Abstract: A Microfluidic Capillary Device for Rapid Cellular Encapsulation and Formation of Multicellular Spheroids Using Calcium Alginate Gelation (2011 SACNAS National Conference)

Friday, October 28, 2011

Hall 1-2 (San Jose Convention Center)

Jacqueline De Lora , Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, NM

Danielle Lussier , Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, NM

Blake Bluestein , Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, NM

Monique Gallegos , Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, NM

Heather Canavan, PhD , Department of Chemical and Biological Engineering, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, NM

James Freyer, PhD , Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, NM

Microfluidic devices have become increasingly important in cell culture methodology because they enable the construction of 3D cellular microenvironments that are well characterized, reproducible, and are better tissue models than conventional 2D monolayers. The challenge for microfluidic cell encapsulation is to provide a physiologically relevant cell culture system that is accessible and offers a wide range of applications. We have devised a microfluidic capillary device for a single-step encapsulation of cells in uniformly sized spheres of porous calcium alginate (CA). The device consists of two, 1.00 mm ID round capillaries with 100 μm and 400 μm orifices coaxially aligned inside a 1.05 mm ID square capillary. Spheres are produced using a water/oil/water double emulsion consisting of: 1) an inner suspension of human colon tumor cells; 2) a surrounding layer of soybean oil; and 3) an outer phase facilitating alginate gelation. We measured the kinematic viscosity for each fluid phase using an Ostwald viscometer. These data were used to derive a quantitative model yielding laminar flow and dripping phenomena in our microfluidic device. Using the derived flow rates, monodispersed 100 μm diameter CA microspheres were obtained. We are generating 100 μm CA microspheres containing a range of cell concentrations (~10-50 cells/sphere) and developing methods for releasing the cells from the sphere to allow for physiological and biochemical assays. Future applications of the cell-encapsulated microspheres include assessment of cellular responses to microenvironment gradients using a perfusion system and formation of a homogenously sized population of multicellular spheroids.