Prof Sumeet Mahajan – University of Southampton
Dr Iris Nandhakumar – University of Southampton
Dr Jurgita Zekonyte – University of Portsmouth
The aim of this proposal is to develop a novel in situ physico-chemical characterisation tool for assessing protein aggregation.
This will be achieved by Atomic Force Microscopy (AFM) as well as using surface-enhanced Raman spectroscopy (SERS) executed through the tip of an AFM probe also called tip-enhanced Raman spectroscopy (TERS). TERS has been shown to achieve single base resolution in single stranded DNA although in dry conditions. Thus TERS can yield morphological, structural (conformation) and chemical level information, all
simultaneously, at the nm-scale that is unparalleled by any other technique. However, TERS imaging under wet conditions is challenging although ~10 nm resolution is achievable with commer-cially available systems.8 The current state-of-the-art in high resolution protein imaging is Cryo-EM; it has been applied to visualise the folds (~1 nm resolution) involved in Tau fibrils, however, the technique requires huge infrastructure costs, is highly laborious, has very limited throughput and cannot be applied to study native structures in physiological (wet) conditions. Furthermore, applications of TERS in neuroscience and to study aggregation species have not yet been developed. In this proposal we would like to study Tau ag-gregate species (especially oligomers and fibrils) in a physiological environment. Application of TERS will thus allow unprecedented insight into chemical composition and conformation at the single oligomer and single fibril level. We will also develop the TERS tech-nique to achieve ~1 nm resolution so that we can obtain conformational information at the level of residues (amino acids) in Tau protein and its aggregates, which will be groundbreaking.