Fluidic force microscopy to access the interactions between gaz/liquid and biological interfaces

Abstract

International audienceThe interactions between gaz/liquid interfaces (bubbles) and cells are involved in manybioprocesses. For example in bioreactors, breathing microorganisms interact with theirgrowth medium but also with the gases present in the medium under the form of bub-bles. While many studies are dedicated to the modelling of such processes, none of themhave yet looked into the interactions between the cells and the bubbles. Thus questioningthese interactions is highly original, and provides relevant data that can be used in manybiotechnological applications. But accessing such interactions presents several technologicalchallenges, the main one being to produce microsized bubbles, stable over time. In this pre-sentation, we show recent developments in which we produce stable bubbles using FluidFMtechnology that combines AFM with microfluidic AFM probes1. In this system, a micro-sized microfluidic channel is integrated in an AFM cantilever and connected to a pressurecontroller system, thus creating a continuous and closed fluidic conduit that can be filledwith air, while the tool can be immersed in a liquid environment. An aperture at the endof the cantilever allows the air to be pushed out of the probe into the liquid, resulting inthe creation of a bubble. Force feedback is then ensured by a standard AFM laser detectionsystem that measures the deflection of the cantilever and thus, interactions can be probeddirectly with cells. Finally, the bubbles produced using this technique can be functionalizedwith surfactants, which allows to modulate the interactions between the bubble and cells