BME PhD Prospectus Presentation: Jisoo Im

Title: "Dehydrating Liquid-Liquid Phase Separation (DLLPS): A Target-Amplification-Free Strategy for Point-of-Care Detection of Nucleic Acid and Protein Biomarkers"

Advisory Committee: N/A

Abstract: Rapid and sensitive point-of-care detection of nucleic acid and protein biomarkers remains a major challenge, as existing methods either require complex instrumentation or lack sufficient sensitivity. While amplification can improve nucleic acid detection, it increases workflow complexity, and protein detection is inherently limited by the difficulty of directly amplifying the antigen. Therefore, new strategies are needed to enhance assay sensitivity without relying on target amplification or specialized equipment. Here, we aim to develop dehydrating liquid–liquid phase separation (DLLPS) as a rapid physical concentration strategy for target amplification-free biomarker detection. DLLPS uses partially water-miscible organic solvents to remove water from an aqueous reaction, shrinking the aqueous phase and concentrating assay components. By forming microdroplets, DLLPS also enhances reaction kinetics by increasing effective local concentrations and interaction frequencies. We will apply DLLPS to an amplification-free nuclease-based nucleic acid detection assay to improve miRNA detection and extend the approach to tiled-probe mRNA detection. We will also integrate DLLPS with a nanobody-based antigen detection assay and develop a simplified direct-biotinylation format to improve target capture efficiency. Finally, we will map DLLPS compatibility across diverse biomolecular assays and develop osmolyte-based strategies to preserve protein and enzyme function during dehydration. Ultimately, this work will provide a practical platform for improving point-of-care detection of nucleic acid and protein biomarkers without target amplification.