William Harvey revolutionalized science 350 years ago when he drew the outlines of hematology. Now we are moving towards a new revolution in which artificial blood is going to be manufactured! Statistics reveal that “more than 100 million pints of blood are transferred to individuals each year during surgery and emergency procedure. In America, 2 to 3 pints of blood are used every 3.7 seconds.”
However, the blood supply has not been able to meet demands due to increasing population as well as risk of infection and various problems are encountered when transporting the blood as well. In this situation, synthetic blood or artificial blood has provided hope for millions of people worldwide and it is anxiously awaited to be manufactured on a large scale.
The pioneer researcher in the field of making artificial cells was Dr. Thomas Chang. As we learn from the United Kingdom Journal, New Scientist, Chang came with the idea of making artificial cells in 1957 when he was searching for his final year project at the McGill University in Montreal where he was completing his under-graduate studies. As we learn from the United Kingdom Journal, New Scientist, he “built” cells, about a millimeter in diameter, that contained haemoglobin wrapped in a thin plastic membrane. It is interesting that even though Chang’s concept has emerged as a new field yet the concept remains as straightforward as his original notion.
“Artificial cells are, basically, artificial microscopic structures about the same size as biological cells and having some of the functional properties of biological cells. The emphasis here is that we are not trying to make models of biological cells. Rather, we are trying to make artificial cells for application in medicine and biotechnology.” The artificial cell is an attempt to copy some of the biological processes of a real cell, and one of the furthest moves in creating artificial life! At the same time, it is a great medical hope as it may ultimately prove most useful as a partial substitute for human cells and organs.
Following Chang’s efforts to create artificial cells, many research companies have started to move towards the creation of artificial blood along the same lines. Three major types of red blood cell substitutes are being developed. According to www.jplabs.com, modified (e.g., crosslinked) hemoglobin is being investigated as a potential product because of its high oxygen-carrying capacity and oncotic properties. Liposome encapsulated hemoglobin, which more closely resembles red blood cells, is another approach being pursued. A different approach involves the development of perfluorocarbon emulsions which have the ability to dissolve large quantities of oxygen.
The company which has which leads the list with the creation of Oxyglobin as the artificial blood product is BioPure. Oxyglobin is already in use at major veterinary hospitals in the US. www.msu.edu reports that oxyglobin is created when hemoglobin molecules are treated with glutaraldehyde, a chemical that binds the hemoglobin molecules together. This provides a stabilizing affect for the molecule, and prevents its decomposition into toxic dimers, a feat normally accomplished by the membrane of the red blood cell. In fact, it is believed that some of the aspects of blood can be improved using oxyglobin. The limitation of the compound however is that in comparison with the Red Blood Cells which can survive in the body from 40 – 60 days, only half of the molecules of oxyglobin can last in the body that also for about 12 hours.
Another promising project in this direction is the preparation of Perfluorocarbons(PFC’s) by the Alliance Pharmaceutical Corporation in San Diego. They claim that “though PFC’s are 40 times smaller than RBCs, they can carry twice as much oxygen twice as quickly due to absorption of the O2 versus the actual bonding completed by the iron in the haemoglobin molecule.” The functioning of the PFCs can be explained as PFCs form an emulsion that acts as a sponge, soaking up the oxygen and releasing it easily at its designation.
The third project in this was the production of HemAssist which involved cross linking of human haemoglobin with an aspirin derivative. The haemoglobin was then suspended in an electrolytic solution. However, the project failed as it caused high mortality rate.
As of now, a lot of research is being done in the direction of producing artificial blood cells and there is hope that the substitute to this may be found soon.