Note: Small technologies are defined at both a nanoscale and microscale. According to the national standards, nano is from 1nm (one nanometre, equal to one-billionth of a metre) to 100nm, and micro is above that length.

Nanoscience is essentially physics and chemistry at sizes that are not well understood. With bio-applications, physicists and chemists copy and learn from biology and, in turn, this helps us to learn more about biology. But very importantly this knowledge can be used in health care and to correct disease.

The big challenge is to determine what small technologies are most suited for a range of possible medical applications. There are nanobiomaterials, nanobiotechnology and nanobionics, as well as nanobiomechanics, biofuel cells and MEMS (micro-electro-mechanical systems) – and many more.

Biomaterials are the basis of many developments. Bionics (biology and electronics) refers to the transfer of electrical charge to and from biological systems, or the release of agents that facilitate this transfer: Biofuel cells are being developed at a nano/micro level and can be used in the body for bionics and other applications where electrical charge is required.

There are a number of basic elements of nanobiomaterials. When reduced in size, particles can change their function; most often the particles can be used as drugs or trophic agents.

Nanobioparticles are used with arterial stents to reduce post-operative stenosis. But more research is required to reverse the disease process.

Nanocomposites are synthesised by dispersing very small inorganic materials in polymers with dendritic-like chains. Due to mixing at a molecular level they have properties that are superior to either constituent. They have application in the body where there is repeated stressing, such as with pacemakers, or as delivery vehicles for radioisotopes for cancer.

A nanobiointerface is one where the material connects to the surface of the cell and influences its function. The materials can also be made to conform to the shape of cells and proteins. This will allow greater attachment of the cells to the polymers for control of the biological reactions.

Biomembranes can be made with porous elements that can let larger molecules pass through more readily than smaller molecules. It could be very important in the body for the differential release of hormones – for example, insulin in diabetes – and there could be feedback from blood glucose levels to control the pore size.

Drug and cell-delivery systems can involve biodegradable polymers. The drugs and cells may be incorporated within the material during curing. An example of a biodegradable polymer is polyurethane. There is great versatility in the chemistry to vary the mechanical properties, porosity and integration with biological materials.

With drug delivery, the agents are presently released by passive processes. Drugs may also be assembled rather than incorporated during the curing process. Frank Caroso, from the University of Melbourne, has shown that drug-containing capsules can be made from a spherical core. It is coated with alternate layers of polymers that are positively and negatively charged. The core of the capsule is removed, leaving a polymer scaffold; the scaffold can be opened with changes in pH, and the drug incorporated and then later released.

Nanobiotechnology applies in particular to the development of nanomaterials for molecular biology, and genetics procedures in particular. This is done through creating biochips for the analysis of DNA, RNA, genes and proteins. Most is presently done in vitro with the polymerase chain reaction to amplify the genetic material under investigation. Real-time analyses are coming onto the market.

With nanobiotechnology, for example, a template for the amino acid sequences for the DNA is created and this is matched to a sensor, then transduced and analysed by the computer to produce a map of the patient’s DNA.

Biochips will be used to analyse blood from a patient, where the chip determines their genetic make-up or diseased state within minutes. This will be made possible because the chip will be linked by a high-speed data cable to a central computer where all the analyses will be performed. This will mean that doctors in country areas will be able to use special diagnostic equipment and be guided in the management of patients, without having to send them to the city.

Nanobionics may also lead to drug and cell-delivery systems with the use of electro-active polymers. The drugs and cells may be incorporated within the material during the curing, or assembled together in stages. When polypyrrole is oxidised it loses an electron to become positively charged. This enables it to attract and incorporate the negatively charged component of a protein or a living cell. The protein, or a nerve growth factor, can then be released by the passage of an electrical current to neutralise that attraction.

Carbon nanotubes have great potential. They are very thin (1/10,000 the diameter of a human hair), conduct electricity and are strong. They have potential application in a number of areas of medicine, including heart valves and stents.

An example of a biosensor developed through nanobionics is a 2 × 2-millimetre silicon chip attached to the skin to measure body temperature. The chip contains a temperature sensor in an integrated circuit. A lithium, thin-film battery supplies the very low level of power required by the circuit and the signal processing and transmission electronics, and an antenna sends the data by radio signals (radio-frequency transmission) to a monitor, either in the hospital ward or central nursing station, when the chip is queried.

There is now considerable optimism that science and new technologies can make a major difference to health care. This applies in particular to the restoration of body function and the control of disease.

The first application for nanobionics with spinal cord repair is in chronic cases. This may be with cyst formation or avulsion of the anterior rami of the motor nerves.

The lateral corticospinal tract is the main motor pathway for the control of movement and scaffolds of electro-active polymer, loaded with growth or inhibitory factors, as well as stem cells, could help bridge the gap. It has also been shown that electrical currents will help guide the spinal nerves to the right location, so the scaffolds could incorporate conducting components. Adult stem cells can be also used and harvested from the fat, muscle and bone marrow and incorporated into the scaffold. Most recently cells have been taken from umbilical cord blood and shown to be effective.

Nanobionics can help improve coronary artery stents and reduce complications. Initially a stent is inserted into the artery and expanded. Some 800,000 angioplasties (mostly with stenting) are carried out in the US each year. In up to 30 per cent of these the artery eventually becomes clogged again, so there is a great need to incorporate drug-eluting material that prevent restenosis.

Epilepsy affects up to two per cent of the world’s population and one-third do not respond to medication. This costs the Australian taxpayer $1.7 billion dollars annually. Our research has commenced to analyse the EEG activity and predict when a seizure is about to happen. Electrodes in the brain will be used then to reverse the seizure. To do so safely will require the use of nanobionics to ensure that the electrode surfaces and impedance is minimal.

Many areas of nanobionics will require electrical charge, and batteries made from nanomaterials will be implantable and self-sustaining. The cell will be fuelled by the body’s metabolic processes for the transformation of two redox reactions for glucose and oxygen. The use of electrodes at a nanoscale is also more efficient.

Advances in medical devices such as catheters, guidewires, stents, pacemakers and other invasive products have enormously improved diagnostic and therapeutic practices in medical care. However, the benefits of catheters and other invasive devices are often limited by the occurrence of infections associated with the devices, even when the best aseptic techniques are practiced.

Each year, as many as two million hospital patients in the US develop nosocomial infections, that is infections which are a result of treatment in a hospital or health care unit, but secondary to the patient’s original condition. Approximately 80 per cent of the 80,000 annual deaths in this country from nosocomial infections are device-related. One possible way of preventing these infections is to use biodegradable polymer and infiltrate it with antibiotic. Furthermore, cells that defend against infection can be incorporated into the material.

The estimated worldwide market for biomaterials is about $35 billion, with a predicted growth rate of 12 per cent a year. Biomaterials and medical devices represent a fast-emerging market of about US$260 billion.

Australia can still play a significant role in this market, underpinned by strategic research.

Professor Graeme Clark is Laureate Professor Emeritus at the University of Melbourne, Founder and Director Emeritus of the Bionic Ear Institute, Senior Scientist at St Vincent’s Hospital, Melbourne, and Professor at the University of Wollongong. He initiated research at the University of Sydney, then led the crucial research at the University of Melbourne and the Bionic Ear Institute which resulted in the multi-channel cochlear implant (bionic ear) for people with severe to profound hearing loss.

The device, developed industrially by Cochlear Ltd, is the first clinically successful method of restoring brain function, and the first advance in helping deaf children to communicate, in the past 200 years. It was the first cochlear implant of any type to be approved by the US Food and Drug Administration as safe and effective for use on children.