Plasmonics-Enhanced Characterization of Cervid PrP (87-114) Fragment Aggregates in Solution

We performed a multimodal characterisation of self-assembled fibrillar aggregates formed by the residue 87-114 fragment of the white-tailed deer (WTD) prion protein (PrP), a disease-relevant region implicated in the structural conversion and transmission of chronic wasting disease (CWD) in cervids. Using an integrated experimental platform combining plasmon-enhanced bright-field microscopy, label-free surface-enhanced Raman spectroscopy (SERS), and Thioflavin T staining, we probed peptide aggregation in solution under ambient conditions. Nanostructured gold films on dielectric fused silica supports served as dual-purpose plasmonic substrates for imaging and SERS. We observed a transition from dispersed states to well-defined fibrillar networks, accompanied by spectral evolution in key backbone-sensitive SERS bands. These results establish the amide III region and tryptophan vibrational features as indicators of fibrillar architecture in SERS assays and offer new insights into the aggregation behavior of amyloidogenic sequences involved in CWD susceptibility.