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）项目的支持下，以及化学、生物工程、环境和运输系统（CBET）系生物传感项目的部分资金支持下，印第安纳州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）和微流体技术对单个颗粒的检测。 为了应对当前分析化学中识别和测量单个实体的挑战，Deiss博士将整合电化学，微流体学，光谱学和材料科学，以产生使用液滴中ECL的单实体电化学方法。 ECL是在电化学和化学反应的级联之后由氧化还原活性分子发射的光。 这项研究将为阐明化学机制提供新的策略，并将发现应用于朝着检测单一细菌的目标取得进展。 如果成功，这项研究将有助于社会产生一种快速和高灵敏度的细菌计数方法，这是临床测试和工业质量控制等领域所需要的，并增加对化学和生物系统的理解。 微流体装置的子类是纸基装置。 它们的多功能性、低成本、便携性和用户友好的特性使得许多研究以及即时护理和现场应用成为可能。 该项目的教育目标是改变目前的知识和研究在微流体纸基分析设备和生产低成本和广泛访问的平台，教实用的分析化学的学生在各种设置通过教学视频。 实验模块的视频系列将托管在免费服务器和教育网站上，以确保其可供广大受众使用。 基于纸张的分析测定和视频模块预计将有助于激发和激发来自各种背景的未来研究人员的兴趣，包括科学技术工程数学（STEM）中代表性不足的少数民族。随着ECL单实体电化学（SEE）平台的发展，该项目的研究目标，在印第安纳州普渡大学印第安纳波利斯分校的Frederique Deiss的指导下，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，例如在基于刃天青的氧化还原指示剂中使用的细菌代谢中涉及的氧化还原机制，（iii）在超低浓度下检测细菌，以及（iv）生成基于纸张的平台和教学视频，以教授实践分析化学模块。 在微流体装置中的电极上产生的液滴将产生单个节点的阵列，以电化学和光谱方式测量单个分析事件。 同时收集电化学和光谱数据与空间和时间信息，应赋予这个SEE平台的优势，并有助于阐明氧化还原机制。 机制的见解可以帮助指导其他SEE液滴为基础的测定的发展。 这项研究也将最终扩大在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检测法进行验证，用于检测细菌细胞，最低可达单细胞水平。该奖项反映了NSF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.