Hemoglobin multiple emulsion as an oxygen delivery system

Area of Science:

• Biomaterials Science
• Biomedical Engineering
• Drug Delivery Systems

Background:

• Multiple emulsion technology enables in vivo delivery of sensitive biomolecules.
• Hemoglobin (Hb) is a potential oxygen carrier but faces challenges in stability and delivery.
• Developing stable Hb-based oxygen carriers is crucial for medical applications.

Purpose of the Study:

• To evaluate a prototype hemoglobin (Hb) multiple emulsion as a stable oxygen delivery system.
• To assess the feasibility of using Hb-in-oil-in-water (Hb/O/W) emulsions as a blood substitute.
• To determine the compatibility of Hb multiple emulsions with physiological requirements.

Main Methods:

• Encapsulation of concentrated hemoglobin (Hb) into a Hb-in-oil-in-water (Hb/O/W) multiple emulsion using mineral oil.
• Evaluation of rheological properties, hydrodynamic stability, encapsulation efficiency, and met-hemoglobin generation.
• Assessment of oxygen affinity and cooperativity compared to whole blood.
• In vivo studies involving isovolemic exchange transfusions in rats with critically low hematocrit.

Main Results:

• Hb/O/W multiple emulsions exhibited satisfactory rheological properties and hydrodynamic stability comparable to whole blood.
• High Hb encapsulation concentration and efficiency were achieved with minimal met-hemoglobin formation.
• The emulsions demonstrated appropriate oxygen affinity and cooperativity.
• Isovolemic exchange transfusions successfully supported life in rats with hematocrit levels as low as 5%, with no acute toxicity observed.

Conclusions:

• Hb/O/W multiple emulsions possess characteristics suitable for use as a blood substitute.
• These findings support the utility of Hb/O/W emulsions as an oxygen-carrying red blood cell substitute.
• The technology shows promise for applications in organ perfusion media.