Cell microarrays based on hydrogel microstructures for the application to cell-based biosensor.

Cell-based biosensors constitute a promising field that has numerous applications ranging from pharmaceutical screening to detection of pathogen and toxicant. The trends toward miniaturization of cell-based biosensor continue to spur development of cell microarray integrated into microfluidic devices. For cell-based biosensors to be useful for larger applications, several technical goals must be realized. First, the cell-patterning method used to generate multi-phenotypic array can accommodate multiple cell lines without major losses of cell viability, maintain total isolation of each cell phenotype, provide for the adequate mass transfer of dissolved gases and nutrients, and easy enough to allow for mass production. Second, cells on microarray must be cultured in three-dimensional environment as they do in real tissue to obtain accurate response of cells against target analyte. Third, physiological status of micropatterned cells must be monitored non-invasively. As one solution to satisfy these requirements, we prepare cell microarrays using microfabricated poly(ethylene glycol)(PEG) hydrogel. Arrays of hydrogel microstructures encapsulating one or more different cell phenotypes can be fabricated using photolithography or photoreaction injection molding, and can be incorporated within microfluidic network. Finally, we demonstrate the potential application of cell-containing hydrogel microarrays for toxin detection by monitoring toxin-induced change of cell viability and intercellular enzymatic reaction.