International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan; Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
Bioelectrochemistry. 2022 Dec;148:108252. doi: 10.1016/j.bioelechem.2022.108252. Epub 2022 Aug 27.
Numerous bacteria owe extracellular electron transport (EET) ability, and the rate enhancement of EET is critical for the emerging sensor technology to detect metabolically active pathogens. Here, the considerable enhancement of microbial current signal was firstly demonstrated in a thin layer electrolyte sandwiched between an agar substrate (AS) containing high concentration riboflavin (RF) and a screen-printed electrode. Covering cells with this AS showed a sharply current increase from 0.033 µA to 1.59 μA (47.7-folds) in EET-capable bacteria Shewanella oneidensis MR-1. Differential pulse voltammograms using gene-deletion mutant strains of S. oneidensis MR-1 revealed thin electrolyte between RF-loaded AS and electrode enhanced the rate of electron transfer via complexes between riboflavin and outer membrane c-type cytochrome. A similar effect in Streptococcus mutans UA159, a biofilm-forming pathogen, was also explored. Moreover, capturing and quantifying both metabolically active microbes from the dry solid surface are demonstrated with RF-loaded AS successfully. The considerable enhancement of the EET in the thin layer electrolyte provides a new direction for designing whole-cell biosensors and understanding a microbe/electrode interaction in a micro-sized space.
许多细菌具有细胞外电子传递（EET）能力，而 EET 速率的增强对于新兴的传感器技术检测代谢活跃的病原体至关重要。在这里，首次在夹在含有高浓度核黄素（RF）的琼脂基质（AS）和丝网印刷电极之间的薄层电解质中证明了微生物电流信号的相当大增强。用这种 AS 覆盖细胞，在具有 EET 能力的细菌希瓦氏菌属（Shewanella oneidensis MR-1 中，电流从 0.033 µA 急剧增加到 1.59 µA（47.7 倍）。使用希瓦氏菌属（Shewanella oneidensis MR-1 的基因缺失突变株的差分脉冲伏安法表明，RF 负载的 AS 和电极之间的薄层电解质增强了通过核黄素和外膜 c 型细胞色素之间的复合物传递电子的速率。在形成生物膜的病原体变形链球菌（Streptococcus mutans UA159 中也探索了类似的效果。此外，还成功地用 RF 负载的 AS 从干燥固体表面捕获和定量两种具有代谢活性的微生物。在薄层电解质中 EET 的显著增强为设计全细胞生物传感器和理解微尺度空间中微生物/电极相互作用提供了新的方向。
