Bertseva, E.Singh, A. S. G.Lekki, J.Thevenaz, P.Lekka, M.Jeney, S.Gremaud, G.Puttini, S.Nowak, W.Dietler, G.Forro, L.Unser, M.Kulik, A. J.2009-06-242009-06-242009-06-24200910.1088/0957-4484/20/28/285709https://infoscience.epfl.ch/handle/20.500.14299/40832WOS:000267612600033A traditional photonic-force microscope (PFM) results in huge sets of data, which requires tedious numerical analysis. In this paper, we propose instead an analog signal processor to attain real-time capabilities while retaining the richness of the traditional PFM data. Our system is devoted to intracellular measurements and is fully interactive through the use of a haptic joystick. Using our specialized analog hardware along with a dedicated algorithm, we can extract the full 3D stiffness matrix of the optical trap in real time, including the off-diagonal cross-terms. Our system is also capable of simultaneously recording data for subsequent offline analysis. This allows us to check that a good correlation exists between the classical analysis of stiffness and our real-time measurements. We monitor the PFM beads using an optical microscope. The force-feedback mechanism of the haptic joystick helps us in interactively guiding the bead inside living cells and collecting information from its ( possibly anisotropic) environment. The instantaneous stiffness measurements are also displayed in real time on a graphical user interface. The whole system has been built and is operational; here we present early results that confirm the consistency of the real-time measurements with offline computations.OPTICAL TWEEZERSTRACKINGtext::journal::journal article::research article