Synthesis of novel fluorescent labels for advanced imaging applications

A picture is worth a thousand words – they can make large and complex data sets interpretable. In the last six decades, use of fluorescent labelling techniques has extensively increased. Synthesis of fluorescent probes for real-time imaging has become a powerful tool for cell biology, systems biology, microbiology and chemical biology and has largely taken over from radioactive tracers. The accuracy and sensitivity of a fluorescent probe allows the monitoring of complex cellular processes such as enzyme activation, protein-protein interactions, cellular re-organisation and trafficking. This thesis describes the design and synthesis of novel fluorescent labels, studies of their basic photophysical properties, and proof-of-principle applications. Chapter 1 gives a brief introduction of the fluorescence process and fluorescent probes. Chapter 2 consists of the synthesis of novel amino-salicylaldehyde based fluorescent probes. This chapter isdivided into two parts. Firstly, the synthesis of novel pyrylium derivatives as turn-on irreversible protein stain for gel electrophoresis, protein labelling and imaging is described. The second part of the chapter includes the synthesis of novel boranil derivatives and their photophysical properties. Chapter 3 mainly focuses on the resynthesis of a GFP-chromophore analogue, its dual emission, photophysical properties and applications in bioanalytical chemistry. Chapter 4 illustrates the synthesis of a novel turnon, suicide substrates for selected enzymes based on difluoromethyl analogues of wellknown fluorophores. In this chapter, attempts are described towards the synthesis of new fluorogenic fluorescein and BODIPY based derivatives that could be used for the detection of specific enzymes in live cells. Appendices at the end of the thesis provide MS, NMR, U.V and fluorescence measurements.