Synthesis and Characterization of Red and Near-Infrared BODIPY-based fluorophores for various Biological Applications
ABSTRACT 4,4-Difluoro-3a,4a-diaza-s-indacene, better known as BODIPY® dyes, have attracted considerable attention due to their intriguing physicochemical and spectral properties, including high absorption coefficient, fluorescence quantum yield and good photochemical stability. Despite the recent progress achieved in this field, the synthesis of BODIPY derivatives that absorb and emit in the red- and NIR-region of the electromagnetic spectrum and their application to biomolecular targets, represents a long-standing challenge in BODIPY chemistry. This research work is therefore focused on the synthesis and characterization of red and NIR-emissive BODIPY-based fluorophores for various bioanalytical and biomedical applications. Chapter 1 of this dissertation represents a concise introduction to the fundamental concepts, synthetic routes, post-synthetic modification strategies and various biological applications of BODIPY dyes, that are further elaborated upon in the following Chapters. Chapter 2 describes the synthesis, characterization, computational modeling and cellular investigations of a series of new functionalized mono- and dibenzo-appended BODIPYs that are promising fluorophores for biolabeling applications. These ring expanded and constrained BODIPYs were synthesized via two different routes from a common tetrahydroisoindole precursor. This work was done in collaboration with Dr. Petia Bobadova-Parvanova of Rockhurst University. Chapter 3 reports on the synthesis and characterization of several styryl- and lysyl-BODIPY conjugates, prepared using Knoevenagel condensation reaction, an attractive strategy for the expeditious synthesis of π-extended BODIPYs in moderate to high yields. The effects of the styryl substituents on their photophysical properties and in vitro photodynamic activities are also described. Chapter 4 discusses an efficient method towards the preparation of a series of BODIPY-PEG and BODIPY-Carbohydrate conjugates via Cu(I)-mediated azide/alkyne cycloaddition, i.e. “click” chemistry. Several NIR-emissive BODIPY conjugates that are potential in vivo imaging agents were prepared in good to excellent overall yields. The photophysical studies of novel BODIPY-PEG and BODIPY-Carbohydrate conjugates are described in addition to the preliminary in vitro investigations.
BODIPY Dyes, Fluorophores, Near-Infrared, Photophysical properties, Cellular studies
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