Report identifies three bio-engineered products that have been developed during the last 50 years, and, that have had a marked impact on people

Assessment Task 4

Abstract

This report identifies three bio-engineered products that have been developed during the last 50 years, and, that have had a marked impact on people. The report will then proceed to describe this impact and what effect these products have had on the quality of people’s lives. As well as this, the report will trace the history of the products, and how they have developed in response to developments in materials and related material-forming processes.

Introduction

The human body is a complex machine, capable of adaptation to most environments and recovery from many illnesses. Nevertheless, it is not invincible. In fact, it is far from it. The body can suffer from diseases and injuries that may permanently disable or even cause death. To counter this problem, bio-medical engineers are constantly improving and reinventing products that can be used to replace and treat human deficiencies. Three of these products include the: Totally Artificial Heart (TAH), Bionic Ear and Artificial Limbs.

In modern society, these products have a marked influence on people. They have helped people to lead almost normal lives and have given them opportunities in life which they otherwise might not have had.

TAH

Effect on People’s lives

The totally artificial heart is a revolutionary development that has dramatically influenced heart patients. The artificial heart offers many advantages over a transplanted heart. There is less chance for rejection, a problem that is ever present in the transplants of natural hearts, so people will not need anti-rejection drugs that cause side effects. However, people who have artificial hearts will need anti-coagulation medication; but this is generally not problematic and has few side effects.

Today, one of the leading manufacturers of the totally artificial heart is a company called Abiomed. Their latest breakthrough, the AbioCor, allows the artificial heart to be implanted directly into the human body. Unlike previous heart assist devices, the AbiCor allows the user optimal manoeuvrability, as they are no longer connected to large machines that power the heart. It therefore gives the user a chance to lead an almost normal lifestyle and do many things otherwise impossible.

The TAH, then, is important as it allows heart patient to lead a normal lifestyle without the threat of heart failure. However, it nevertheless has its limits. Users are unable to participate in intensive exercises that may aggravate or dramatically increase the need for oxygen. The heart may be unable to supply this oxygen, and result in a stroke.

Therefore, artificial hearts are useful, as they vastly improve the quality of life of previously bedridden patients by allowing them to ‘get on’, as it were, with daily aspects of life, but without allowing them physical exertion.

Development in relation to materials and material forming

The TAH has been in development since the 1960’s, when it was first tested on human patients. These earlier versions were crude ancestors of the present day model, and contaminated and infected blood as well as caused strokes and clots in the body. Since then, the product has developed in response to developments in materials and related material forming processes.

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Development in relation to materials and material forming

The development of the artificial heart has always been primarily concerned with finding and forming materials that are biocompatible with human blood. The first artificial heart, the Liotta, was developed in 1969 and was used to bridge the period between a transplant and availability of a donor heart. Unfortunately, the patient died 32 hours later, as a result of corrosion poisoning.

In 1974, scientist David M. Lederman discovered materials that could withstand the corrosive environment of the bloodstream, without damaging cells or promoting the growth of blood clots that can cause strokes. His research helped development of TAH’s by providing bioengineers materials suitable for use in artificial hearts.

In 1982, the Jarvik-7 TAH was implanted on Barney Clark, who lived for 112 days. This was followed by William Schroeder’s implant of the Jarvik-7, who suffered from strokes and clots in his system. The main problem with the Jarvik-7 was its tendency to cause thrombosis and sepsis in patients. This was caused by the material that was used in the blood pump – the smooth surface, the actual geometry with in the blood pump, as well as the presence of cracks and crevices in the valves.

However, new material forming processes such as powder metallurgy and internal fabrication allowed new development in the TAH to reduce the chance of such infections. Newer models began to use a pump diaphragm that is fabricated of integrally textured polyurethane as well as by powder coating the metallic surfaces of the pump. This led to a dramatic decrease in users of artificial hearts being infected with thrombosis.

As modern technology advanced, engineers developed a true totally artificial heart – the AbioCor. The model uses computers in the forming and designing of particular materials and parts.

One significant advantage to the Abiocor is the smooth surface of it’s blood sacs. Smooth plastics are important in order to ensure constant motion of blood cells. Any time blood stops moving along the surface of a material, potential for clotting develops. The smoothness of the plastic, called Angioflex, allows for minimal damage to the blood. Angioflex is also durable enough to withstand 100,000 beats a day for several years.

Today, with the development of polyurethane, the artificial heart has advanced even further. This material provides optimal mechanical properties that offer the TAH the endurance necessary to withstand the rigorous vibrational strain. Such properties include a low modulus of elasticity of 5.9 MPa, allowing for high flexibility, a percent elongation of 850% before breakage. Polyurethane far exceeds the amount of elongation necessary to withstand the vibrational cycles of the TAH. Segmented polyurethane’s level of water absorption, 1.5% (very low), ensures that water will not seep into the chamber of the total artificial heart.

However, one drawback of this material, like in materials used in the Jarvik-7, is that it still promotes thrombosis and bacterial infection. To minimize the possibility of defects, the polyurethane is hand poured over moulds in order to create the TAH. A clean room environment for fabrication is also utilized to avoid contamination of the polyurethane by extraneous material. Polyurethane has greatly helped in the development of artificial hearts, as it exhibits almost all the mechanical and physical properties needed by the artificial heart.

Artificial limbs

Effect on people’s lives

The dramatic impact that prosthetic limbs have had on the quality of people’s lives can not be undermined. Prosthetic limbs have allowed many people to lead a normal life, and given them freedom from crutches and wheelchairs.

Today, development in materials has allowed users of prosthetic limbs to reach a new phase in freedom. Their strength, flexibility and impact absorption enables users to access all types of terrain and areas. It has led to improved quality of life for many people, as well as allowing them to get on with normal lives.

Artificial limbs have also been adapted to match skin colour and look part of the body. As such, the person no longer has to feel awkward or self-conscious about how they look, and this in turn has boosted self confidence and empowered people, and enhanced value of their lives.

However, for most people, there is still a need for intensive training and rehabilitation process that has to be undertaken before prosthetic limbs can be used. This is somewhat of a drawback, as the person cannot immediately get back to their life after recovery.

Development in relation to materials and material forming

The idea of prosthetic limbs is nothing new. However, it is only in the last fifty or so years that it has really been developed. The concept of prosthetic limbs can be traced back to the 1500’s, when these primitive artificial body parts were no more than sticks or stiff material strapped to the appropriate part of the body using fastening methods. Later on, with knowledge of metals and forging, artificial body parts were developed using metals i.e. hooks were used to replace hands.

After World War II, with the huge increase in young amputees, the need for better limb control became more apparent. This led to innovation of limbs using plastic, with technology being concentrated on developing a new knee that would stabilise during weight bearing but swing freely during walking.

In the 1970’s there was a development of the ‘Modular Assembly Prosthesis’ process, which allowed the assembly of a prosthetic limb from a series of stock components. Then, in the 1980’s, with the development of materials in the aircraft industry, the world’s first carbon fibre prosthetic system was made. This technology promoted high strength and light weight system.

With the discovery of composites, there was a huge boom in the artificial limbs sector; they became lighter, easier to work with and more durable.

As computers became more common, the development of CAD CAM computer program, material forming and shaping processes became much more accurate. Plastic moulded limbs were introduced, fitting comfortably over the residual limb. Cosmetic skins were also being introduced around this time with the development in silicone technology.

Today, modern material forming processes have allowed bio-medical engineers to develop materials that are better suited to artificial limbs. Using a method known as ‘Hot Isostatic Pressing’, heat and high pressure is applied in all directions on the heated material. This forms the material and removes the flaws, thus resulting in improved strength, flexibility and fatigue life of the component.

Bionic Ear

Effect on people’s lives

The bionic ear can be considered to be one of the greatest Australian inventions. Allowing people regain the use of one of their most powerful senses, the artificial ear has revolutionised the modern world.

To those who have previously experienced hearing, they suffer a huge loss, both socially and emotionally, when it is lost. They often experience severe depression and feelings of both hopelessness and helplessness. Therefore, receiving an implant dramatically improves their quality of life by boosting their self confidence, as well as allowing them to resume their normal lives.

The cochlear implant has also enabled deaf born people with a new opportunity. These people have not had previous experience in hearing, and therefore do not experience the emptiness felt by people who have experienced hearing. Nevertheless, they feel, and are, severely disadvantaged in a noise dependent society. To these people, the bionic ear enables them another chance at life, and vastly improves their quality of life.

However, because these people have never heard human speech, they require help from an audiologist to help them understand and get used to speech. Although this is difficult for some, it poses very little trouble for many, and vastly improves quality of life of the user.

Development in relation to materials and material forming

The first primitive versions of the bionic ear were fitted on humans in 1978. Since then, the implant has developed to a more sophisticated, non-intrusive and reliable system, thanks to the developments in materials and related material forming processes.

Initial prototypes of the cochlear implant allowed the user to hear. Nevertheless, these were crude designs, and often had trouble picking up most syllables or sounds. The person could recognize it as speech, but had difficulty in interpreting their meaning.

With the development of sound absorbent materials, such as plastics and advanced composites, bioengineers were able to further develop the bionic ear. The resulting design allowed users to hear sounds better, with improved clarity and volume.

The development of semiconductor materials, such as silicon, enabled the improvement of integrated circuits. Thus, circuits were developed for the bionic ear. This new technology meant that the bionic ear could become smaller. It also allowed many more components on a single chip, thus increasing efficiency.

The latest technology utilized by the bionic ear is known as the ‘intelligent polymers’. These plastics allow optimum hearing efficiency and clarity, by absorbing, directing and amplifying incoming sound waves. This technology has been a huge step forward in further development of the bionic ear.

Conclusions

Modern biotechnology is far from prefect. There is still research that is conducted in an effort by bioengineers to develop new material more suitable for products. Research has also been conducted into material forming processes to develop products.

Nevertheless, the development of materials has progressed a long way. The TAH, Artificial limbs and Bionic Ear are just some of the examples which portray this development. As research and development of materials continue, these, and other bioengineered products, are sure to improve to suit peoples needs.