High-throughput Sensing Arrays

There is a large global effort to improve microbial fuel cell (MFC) techniques and advance their translational potential toward practical, real-world applications. Significant performance breakthroughs cannot be achieved through naturally existing species without the power of genetic engineering techniques, either maximizing a specific organism’s electrogenic potential, stitching together genes involved in electrogenesis from various organisms or a bacterial electrogenic consortium. Although substantial research has been conducted on genetic engineering of microbial metabolic pathways for biofuel generation, the genetic approaches for their higher electricity generation is quite limited to date. This is mainly due to the limitations in current screening methods for the bacterial electrical properties, while microbial biofuel-producing capacity can be readily performed by using well-established microarray techniques, which are widely used to monitor gene expression under different cell growth conditions and detect specific mutations in DNA sequences. Microbial screening arrays for bioelectricity generation require much more complicated device configurations and fabrications, which include an active feeding system and dual chambers separated by a proton exchange membrane, compared to the general microbial microarray including only one chamber without any electrical measurements. Recently developed MFC arrays have complex MFC architectures with many tubings/channels that operate with external pumps, constraining the number of distinct wells on the array only to 24. If a 24-well MFC array was designed to have a two-chambered configuration requiring individual anolyte/catholyte inlets and outlets, 96 tubing ports and fluidic pathways would have to be implemented and operated by several multichannel syringe or peristaltic pumps. The electrical contacts for electrical characterization of the MFC units may increase the complexity of the device architecture. Furthermore, each MFC unit requires long start-up times for bacterial accumulation and acclimation as biofilms adhere to the anode. These limitations have motivated us to develop a new conceptual MFC array, such that the high-throughput and rapid power assessment can be significantly improved with a compact and simple device design. Currently, we are developing a paper-based microbial sensor array as a high-throughput, rapid screening tool for microbial electricity generation study.