Studying Interactions Between Proteins, Nanoparticles and Living Systems at the single-molecule and single-cell level

J. Rädler
Ludwig-Maximilians Universität, Munich, DE

Keywords: nanomaterials, nanoparticles

Summary:

Protein adsorption to nanoparticles (NPs) and its effect on uptake of NPs by living cells is key to understand NP-cell interactions. We use fluorescence correlation spectroscopy (FCS) to assess the absolute number of molecules adsorbed to polystyrene NPs and their exchange dynamics in body fluids. It is found that the fraction of molecules bound to NPs falls onto a single, universal adsorption curve showing the build-up of a strongly bound monolayer up to the point of monolayer saturation, beyond which a secondary, weakly bound layer is formed. Towards development of cell-based nanotoxity assays we study the uptake of NPs that were deposited at defined density on solid surfaces and subsequently overgrown by living cells. Automated time-lapse microscopy provides access to the unbiased dynamics of the cellular response to NP exposure (e.g. apoptosis) at the single cell level and hence allows to detect cell-to-cell variability. We report on efforts to develop microstructured substrates for high throughput screening of NP-cell interactions.