COLUMBUS, Ohio - Treatment for life-threatening diseases and relief from disease-related pain may one day be supplied by microscopic chips that could be implanted in the body, according to researchers in the new field of biomedical nanotechnology.
Such chips - called biological microelectromechanical devices (bioMEMS) - are less than half the width of a human hair. They could contain drugs, muscle cells or even be equipped to monitor a patient's condition minute-to-minute. And these devices already show therapeutic potential for treating heart disease and diabetes.
"The development of these microscopic chips will let us do a whole host of exciting things in biomedicine," said Robert Michler, chief of cardiothoracic surgery at Ohio State University. Michler and several colleagues discussed the role nanotechnology may play in medicine of the future during a presentation Sept. 26 in Columbus at the BioMEMS and Biomedical Nanotechnology World 2000 meeting, co-sponsored by Ohio State.
Michler said doctors in the future will combine the use ofnanotechnology with another revolutionary process - robotic surgery. Michler led a study using robotic techniques to perform open-heart surgery on 60 patients. Surgeons in the study took arteries from the patients' chest walls and sewed them on to their hearts. Robotic surgery has the advantage of precision, as it "can gain access to very small areas inside the body," he said.
Michler envisions using robotic surgery to place microchips inside the body, such as on heart tissue or blood vessels. The chips could contain stem cells - cells that give rise to specific types of cells, such as those comprising muscles, organs, blood and other tissues. They could also contain chemicals that would stimulate the growth of blood vessels, or medication that is slowly released into the body, Michler said.
"The use of microscopic chips will take heart disease treatment to the next level," he said. "It has the potential to let physicians assess the benefit of their work right in the operating room, rather than waiting to see if symptoms show up.
"We're ready to create the chips and use the robot to insert them into the hearts of lab animals," Michler said. "We're looking at probably five years before human clinical trials begin."
Joining Michler on the panel were Costantino Benedetti, director of cancer pain, therapy and palliative medicine at the James Cancer Hospital at Ohio State; Michael Caligiuri, the associate director for clinical research at Ohio State's Comprehensive Cancer Center; and Pascal Goldschmidt, chief of cardiology at Duke University. They offered their perspective on how nanotechnology will affect patient treatment in the future:
Treating the pain associated with surgery is poorly done in more than 50 percent of patients, even with today's technology, says Benedetti. Benedetti hopes for the development of a local anesthetic that could last days - or even weeks - and be released inside the body through slow-release technology. Today's strongest local anesthetics last a maximum of eight hours, Benedetti said. "A drug delivery system that would allow a short-acting anesthetic to be released slowly would be advantageous," he said. For example, a surgeon could place the slow-release anesthetic in the wound at the end of the surgical procedure, forgoing the need for traditional post-operation pain relief. A painkiller released slowly inside the body would prevent the pain impulses from reaching the brain, so a patient would never feel the pain.
While the field of cancer vaccines is in its "infancy," said Caligiuri, there is the potential to develop a vaccine-containing chip or slow-release capsule taken orally that can target specific types of cancer. "Cancer prevention via vaccination is a huge frontier," he said. Other than developing the appropriate vaccines, obstacles to overcome also include determining the right dose of the vaccine, where in the body to deliver it and the duration of delivery. "Drug delivery devices would give us much better control of dosing, thus enhancing the effectiveness of the drug while limiting its toxicity," Caligiuri said.
Also, a chip could house the tools to relay to physicians information on potentially cancerous tissues. "Most men 70 and older harbor some evidence of pre-malignant or even malignant cancer in the prostate tissue, although the majority of these will never become a problem during their lifetime," Caligiuri said. But microchips equipped with sensors could detect mutated genes or dangerous levels of hormones, and enable doctors to determine which tissues to treat.
Microchips could contain stem cells - cells that give rise to other specialized cells - that would grow and proliferate inside the body. This chip technology could even create new tissue on damaged organs. "Instead of transplanting a whole organ, we would do a transplant using stem cells," Goldschmidt said. "These cells can be engineered inside the body to ensure that normal heart tissue would form even in the region damaged by a heart attack."
The possibilities also include cellular therapy - Goldschmidt envisions one day using a device called a nanoneedle to analyze the cells of heart tissue in a patient with heart disease. Using such a small needle would allow doctors to "see" damaged genes. They could then use stem cell transplantation to replenish the damaged tissue. "It's a totally new way of detecting faulty genes," Goldschmidt said. "We could look at the tissue in question and, without having to do a biopsy, see if the tissue is damaged."
Goldschmidt also talked about "smart stents" - these stents would support tissue and keep the blood vessels of the heart open, and also be able to detect changes in blood flow. "Smart stents would have a sensory role," Goldschmidt said. "They would gather information on how blood flows through the organ, without the need for a physician to directly examine the blood vessels."
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