Final Report Summary - PORPH_IMP_SHG (Porphyrin-Based Dyes for Imaging Membrane Potential via Second Harmonic Generation)
Understanding brain function is a modern frontier in science. Following communication in neuronal pairs and networks will lead to clearer interpretations of physiological experiments, better modelling of brain activity and advances towards cures for neurodegenerative disorder. Second harmonic generation (SHG) imaging is a promising technique for the imaging of the transmembrane potentials which drive neuron function. Push-pull chromophores orientated in the neuronal plasma membrane generate a high contrast signal that is sensitive to the local electric field. Furthermore, SHG is a scattering effect and it does not require the population of excited-states, so it should be possible to design SHG dyes which are free from photobleaching and photo-induced degradation. The high polarizability and intense optical transitions of porphyrins make them excellent candidates for engineering efficient SHG voltage-sensitive probes.
A first generation of amphiphilic donor-acceptor meso-ethynyl porphyrins, with polar pyridinium acceptor head- groups and hydrophobic dialkyl-aniline donors has been synthesised and tested with the aim of exploring how different structural parameters such as charge on the head-group or meso-substituent affect both photophysical and biophysical properties. These compounds were first synthesised2 before the start of my fellowship, but I significantly improved their synthesis and carried out detailed experiments to explore their properties.
A first generation of amphiphilic donor-acceptor meso-ethynyl porphyrins, with polar pyridinium acceptor head- groups and hydrophobic dialkyl-aniline donors has been synthesised and tested with the aim of exploring how different structural parameters such as charge on the head-group or meso-substituent affect both photophysical and biophysical properties. These compounds were first synthesised2 before the start of my fellowship, but I significantly improved their synthesis and carried out detailed experiments to explore their properties.