Researchers in Shanghai Institute of Applied Physics CAS recently developed a new method to examine clustering states of nanoparticles in a semi-quantitative way, which was published in Nature Communications, 2017, 5, 15646.

Mechanistic understanding of the endocytosis and intracellular trafficking of nanoparticles is essential for designing smart theranostic carriers. Physico-chemical properties, including size, clustering and surface chemistry of nanoparticles regulate their cellular uptake and transport. Significantly, even single nanoparticles could cluster intracellularly, yet their clustering state and subsequent trafficking are not well understood. Authors used DNA-decorated gold (fPlas-gold) nanoparticles as a dually emissive fluorescent and plasmonic probe to examine their clustering states and intracellular transport. Evidence from correlative fluorescence and plasmonic imaging shows that endocytosis of fPlas-gold follows multiple pathways. In the early stages of endocytosis, fPlas-gold nanoparticles appear mostly as single particles and they cluster during the vesicular transport and maturation. The speed of encapsulated fPlasgold transport was critically dependent on the size of clusters but not on the types of organelle such as endosomes and lysosomes. These results provide key strategies for engineering theranostic nanocarriers for efficient health management.