松油烯-4-醇脂质体/CS-PEO纳米纤维的控释机理及抗菌机制研究

Essential oil-containing chitosan antimicrobial materials are widely studied and applied due to their excellent biological compatibility and antimicrobial function. According to the problems in many previous studies that the obvious burst effect of essential oil and the decreased antimicrobial activity caused by the weak bonding force of essential oil components and chitosan, liposomes are used to encapsulate terpinen-4-ol which is the main antimicrobial ingredient of tea tree oil and added into chitosan-polyethylene oxide spinning solution to prepare chitosan-polyethylene oxide nanofibers containing terpinen-4-ol liposomes by electrospinning. The combination of terpinen-4-ol liposomes and chitosan, terpinen-4-ol liposomes distribution in the nanofibers and the surface activity of nanofibers are optimized. The release process of terpinen-4-ol is studied and the effects of distribution effect of liposomes, fiber diameter and porosity on the release behavior of terpinen-4-ol are explored. The controlled-release mechanism is clarified through the release kinetics and thermodynamic model. The antimicrobial performance of nanofibers are evaluated and the effects of terpinen-4-ol liposomes concentration, fiber structure, fiber surface charge and functional groups on antimicrobial property are explored. Whether there is a synergistic antimicrobial effect between terpinen-4-ol liposomes and chitosan is verified through micro-structure analysis of material, the combination of microorganisms and cell biology technology to clarify the antimicrobial mechanism of nanofibers. These researches will provide a certain theoretical basis for the development of a novel, controlled-release, efficient antimicrobial composite material.

精油壳聚糖抗菌材料凭借其优良的生态相容性和抗菌性能，广泛地受到研究和应用。本项目针对以往的许多研究中精油成分与壳聚糖结合力弱引起的精油突释效应明显以及抗菌活性下降等问题，利用脂质体包载茶树精油主要抗菌成分松油烯-4-醇掺入壳聚糖-聚氧化乙烯纺丝液中，静电纺丝法制备松油烯-4-醇脂质体/CS-PEO纳米纤维，优化松油烯-4-醇脂质体与壳聚糖的结合及在纤维中的分布、纤维表面活性；研究松油烯-4-醇的释放过程，探究脂质体分配效应和纤维直径、孔隙率对松油烯-4-醇释放行为的影响，通过释放动力学、热力学模型阐明控释机理；评估纳米纤维的抗菌性能，探究松油烯-4-醇脂质体浓度和纤维结构、表面电荷与官能团对抗菌性能的影响。通过材料微结构分析，结合微生物及细胞生物学技术验证松油烯-4-醇脂质体与壳聚糖是否存在协同抗菌作用，阐明抗菌机制。本项目的研究为开发新型、可控释、高效的复合抗菌材料提供一定的理论依据。

为了进一步提高精油组分在抗菌材料中分布的均一、稳定性和释放的可控性，增强材料长时程抗菌性能，本课题采用松油烯-4-醇脂质体掺入CS-PEO纺丝溶液中，静电纺松油烯-4-醇脂质体/CS-PEO纳米纤维。系统研究了纳米纤维的外观形态、化学组成、晶体结构等特征，分析和阐明了材料中松油烯-4-醇的释放行为和控释机理、材料的抗菌性能和抗菌机制。.1）采用脂质体技术包裹茶树精油有效抗菌组分松油烯-4-醇，以壳聚糖、聚氧化乙烯为成纤基材，将松油烯-4-醇脂质体掺入壳聚糖、聚氧化乙烯混合溶液，静电纺制备松油烯-4-醇脂质体/CS-PEO纳米纤维材料。.2）具体研究了材料基本结构和性能的影响规律。随着松油烯-4-醇脂质体掺入量的增加，纤维直径增大，孔隙率降低，水蒸气透过率降低，吸水性下降，保水时间逐渐提高，干湿态下拉伸强度、杨氏模量和断裂伸长率逐渐降低，体外降解速率加快，凝血能力下降。纺丝液中加入抗氧化剂能增强松油烯-4-醇脂质体/CS-PEO纳米纤维膜的抗氧化能力，使松油烯-4-醇更加稳定。.3）详细研究了材料中松油烯-4-醇的释放过程和影响规律，阐明控释机理。随着TOLs浓度降低，聚合物浓度增加，CS/PEO比例增大，交联剂用量增加，抗氧化剂浓度增大，材料中松油烯-4-醇的突释效应减弱，累积释放率逐渐减小。采用修正的溶胀控释模型对纤维中松油烯-4-醇释放行为进行拟合，材料中松油烯-4-醇释放受Fick扩散的控制。.4）系统研究了松油烯-4-醇脂质体的掺入对材料抗菌性能的影响，阐明抗菌机制。松油烯-4-醇脂质体/CS-PEO纳米纤维对金黄色葡萄球菌、大肠杆菌和白色念珠菌有显著抑制效果。随着松油烯-4-醇脂质体浓度的提高，抑菌效果增强。经过该材料处理后，金黄色葡萄球菌菌体外膜破裂，内容物尚未流出；大肠杆菌菌体外膜结构基本未被破坏，细胞内的组分发生变性、凝聚；白色念珠菌细胞结构被完全瓦解，内容物大量外流。该纳米纤维直接将菌体吸收、截留在材料内部进行杀灭，松油烯-4-醇在细胞内作用，其局部松油烯-4-醇浓度可达到较高水平，完全满足杀灭各种微生物的要求。