A plasmonic imaging approach for single nanovesicle characterization and profiling

Label-free optical observation of transparent nano-objects is challenging. Here, we demonstrate PlAsmonic NanO-apeRture lAbel-free iMAging (PANORAMA) that addresses existing issues for both SPR and LSPR imaging. PANORAMA involves a standard commercial bright-field microscope without the need for laser or interferometric detection. PANORAMA can image, size, count, and monitor a single polystyrene nanoparticle down to 25 nm at a millisecond timescale. The extrapolated size limit of detection is sub-10 nm. Higher imaging speed is achievable with high-speed cameras. Molecular imaging is envisioned with functionalized substrates for single nanoparticle analysis for extracellular vesicles (e.g., exosomes) and pathogens (e.g., viruses).