Developing a library of near-infrared fluorophores for multiplexed in vivo fluorescence lifetime imaging of disease biomarkers. - Project Summary/Abstract: This Mentored Research Scientist Development (K01) Award will support the training and career development of Dr. Rahul Pal, a junior investigator at Massachusetts Eye and Ear (MEE) hospital. Dr. Pal is an expert in molecular fluorescence imaging for pre-clinical and clinical applications across various diseases. His career goal is to advance multiplexed imaging techniques for the noninvasive detection and quantification of disease biomarkers and to establish new clinically translatable biomarkers using these methods. Near-infrared (NIR) fluorescence imaging has shown promise for in vivo biomarker detection in preclinical and clinical settings, addressing the limitations of conventional tissue biopsies that fail to capture the heterogeneous and dynamic biomarker expression landscapes across whole tumors. Dr. Pal has recently shown using biomarker targeted NIR probes that fluorescence lifetime (FL), a fundamental photophysical property of fluorescent agents, provides a higher accuracy compared to intensity-based imaging techniques for the in vivo detection and quantification of biomarkers. While in vivo quantification of a single biomarker can be valuable, simultaneous and longitudinal evaluation of multiple targets through multiplexed imaging is essential for patient stratification for combination therapies and monitoring therapy responses. However, traditional methods often struggle to achieve accurate quantification of multiple targets in vivo due to the limited availability of NIR probes with distinct FLs. The short FLs of commonly used NIR fluorophores provide limited options for fluorophore multiplexing pairs, which represents a significant barrier to advancing multiplexed FL imaging (FLI). This K01 proposal seeks to overcome these challenges through three specific aims: Aim 1 - Develop a comprehensive library of novel NIR fluorophores with distinct FLs suitable for in vivo multiplexed imaging. This includes screening existing dyes and synthesizing new candidates. Aim 2 - Identify the optimal FL pairs for multiplexed imaging of two cancer biomarkers, epidermal growth factor receptor (EGFR) and programmed death ligand 1 (PD-L1). Aim 3 - Establish metrics for the in vivo quantification of EGFR and PD- L1 expression using NIR-FLI multiplexing and evaluate their utility in monitoring immunotherapy responses. The immediate application of this research will be in head and neck (HN) cancer, where the simultaneous quantification of EGFR and PD-L1 can aid in identifying potential responders for combination immunotherapy. Through a rigorously designed training plan, Dr. Pal will gain new expertise in NIR probe chemistry and cancer immunology, which will enable him to lead independent research beyond his postdoctoral work and prepare for an R01 application. This K01 award will serve as a pivotal step towards establishing his independent career in multiplexed molecular imaging. His mentoring team, which includes experts in NIR probe chemistry (Drs. Choi and Berezin) and immunology (Dr. Duda), will provide comprehensive guidance to ensure the success of this proposal and his development as an independent investigator.
