Self-Assembled Microfiber-Like Biohydrogel for Ultrasensitive Whole-Cell Electrochemical Biosensing in Microdroplets

• Published in: Analytical chemistry (Washington) Vol. 95; no. 5; pp. 2628 - 2632
• Main Authors: Ma, Xiao-Meng, Wang, Jian-Wei, Zhao, Li-Ting, Zhang, Yafei, Liu, Jun-Ying, Wang, Songmei, Zhu, Daochen, Yang, Zhugen, Yong, Yang-Chun
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.02.2023
• Subjects: Bacteria; Biosensing Techniques - methods; Biosensors; Calibration; Capillary tubes; Cell density; Cell size; Chemistry; Electric Conductivity; Electrochemical Techniques - methods; Electrochemistry; Fumarates; Graphene; Graphite; Limit of Detection; Microfibers; Residential density; Self-assembly; Silver chloride; Systems design
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.2c05155

A novel microfiber-like biohydrogel was fabricated by a facile approach relying on electroactive bacteria-induced graphene oxide reduction and confined self-assembly in a capillary tube. The microfiber-like biohydrogel (d = ∼1 mm) embedded high-density living cells and activated efficient electron exchange between cells and the conductive graphene network. Further, a miniature whole-cell electrochemical biosensing system was developed and applied for fumarate detection under −0.6 V (vs Ag/AgCl) applied potential. Taking advantage of its small size, high local cell density, and excellent electron exchange, this microfiber-like biohydrogel-based sensing system reached a linear calibration curve (R2 = 0.999) ranging from 1 nM to 10 mM. The limit of detection obtained was 0.60 nM, which was over 1300 times lower than a traditional biosensor for fumarate detection in 0.2 μL microdroplets. This work opened a new dimension for miniature whole-cell electrochemical sensing system design, which provided the possibility for bioelectrochemical detection in small volumes or three-dimensional local detection at high spatial resolutions.