脂肽递送系统的构建及其抑菌作用研究

Construction and Antibacterial Activity Evaluation of a Lipopeptide Delivery System

摘要:

【目的】通过构建稳定的脂肽（lipopeptide，LP）递送系统，提升其环境稳定性和分散性，进而增强其抗菌效果。【方法】利用壳聚糖（chitosan，CS）和海藻酸钠（sodium alginate，SA）构建LP微粒，通过差异构建及单因素试验研究其组装性质的变化；采用傅里叶红外光谱仪（FT-IR）和流变仪研究CS、LP、SA之间的相互作用及体系的流变特性；以大肠杆菌（Escherichia coli，E. coli）和金黄葡萄球菌（Staphylococcus aureus，S. aureus）为模型菌株，探究LP微粒的抗菌效果。【结果】将相对分子质量300 000的CS滴入低黏度SA与LP的混合溶液中，且当三者质量比为1∶1∶1、搅拌速率为150 r/min、pH为4时，所构建的LP微粒封装效果最佳；此时LP微粒的封装率为（92.95±1.31）%，载药量为（41.14±1.63）%，粒径为420~489 nm，Zeta电位为（-21.56±3.54） mV。FT-IR结果表明，LP被包埋于LP微粒内部，微粒外壳为SA；流变学数据显示，该复合物为水凝胶结构。此外，LP微粒对E. coli和S. aureus具有较强的抑制作用，且其对温度和紫外辐照的敏感性较低。【结论】该研究构建的LP微粒可有效抑制LP的聚集效应，提升其抵抗环境胁迫的能力，为脂肽类抗菌剂在食品保鲜等领域的应用提供了一种新方案。

Abstract:

[Objective]This study constructed a stable lipopeptide (LP) delivery system to improve the stability and dispersibility of LP, thereby enhancing their antibacterial efficacy.[Method]LP particles were constructed with chitosan (CS) and sodium alginate (SA). Assembly property changes were evaluated by means of different construction and single factor experiments. Interactions among CS, LP, and SA were investigated by Fourier transform-infrared spectroscopy (FT-IR), and the rheological properties of the system were examined by a rheometer. Antibacterial activity of LP particles was evaluated with Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus) as model microorganisms.[Result]LP particles prepared by dripping CS with the relative molecular mass of 300 000 into a mixed solution of SA (low viscosity) and LP at the CS∶LP∶SA mass ratio of 1∶1∶1, 150 r/min, and pH 4 achieved the best encapsulation performance. The LP particles prepared under the conditions above showed the encapsulation rate of (92.95±1.31)%, loading content of (41.14±1.63)%, particle size of 420~489 nm, and Zeta potential of (–21.56±3.54) mV. FT-IR results indicated that LP was encapsulated inside the particles, with SA forming the outer shell. Rheological data confirmed a hydrogel-like structure. In addition, LP particles showed strong inhibitory effects against both E. coli and S. aureus and resistance to thermal and UV stress.[Conclusion]LP particles constructed in this study not only reduce LP aggregation but also provides effective protection against environmental stress, offering a promising strategy for the delivery of LP-based antimicrobials in fields such as food preservation.