%0 Journal Article %J Biomed Microdevices %D 2010 %T Patterning alginate hydrogels using light-directed release of caged calcium in a microfluidic device %A Chueh, Bor-han %A Zheng, Ying %A Torisawa, Yu-suke %A Hsiao, Amy Y %A Ge, Chunxi %A Hsiong, Susan %A Huebsch, Nathaniel %A Franceschi, Renny %A Mooney, David J %A Takayama, Shuichi %K Alginates %K Animals %K Calcium %K Cell Culture Techniques %K Cell Proliferation %K Cells, Cultured %K Endothelial Cells %K Equipment Design %K Equipment Failure Analysis %K Flow Injection Analysis %K Glucuronic Acid %K Hexuronic Acids %K Humans %K Hydrogels %K Light %K Mice %K Microfluidic Analytical Techniques %X This paper describes a simple reversible hydrogel patterning method for 3D cell culture. Alginate gel is formed in select regions of a microfluidic device through light-triggered release of caged calcium. In the pre-gelled alginate solution, calcium is chelated by DM-nitrophen (DM-n) to prevent cross-linking of alginate. After sufficient UV exposure the caged calcium is released from DM-n causing alginate to cross-link. The effect of using different concentrations of calcium and chelating agents as well as the duration of UV exposure is described. Since the cross-linking is based on calcium concentration, the cross-linked alginate can easily be dissolved by EDTA. We also demonstrate application of this capability to patterned microscale 3D co-culture using endothelial cells and osteoblastic cells in a microchannel. %B Biomed Microdevices %V 12 %P 145-51 %8 2010 Feb %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/19830565?dopt=Abstract %R 10.1007/s10544-009-9369-6