Figure 4.

SERS spectra large variability. SERS efficiency and enhancement is strongly dependent upon the probed position over Au nanoparticles because of the nanoscale size of hot spots. This in turn negatively affects SERS reproducibility, even within the same experimental session. Several SERS spectra are reported close to one another, in the shape of a 3D landscape, for MGUS-, aMM-, and sMM-derived exosomes (at least 20 spectra for each group are chosen among the most intense ones). This representation shows at once the large differences occurring in SERS measurements.