Microfluidic Biomaterial Delivers, Extracts Species

Most materials used for biomedical applications lack a way to modulate the concentration of soluble species within their bulk, a function served in living tissue by the vascular system. Abraham D. Stroock, assistant professor of chemical and biomolecular engineering at Cornell University, and coworkers have constructed a “microfluidic biomaterial” that consists of a network of channels in a calcium alginate hydrogel (J. Am. Chem. Soc., published online Sept. 15, dx.doi.org/10.1021/ja054820t).

The device is sturdy and impermeable enough to contain distinct flow paths, yet permeable enough for materials to diffuse through it. Using solutions of fluorescein or fluorescently labeled dextran (red), Stroock and coworkers show that soluble species can diffuse between the channels and the bulk, providing a way to deliver (left, top to bottom) or extract (right, top to bottom) them. A pressure-driven flow through the channels speeds up mass transfer through the device.

Stroock hopes to use such a device as a physiologically accurate scaffold for tissue engineering by seeding cells into the bulk material.