Papers by Clémentine Lipp
The understanding of cell-cell and cell-matrix interactions via receptor and ligand binding relie... more The understanding of cell-cell and cell-matrix interactions via receptor and ligand binding relies on our ability to study the very first events of their contact. Of particular interest is the interaction between a T cell receptor and its cognate peptide-major histocompatibility complex. Indeed analyzing their binding kinetics and cellular avidity in large-scale low-cost and fast cell sorting would largely facilitate the access to cell-based cancer immunotherapies. We thus propose a microfluidic tool able to independently control two types of micro-sized objects, put them in contact for a defined time and probe their adhesion state. The device consists in hydrodynamic traps holding the first type of cells from below against the fluid flow, and a dielectrophoretic system to force the second type of object to remain in contact to the first one. First the device is validated by performing an adhesion frequency assay between fibroblasts and fibronectin coated bead. Then, a study is cond...
S1 is a 2x accelerated video of the trapping of 5 µm in diameter polystyrene beads in an array of... more S1 is a 2x accelerated video of the trapping of 5 µm in diameter polystyrene beads in an array of 522 traps using an inlet pressure of 40 mbar and a control pressure of 0 mbar. S2 represents the trapping of Colo205 cells stained using calcein AM in an array of 25 traps using an inlet pressure of 40 mbar and a control pressure of 0 mbar. S3 shows the movement of Colo205 cells flowing around the trapped cells.
Quality factor of Contour Mode Resonators (CMR) are mainly affected by energy losses due to acous... more Quality factor of Contour Mode Resonators (CMR) are mainly affected by energy losses due to acoustic waves leaving the resonator through the anchors. An engineering of the anchors in order to create a periodic variation in the acoustic impedance of the material, structures known as Phononic Crystals (PnCs), can help improve the Q factor by reflecting part of the acoustic waves. During this project, FEM models have been validated for both 1D and 2D PnCs. The behavior of the band diagram and quantification of transmission has been studied for three different PnC geometries: circle, cross and square unit cell. Parameters such as unit cell size, filling factor, material composition, thickness and number of repetitions have been varied and comparisons between transmission graph and band diagram allowed to understand better the nature of the modes. It has been found that a linear approximation can predict with a good precision the position of the band gap as a function of the unit cell si...
Frontiers in Bioengineering and Biotechnology, Jul 14, 2022
We present a microfluidic dielectrophoretic-actuated system designed to trap chosen single-cell a... more We present a microfluidic dielectrophoretic-actuated system designed to trap chosen single-cell and form controlled cell aggregates. A novel method is proposed to characterize the efficiency of the dielectrophoretic trapping, considering the flow speed but also the heat generated by the traps as limiting criteria in cell-safe manipulation. Two original designs with different manufacturing processes are experimentally compared. The most efficient design is selected and the cell membrane integrity is monitored by fluorescence imaging to guarantee a safe-cell trapping. Design rules are suggested to adapt the traps to multiple-cells trapping and are experimentally validated as we formed aggregates of controlled size and composition with two different types of cells. We provide hereby a simple manufactured tool allowing the controlled manipulation of particles for the composition of multicellular assemblies.
Lab on a Chip
A new process for the fabrication of two superposed layers of microfluidic channels connected by ... more A new process for the fabrication of two superposed layers of microfluidic channels connected by vias is used to trap and release particles in a transparent chip. Parallel manipulation of beads is studied and the rules for cell trapping are defined.
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Papers by Clémentine Lipp