Of the scores of technologies that appear to have enormous potential with respect to medical applications, one of the most promising is the use of bionic implants. Some such implants are already widely used and are well known to the general public; the pacemaker, used to regulate the beating of the heart, was one of the first bionic devices to be commonly used. Perhaps the most publicized bionic devices in recent times are the increasingly sophisticated artificial limbs that have received a great deal of attention in the press because of their impact on the lives of soldiers who have lost arms and legs in the fighting in the Middle East.

Relatively unknown to most people, however, are a host of new, exotic bionic applications now on the horizon. Some of these involve the use of nanotechnology. "Nano" means a billionth of any unit of measurement; therefore "nanotechnology" means technology involving extremely small components. Nanotechnology is being used to create minute implants that interact at the cellular and molecular level with living tissues. This is bionics "writ small," but the hoped for gains may be spectacular.

One instance of this kind of research is currently being pursued at the ARC Centre for Excellence for Electromaterials Science in Australia. At ARC, filaments of polymers-- very large molecules like starches, proteins, and nylon that are formed by linking together many small molecules--that conduct electricity are being inserted into living tissues. There the polymers interact with cells, transmitting electrical, mechanical, and chemical "messages" to them and feeding back information to the microprocessors at the other end. These polymers are being loaded with growth-inducing chemicals that stimulate the production of nerve cells in the laboratory. As the ability to grow nerve cells is crucial to restoring mobility to people who have been paralyzed by spinal cord injuries, the use of such technology present exciting possibilities in the area rehabilitation of paraplegics and quadriplegics.

At both the cellular/molecular level and the level of such large structures as limbs, bionic implants may one day give those who are born with physical defects or who suffer from catastrophic injuries a chance to enjoy the benefits of full functionality. But some have fears and doubts about where this technology may lead, and they question whether or not it is ethical to pursue all of the avenues down which it is heading. Some rather nightmarish scenarios have been suggested--almost everybody is familiar with the science fiction representations of cold, implacable beings who are half machine and half human. While this image of the future is perhaps an exaggeration of what might happen, the field of bionics does pose questions that ethicists and technical people need to address.

The Center for Bionic Ethics has stated that the primary focus of bionic research should be medical, but has acknowledged that there are other avenues of interest. One such area is defense, with the idea not of restoring lost functionality to a wounded soldier but of enhancing of healthy humans with military-related bionics--the creation of biomechanical soldiers.

To some people, the concept of bionic solders--artificially created beings who are quite physically distinct from the rest of us--seems something horrific and dangerous. Others are not disturbed by such a prospect. For example, at least one organization advocates the coming of what it calls "transhumans," but in the present climate of ethical opinion, this is a radical, fringe-group position.

However, the notion of using technology to alter human beings involves many ethical questions. One of the most basic is this: how are we to define the term "human being" if we use this emerging technology of bionics to alter ourselves in some very fundamental ways, say, by tripling or quadrupling our capacity to remember? Another is what are the chances that the unrestricted use of bionic technology would result in an extreme situation such as the sci-fi scenario of a "war" between the new beings and the old ones--the old ones representing humanity as we know it today? What would be the social consequences if the well-off in the world were the only ones who could purchase bionic "enhancements" for themselves while the rest of us were condemned to live in the "unenhanced" state we were born in?

In addition to these questions about where the theoretical future of bionics might take us, there are also more immediate, practical questions that need to be addressed. When considering where to spend limited medical research funds, how much should be devoted to bionics? With regards to spinal cord injuries, for example, should we fund bionic research into the problem of learning how to create nerve cells, or should we spend the money on other promising avenues offered by stem cell research? This is a decision that, perhaps, should not be left to the technicians who do the research, for they tend to be biased in favor of their own work. Independent and objective analysis is needed to help determining what research projects should be pursued in the hopes of delivering the most promising and cost-effective technologies.