Yes, it is possible, and sometimes required when studying hydrophobic small-molecular-weight compounds. But, of course, if you are studying protein interactions, you cannot use 100% DMSO, because that would denature proteins. You may use up to 10% DMSO, provided that all your solutions (syringe and cell) have the same DMSO concentration and your protein tolerates the selected DMSO concentration (some proteins tolerate even 12% DMSO, others not even 1%). It is usual to employ 1-3%DMSO concentrations. If you have a small mismatch in % DMSO between syringe and cell solutions, there will be heat artifacts (large injection peaks).

Please, check this paper:

http://www.ncbi.nlm.nih.gov/pubmed/17406231

Yes, it is possible, and sometimes required when studying hydrophobic small-molecular-weight compounds. But, of course, if you are studying protein interactions, you cannot use 100% DMSO, because that would denature proteins. You may use up to 10% DMSO, provided that all your solutions (syringe and cell) have the same DMSO concentration and your protein tolerates the selected DMSO concentration (some proteins tolerate even 12% DMSO, others not even 1%). It is usual to employ 1-3%DMSO concentrations. If you have a small mismatch in % DMSO between syringe and cell solutions, there will be heat artifacts (large injection peaks).

Please, check this paper:

http://www.ncbi.nlm.nih.gov/pubmed/17406231

In addition to Adrian’s detailed response, the following conditions should be considered when deciding on an appropriate DMSO concentration. Does the hydrophobic compound prepared in 100 % DMSO remain fully soluble when the latter is diluted? A test to ensure that the ligand and/or macromolecule do not aggregate in diluted DMSO solutions is to perform a titration of either into buffer containing DMSO at the exact concentration used to prepare the solutions. The resultant ITC profile should exhibit negligible dilution heats. Another consideration is to identify a suitable method to evaluate the impact of DMSO on protein structure (e.g. CD, DSC, etc) and function (measurable activity). For protein systems that tend to aggregate easily, the impact of DMSO is often difficult to predict and can be detrimental by actually accelerating the aggregation process. It is therefore imperative to evaluate protein integrity (i.e., structure, function, oligomeric state) in various DMSO concentrations prior to conducting an ITC experiment. I hope this information assists you in designing the ITC experiments.

Thank you for the in-depth responses. These answers have given me a lot to think about, I really appreciate it.