Detection of Alpha-Synuclein by LSPR with Different Lipid Layers and Self-Templating Properties

Using localized surface plasmon resonance (LSPR) with immobilized phospholipid layers, sensitive detection of alpha-synuclein (aSyn) proteins, a causative agent of Parkinson's disease, is demonstrated. Although the detection of the target has been confirmed in our previous studies, further improvements in sensitivity are still an issue. In this study, the detection ability of aSyn fibrils by two different immobilized lipid species (DMPC, DPPC) and two different layer structures (monolayer, bilayer) on the sensor surface is investigated. In addition, the self-templating properties of aSyn are investigated by adding monomers to increase the sensitivity. The results show that DMPC improves the LSPR wavelength peak shift compared to DPPC for both monolayers and bilayers. Using aSyn's self-templating properties, we confirmed a 14.5-fold increase in sensor signal per aSyn fibril concentration. These results suggest that lipid species selection, lipid layer structure, and the use of self-templating properties are useful for the detection of aSyn fibrils by LSPR.