ε-Polylysine-loaded chitosan-sodium alginate nanoparticles (ε-PL NPs) were synthesized and characterized in terms of particle size distribution, surface morphology, thermal properties and structure, respectively. Their antibacterial activity on Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus were studied. The ε-PL NPs were well dispersed as spherical particles within the range of 200-500 nm. In vitro release studies showed an initial burst release of ε-PL from the nanoparticles followed by a sustained release. The minimum inhibitory concentrations (MIC) of ε-PL NPs against four test bacteria were 7.81 μg/mL (E. coli), 31.25 μg/mL (B. subtilis), 15.63 μg/mL (S. aureus) and 38.67 μg/mL (M. luteus), respectively. The bacteriostatic activity of ε-PL NPs was three times higher (P < 0.05) than that of free ε-PL in terms of inhibition zone diameter, suggesting that ε-PL NPs has stronger antibacterial activity. These findings may provide some basis for the application of ε-PL NPs as a promising food preservative.

合成了ε-聚赖氨酸负载的壳聚糖-海藻酸钠纳米颗粒（ε-PLNPs），并分别从粒径分布，表面形态，热性能和结构方面进行了表征。研究了它们对大肠杆菌，枯草芽孢杆菌，金黄色葡萄球菌和黄褐微球菌的抗菌活性。ε-PLNPs以200-500 nm范围内的球形颗粒形式良好分散。体外释放研究表明，ε-PL从纳米颗粒开始突然释放，然后持续释放。ε-PLNPs对四种测试细菌的最低抑菌浓度（MIC）为7.81μg/ mL（大肠杆菌），31.25μg/ mL（枯草芽孢杆菌），15.63μg/ mL（大肠杆菌）金黄色葡萄球菌（S. aureus）和38.67μg/ mL（M. luteus）。就抑制区直径而言，ε-PLNPs的抑菌活性是游离ε-PL的三倍（P <0.05），表明ε-PLNPs具有更强的抗菌活性。这些发现可能为将ε-PLNPs用作有前途的食品防腐剂提供一些依据。