Authors:
L. Costa
A. Terekhov
D. Rajput
W. Hofmeister
Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388

D. Jowhar
G. Wright
Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240

C. Janetopoulos
Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240 and Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37240

Microfluidic devices designed for chemotaxis assays were fabricated on fused silica substrates using femtosecond laser micromachining. These devices have built-in chemical concentration gradient forming structures and are ideally suited for establishing passive diffusion gradients over extended periods of time. Multiple gradient forming structures, with identical or distinct gradient forming characteristics, can be integrated into a single device, and migrating cells can be directly observed using an inverted microscope. In this paper, the design, fabrication, and operation of these devices are discussed. Devices with minimal structure sizes ranging from 3 to 7 μm are presented. The use of these devices to investigate the migration of Dictyostelium discoideum cells toward the chemoattractant folic acid is presented as an example of the devices’ utility.