A brief analysis of capillary sealing methods and their effectiveness

Protein crystals and the solutions from which they are grown must be carefully protected against dehydration. In the absence of a proper seal, the crystals will dehydrate and lose their original properties and subsequently the ability to diffract X-rays. We conducted a systematic study of the efficacy of the most common sealing materials in use and we report the results here. The study shows that no single material is completely effective in both untreated and silanized glass capillaries. Various combinations of two materials, however, give excellent seals that will prevent dehydration for long periods of time. Recommendations are made for sealing materials to be used.