Rebuilding humans using bionics

You only have to go to the movies to get an insight into the possibilities of bionics. The films Terminator, Ironman and Robocop all feature characters with artificial body parts.

One of the most well-known examples is Anakin Skywalker, of the Star Wars films. Skywalker was left for dead following a light sabre duel with Obi-Wan Kenobi. Having lost both legs and an arm and with his body badly burned, Skywalker was transformed into Darth Vader, with his distinctive black armour working as a life support system. Likewise, his son Luke Skywalker also received a bionic right hand after it was cut off in a light sabre duel.

Darth Vader and Luke Skywalker might be fictional characters from a galaxy far, far away, but creation of high-tech artificial body parts is already science fact here on Earth.

Research is underway in several key areas and although much has been achieved, bionics is still very much in its infancy. Scientists are striving to develop better controlled, lighter, smaller, more life-like and affordable bionic options. Here’s a rundown on the body parts you might be using in years to come.

Bionic limbs

Artificial limbs have been around for hundreds of years. For instance, the Anglesey wooden leg was designed for the Marquis of Anglesey after he lost a leg in the Battle of Waterloo in 1815.

Such a replacement body part is known as a prosthesis. Prostheses can also be internal parts, such as artificial knees, hips or even false teeth.

But what’s different about the new generation of body parts is the way they combine several areas of technology and science such as electronics, biotechnology, hydraulics, computerisation, medicine and nanotechnology.

The term ‘bionics’ is relatively new, combining the prefix ‘bio’ – meaning life – with electronics. Bionic technologies create mechanical or electronic versions of living things or body parts.

The i-Limb™ has independently powered fingers that can pick up everyday objects. (Image: Touch Bionics)

The i-LIMB™, for instance, is an artificial hand with four independently powered fingers and a thumb. Each digit has a small motor and people using the artificial hand can grasp and pick things up, use scissors and even play cards. The i-LIMB™ attaches to the person’s arm stump and picks up small electrical signals from muscles in the arm to control movement of the digits.

A different type of bionic hand is the award-winning rehab glove designed in Sydney. Using a computer and artificial muscles, the glove allows people with paralysed or injured hands to move their hand or grasp objects.

Although artificial legs and knees have been around for some time, now they’re incorporating hydraulics, electronics and computer programming. These bionic legs enable better movement control by responding to the body and walking conditions. Other technology that uses electrical stimulation of the body’s existing muscles, enables paraplegics to walk again.

Bionic hearts

Artificial cardiac pacemakers that use electrical impulses to regulate a person’s heartbeat have been used for around 50 years. More recent is the development of artificial hearts; for now, these remain short-term treatments often used to buy time until a heart transplant becomes available.

The AbioCor artificial heart consists of a hydraulic pumping system which is totally implanted in the patient’s chest. An internal battery and electronics package are implanted in the patient’s abdomen to monitor and control the pumping of the heart. It is used for patients who have a life expectancy of less than 30 days and no other viable treatment options such as heart transplant. The first recipient, Robert Tools, lived for 150 days with the artificial heart before dying in 2001. Another patient lived for more than 500 days with his artificial heart.

And more than 400 people worldwide have received the Australian-designed Vetrassist device. This device is attached to the left ventricle and helps the heart to pump blood to the body. However, the future of the Ventrassist technology is in doubt after the company went into liquidation in mid-2009.

Bionic ears

Parts of the bionic ear a. microphone; b. thin cord connecting microphone to speech processor; c. speech processor; d. transmitting coil; e. receiver/stimulator; f. electrode array; g. cochlea; h. auditory nerve. (Image: ©Department of Otolaryngology, University of Melbourne)

Related site: Cochlear implants – wiring for sound Covers the development of the cochlear implant and how it works. (Nova: Science in the news, Australian Academy of Science)

Deafness is often caused by damage to the minute hairs in the ear; these normally turn sound into tiny electrical signals that the cochlear nerve then sends to the brain. The bionic ear uses an external microphone that picks up sounds which are then sent via a processor to the implant. There, a receiver turns the sound signals into electrical impulses, which are sent via an electrode array to the brain.

Scientists are constantly improving the cochlear implant technology.  The challenge now is to improve the clarity of hearing for recipients of the implant, particularly in places like crowded rooms or when listening to music.

Bionic eyes

The Australian government has allocated $50 million to fast track research into the bionic eye. Developing a bionic eye is a challenging task; Australian scientists are meeting the challenge from a couple of different angles (Box 1: Focusing on bionic eyes).

There are three main types of bionic eye being developed around the world. These usually involve one of the following approaches:

• Electrical stimulation of the retina, where images from an external camera are transmitted to a microchip on the retina wall or the eyeball, with electrodes stimulating the optic nerve to send signals to the brain.
• ‘Mini telescopes’ implanted into the eye that magnify images onto the retina. Such implants are being developed for people suffering from macular degeneration; and
• Bypassing the eye, where the image information collected by a tiny external camera is sent to a processor then to electrodes implanted in the brain.

Although early trials have proved promising, so far there is very limited resolution or detail in what a person can see using such devices. But it’s still early days and the technology is developing rapidly.

Brain bionics

One of the most challenging areas of bionics is to allow a person to control a bionic device by using their brain – in effect, turning their thoughts into actions.

Already scientists are developing implanted neural interfaces – nerve interfaces or brain implants – to help achieve this. One team has reported being able to assist a quadriplegic check emails and play video games using a computer chip implanted on the surface of his brain. Elsewhere brain-computer interfaces are being developed that let people move their wheelchairs around objects using electrical signals from their brain.

In other developments, researchers are looking at implanting electrodes in a person’s brain – known as deep brain stimulation or a ‘brain pacemaker’ – to treat Alzheimer’s disease, depression, epilepsy or Parkinson’s disease.

Nanobionics

Incredible as it might seem, a new area of bionics is also being developed using nanotechnology. Known as nanobionics, it involves the use of tiny electrical circuits and materials made at the atomic or molecular level.

At such a scale, tissues of the body can be targeted more effectively and bionic technologies can be miniaturised. For instance, Australian researchers are looking at using minute carbon nanotubes to help implants connect better with living tissues and nerves. The technology may contribute to the next generation of bionic ears: nanoelectrodes could improve the implant’s connection with nerves compared to the current platinum electrodes.

Similarly, nanobionics is being embraced to help repair spinal cord injuries – or other damaged nerves. Implanted nanoscale materials like carbon nanotubes can be used to encourage regrowth of damaged nerves and at the same time guide the direction of their growth. While the safety of carbon nanotubes is yet to be confirmed, Australian scientists are trialling implants using intelligent plastics which – with electric stimulation – can deliver molecules that encourage nerve regrowth.

The emerging field of medical bionics

In 2007 Professor Graeme Clark pointed out that technology is again heralding a new era of medicine. He and others use the term ‘medical bionics’ to refer to the use of technology to restore body functions. That term, and others such as nanobionics are still so new many people haven’t heard of them.

Bionics might be a relatively new field, but chances are even Luke Skywalker would be impressed by what’s already been achieved as part of the bionic revolution.

Box 1 | Focusing on bionic eyes

Australian research teams are part of the world-wide race to develop a bionic eye.

One system they are developing, uses a microchip implanted on the retina. The microchip receives images via radio waves from a small camera attached to the patient’s glasses. The chip then converts the image data into electrical impulses that travel via electrodes along the optic nerve to the brain, which ‘sees’ the images.

(Image: courtesy of the Bionic Ear Institute, Bionic Vision Australia team member)

Another approach is building on the techniques used in developing the bionic ear that allowed stimulation of nerves in the inner ear from electrodes lying around the periphery. Instead of a retinal implant, electrodes are wrapped around the outer surface of the eyeball. Images from a camera in the patient’s glasses are fed to a small computer, which might be worn or carried like an MP3 player. The computer converts the images to an electrical signal and sends this to the electrodes, which feed the signal to the optic nerve via an electric field.

Each method has its advantages. The retinal implant will be able to achieve finer resolution but involves eye surgery, which could risk damaging what remaining vision a person might have.

But the Australian teams will have to hurry if they want to win the race to develop a bionic eye. There are some 20 research teams around the world also working on developing the technology. In fact, American research into the bionic eye started back in 1967 when Australian’s were working on the bionic ear. One US company has already tested its Argus II bionic eye, based on a retinal implant, in some 20 patients world-wide. The device reportedly has been able to restore limited sight: one blind man can now see flashes of light and follow the white lines on a road.

One of the challenges for researchers developing retinal implants is to come up with microchips that have more electrodes, which will allow for more pixels and better vision for the person affected.

Related sites

• Bionic Vision Australia
• Our approach
• About us

• How does a bionic eye work? (Australian Bionic Eye Foundation)
• How does a ‘bionic eye’ allow blind people to see? (How Stuff Works, USA)

Activities

• The bionic body: Teaching guide (Public Broadcasting Service, USA)
• Activity 1: Coordinated control – students observe some of the challenges of coordinated control using a constructed circuit. They then relate this to electrical stimulation and control of muscles.
• Activity 2: Nuclear transplants – students model the removal of a cell nucleus and its insertion into another cell to learn about stem cell technology.
• Activity 3: Uncovering a signal – students compare and contrast electroencephalogram recordings.

• Discovery Education (USA)
• The real bionic man – students discuss bionics and compare the parts of a bionic eye to the parts of a real eye.

• Science upd8 (UK)
• Bionic vision – students compare the parts of the natural eye to a bionic eye. They then evaluate having a bionic eye.

• Innovation – Life, inspired. For teachers. (Public Broadcasting Service, USA)
• How to make an artificial organ – a series of 14 lessons in which student groups build a model of an artificial organ or limb and present it to the class. (Note: This activity requires the video The human body shop but could be adapted for use without the video)

• Learning network (The New York Times, USA)
• In the eyes of the beholder – students learn about the structure and function of the eye, dissect an eye and discuss eye diseases. They then learn about retinal implants and produce a poster on an eye disease and technology aids for the disease.

• Blind people with eye damage may someday use chips to see – the article referred to in the above activity. (Note: More recent retinal implant information is available in Box 1: Focusing on bionic eyes and Further reading).

Activity 1.

Modelling the bionic spinal cord

In 1995 when Christopher Reeve – an actor who played Superman – suffered a spinal injury in a horse riding accident, he became a quadriplegic. His spinal cord nerves were no longer able to pass nerve impulses from the brain through to muscles in his body.

Reeve worked tirelessly to support spinal cord research, but unfortunately he died in 2004. However, Australian research into special materials that conduct electricity might one day help people with spinal injuries like Reeve had, to walk again. Using these materials to help the body bypass the damaged area of the spinal cord, scientists hope to create a bionic spinal cord.

You are going to build an electric circuit as a simplified model to show the effect of damage to the spinal cord and how a bionic spinal cord could work.

Equipment

a 2.5 volt globe and holder
a 1.5 volt battery and holder or DC power supply
6 electric leads with alligator clips
a switch

Build the circuit below – this represents the flow of nerve impulses through the body’s nervous system with an intact spinal cord. In the body, electricity is the flow of electrons from negative to positive regions of nerve cells.

1. Make sure the switch is closed. Does the globe light up?

2. Open the switch. What happens to the globe?

The globe relies on electricity to light up. When the circuit is broken (by opening the switch) the globe doesn’t light up. The body’s nervous system also uses electricity. When the spinal cord is damaged, electric signals can’t get through to the nerves in contact with our muscles to tell them to move.

3. Now connect a bypass to the open switch as shown in the above circuit. This is a simplified model of how a bionic spinal cord will work. What happens to the globe?

4. Match the parts of the circuit labelled A, B C and D above to the body parts they represent listed in the table below.

5. Suggest ways the human body functions differently from the circuit model.

Australian scientists are trying to mend the area of damaged spinal cord using a bridge made of ‘intelligent’ plastic that conducts electricity. The plastic will contain nerve growth hormones that encourage nerves to regrow across the bridge. Electrical stimulation of the plastic via a radio transmitter will control the direction of nerve regrowth.

6. What do you think might happen if the plastic bridge wasn’t electrically stimulated?

Extension activities

1. Find out how electrical impulses are generated by nerves in the human body.

2. Watch the video Nerves of steel. What advantages might a bionic spine have over direct stimulation of muscles?

Further reading

Useful sites

Australian Academy of Science

• Cochlear implants – wiring for sound (Nova: Science in the news)
  Provides information, activities and resources on cochlear implants.
  http://www.science.org.au/nova/029/029key.htm

• Gregg Suaning (Interviews with Australian scientists)
  Transcript of an interview with Gregg Suaning who has worked on cochlear and eye implants.
  http://www.science.org.au/scientists/gs.htm

How stuff works (USA)

• How artificial hearts work
  Describes how an artificial heart functions and the role of its various parts.
  http://health.howstuffworks.com/artificial-heart.htm

• How does a ‘bionic eye’ allow blind people to see?
  Explains how a retinal implant works.
  http://health.howstuffworks.com/bionic-eye.htm

• How biomechatronics works
  Covers development of bionic parts, such as mechanical limbs, that interact with the human body. Components of bionic parts are also explained.
  http://health.howstuffworks.com/biomechatronics.htm

The bionic body (Public Broadcasting Service, USA)

Provides information and video on bionic eyes, replacement organs, nerve regeneration and electronic muscle stimulation. Includes a teaching guide and activities.
http://www.pbs.org/saf/1107/index.html

Bionic humans: Top ten technologies (Live Science, USA)

A simple, interactive look at ten bionic technologies for the human body.
http://www.livescience.com/technology/top10-bionic-tech-1.html

Research overview (The Bionic Ear Institute, Australia)

Lists the different medical bionics research programs of the Bionic Ear Institute including improved bionic ears, a bionic eye, drug delivery systems to prevent and reverse hearing loss and implantable devices to repair the spinal cord and treat epilepsy.
http://www.bionicear.org/research/index.html

Bionic Vision Australia

Provides information on Bionic Vision Australia including research partners and their approach to developing a bionic eye, using retinal implants.
http://bionicvision.org.au

Australian Bionic Eye Foundation

Provides information on the organisation’s research into developing a bionic eye, using electrodes on the outer surface of the eye.
http://www.bioniceye.org.au/index.html

Australian Broadcasting Corporation

• Spare parts (In Depth, 31 August 2009)
  Covers Australian research into bionic eyes and a bionic spine.
  http://www.abc.net.au/science/articles/2009/08/31/2656359.htm

• 2020 vision for bionic eye (The 7.30 Report, 25 June 2008)
  Details bionic eye research in Australia (8 minute video and transcript).
  http://www.abc.net.au/7.30/content/2007/s2285985.htm

• Shaping the future (Radio National, 16 December 2007)
  Transcript of a lecture by Professor Graeme Clark on the potential of a range of medical bionics technologies.
  http://www.abc.net.au/rn/boyerlectures/stories/2007/2084257.htm

• Rocket fuel powers bionic arm (News in Science, 3 September 2007)
  Reports on research into a bionic arm that can move faster and in a wider range of directions than conventional prosthetic arms.
  http://www.abc.net.au/science/articles/2007/09/03/2022312.htm

• Deep brain stimulation (Catalyst, 8 March 2007)
  Covers the successful use of deep brain stimulation to treat a young patient with a movement disorder.
  http://www.abc.net.au/catalyst/stories/s1864329.htm

• iHuman (Science Show, 14 January 2006)
  Explores neural prosthetics, electronic implants and robotics.
  http://www.abc.net.au/rn/scienceshow/stories/2006/1544523.htm

• New bionic ear uses smart plastic (News in Science, 12 April 2005)
  Reports on Australian research into a cochlear implant with chemicals that stimulate nerve growth in the inner ear.
  http://www.abc.net.au/science/articles/2005/04/12/1342345.htm

• Brave new world (The Lab, 4 November 2004)
  Briefly covers the rehabilitation glove, bionic hearts, neuroswitching and artificial muscles.
  http://www.abc.net.au/science/features/brave/

i-LIMB – pointing to the future? (Science Museum, United Kingdom)

Covers an award-winning bionic hand with independently moving fingers.
http://www.sciencemuseum.org.uk/antenna/macrobert/111.asp

Glossary

bionics. The study of biological systems as a basis for developing mechanical and electronic technology (eg, for robot development or replacing body parts).

biotechnology. Technology that relies on biological organisms or processes to produce useful products. Includes fields such as bionics, bioengineering, fermentation (eg, in brewing or baking) and production of hormones for medical use (eg, insulin).

brain pacemaker. A device which sends electrical impulses to brain tissue in order to treat or prevent diseases such as depression, epilepsy and Parkinson’s disease.

deep brain stimulation. Treatment that involves the use of a brain pacemaker to electrically stimulate particular areas deep within the brain. Deep brain stimulation is used to treat conditions such as depression and Parkinson’s disease. For more information see How deep-brain stimulation works (Time Magazine, USA).

electrode array. A series of electrodes which conduct electricity. An electrode can be used to deliver electricity to the body or to receive electricity from it. Delivering electricity to the body is used to stimulate; receiving electricity from the body can be used to detect and record signals.

With the multi-channel cochlear implant, electrodes are used to stimulate the cochlea by delivering electricity to it. There are 22 electrodes at different positions along the implant so that it is possible to stimulate many different sites. When the implant is inserted into the cochlea, the 22 electrodes allow auditory nerve fibres at different sites from the base of the cochlea to its apex to be stimulated selectively, thus enhancing the ability of the patient to distinguish different frequencies of sound.

hydraulics. The study or use of the mechanical properties of liquids. In engineering, systems involving liquids may be used to operate machinery such as in hydraulic cylinders. In a bionic limb a hydraulic system can be used to improve movement control.

left ventricle. One of four chambers of the heart. The left ventricle is the lower, left chamber that is responsible for pumping oxygenated blood through the aorta to the body. It has thick muscular walls to enable it to pump blood at a higher pressure to the body.

macular degeneration. A disease that causes a loss of central vision due to damage to the central area (macula) of the retina. Macular degeneration is believed to be caused by environmental and genetic factors and is more common in older people.

nanometre (nm). One-millionth of a millimetre (or one-billionth of a metre). This is the scale at which we measure atoms and molecules. For example, ten hydrogen atoms laid side by side measure a nanometre across, and a pin head is around a million nanometres wide. The 'machines' inside our cells and the molecular constructions they put together are measured in nanometres.

nanotechnology. Engineering at the molecular or atomic level. It’s about manipulating matter over the scale of 1 to 100 nanometres. Nanotechnology is used in a range of applications from nanoscale electrodes and water filters to nanopowders for  sunscreen and cosmetics.

nanotubes.Extremely small tubes, usually made from carbon. For more information see IPE nanotube primer (Institut de Physique des Nanostructures, Switzerland).

retina. The light sensing inner lining at the back of the eye. Images focused by the lens onto the retina are converted to nerve impulses and sent via the optic nerve to the brain.

retinitis pigmentosa. An inherited disease that is caused by abnormal pigmentation of the retina. The disease is progressive, starting with problems with night vision, followed by loss of peripheral vision and sometimes ending with complete blindness.