Robert Langer is an Institute Professor at MIT. This is his first piece to be published on Webdiary.
by Robert Langer
One of the most important efforts in health care research over the next decade will be to integrate advances in biology, material sciences, and chemical and bioengineering to create a revolutionary new generation of medical devices and drug delivery systems. Indeed, the main challenge facing researchers in these diverse fields may not be a lack of scientific progress, but rather a shortage of adequate interdisciplinary training.
A key area for research will involve tissue engineering, which generally involves combining the cells of mammals (including stem cells) with polymer-materials to create new tissues or organs. It is now estimated that nearly half a nation‘s health care costs can be attributed to tissue loss or organ failure. The ability to create new livers, spinal cords, hearts, kidneys, and many other tissues or organ-based systems could radically decrease hospitalization time, relieve suffering, and prolong life.
The challenges here are, of course, huge. In particular, an appropriate source must be found for producing a large enough supply of differentiated cells quickly enough. Stem cells represent a potentially important potential source, but problems in controlling their differentiation and growth must first be overcome, as must rejection by the human immune system.
Another path to be pursued involves the development of micro-electrical mechanical systems (MEMS) that can be used in drug delivery. These microdevices would be made of silicon or other materials that can be loaded with drugs (or sensors) and covered with caps made of gold or other substances. An electrical signal to the implant would dissolve the gold cover to release the drug.
Such systems have the potential to deliver new kinds of drugs in complex regimens which might be useful for cancer chemotherapy, for example. They could also provide new means of localized drug delivery that might be useful in several areas, including delivery of multiple drugs. Finally, such systems might also create new opportunities for bio-sensing devices that could be placed on a computer chip.
New kinds of biomaterials for medical devices are also on the horizon. Currently, most biomaterials are off-the-shelf materials that were originally used in consumer applications. For example, the material in the artificial heart was originally used to make girdles for women. Some breast implant materials were originally used in mattress stuffing.
A potentially important area here is the development of materials that have a “shape memory.” For example, a surgeon might place something like a string
through a small endoscopic hole; in the presence of an appropriate stimulus (for example, temperature or light), it would then convert itself into an appropriately shaped medical device such as a stent, or a sheet to prevent adhesion. Another potential use for such materials might be self-tying sutures that could be employed in minimally invasive surgery.
New materials will also be necessary to overcome one of the main obstacles to successful gene therapy: the absence of appropriate delivery systems. While viruses are a highly efficient means, they pose safety risks. Likewise, the non-invasive delivery of complex molecules such as peptides or proteins remains a major challenge. Currently such molecules are given by injection. But if scientists can develop better delivery systems or synthetic agents that are safer, cheaper, and easier to manufacture, enormous opportunities will be created for complex drugs that could be given without injections.
New advances in engineering medicine may help in targeting drugs at specific cells, particularly cancer cells, which has been extremely difficult to do for several reasons. One challenge is to design micro or nano particles that can travel throughout the bloodstream without being absorbed by other cells along the way. If that can be accomplished, “magic bullets” to fight cancer, heart disease, and other disorders might someday be possible.
All of these looming changes will likely have an enormous impact on drug development and diagnostics.
However, developing and exploiting the full array of potential new disease-fighting weapons will require outstanding scientists and engineers, including those with interdisciplinary training.
Copyright: Project Syndicate, 2007.