Synthesis of Functional Fluorophores for Cellular Imaging and its Applications

Abstract

This thesis presents the synthesis and application of functional fluorophores designed for the selective detection of key biomolecules, enzymes, and microenvironments, from cellular models to small organisms such as zebrafish. Chapter 1 introduces the importance of fluorophores, their functionalization, and fluorescence imaging, spanning in vitro to in vivo applications. Chapter 2 describes the development of a mitochondria-targeted fluorescent probe specifically designed to monitor esterase activity, enabling differentiation between live and dead cells. Quantum mechanics/molecular mechanics (QM/MM) calculations were employed to clarify the ester bond cleavage pathway mediated by the enzyme. Chapter 3 investigates the distance-dependent Photoinduced Electron Transfer (PET) mechanism through the synthesis of three fluorophores with varying carbon chain lengths, with one successfully applied to monitor pH variations during mitochondrial damage. Chapter 4 presents a fluorescent probe synthesized for the sensitive detection of nitric oxide (NO) and its derivative, peroxynitrite (ONOO-), and applied to visualize NO dynamics in neuronal cells during activation, as well as monitor NO in zebrafish and exosomes overexpressing inducible nitric oxide synthase (iNOS), which serves as a potential NO carrier. Chapter 5 introduces a series of fluorescent probes with diverse structural modifications for detecting hypochlorite (HOCl), a reactive oxygen species, used to study pollutant-induced oxidative stress in kidney cells, linking HOCl activity to the early stages of chronic kidney disease. Collectively, these fluorescent probes provide versatile tools for real-time bioimaging and hold significant potential for advancing diagnostic methodologies in cellular health and environmental studies. newline