The study of the first contacts of nanoparticles (NPs) with cell membranes is a prerequisite either for a deep understanding of cytotoxicity mechanisms and for improving drug delivery system. Indeed, unravelling fundamental interactions of NPs with the cell barrier may help explaining macroscopic responses. Most often, the NPs/membrane interface is studied in static conditions. However, in living systems water is motion, so that physicochemical properties and biological processes can depend on the flow parameters. Here, in order to mimic the dynamic conditions of the physiological environment, we investigated the NPs/membrane interface upon a water flow. To achieve this goal, we modelled the NPs/membrane interface through a solid-supported lipid bilayer of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) on SiO2 in interaction with positively charged 5 nm gold NPs. Thanks to the high sensitivity of vibrational sum-frequency generation (SFG) spectroscopy to liquid interfaces, and under dynamic conditions, we investigated the effects of the liquid flow on the above nano-bio-interface (Figure 1). We measured the vibrational response of the lipid molecules and of its close water environment, between 2800 cm-1 and 3600 cm-1, and upon increasing flow rates, between 130 μL/min and 20 ml/min. With this study, we showed that the liquid motion modified the kinetics of interaction of NPs with the model membrane, and we derived a dependence on the flow rate.

Interactions between gold nanoparticles and lipid membranes: The effect of the liquid flow

256th National Meeting (2018)

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