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

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.