Liposome encapsulated hemoglobin: long-term storage stability and in vivo characterization

More than a Confinement: “Soft” and “Hard” Enzyme Entrapment Modulates Biological Catalyst Function

Catalysis makes chemical and biochemical reactions kinetically accessible. From a technological point of view, organic, inorganic, and biochemical catalysis is relevant for several applications, from industrial synthesis to biomedical, material, and food sciences. A heterogeneous catalyst, i.e., a catalyst confined in a different phase with respect to the reagents’ phase, requires either its physical confinement in an immobilization matrix or its physical adsorption on a surface. In this review, we will focus on the immobilization of biological catalysts, i.e., enzymes, by comparing hard and soft immobilization matrices and their effect on the modulation of the catalysts’ function. Indeed, unlike smaller molecules, the catalytic activity of protein catalysts depends on their structure, conformation, local environment, and dynamics, properties that can be strongly affected by the immobilization matrices, which, therefore, not only provide physical confinement, but also modulate catalysis.

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.

Transfusion medicine in obstetrics and gynecology

Obstetricians and Gynecologists care for many patients with conditions potentially requiring blood transfusions. Cesarean section and hysterectomy are the two surgeries performed most frequently and both have the potential for blood loss requiring transfusion. Other examples include postpartum hemorrhage, placenta previa, and ruptured ectopic pregnancy. Obstetricians and gynecologists need to become knowledgeable about the ever-changing aspects of blood transfusion and apply it in their clinical practice. This review intends to update obstetricians and gynecologists and other health care professionals about the basic as well as the latest technologies of blood transfusion. The different types of blood components are discussed including their preparation, indications, risks, and benefits. The complications of blood transfusion and their management are reviewed, including infections, noninfectious, and immunological etiologies. HIV and hepatitis are explored, these being the most serious infectious risks of transfusion. Autologous blood transfusion, an underutilized option, is examined. Hemodilution and intraoperative blood salvage, other techniques for using the patient's own blood, are discussed. Finally, synthetic agents such as erythropoietin, granulocyte colony-stimulating factors, factors, desmopressin acetate, gonadotropin-releasing hormone agonists, and new products are introduced as potential replacements to blood transfusion in the future.