INDENTING CELLS INSIDE THE EXTRACELLULAR MATRIX: We are developing a fiber-top indenter that should be able to probe a cell immersed in its most natural environment: the extracellular matrix. The probe consists of a nanocantilever fabricated on top of a 15 micron diameter optical fiber. Light coupled from the opposite end of the fiber allows measurements of the bending of the cantilever, and, thus, of the mechanical properties of the cell. This study should elucidate whether the mechanical properties of a cell in the extracellular matrix differ from those already found for cells that adhere to a flat substrate, and contribute to shed light on the role of mechanical stimuli in cell biology.
CELL MECHANICS UNDER HYPERGRAVITY CONDITIONS: In collaboration with the European Space Agency, we are developing an fiber-top atomic force indenter for utilization in high-g centrifuge experiments. The indenter consists of a microcantilever fabricated on top of a mm-size ferruled optical fiber. Light coupled from the opposite end of the fiber allows measurements of the bending of the cantilever, and, thus, of the mechanical properties of the cell. Detection of NO release upon calibrated mechanical pressure should also be possible by equipping the probe with an micromachined NO optical sensor. This study should shed light on the role of high accelerations in the cell physiology.
COUPLING MECHANICS WITH OPTOGENETICS, SPECTROSCOPY, OPTICAL IMAGING: Fiber-top and ferrule-top sensors are a new generation of all-optical devices obtained by fabricating tiny mechanical pieces (MicroElectroMechanicalSystems, or MEMS) on the tip of an optical fiber or of a ferruled optical fibers. In principle, these sensors allow one to exert a calibrated pressure on cells or tissues and simultaneously collect light from or shine light to the sample exactly in the point where the pressure is applied. We are exploring whether this possibility can be used to combine indentation with optogenetics, spectroscopic techniques, and optical imaging techniques to shed new light in cell and tissue biology, with applications ranging from fundamental biophysics questions to the development of novel clinical instruments.