The Chemistry of Lyophilized Blood Products

With the development of new biologics and bioconjugates, storage and preservation have become more critical than ever before. Lyophilization is a method of cell and protein preservation by removing a solvent such as water from a substance followed by freezing. This technique has been used in the past and still holds promise for overcoming logistic challenges in safety net hospitals with limited blood banking resources, austere environments such as combat, and mass casualty situations where existing resources may be outstripped. This method allows for long-term storage and transport but requires the bioconjugation of preservatives to prevent cell destabilization. Trehalose is utilized as a bioconjugate in platelet and red blood cell preservation to maintain protein thermodynamics and stabilizing protein formulations in liquid and freeze-dried states. Biomimetic approaches have been explored as alternatives to cryo- and lyopreservation of blood components. Intravascular hemostats such as PLGA nanoparticles functionalized with PEG motifs, topical hemostats utilizing fibrinogen or chitosan, and liposomal encapsulated hemoglobin with surface modifications are effectively stored long-term through bioconjugation. In thinking about the best methods for storage and transport, we are focusing this topical review on blood products that have the longest track record of preservation and looking at how these methods can be applied to synthetic systems.