Rapid vertical flow immunoassay capable of advancing point of care diagnostics by amplifying underutilized signals via site-specific assembly of antibody and augmented plasmonic coupling

The National Institute of Biomedical Imaging and Bioengineering awarded the Board of Trustees of Illinois State University $553,931 on August 25, 2026, for development of a surface-enhanced Raman scattering (SERS)-based rapid vertical flow assay (RVFA) for point-of-care diagnostic testing under the Discovery and Applied Research for Technological Innovations to Improve Human Health program (CFDA 93.286).

The award funds research to advance infectious disease diagnostics by improving analytical sensitivity through site-specific immobilization of antibodies on plasmonic nanoparticles and controlled assembly of plasmonic particles. The research will explore a chemo-enzymatic approach to localize and orient capture antibodies on plasmonic paper to maximize SERS signal; conduct SERS analysis of augmented plasmonic nanoparticle assemblies driven by antibody-antigen interactions; and demonstrate simultaneous quantitation of multiple antigens in a multiplexed assay with established quality control parameters.

Performance occurs in Normal, Illinois. The period of performance runs through August 24, 2029. The assistance type is a Project Grant.

Abstract

Improvements in infectious disease prevention and management may be achieved through better diagnostics. Point-of-care (POC) diagnostic tests are poised to make the greatest impact, yet despite substantial effort, current approaches suffer from limited analytical sensitivity resulting in poor diagnostic accuracy. The long-term goal of this research is to develop a surface-enhanced raman scattering (SERS)-based rapid vertical flow assay (RVFA) suitable for POC testing that provides requisite sensitivity and multiplexing capacity as an advanced strategy for disease intervention. The central hypothesis is that site-specific immobilization of antibodies (AB) on structurally regulated nanoparticles (NPS) and controlled assembly of plasmonic particles will significantly improve RVFA performance by enhancing the selective extraction of targeted antigens (AG), maximizing SERS signal, and enabling simultaneous detection of multiple biomarkers. Our rationale for these studies is that successful completion would provide the scientific foundation for the development of new platform technologies critically needed for disease management. Driven by compelling preliminary data, we will test our hypothesis and progress toward our long-term research goal by completing three specific aims. In aim 1, we will explore a unique chemo-enzymatic approach to selectively localize and orient the capture AB on plasmonic paper, which will result in all AG being properly positioned between plasmonic NPS to maximize the SERS signal. In aim 2, we will complete the SERS analysis of augmented plasmonic NP assemblies driven by AB-AG interactions using plasmonic NPS to amplify signal enhancement. In aim 3, we will demonstrate the simultaneous quantitation of two AG in a multiplexed assay, establish quantitative metrics, and benchmark analytical performance to a conventional elisa or lateral flow assay. This work represents an innovative approach to greatly improve the sensitivity of underutilized biomarkers by engineering plasmonic architectures and configurationally manipulating bioconjugate chemistry. Overall, these important features will be central to the culminating bioanalytical platform that addresses the need for high sensitivity, reduced assay time, ease of use, and multiplexing capability. The project is significant because IT leads to generalized design principles to enable precise control of antibody immobilization and leverages strategic plasmonic assemblies that will streamline development of rapid and more sensitive diagnostic platform, positively impacting disease management. In addition to the scientific agenda, a significant aspect of this proposed work is student learning and development through unique hands-on and intensely focused research opportunities.