Lyophilization is a method commonly used to preserve proteins while maintaining their stability and activity for long-term storage. The process typically begins with the preparation of a protein solution, where the protein of interest is dissolved in a suitable buffer solution or solvent. This solution is then rapidly frozen to form ice crystals, usually achieved by immersion in liquid nitrogen or through a freeze-dryer with pre-cooled shelves.
Once frozen, the lyophilization chamber’s pressure is reduced, and heat is applied to induce sublimation, the direct transition of water from solid to vapor. This primary drying step removes the majority of the water content from the protein solution, preserving the protein matrix. Subsequently, residual bound water molecules are removed during secondary drying at slightly elevated temperatures, ensuring complete dehydration of the protein sample.
After lyophilization is complete, the dried protein is sealed in vials or containers under inert gas to prevent moisture uptake and degradation. Properly lyophilized proteins can remain stable for extended periods at appropriate storage temperatures, making them valuable for various research, diagnostic, and biotech applications.