Differential scanning microcalorimetry

Differential scanning calorimetry (DSC) is an experimental technique to measure the heat energy uptake that takes place in a sample during controlled increase (or decrease) in temperature. At the simplest level it may be used to determine thermal transition (“melting”) temperatures for samples in solution, solid, or mixed phases (e.g. suspensions). But with more sensitive apparatus and more careful experimentation it may be used to determine absolute thermodynamic data for thermally-induced transitions of various kinds. Formerly this was more the realm of the dedicated specialist, but now with the ready availability of sensitive, stable, user-friendly DSC instruments, microcalorimetry has become part of the standard repertoire of methods available to the biophysical chemist for the study of macromolecular conformation and interactions in solution at reasonable concentrations. And, to the extent that thermal transitions might be affected by ligand binding, DSC can provide useful information about protein-ligand binding. The advantages of calorimetric techniques arise because they are based on direct measurements of intrinsic thermal properties of the samples, and are usually noninvasive and require no chemical modifications or extrinsic probes. Furthermore, with careful analysis and interpretation, calorimetric experiments can directly provide fundamental thermodynamic information about the processes involved.