1.4. From Body Part Healing To Life Extension

Researchers anticipate that bionics will be used to replace diseased or aged organs thereby increasing lifespans. One of the main goals is to make bionics of all types less invasive and cumbersome and with new materials and designs there is constant improvement. Professor William Craelius of Rutgers school of Engineering studies how bionics can restore mobility to people with impaired limbs using prostheses. Craelius’s research includes work with patients paralyzed due to stroke, brain injury, and cerebral palsy and the development of connections between nerves and bionic devices.

1.5. Part Human, Part Machine

Bionics, also called biomimicry, biomimetics, biomimetrics, and biognosis, is being touted as creative engineering technology that can restore almost any lost function. According to Craelius, scientists see the day when human flesh will be removed in favor of high-tech machinery, giving way to “body modification” that will be more complex and far-reaching than simple nose rings and facelifts.

Once human brains are able to manage bionic parts and hearts and lungs no longer need to power as much of the body, humans will enjoy increased fitness and stamina and will have an incentive to replace underperforming body parts. There are already artificial neurons, neural networks new field of “swarm intelligence”.

In the interim, “strap on robots” such as exoskeletons or wearable robots will enhance strength, mobility and endurance for the disabled and fit alike.

Not so fast warn some bionic researchers: bionics does not function well in temperatures below 0 °C and some give off radiation that can be detected using a Geiger counter. Doctors are already able to attach bionic limbs and operate them using surviving sensory nerves that transmit temperature, pressure and vibration.

2. DIFFERENT BODY PARTS

2.1. Artificial blood vessels

Artificial blood vessels are tubes made from synthetic (chemically produced) materials to restore blood circulation. During World War I (1914–1918) FrenchAmerican surgeon Alexis Carrel (1873–1944) perfected a procedure for sewing the ends of blood vessels together. This achievement won him the 1912 Nobel Prize in medicine. Carrel also made artificial blood vessels with tubes of glass and aluminum.

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The most successful artificial blood vessels in use today come from surgical techniques developed in the 1940s and 1950s. To replace damaged or diseased arteries or veins, surgeons initially transplanted arteries or veins from donors, but these transplants frequently failed. In some cases the donor arteries were rejected by the recipient, while in other cases the vessels developed arteriosclerosis (“hardening of the arteries”). Transplanting vessels from the patient's own body was problematic because two surgeries were required, one to harvest the needed vessel and a second to transplant it. Furthermore, many patients with circulation problems had no suitable vessels that could be transplanted.

To overcome these problems, researchers began to experiment with synthetic blood vessel materials such as polyethylene (a soft and waxy plastic) and siliconized rubber (rubber formed with silicone). These synthetic fabrics showed the most promise.

2.2. Synthetic Materials Outperform Natural Ones

A porous material called vinyon, which had been tried on dogs, was first used by A. B. Voorhees on humans in 1953. A variety of synthetic fabrics were subsequently used in experiments; of these, the plastic Teflon and synthetic fiber Dacron proved to work best. Blood vessels made from these synthetics are not rejected by the body's immune system, and the materials are easily available and extremely durable.

While large Dacron blood vessels work very well, small ones have a tendency to become blocked by clots. Researchers are working on ways to make the interior walls of these small synthetic vessels smoother, thus preventing clot formation.

2.3. Hybrid Vessels

In the early 1980s chemist Donald Lyman of the University of Utah (Salt Lake City) synthesized a polymer (a plastic formed by long chains of carbon molecules) that had two advantages. Due to a high attraction for albumin (the protein in blood serum), Lyman's polymer reduced clot formation. The polymer also exhibited more elasticity (stretchiness), thereby reducing strain at the site where the natural and artificial vessels were surgically joined. Research Industries of Salt Lake City began testing Lyman's vessels on humans in 1988.

Surgeon David Annis of the University of Liverpool (England) produced a similar flexible, smooth-walled plastic vessel and also began human trials in the late1980s. In 1990 Organogenesis (a bio-research company) of Cambridge, Massachusetts, began animal testing of its living blood vessel equivalent, which is

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a hybrid (specialized combination) of natural and artificial materials. This artificial vessel features a smooth inner layer grown in the laboratory from human cadaver (dead body) artery cells and tubules strengthened with Dacron mesh. Another approach worked out by Stuart Williams at Jefferson Medical College, Philadelphia, Pennsylvania, uses cells from the patient's own inner blood vessel lining to grow a lining on the inside of Dacron synthetic vessels.

2.4. Artificial blood vessels created on a 3D printer

Until now, the stumbling block in tissue engineering has been supplying artificial tissue with nutrients that have to arrive via capillary vessels.

A team at the Fraunhofer Institute in Germany has solved that problem using 3D printing and a technique called multiphoton polymerisation.

Out of thousands of patients in desperate need of an organ transplant there are inevitably some who do not get it in time.

To make sure more patients receive these life-saving surgeries, researchers in tissue engineering all over the globe have been working on creating artificial tissue and even entire organs in the lab.

But for a lab-made organ to function, it needs to be equipped with artificial blood vessels – tiny and extremely complex tubes that our organs naturally possess– used to carry nutrients.

The individual techniques are already functioning and they are presently working in the test phase.

Numerous attempts have been made to create synthetic capillaries, and the latest one by the German team seems to be especially promising.

“The individual techniques are already functioning and they are presently working in the test phase; the prototype for the combined system is being built,” said Dr Gunter Tovar, who heads the BioRap project at Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart.

2.5. Elastic biomaterials

3D printing technology has been increasingly used in numerous industries, ranging from creating clothes, architectural models and even chocolate treats.

But this time, Dr Tovar's team had a much more challenging printing mission. To print something as small and complex as a blood vessel, the scientists combined the 3D printing technology with two-photon polymerisation – shining intense laser beams onto the material to stimulate the molecules in a very small fo-

cus point.

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The material then becomes an elastic solid, allowing the researchers to create highly precise and elastic structures that would be able to interact with a human body's natural tissue.

So that the synthetic tubes do not get rejected by the living organism, their walls are coated with modified biomolecules.

Such biomolecules are also present in the composition of the “inks” used for the blood vessel printer, combined with synthetic polymers.

“We are establishing a basis for applying rapid prototyping to elastic and organic biomaterials,” said Dr Tovar.

“The vascular systems illustrate very dramatically what opportunities this technology has to offer, but that's definitely not the only thing possible.”

2.6. Scientists develop bionic heart

Scientists in Australia have developed a groundbreaking bionic heart that works without having a pulse. The device, which was successfully tested on a sheep, is set to start clinical trials within three years.

A bionic heart could save millions of lives every year.

The device was developed by Brisbane engineer Dr Daniel Timms, who instigated the project in 2001 while studying at the Queensland University of Technology. The mechanism is, at its core, fairly simple; it has a spinning disc with small blades on each side that pump blood around the body and lungs, without actually beating. In other words, the user of this bionic heart wouldn’t have a pulse. The small bladed disks, which spin at 2000 revolutions per minute, represent a significant change in departure from traditional pulse-based designs.

Timms explained that the device, called BiVACOR, could last ten years longer than previous designs due to the lack of wear and tear on the components.

“There were other devices that were quite large, and they also would break quite easily,” Dr Timms says in a video explaining the concept. And the reason they would break is they would have a sac, so if you’re beating them billions of times per year, they’re going to break.”

Another key innovation is the fact that the components are kept in place through magnetic force, and they don’t directly touch each other, something which reduces wear and tear even more.

“It means there’s no wear and that’s the key of the device in that it can actually last for up to 10 years or longer without wearing out,” he said. And that’s a paradigm shift actually from these earlier pulse-style devices that couldn’t last for more than two years.”

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