MEMS calorimetric devices for biomolecular characterization   Measurement of heat, or calorimetry, has distinct advantages over other techniques for biomolecular characterization because it is solution-based and label-free, thus can be used for direct determination of thermodynamic properties of a wide variety of biomolecules in that almost all reactions are thermally active. For instance, an important calorimetric operation mode, differential scanning calorimetry (DSC) involves measuring heat by monitoring the differential thermal activity between a biomolecular sample and a reference material in two matched calorimetric chambers whose temperatures are scanned at a specified rate over a chosen range. Thus DSC can provide quantitative information about biomolecular thermodynamic properties over the temperature range. Conventional DSC instruments in general are rather complicated in construction and low in throughput, and require large amounts of biological material. We are developing MEMS calorimeters that will greatly facilitate addressing these issues.    We have developed a MEMS DSC device in which highly sensitive thermal sensing and control elements are integrated with microfluidic handling capabilities. Using the device, we have demonstrated the measurement of protein unfolding, yielding data that allowed determination of important thermodynamic parameters such as the enthalpy of unfolding and melting temperature of proteins.