Creation of a Spatial Chemical Gradient with the Help of a Microfluidic Device

Of paramount importance in the culture of cells and organisms is efficient access to various nutrients. A useful tool in the study of organism response to various nutrients is a microfluidic cell where precise spatial control of species concentration is readily available. In this work, we have fabricated devices which create linear gradients of nutrients, such as oxygen or potassium and nitrate ions, directly in the cell culture chamber. All microfluidic structures were fabricated from the negative tone photoresist SU-8 because of its high optical clarity and for its compatibility with on-chip optical waveguide manufacture. Nutrient-sensitive fluorophores were immobilized in conjuction with optical waveguide posts to allow for characterization of the cell culture chamber microenvironment.