A plasmon-based nanoruler to probe the mechanical properties of synthetic and biogenic nanosized lipid vesicles

In this manuscript a novel optical assay, based on citrated gold nanoparticles, for estimating the stiffness of nanosized lipid vesicles is presented. The aggregation and clustering of AuNPs on the vesicles is mediated by the rigidity of their membranes, thus generating different plasmon absorbance spectra for different membrane rigidities. Combined with the stiffness obtained by AFM-Force Spectroscopy, this phenomenon is exploited for building up a calibration curve that allows retrieving the stiffness of unknown vesicle samples just from their absorbance spectra, following the interaction with AuNPs.