Microcal VPViewerTM Differential Scanning Calorimeter

Differential Scanning Calorimetry (DSC) is used to measure the thermal transitions of DNA, proteins or peptides as they are heated or cooled. This is achieved by comparing the amount of energy required to heat a sample to the amount of energy required to heat the buffer of that sample (Δcp) at constant pressure. There are two cells located on top of the instrument termed sample (S) and reference (R) (Figure 1). The user should load 700 uL of buffer into both the sample and the reference cell and use a specially designed syringe to equal the level of the buffers between the two cells. Generally a program is set up and run overnight with both cells containing buffer to get a good baseline. The next morning the buffer in the sample cell will be replaced with your sample and the program will continue. After recording data, analysis can be performed in Origin software, which is provided with the instrument (Figure 2). It is important to note that in order to obtain consistent DSC data, it is advised that the user become familiar with the technique of loading the sample and reference cells. The instrument is very sensitive to any differences in the cells which may include any air in either cell and differences in the volumes loaded. These differences will lead to unusable data and users should become familiar with loading the cells using water until reproducible data is obtained.