CAREER: Electrochemiluminescence in Microfluidics for Mechanistic Studies of Redox Reactions and Single Particle Sensing

在化学系化学测量和成像(CMI)计划的支持下，以及化学、生物工程、环境和运输系统(CBET)部生物传感计划的部分资助下，印第安纳大学-普渡大学印第安纳波利斯分校的弗雷德里克·戴斯将研究还原-氧化(Redox)反应，以及利用电化学发光(ECL)和微流控技术检测单个颗粒。为了应对当前分析化学中单一实体的识别和测量方面的挑战，戴斯博士将整合电化学、微流体学、光谱学和材料科学，利用液滴中的ECL来产生单一实体电化学方法。ECL是氧化还原活性分子在一系列电化学反应后发出的光。这项研究将为阐明化学机制提供新的策略，研究结果将应用于朝着检测单个细菌的目标取得进展。如果成功，这项研究将通过产生一种快速和高灵敏的细菌计数方法来帮助社会，这是临床测试和工业质量控制等领域所需的，并增加对化学和生物系统的理解。微流控设备的一个子类是纸基设备。它们的通用性、低成本、便携性和用户友好特性使许多研究以及护理和现场应用成为可能。该项目的教育目标是转变微流控纸基分析设备的现有知识和研究，并制作低成本和广泛使用的平台，通过教学视频在各种环境中向学生讲授实用分析化学。实验模块的视频系列将托管在免费服务器和教育网站上，以确保其能够接触到广泛的观众。随着ECL单一实体电化学(SEE)平台的开发，在印第安纳大学-普渡大学印第安纳波利斯分校Frederique Deiss的指导下，本项目的研究目标是(I)研究常见发光体/共反应物的不同ECL途径，(Ii)探索其他氧化还原机制，例如参与细菌新陈代谢的氧化还原机制，(Iii)检测低浓度、低浓度的细菌以及(4)制作纸质平台和教学视频，教授动手分析化学模块。在微流控装置的电极上产生的液滴将产生一组单独的节点，以电化学和光谱的方式测量单独的分析事件。同时收集电化学和光谱数据以及空间和时间信息，应该会为这个SEE平台提供优势，并有助于阐明氧化还原机制。这些机理上的见解可以帮助指导其他基于SEE液滴的分析的发展。这项研究还将最终扩大液滴界面的电化学知识和SEE的新领域。此外，它的分析性能将通过反向ECL检测细菌细胞来证明。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry and partial funding from the Biosensing Program in the Division of Chemical, Bioengineering, Environmental, and Transport Systems (CBET), Frederique Deiss of Indiana University–Purdue University Indianapolis will study reduction-oxidation (redox) reactions and the detection of single particles with electrochemiluminescence (ECL) and microfluidics. To answer current challenges in analytical chemistry for the identification and measurements of a single entity, Dr. Deiss will integrate electrochemistry, microfluidics, spectroscopy, and materials sciences to produce methods for single-entity electrochemistry using ECL in droplets. ECL is the emission of light by a redox-active molecule after a cascade of electrochemical and chemical reactions. This research will provide new strategies to elucidate chemical mechanisms, with findings applied to making advances toward the goal of detecting single bacteria. If successful, this research will help society by generating a method for rapid and highly sensitive enumeration of bacteria, which is needed in fields such as clinical tests and industrial quality control, and to increase the understanding of chemical and biological systems. A sub-class of microfluidic devices are paper-based devices. Their versatility, low-cost, portability, and user-friendly features have enabled many studies, as well as point-of-care and in-field applications. The educational objective of this project is to transform the current knowledge and research in microfluidic paper-based analytical devices and produce low-cost and widely accessible platforms to teach practical analytical chemistry to students in a variety of settings via instructional videos. The video series of the lab modules will be hosted on free servers and educational websites to ensure its access to a broad audience. The paper-based analytical assay and video modules are expected to help motivate and spark interest in future researchers from all backgrounds, including underrepresented minorities in science-technology-engineering-mathematics (STEM).Concomitant to the development of the ECL single-entity electrochemistry (SEE) platform, the research objectives of this project, under the direction of Frederique Deiss of Indiana University–Purdue University Indianapolis, are to (i) study the different ECL pathways of common luminophore/co-reactant, (ii) explore other redox mechanisms such as the ones involved in bacterial metabolism used in resazurin-based redox indicators, (iii) detect bacteria at ultralow concentration, and (iv) generate paper-based platforms and instructional videos to teach hands-on analytical chemistry modules. Droplets generated on electrodes in a microfluidic device will yield an array of individual nodes to measure individual analytical events electrochemically and spectrally. The simultaneous collection of electrochemical and spectral data with space and time information should confer an edge to this SEE platform and help elucidate redox mechanisms. The mechanistic insights could help guide the development of other SEE droplet-based assays. This research will also ultimately expand the knowledge of electrochemistry at the interface of droplets and the new field of SEE. Additionally, its analytical performance is set to be demonstrated with a reverse ECL assay for the detection of bacterial cells down to the single cell level.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.