Microcontact printing for controlling T cell activation and mechanics

We introduced the use of “shaped cells” since the spreading state of cells, on any adhesive molecule, is strongly inhomogeneous, hence giving rise to strong dispersion of the mechanical parameters of the population. The cells are adhered on micro-stamped adhesive / repulsive patterns that will impose a cell shape. The stamps are made of PDMS following classical photolithography methods.

Patterned T cells as imaged in confocal (left) and mechanically tested using AFM colloidal force probe (right). The image is the superposition of fluorescence (for the patterns, 15µm in diameter) and transmission microscopies.

Since the T cells are small (~ 10 µm), and are extremely activable, the patterns have been designed in our lab (by O. Théodoly) and required specific passivation strategies to achieve patterned T cells and model APCs with very little basal activation of T cells and a good reactivation pattern. The cells were characterized mechanically using AFM indentation [article in preparation]. We imaged, using RICM, fluorescence and confocal the adhesion and structures of the patterned cells (membrane, cytoskeleton, nucleus) to quantify the standardization of selected cell structural parameters. We also developped patterns that are asymetrical to evaluate the influence cell shape and symetry, together with cell mechanics, on activation since and activated and migrating T cell presents a strong asymetry which may determine its activity as an effector when meeting its target.

This work was supported by a PhD grant from Labex INFORM.