Dynamic measurement of altered chemical messenger secretion after cellular uptake of nanoparticles using carbon-fiber microelectrode amperometry

In this work, carbon-fiber microelectrode amperometry is used to characterize serotonin exocytosis from murine peritoneal mast cells cocultured with fibroblasts in the presence of Au nanoparticles. In the case of mast cell exposure to 1 nM 28 nm diameter spherical Au nanoparticles, there is a decrease of greater than 30% in the number of successful granule transport and fusion events, greater than 30% increase in the rate of intragranular matrix expansion, and greater than 20% increase in the number of secreted serotonin molecules per granule. These results suggest that nanoparticles interrupt the dense-core biopolymer intragranular matrix and present the potential for systematic studies showing how exocytotic function is influenced by nanoparticle size, shape, and composition.