贪铜杆菌Cupriavidus sp. SHE细胞上清液合成纳米硒

Characteristics of selenium nanoparticles synthesized by cell-free supernatant Cupriavidus sp. SHE

摘要:

近年来，纳米硒凭借其良好的导电、光热以及抗癌等特性，在纳米技术、生物医学以及环境修复等诸多领域得到广泛应用。实验选择前期筛选得到的贪铜杆菌Cupriavidus sp. SHE，文中探究了该菌株的细胞上清液、全细胞以及胞内提取物合成纳米硒的能力，并对细胞上清液合成的纳米硒进行形貌表征与官能团分析，最后选取革兰氏阳性菌假单胞菌Pseudomonas sp. PI1和革兰氏阴性菌大肠杆菌Escherichia coli BL21进行抗菌实验。结果表明，菌株Cupriavidus sp. SHE的细胞上清液、全细胞以及胞内提取物均具有合成纳米硒的能力。对于菌株Cupriavidus sp. SHE细胞上清液而言，在该实验中，研究范围内其合成纳米硒的最佳条件是SeO2浓度为5 mmol/L，pH为7。透射电子显微镜结果表明合成的纳米硒颗粒主要为球形，平均直径为196 nm。X射线衍射结果表明合成的纳米硒晶体类型为六方形结构。傅立叶转换红外光谱和聚丙烯酰胺凝胶电泳结果表明纳米硒表面有小分子蛋白结合，可能参与了纳米硒的合成和稳定过程。此外，抗菌实验表明菌株Cupriavidus sp. SHE细胞上清液合成的纳米硒颗粒对菌株E.coli BL21和Pseudomonas sp. PI1均无明显的抗菌活性。综上，该研究表明菌株Cupriavidus sp. SHE在细胞上清液中产生的蛋白类物质在其合成纳米硒的过程中发挥了重要作用，合成的生物纳米硒颗粒无毒且生物相容性良好，未来在生物医学等领域具有较好的应用潜力。

Abstract:

In recent years, selenium nanoparticles (SeNPs) have been widely used in many fields such as nanotechnology, biomedicine and environmental remediation due to their good electrical conductivity, photothermal properties and anticancer properties. In this study, the cell-free supernatant, whole cell and the cell-free extracts of the strain Cupriavidus sp. SHE were used to synthesize SeNPs, and several methods were applied to analyze the crystal structure and surface functional groups of the nanoparticles. Finally, Pseudomonas sp. PI1 (G+) and Escherichia coli BL21 (G-) were selected to investigate the antibacterial properties of SeNPs. Cell-free supernatant, whole cell and cell-free extracts of the strain could synthesize SeNPs. As for the cell-free supernatant, selenite concentration of 5 mmol/L and pH=7 were favorable for the synthesis of SeNPs. TEM images show that the average size of nanospheres synthesized by the supernatant was 196 nm. XRD analysis indicates the hexagonal crystals structure of SeNPs. FTIR and SDS-PAGE confirmed the proteins bound to the surfaces of SeNPs. SeNPs synthesized by cell-free supernatant showed no antimicrobial activities against Pseudomonas sp. PI1 and Escherichia coli BL21 (DE3). These results suggest that proteins played an important role in biotransformation of SeNPs in an eco-friendly process, and SeNPs synthesized in this study were non-toxic and biologically compatible, which might be applied in other fields in the future.