disruption induced by the microspheres. This study highlights the potential of nisin-loaded CS/SA microspheres as an innovative antimicrobial delivery system with improved stability and antimicrobial efficacy against S. aureus, addressing limitations associated with nisin applied alone.