Stablisation of enzymes by microencapsulation with a concentrated protein solution or by microencapsulation followed by cross-linking with glutaraldehyde

Artificial Cells, Nanomedicine, and Biotechnology

2013

Even though erythrocytes transport both oxygen and carbon dioxide, research on blood substitutes has concentrated on the transport of oxygen and its vasoactivity and oxidative effects. Recent study in a hemorrhagic shock animal model shows that the degree of tissue PCO 2 elevation is directly related to mortality rates. We therefore prepared a novel nanobiotechnological carrier for both O 2 and CO 2 with enhanced antioxidant properties. This is based on the use of glutaraldehyde to crosslink stroma free hemoglobin (SFHb), superoxide dismutase (SOD), catalase (CAT) and carbonic anhydrase(CA)to form a soluble PolySFHb-SOD-CAT-CA. It was compared to blood and different resuscitation fluids on the ability to lower elevated tissue PCO 2 in a 2/3 blood volume loss rat hemorrhagic shock model. Sixty minutes of sustained hemorrhagic shock at 30 mm Hg resulted in the increase of tissue PCO 2 to 95 mm ± 3 mmHg from the control level of 55 mm Hg. Reinfusion of whole blood (Hb 15 g/dL with its RBC enzymes) lowered the tissue PCO2 to 72 ± 4.5 mmHg 60 minutes after reinfusion. PolySFHb-SOD-CAT-CA (SFHb 10 g/dL plus additional enzymes) was more effective than whole blood in lowering PCO 2 lowering this to 66.2 ±3.5 mmHg. Ringer's Lactated solution or polyhemoglobin lowered the elevated PCO2 only slightly to 87 ± 4.5 mmHg and 84.8 ± 1.5 mmHg, respectively. Moreover, ST-elevation for whole blood (Hb 15 g/dL) and PolySFHb-SOD-CAT-CA (Hb 10 g/dL) was respectively 12.8% ± 4% and 13.0% ± 2% of the control 60 minutes after reinfusion. Both are significantly better than those in the Ringer's lactated group and the PolyHb group. In conclusion, this novel approach for blood substitute design has resulted in a novel nanobiotechnological carrier for both O 2 and CO 2 with enhanced antioxidant properties.

Section: Introductionmentioning

confidence: 99%

Lowering of elevated tissue PCO₂in a hemorrhagic shock rat model after reinfusion of a novel nanobiotechnological polyhemoglobin-superoxide dismutase-catalase-carbonic anhydrase that is an oxygen and a carbon dioxide carrier with enhanced antioxidant properties

Bian

Gao

Artificial Cells, Nanomedicine, and Biotechnology

2013

“…One of these is based on the basic research on glutaraldehyde crosslinked polyhemoglobin (Chang 1971). The group from Northfield has independently developed glutaraldehyde crosslinked human polyhemoglobin and carried out very extensive clinical trials (Moore et al 2009).…”

Section: Hemoglobin Based Oxygen Carriers (Hboc)mentioning

confidence: 99%

From artificial red blood cells, oxygen carriers, and oxygen therapeutics to artificial cells, nanomedicine, and beyond

Artificial Cells, Blood Substitutes, and Biotechnology

2012

The first experimental artificial red blood cells have all three major functions of red blood cells (rbc). However, the first practical one is a simple polyhemoglobin (PolyHb) that only has an oxygen-carrying function. This is now in routine clinical use in South Africa and Russia. An oxygen carrier with antioxidant functions, PolyHb-catalase-superoxide dismutase, can fulfill two of the three functions of rbc. Even more complete is one with all three functions of rbc in the form of PolyHb-catalase-superoxide dismutase-carbonic anhydrase. The most advanced ones are nanodimension artificial rbc with either PEG-lipid membrane or PEG-PLA polymermembrane. Extensions in to oxygen therapeutics include a PolyHb-tyrosinase that suppresses the growth of melanoma in a mice model. Another is a PolyHb-fibrinogen that is an oxygen carrier with plateletlike function. Research has now extended well beyond the original research on artificial rbc into many areas of artificial cells. These include

“…Although an excellent oxygen carrier, Hb extracted from the blood cells cannot be used for infusion because it is highly toxic to the kidney 2 . Even highly purified stroma-free Hb (SFHb in which the rbc membrane stroma is removed) still showed toxicity to the kidney 3 It is now known that when free Hb is infused into the body, the tetramer (α1β1α2β2) breaks down into toxic dimers (α1β1 and α2β2) that causes renal toxicity and other adverse effects. The challenge is how to make use of the excellent oxygen carrying properties of Hb but prevent it from having toxic effects.…”

Section: First Generation Blood Substitutesmentioning

confidence: 99%

“…1) 2,3 The first bifunctional agent used was sebacyl chloride 2 . The second bifunctional agent used was glutaraldehyde 3 Glutaraldehyde crosslinked polyHb is the basic principle that has been later developed independently by two groups with ongoing Phase III clinical trials and one of these has been approved for routine use in South Africa. One is pyridoxalated glutaraldehyde human polyHb containing <1% unpolymerized molecular Hb (www.northfieldlabs.com) [4][5] .…”

Section: First-generation Modified Hb Based On Nanobiotechnologymentioning

confidence: 99%

Blood substitutes based on nanobiotechnology

Trends in Biotechnology

2006

Stimulated by concerns of potential infective agents in donated blood, since the 1900s, there have been considerable commercial attempts to develop blood substitutes. After many years of development a few of the many leads have shown promise. This review article describes promising nanobiotechnological approaches that are now in Phase III clinical trials. This is followed by a discussion of how important basic knowledge gained is now being used to develop new generations of blood substitutes based on nanobiotechnology. INTRODUCTION: