Unlocking the Promise of Bacterial Electrogenicity

微生物电子转移能力，或“电致性”创造了大量的概念和潜在的应用，在生物燃料、废水处理、生物修复、海水淡化和生物传感等领域提供了环境可持续发展的进步。尽管其巨大的潜力和显著的研究努力，细菌电原性可以说是最不发达的技术用于这些应用。对自然存在的微生物的内在能量和电子转移过程施加了严格的限制。随着合成生物学的发展，这项技术的重大进步可以实现，合成生物学可以操纵微生物的电子转移途径，提高它们的发电潜力。我们需要的是一种高通量、快速和高灵敏度的测试阵列，用于研究数百种新发现的基因工程细菌物种的电原性。这绝不是一个简单的挑战，因为准确和平行的细菌电性定量测量需要很长的测量时间（10天），不断引入有机燃料（10毫升），复杂的设备架构和劳动密集型操作。这项NSF提案的总体目标是创造一种快速（5分钟）、灵敏（10倍改进）和高通量（384孔）的能力，从一滴培养物（1微升）中表征细菌的电性。研究结果将首先通过当地和国际会议和期刊出版物在学科内传播；然后，它们将通过教育场所分发，最大限度地扩大项目的覆盖范围和影响。该项目的目的是研究一系列令人兴奋的可能性，以支持将微生物燃料电池技术与新兴的纸质电子领域“papertronics”融合在一起的目标。优化后的组合可以创建一种新的可扩展，高通量传感阵列，用于简单，敏感和快速的微生物电性定量。本研究将使用纸作为设备衬底，它固有地为微生物液体样品的简单、快速和敏感控制创造有利条件。这种高通量阵列将通过3d毛细管驱动传感器在一张纸上的打印工艺批量制造。通过改善导电纸储层中微生物与电极的电子交换，并使用固体电子受体降低阴极过电位，可以实现高性能纸上微生物燃料电池的完全集成。此外，纸张固有的毛细力和工程储层容量的增加将允许细菌样品的快速吸附，并促进微生物细胞立即附着在电极上，从而仅用少量液体即可立即发电。所提议的研究的直接潜在好处是：(i)它将为大规模生物传感应用创造第一个基于纸张的方法，结合流体和电子元件，这将增加纸张电子学的早期工作；（ii）它将提供数百种细菌电原性的高通量并行分析，深入了解与其基因工程相关的细胞外电子转移途径。（iii）它将促进能源和环境相关的研究，帮助扩大科学家对大规模利用可持续可再生能源的理解和能力，从而激发下一代的科学思想。

Microbial electron transfer capability, or 'electrogenicity' creates a plethora of concepts and potential applications that offer environmentally sustainable advances in the fields of biofuels, wastewater treatment, bioremediation, desalination, and biosensing. Despite its vast potential and remarkable research efforts, bacterial electrogenicity is arguably the most underdeveloped technology used for those applications. Severe limitations are placed on the intrinsic energy and electron transfer processes of naturally occurring microorganisms. Significant boosts in this technology can be achieved with the growth of synthetic biology that manipulates microbial electron transfer pathways and improves their electrogenic potential. What is needed is a high-throughput, rapid and highly sensitive test array for investigating the electrogenicity of hundreds of newly discovered, genetically engineered bacterial species. This is by no means a simple challenge, as accurate and parallel quantitative measurements of bacterial electrogenicity require a long measurement time (10's of days), continuous introduction of organic fuels (10's of milliliters), complex device architectures, and labor-intensive operation. The overall objective of this NSF proposal is to create the ability to achieve rapid (5 min.), sensitive (10-fold improvement), and high-throughput (384 wells) characterization of bacterial electrogenicity from a single drop of culture (1 microliter). Findings will first be disseminated within the discipline through local and international conferences and journal publications; then they will be distributed through educational venues maximizing the project's reach and impact.The purpose of this project is to investigate an exciting range of possibilities which support the goal of fusing microbial fuel cell technology with 'papertronics' the emerging field of paper-based electronics. An optimized combination can create a new kind of scalable, high-throughput sensing array for simple, sensitive, and rapid quantification of microbial electrogenicity. This research will use paper as a device substrate that inherently produces favorable conditions for easy, rapid, and sensitive control of a microbial liquid sample. The high-throughput array will be batch-fabricated through printing-only processes of 3-D capillary-driven sensors on a single sheet of paper. Full integration of a high-performance microbial fuel cell on paper can be achieved by improving the microbial electron exchange with the electrodes in an engineered conductive paper reservoir and reducing cathodic overpotential using a solid electron acceptor on paper. Furthermore, the intrinsic capillary force of the paper and the increased capacity from the engineered reservoir will allow for rapid adsorption of the bacterial sample and promote immediate microbial cell attachment to the electrode, leading to instant power generation with only a small amount of the liquid. The immediate potential benefits of the proposed research are that (i) it will create the first paper-based approach for large-scale biosensing applications, incorporating fluidic and electronic components, which will augment early work in papertronics, (ii) it will provide a high-throughput parallel analysis of hundreds of types of bacterial electrogenicity with in-depth understanding of extracellular electron transfer pathways that are relevant to their genetic engineering, and (iii) it will catalyze energy and environment-related research, helping to expand scientists' understanding of, and ability to, harness sustainable renewable energy sources that scale, thus inspiring the next generation's scientific minds.