02/10/2026
By Kwok Fan Chow

The Kennedy College of Science, Department of Chemistry, invites you to attend a Ph.D. Dissertation defense by Ajoke Williams entitled “Ultrasensitive Detection of Biomarkers to Enable Point-of-Care Diagnostics.”

Date: Thursday, Feb. 19, 2026
Time: 3:30 p.m.
Location: Olney, Room 518

Committee:

  • Advisor: Suri Iyer, Department of Chemistry, University of Massachusetts Lowell
  • Marina Ruths, Department of Chemistry, University of Massachusetts Lowell
  • Matthew Gage, Department of Chemistry, University of Massachusetts Lowell
  • Michael Ross, Department of Chemistry, University of Massachusetts Lowell

Abstract:
Advances in biomarker detection technologies now enable increasingly sensitive, specific, and rapid identification of disease signatures, underscoring the importance of developing innovative analytical platforms for early-stage diagnosis. This dissertation focuses on single molecule biosensing and developing assays with potential applications in point-of-care (POC) diagnostics. The first chapter discusses a brief introduction to biosensors, different types of biosensors, single-molecule biosensors, proof of concept for Cancer and Covid-19 biosensors, focusing on the Scanning Tunneling Microscopy-assisted Break Junction (STM-BJ). We first employ STM-BJ technique to achieve single-molecule conductance-based detection of nucleic acid biomarkers with exceptional precision. Then, a case is made here for sustainable biosensors, how they can help, the paradigm shift needed to achieve them, and some potential applications. The second chapter focuses on two sensor platforms to detect KRAS G12V RNA biomarkers, a bio‑electrochemical sensor and a quantum‑transport‑based single‑molecule sensor that measures conductance changes of individual DNA:RNA hybrids using STM‑BJ. By comparing both approaches, we evaluate their key performance metrics such as limit of detection, specificity, and robustness in biologically relevant complex media. The third, fourth and fifth chapters focus on the development of ultrasensitive multilayer sandwich immunoassays to detect HIV-related biomarkers, HIV-1 p24 antigen and Inflammatory bowel disease (IBD) biomarkers, Tumor Necrosis Factor-alpha (TNF-α) and Interliukin-10 (IL-10) using bioorthogonal chemistry and dye-encapsulated fluorescent silica nanoparticles. This approach achieved significant signal enhancement through a layer-by-layer assembly, with two platforms explored: a microwell plate-based system and a fluorescent lateral flow immunoassay (FLFIA). Finally, this work introduces fluorescent lateral flow immunoassays as an effective POC testing method compared to the traditional methods. These developments present a promising approach for early HIV detection, viral load monitoring, and IBD management particularly in resource-limited areas while making healthcare more accessible.

All interested students and faculty members are invited to attend.