Device for mechanical and hydrodynamic microfluidic transfection

A system for introducing exogenous material into cells suspended in a moving fluid through a flow channel of a microfluidic device, comprising:

• a substrate;
• at least one flow channel within said substrate, said flow channel having at least one inlet, at least one outlet, opposed sidewalls, a width from one of said sidewalls to the other of said sidewalls, and a length perpendicular to the width, said flow channel including a first array of posts along the width of said flow channel, said flow channel including at least a second array of posts along the width of said flow channel;
• and
• a pump configured to move the fluid, cells and exogenous material along the flow channel in a laminar flow to the first array of posts;
• wherein the flow channel, arrays of posts, and the pump are configured to cause inertial forces within the fluid to act on the cells in an unsteady flow to permeabilize the cells and introduce the exogenous material into the cells while maintaining at least one viable cell, said second array being shifted a distance relative to said first array to bifurcate the flow coming through said first array, the distance of the shift between said first array and said second array being configured to accommodate the flow of a range of cell sizes, and the flow around each post in a region of the flow channel has an object Reynolds number of at least 40.