MICROMACHINED MULTICHANNEL SYSTEMS FOR THE MEASUREMENT OF CELLULAR-METABOLISM

Using living cells as the biological recognition element in a biosenso r has two important advantages: cell receptors provide functional rath er than structural specificity, and the cells provide second messenger pathways that amplify the receptor/ligand binding events. Cellular re sponses can be detected by measuring extracellular acidification with a silicon sensor. By using silicon micromachining technology, we can i ntegrate the fluidic pathways and chambers for immobilizing cells with the silicon sensor. We describe a multichannel chip in which each cha nnel is etched into the surface, and has its own flow of tissue-cultur e medium past the cells. Measurements have been made on adherent cells in which a muscarinic acetylcholine receptor is transfected. Response s to the agonist carbachol are shown.