Genipin交联明胶/溶菌酶缓释抗菌膜材料的微结构与性能研究

Microstructure and Physical Performance of Genipin Crosslinked Gelatin/Lysozyme Films with Controlled-release Behavior

针对亲水明胶膜材料对抗菌剂缓释能力较差的问题,采用生物交联剂(genipin)调节膜材料微结构,制备出新型控释明胶/溶菌酶复合膜材料。系统研究了复合膜材料的力学性能、水汽阻隔性能、膨胀性和热性质等物理性能,并用AFM研究了膜材料的表面微结构,探讨了其结构-性能之间的关系。结果表明:genipin交联显著改善复合膜材料的力学性能,TS值从9.72 MPa逐渐增加至18.80 MPa;复合膜材料的膨胀度(swelling)随genipin浓度增加急剧下降,从1316%降至~200%;genipin交联提升复合膜材料的热稳定性。复合膜材的表面粗糙度依赖于genipin浓度,在低浓度段(0~1.0%),膜材料呈现平整表面微结构;高浓度(2.0%)时,膜表面出现不规则的突起,变得粗糙。适度的genipin交联有助于形成有序的三维网络结构,改善复合膜材料的物理性能;高浓度的genipin过度交联明胶基质,形成团聚状聚集物,及弱化明胶分子间相互作用,进而弱化膜材料的水汽阻隔能力。

Hydrophilic gelatin films are of weak controlled release behavior for antimicrobials, especially at high humidity. In order to solve this problem, novel gelatin films with controlled release of lysozyme were fabricated via the crosslink by a naturally biochemical crosslinker(genipin). Tensile property, water vapor permeability(WVP), swelling and thermal properties of composite antimicrobial films were evaluated, and their surface morphologies were visualized by AFM. The possible structure-function relationship of the films was discussed. Upon increasing genipin concentrations, mechanical resistance and stiffness of the films were enhanced, and the tensile strength(TS) gradually increased from 9.72 to 18.80 MPa. Both water stability and thermal stability were improved by genipin crosslinking, and the swelling decreased from 1316%(control) to ~ 200%. Surface roughness of the films depended on the genipin concentrations used, the surface of composite films were smooth at concentrations of 0~1.0%, with low Rq and Ra. In contrast, irregular projections were clearly visualized on the surface of the films crosslinked by 2.0% genipin. In brief, mild genipin crosslink facilitated to form ordered three-dimensional network structure in film matrix while agglomerate structure was observed in the case of high genipin concentrations(2.0%). Furthermore, the presence of genipin, especially at high concentrations may weaken the interaction between gelatin molecules, impairing the water vapor barrier capability of the films.