Bio-printer

The bio-printer is the product of nScrypt Inc. It is a fully computer-controlled delivery device. Three-dimensional printing is achieved by the movable x-y stage and three z-directional printing heads. Two of these are used to print the bio-ink particles, which are extruded from a bio-cartridge (a micropipette filled with bioink particles) by the positive displacement of a piston within the micropipette. The third unit is pressure operated and is used to print the bio-paper/substrate (e.g. collagen gel). Each extruder is equipped with a camera, providing full visual control of printing.

 

Tensiometer

The parallel plate compression device allows determining tissue surface tension and characteristic elastic and viscous parameters. A spherical cell aggregate (A) is placed between the lower (LCP) and upper (UCP) compression plates, in the inner chamber filled with tisssue culture medium. A water jacket, the outer chamber (OC) heats up the system to maintain 37C physiological temperature. The upper plate hangs from a nickel-chromium wire (NCW) attached to an electrobalance (B) that monitors the force applied to the aggregate. Raising the lower compression plate compresses the cell aggregate. This deformation is maintained throughout the compression to measure force dissipation under constant strain. Equilibrium is reestablished through a biphasic relaxation process; the equilibrium force and the geometric parameters are used to calculate the tissue surface tension via the Laplace-Young equation. Viscoelastic properties are determined employing the full relaxation curve.

Magnetic Tweezers

The magnetic tweezers allows measuring intracellular and cell-level viscoelastic parameters. It is a 2-coil design, capable of generating a constant magnetic gradient (and implicitly a constant magnetic force) over a surface exceeding 4x10⁵ square microns. It is a miniaturized Faraday balance mounted on the stage of an inverted Olympus IX-70 microscope. The force (in the range of 1-1000 pN) is applied unidirectionally, in the horizontal plane, through paramagnetic beads attached to the biological sample. The bead motion under magnetic force is recorded and the trajectory is determined with sub-pixel accuracy by an in-house developed particle tracking program. Physical parameters are determined from the analysis of the bead trajectory.