桑蚕丝胶/柞蚕丝素/明胶基共混抗菌膜的制备及表征

Preparation and characteristics of bombyx mori sericin/tussah silk fibroin/gelatin-based blended antibacterial films

为了制备出安全、抗菌性能优的生物膜,文章以桑蚕丝胶、柞蚕丝素和明胶为生物基材,聚乙二醇200作为交联剂,制备桑蚕丝胶/柞蚕丝素/明胶基(BS-TSF-GEL)共混膜。通过设计单因素试验和正交试验优化BS-TSF-GEL共混膜的制备工艺,对膜的结构与性能进行表征,并利用吸附的方式载入抗菌肽,获得抗菌生物膜。研究结果表明,BS-TSF-GEL共混膜优化后的配方为体积比2︰1的桑蚕丝胶(4.50μg/mL)/柞蚕丝素(27.5 mg/mL)混合液,聚乙二醇200和明胶溶液(360 mg/mL),它们在总体系中占比分别为35%、40%和25%。所制备的BS-TSF-GEL共混膜溶失率为34.62%,断裂伸长率为34.15%,断裂强度为578.8 kPa。傅里叶红外光谱及X-射线衍射结果表明,BS-TSF-GEL共混膜以SilkⅡ为主,并伴有少量的SilkⅠ结构;BS-TSF-GEL共混膜呈淡黄色,表面含有微孔,负载抗菌肽的共混膜对大肠杆菌和金黄色葡萄球菌均具有良好的抑制作用,有望在伤口敷料等一次性使用的生物医用材料领域得到应用。

A large number of wound dressings are currently used in the treatment of burns,chronic ulcers,etc.An ideal wound dressing should prevent dehydration of the wound and retain a favorable moist environment at the wound interface.It should have good antibacterial properties and be easily removed without trauma,too.Wound dressings are generally made of readily available bio-materials that require minimal processing,possess nontoxic,non-allergenic,and antimicrobial properties,as well as promote wound healing.Clinically,collagen,chitin,chitosan,etc.are usually used as materials for producing wound dressings as these materials are capable of accelerating the healing processes at molecular,cellular,and individual levels.Tussah silk fibroin,bombyx mori sericin,and gelatin,non-toxic and extensive,have good bio-compatibility,degradability,and film-forming properties,which are conducive to cell adhesion.In order to prepare safe biofilms with excellent antibacterial properties,we prepared a kind of bombyx mori sericin/tussah silk fibroin/gelatin(BS-TSF-GEL) blended film by using tussah silk fibroin,bombyx mori sericin,and gelatin as bio-based materials,and polyethylene glycol 200 as the cross-linking agent.Firstly,we designed the single factor experiment and orthogonal experiment to optimize the preparation process of the BS-TF-GEL blended film.On this basis,the blended film was modified with ethanol of different concentrations to improve its strength and crystallinity.The structure and properties of the blended film were characterized by measuring the dissolution loss rate,tensile properties,microscopic morphology,and crystal structure.Finally,antimicrobial peptides were loaded by adsorption to obtain the BS-TSF-GEL antimicrobial film.The results showed that the ratio of the optimum formula for the BS-TSF-GEL blended film required a mixture of bombyx mori sericin(4.50 μg/mL) and tussah silk fibroin(27.5 mg/mL) with a volume ratio of 2︰1,polyethylene glycol 200 and gelatin solution(360 mg/mL),which accounted for 35%,40% and 25%,respectively of the total system.The dissolution loss rate of the BS-TSF-GEL blended film was 34.62%,the elongation at break was 34.15%,and the breaking strength was 578.8 kPa after being treated with anhydrous ethanol.FTIR and X-ray diffraction results showed that Silk Ⅱ dominated the BS-TSF-GEL blended film,while Silk Ⅰ was in a small amount.The BS-TSF-GEL blended film was pale yellow and porous on the surface,which was the ideal material for loading antimicrobial peptides.The BS-TSF-GEL blended film loaded with antimicrobial peptides had a good inhibitory effect on both Escherichia coli and Staphylococcus aureus.It is expected to be used in the field of disposable biomedical materials such as wound dressings.In this study,three natural materials with unique advantages were selected as substrates for biofilms,and polyethylene glycol with high bio-safety was used as the cross-linking agent to enhance the application value of the blended film by loading antimicrobial peptides.The results broaden the application field of silkworm silk and provide a new way for the development and exploitation of silk fibroin in biological dressings and other medical bio-materials.Bombyx mori sericin,tussah silk fibroin,and gelatin have been widely used in biological tissue engineering as natural biological materials.In this study,three natural materials were used as the biofilm substrate to successfully prepare excellent-performance BS-TSF-GEL blend film using polyethylene glycol cross-linking and ethanol post-treatment techniques.Moreover,specific properties can be conferred by replacing different loading substances,such as antimicrobial biofilm carrying antimicrobial peptides,and biofilm sustained release carrier loading drugs.In addition,3 D printing,electrostatic spinning,and other technologies can also be used to shape the BS-TSF-GEL into different shapes to meet the application requirements under different conditions.In conclusion,the research results explore a new way for the application of silk protein.