A laminar-flow microfluidic device for quantitative analysis of microbial electrochemical activity.
We report a laminar flow-based microfluidic bioelectrochemical system (BES) that was fabricated by using polydimethyl siloxane (PDMS) channels and gold electrodes. The microfluidic BES was operated as a potentiostatically controlled two-electrode system. A pure culture of Geobacter sulfurreducens strain PCA, which is a model electrode-respiring bacterium, was grown in the channel and respired with the electrode under strict anaerobic conditions. We took advantage of the short hydraulic retention time (≈ 2 min) and response times (<21 min) to rapidly test the effect of certain chemical stimuli, such as O(2) and anthraquinone disulfide (AQDS), on electric current production by G. sulfurreducens. The results showed that: i) short-term (2 min) exposure to O(2) -saturated solution did not cause any irreversible toxicity to G. sulfurreducens, and ii) AQDS can be used as a redox mediator by G. sulfurreducens for shuttling electrons between the microbe and the electrode. We, therefore, demonstrate that the microfluidic BES is a promising research tool for gaining insight into microbial electrochemical activity. In our two-dimensional microfluidic-based research tool, a well-defined electrochemical environment can be maintained with the help of laminar flow without a membrane to separate two electrodes.
Department of Biological and Environmental Engineering, Cornell University, 214 Riley-Robb Hall, Ithaca, NY 14853, USA.
Zhongjian
Z
Li
Arvind
A
Venkataraman
Miriam A
MA
Rosenbaum
Largus T
LT
Angenent
D000880:Anthraquinones / Q000378:metabolism; D001674:Bioelectric Energy Sources; D004563:Electrochemistry / Q000295:instrumentation; D004566:Electrodes; D045302:Geobacter / Q000502:physiology*; D006046:Gold; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*
D000880:Anthraquinones; C408124:anthraquinone-2,6-disulfonate; D006046:Gold