Parallel determination of phenotypic cytotoxicity with a micropattern of mutant cell lines

This work presents a novel tool, the Continuous Flow Microspotter (CFM) and its use in patterning cellular microarrays of multiple cell types into the bottom of a tissue culture well. The CFM uses a system of isolated microfluidic channels to make an array of localized microspots of adhesion dependent cells in the bottom of a conventional tissue culture well. With this device we have created micropatterns of multiple cell lines in a single tissue culture well and used this system to conduct simultaneous cytotoxicity tests and recover dose survival curves in a parallel study. This mechanism of parallel testing allows the researcher to employ the use of positive and negative controls, as well as compare the chemical response of phenotypes in a tightly controlled microenvironment. For the experiments presented in this paper we have fabricated a CFM with a set of ten microchannels (five inlet channels and five outlet channels) to pattern a row of five microspots consisting of four cellular microspots and one empty spot for background measurements. Micropatterns containing a set of four different Chinese hamster ovarian cell (CHO) mutant phenotypes were deposited into the bottom of commercially available tissue culture wells then interrogated with mitomycin C, a chemotherapeutic agent. This study shows statistically significant ( P