Material Nanochemistry Laboratory, Physical Sciences Division, and ‡Drug Discovery Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology , Paschim Boragaon, Garchuk, Guwahati 781035, India.
ACS Appl Mater Interfaces. 2016 Aug 17;8(32):20625-34. doi: 10.1021/acsami.6b07510. Epub 2016 Aug 2.
We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis potentiality tests and MTT assays of the nanocomposite films indicated a noncytotoxic nature of the films, which conveyed the possibility of potential applications of these soft and tough films in biomedical as well as in the food industry.
我们报告了一种由壳聚糖-氧化铁涂覆的氧化石墨烯纳米复合材料水凝胶制成的具有抗菌性能的稳健生物膜。我们首次使用共沉淀法成功合成了氧化铁涂覆的氧化石墨烯（GIO）纳米材料。在此之后，我们通过凝胶铸造技术制备了薄膜，并借助壳聚糖水凝胶网络系统的自修复能力来辅助。我们使用扫描电子显微镜、傅里叶变换红外光谱、X 射线衍射和振动样品磁强计等技术对纳米材料和纳米复合材料薄膜进行了表征。对薄膜的热力学稳定性和机械性能的测量表明，它们的热学和力学性能得到了显著改善。此外，应力-应变曲线表明了纳米复合水凝胶薄膜的韧性。因此，这些改进表明 GIO 纳米材料与壳聚糖水凝胶基质之间存在有效的相互作用和良好的相容性。此外，还可以通过改变水凝胶基质中 GIO 纳米材料的负载百分比，简单地制备具有可调表面性质的薄膜，例如疏水性。有趣的是，壳聚糖-氧化铁涂覆的氧化石墨烯纳米复合材料水凝胶薄膜对金黄色葡萄球菌、金黄色葡萄球菌和大肠杆菌等革兰氏阳性和革兰氏阴性细菌菌株以及机会性皮肤真菌白色念珠菌表现出显著的抗菌活性。我们通过琼脂扩散试验和基于直接接触的抗菌试验来测试薄膜的抗菌活性。将壳聚糖-GIO 纳米复合材料水凝胶薄膜的抗菌活性与单独的壳聚糖-氧化石墨烯和壳聚糖-氧化铁纳米复合材料薄膜进行比较，结果表明，在这两种类型的试验中，前者的抗菌活性更高。纳米复合薄膜的体外溶血潜力试验和 MTT 分析表明，这些薄膜具有非细胞毒性，这传达了这些柔软坚韧的薄膜在生物医学和食品工业中有潜在应用的可能性。
