In situ analysis of a silver nanoparticle-precipitating Shewanella biofilm by surface enhanced confocal Raman microscopy

Shewanella oneidensis MR-1 is an electroactive bacterium, capable of reducing extracellular insoluble electron acceptors, making it important for both nutrient cycling in nature and microbial electrochemical technologies, such as microbial fuel cells and microbial electrosynthesis. When allowed to anaerobically colonize an Ag/AgCl solid interface, S. oneidensis has precipitated silver nanoparticles (AgNp), thus providing the means for a surface enhanced confocal Raman microscopy (SECRaM) investigation of its biofilm. The result is the in-situ chemical mapping of the biofilm as it developed over time, where the distribution of cytochromes, reduced and oxidized flavins, polysaccharides and phosphate in the undisturbed biofilm is monitored. Utilizing AgNp bio-produced by the bacteria colonizing the Ag/AgCl interface, we could perform SECRaM while avoiding the use of a patterned or roughened support or the introduction of noble metal salts and reducing agents. This new method will allow a s...

奥奈达希瓦氏菌MR-1（Shewanella oneidensis MR-1）是一种电活性细菌，能够还原胞外不溶性电子受体，因此在自然环境的营养循环以及微生物燃料电池、微生物电合成等微生物电化学技术中均具有重要应用价值。当该菌厌氧定植于Ag/AgCl固体界面时，可沉淀生成银纳米颗粒（AgNp），从而为其生物膜的表面增强共聚焦拉曼显微镜（SECRaM）研究提供了可行途径。该方法可对随时间推移发育形成的生物膜进行原位化学图谱分析，实时监测未扰动生物膜内细胞色素、还原型与氧化型黄素类化合物、多糖以及磷酸盐的分布情况。通过利用定植于Ag/AgCl界面的细菌生物合成的AgNp，本研究可在无需使用结构化或粗糙化载体，也无需引入贵金属盐与还原剂的条件下开展SECRaM检测。这一全新方法将能够实现……