Binding event measurement using a chip calorimeter coupled to magnetic beads

Chip calorimetry is a promising method for the label-free detection of biomolecules. Miniaturized calorimetric devices using stagnant droplets require sample volumes in the nano-liter range, but exhibit some limitations regarding volume specific signal resolution, baseline stability, and evaporation. In this paper, we describe the application of a silicon chip based flow-through calorimeter for the detection of biotin and aptamers. To achieve high sensitivity, receptors coupled to magnetic beads were used. Streptavidin served as a receptor for the detection of biotin. For the first time, the chip-calorimetric response to DNA hybridization has been successfully demonstrated. For these experiments, the biotinylated complement of the DNA oligomer was coupled to the streptavidin surface of magnetic beads.