A cell-based immunobiosensor with engineered molecular recognition--Part II: Enzyme amplification systems

Immune cells in vivo routinely perform highly selective immunosensing in blood and tissues as part of their normal immune surveillance functions. We have been investigating the potential of exploiting the immunosensing detection abilities of excitable immune cells (i.e. the mast cell) for the development of whole cell immunobiosensors. A key feature is that these immune cells can be selectively engineered to recognize specific antigens in vitro. In the presence of antigen, these cells undergo excitable activation responses which result in increased metabolism and the exocytosis of stored intracellular mediators. We have previously determined that mast cell metabolic responses can be thermally transduced in real time, thus indicating the possibility of whole cell thermoelectric immunobiosensing. In this work we investigated the use of enzyme amplification systems to enhance the direct transduction of immune cell responses to analyte. It was found that with appropriate enzymes, peak outputs occurred within approximately 5 min (4-20 times faster than without enzymes) and peak response magnitudes were up to nine-fold greater than without enzymes.