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

在化学学部化学测量和成像（CMI）项目的支持下，以及化学、生物工程、环境和运输系统（CBET）部门生物传感项目的部分资助下，印第安纳大学-普渡大学印第安纳波利斯分校的Frederique Deiss将研究还原-氧化（氧化还原）反应以及电化学发光（ECL）和微流体检测单颗粒。为了应对当前分析化学在识别和测量单个实体方面的挑战，戴斯博士将整合电化学、微流体、光谱学和材料科学，以生产使用ECL在液滴中的单个实体电化学方法。ECL是由氧化还原活性分子在一系列电化学和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，其发现将应用于实现检测单个细菌的目标。如果成功，这项研究将产生一种快速和高度敏感的细菌计数方法，这在临床试验和工业质量控制等领域是需要的，并将增加对化学和生物系统的理解，从而帮助社会。微流体装置的一个子类是基于纸的装置。它们的多功能性、低成本、便携性和用户友好性使许多研究以及护理点和现场应用成为可能。该项目的教育目标是改变目前在微流体纸质分析设备方面的知识和研究，并生产低成本和广泛可访问的平台，通过教学视频在各种环境中向学生教授实用的分析化学。实验模块的视频系列将放在免费的服务器和教育网站上，以确保广泛的受众可以访问。基于纸张的分析分析和视频模块有望帮助激发和激发来自所有背景的未来研究人员的兴趣，包括在科学-技术-工程-数学（STEM）中代表性不足的少数民族。在印第安纳大学-普渡大学印第安纳波利斯分校的Frederique Deiss的指导下，随着ECL单实体电化学（SEE）平台的发展，该项目的研究目标是(i)研究常见发光团/共反应物的不同ECL途径，（ii）探索其他氧化还原机制，例如瑞唑脲基氧化还原指标中涉及细菌代谢的机制，（iii）检测超低浓度的细菌，（iv）生成纸质平台和教学视频，教授动手操作的分析化学模块。微流控装置中电极上产生的液滴将产生一系列单独的节点，用于电化学和光谱测量单个分析事件。同时收集具有空间和时间信息的电化学和光谱数据应该赋予这个SEE平台优势，并有助于阐明氧化还原机制。这种机制见解可以帮助指导其他基于SEE液滴的检测方法的开发。这项研究也将最终扩展液滴界面电化学的知识和SEE的新领域。此外，它的分析性能将通过反向ECL试验来证明，用于检测细菌细胞到单细胞水平。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.