Four microlitres of the sample solution (~1 nM, 1% PVP) were loaded on an aqua regia-treated cover glass, and after 1 min, the excess solution was removed by air blowing. Single-particle dark-field scattering and dark-field microscopy-correlated single-particle SERS measurements were performed using a dark-field equipped nano-Raman microscope. A 60× objective lens (NA = 0.90, Olympus) was used for dark-field spectroscopy. Singleparticle dark-field scattering spectra were recorded with an acquisition time of 1 s. The slit size was 100 μm. For single-particle SERS measurements, particles previously identified through dark-field scattering were relocated in the bright field using a marker (Fig. ). A 100× oil-immersion objective lens (NA = 1.4, Olympus) and a 633 nm laser were employed. For nano-Fanowmen (Figure ), a 0.50 μW (0.76 μW/μm 2 ) 633 nm laser was used with an integration time of 5 s. However, at this laser power, SERS signals from most other particle types (Figure ) were undetectable. Therefore, the laser power was increased (2.95 μW for resonant NNPs and 7.55 μW for the other particles) to obtain measurable signals.