Tethered Entity Electrochemistry

This project focuses on the development of a novel method to investigate how single biomolecules behave on a surface using scanning electrochemical cell microscopy (SECCM). DNA-modified surfaces are widely used in biotechnology and underpin a range of applications, including biomolecule synthesis, DNA sequencing, and the detection of biologically and environmentally relevant targets. Most current techniques that use these surfaces rely on measurements averaged across many molecules, which can obscure important details. This project will examine how individual DNA molecules interact with other molecules and how their attachment to a surface influences these interactions. By focusing on single-molecule behavior, the team aims to reveal fundamental processes that are often hidden in bulk measurements. Insights from this work will enable the design of surfaces with precisely tailored functions, including the ability to detect and measure single molecules with unprecedented sensitivity. Such capabilities could provide actionable sensing information in areas such as healthcare, environmental monitoring, and threat detection. In addition, trainees involved in this project will develop interdisciplinary expertise in biophysics, biochemistry, and electrochemical measurement science. They will also strengthen critical thinking and problem-solving skills that are essential for success in the STEM workforce. To achieve the goals of this project, the investigators will develop a tethered entity electrochemistry system that relies on a catalytic metal nanoparticle tethered to an electrode surface via a nucleic acid aptamer. The premise of the project is that the nucleic acid tether dictates the collisional frequency of the terminal metal nanoparticle and this frequency will change when the nucleic acid aptamer interacts with a specific analyte. This mechanism, at bulk, is what drives the field of electrochemical, aptamer-based sensors – a promising sensing platform for real-time measure of small molecules. To achieve the goal of this work, the team will investigate how electrode surface chemistry influences single nanoparticle collision behavior and establish strategies to precisely control these interactions. By systematically varying surface functional groups, the team will quantify the interfacial chemistry effects on nanoparticle collision dynamics to enable conditions suitable for tethered entity electrochemistry. Building on this understanding, they will develop nucleic acid–based architectures to tether individual platinum nanoparticles to electrode surfaces, with controlled spacing and surface coverage dictated by aptamer structure. These engineered interfaces will enable linking nanoparticle motion directly to biomolecular interactions at the single-molecule level. Ultimately, to achieve these measurements at the single molecule level, the team will use scanning electrochemical cell microscopy (SECCM) to measure aptamer–target binding kinetics and thermodynamics from current-time signals, establishing a new platform for probing individual biomolecule interactions on surfaces. 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. NSF Award ID: 2603679 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Ryan White | Institution: University of Cincinnati Main Campus, CINCINNATI, OH | Award Amount: $662,791 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2603679 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2603679.html