Interaction of gold nanoparticles with proteins and HUVEC cells followed with confocal fluorescence microscopy techniques

The increasing use of metal nanoparticles as new multi-functional platforms for diagnostic and drug delivery requires characterization of their interaction with biological substrates under both static and flow conditions. In this work we will follow the interaction of 20 nm gold nanoparticles (capped with different surfactants) with the BSA protein through experiments of fluorescence correlation spectroscopy and fluorescence lifetime imaging. In particular we will analyze independently the behavior of free gold nanoparticles as well as BSA (tagged with a fluorescent label) inside a microfluidic device as a function of the channel surface coating and the flow speed of the device. Then we will address the characterization of adsorption dynamic of BSA on the gold nanoparticles both in static and in flow conditions. Flow condition will be realized by fabrication of Y shaped microfluidic devices in polydimethylsiloxane (PDMS) and glass and continuous flow will be provided by syringe pumps. At the same time we will present our result on the uptake and toxicity of the same nanoparticles with respect to HUVEC (Human Umbilical Vein Endothelial Cells) cultured in stationary vs flow conditions, realized also via PDMS microfluidic devices.The continuous perfusion provided by a microfluidic system simulates the physiological characteristics of the circulatory system and creates a cellular microenvironment that is typically found in the biological systems.