Differential Scanning Calorimetry
Differential scanning calorimetry (DSC) is a technique that allows measurement of thermal transitions within a sample. In the biopharmaceutical arena, its primary use is measuring the thermal stability of a bio-molecule as a transition mid-point. DSC is a powerful technique that can also be used to determine thermodynamic parameters related to a sample.
A differential scanning calorimeter is a highly sensitive instrument that measures the difference in heat energy required to heat a sample cell (containing a bio-molecule in buffer) to a given temperature compared to a reference cell (containing only buffer). Endothermic transitions, such as protein unfolding, require more heat energy than the buffer, and result in a positive response, whereas exothermic transitions, such as protein aggregation, require less heat energy than the buffer and result in a negative response.
The transition mid-point is used as a marker of thermal stability, and the area under the curve is a direct measure of the enthalpy of the transition, which can be used to calculate the thermodynamic stability at a given temperature.
The sensitivity of a differential scanning calorimeter to measuring differences in heat energy makes DSC particularly powerful in comparability, stability and formulation studies.
Facilities
DSC thermograms are measured on a MicroCal VP-DSC, which has a working range of -10 °C –130 °C.