It is a really, really small robot. Nanobots do not exist yet, but when they do, futurists predict possible uses for nanorobots will include molecular manufacturing nanofactories and medical nanobots that steer autonomously through your blood stream making repairs and guarding against infection. The bad side of nanobots will be their obvious suitability for spying and the possibility, however unlikely, of a nanobot takeover, aka grey goo. More specifically, nanorobotics refers to the still largely hypothetical nanotechnology engineering discipline of designing and building nanorobots, devices ranging in size from 0. As of nobody has yet built artificial non-biological nanorobots: they remain a hypothetical concept.
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E-mail: moc. This article has been cited by other articles in PMC. Abstract Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology.
Development of the first blood substitutes dates back to the early s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. Keywords: Blood, artificial blood, Perfluorocarbons Background Blood is a special type of connective tissue that is composed of white cells, red cells, platelets, and plasma.
It has a variety of functions in the body. Plasma is the extracellular material made up of water, salts, and various proteins that, along with platelets, encourages blood to clot.
Proteins in the plasma react with air and harden to prevent further bleeding. The white blood cells are responsible for the immune defense. They seek out invading organisms or materials and minimize their effect in the body. The red cells in blood create the bright red color.
As little as two drops of blood contains about one billion red blood cells. These cells are responsible for the transportation of oxygen and carbon dioxide throughout the body. On the membranes of these cells are proteins that the body recognizes as its own. For this reason, a person can use only blood that is compatible with her type. Currently, artificial blood products are only designed to replace the function of red blood cells.
It might even be better to call the products being developed now, oxygen carriers instead of artificial blood. History There has been a need for blood replacements for as long as patients have been bleeding to death because of a serious injury. According to medical folklore, the ancient Incas were responsible for the first recorded blood transfusions.
No real progress was made in the development of a blood substitute until , when William Harvey described how blood is circulated throughout the body. In the years to follow, medical practitioners tried numerous substances such as beer, urine, milk, plant resins, and sheep blood as a substitute for blood. The first successful human blood transfusions were done in Unfortunately, the practice was halted because patients who received subsequent transfusions died.
Of the different materials that were tried as blood substitutes over the years, only a few met with minimal success. Milk was one of the first of these materials. In , patients were injected with milk to treat Asiatic cholera. Physicians believed that the milk helped regenerate white blood cells. In fact, enough of the patients given milk as a blood substitute seemed to improve that it was concluded to be a safe and legitimate blood replacement procedure.
However, many practitioners remained skeptical so milk injections never found widespread appeal. It was soon discarded and forgotten as a blood replacement.
Another potential substitute was salt or saline solutions. In experiments done on frogs, scientists found that they could keep frogs alive for some time if they removed all their blood and replaced it with a saline solution. These results were a little misleading, however, because it was later determined that frogs could survive for a short time without any blood circulation at all.
After much research, saline was developed as a plasma volume expander. Other materials that were tried during the s include hemoglobin and animal plasma. In , researchers found that solutions containing hemoglobin isolated from red blood cells could be used as blood replacements.
In , they also examined the use of animal plasma and blood as a substitute for human blood. Both of these approaches were hampered by significant technological problems. First, scientists found it difficult to isolate a large volume of hemoglobin. Second, animal products contained many materials that were toxic to humans. Removing these toxins was a challenge during the nineteenth century.
This product evolved into a human product when lactate was added. Karl Landsteiner [ Figure 1 ], who has been called the father of immunology, was the only child of Leopold Landsteiner, a prominent Austrian journalist and editor, and Fanny Hess Landsteiner. Landsteiner was educated at the University of Vienna, where he received his medical degree in While in medical school, Landsteiner began experimental work in chemistry, as he was greatly inspired by Ernst Ludwig, one of his professors.
After receiving his medical degree, Landsteiner spent the next five years doing advanced research in organic chemistry for Emil Fischer, although medicine remained his chief interest. During , he combined these interests at the Institute of Hygiene at the University of Vienna where he researched immunology and serology.
Landsteiner was primarily interested in the lack of safety and effectiveness of blood transfusions. Landsteiner was intrigued by the fact that when blood from different subjects was mixed, the blood did not always clot.
He believed there were intrinsic biochemical similarities and dissimilarities in blood.
Freitas Jr. It could eradicate heart disease, stroke, and other vascular problems; remove parasites, bacteria, viruses, and metastasizing cancer cells to limit the spread of bloodborne disease; move lymphocytes faster to improve immune response; reduce susceptibility to chemical, biochemical, and parasitic poisons; improve physical endurance and stamina; and partially protect from various accidents and other physical harm. With the availablitity of mature molecular nanotechnology we could replace blood with a single complex robot. This robot would duplicate all essential thermal and biochemical transport functions of the blood, including circulation of respiratory gases, glucose, hormones, cytokines, waste products, and all necessary cellular components.
Trends in Drug Delivery
A ribosome is a biological machine. Hibbs suggested that certain repair machines might one day be reduced in size to the point that it would, in theory, be possible to as Feynman put it " swallow the surgeon ". These nano-robot swarms, both those unable to replicate as in utility fog and those able to replicate unconstrained in the natural environment as in grey goo and synthetic biology , are found in many science fiction stories, such as the Borg nano-probes in Star Trek and The Outer Limits episode " The New Breed ". Some proponents of nano-robotics, in reaction to the grey goo scenarios that they earlier helped to propagate, hold the view that nano-robots able to replicate outside of a restricted factory environment do not form a necessary part of a purported productive nanotechnology, and that the process of self-replication, were it ever to be developed, could be made inherently safe. They further assert that their current plans for developing and using molecular manufacturing do not in fact include free-foraging replicators.
Department of Pathology, J. Received Mar 2; Accepted Oct Nanotechnology has important implications in nearly all the branches of medicine and it has all the capabilities to revolutionize the vast field of medicine in future. Nanotechnological advancements have been used for the preparation of artificial hemoglobin. It is formed by assembling the hemoglobin molecules into a soluble complex. A recent approach includes the assembling of this artificial hemoglobin with enzymes such as catalase and superoxide dismutase into a nano-complex. This complex acts as an oxygen carrier as well as an antioxidant in conditions with ischemia—reperfusion injuries.
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Nanobots in Medicine Nanorobots are a promising new technology that has several potential uses. However, most of the applications that we have so far considered have revolved around medicine. Haematology One such case is in the field of haematology, which is the science of blood and blood diseases. One main application of nanobots is to emulate red blood cells. This design would allow the robots to pass into the smallest capillaries and ensure much more efficient delivery of oxygen to tissue than is possible with organic red cells.