A conductive patch of carbon nanotubes can regenerate heart tissue growing in a dish, according to preliminary research from Brown University. The patch, made of tiny chains of carbon atoms that fold in on themselves, forming a tube, conducts electricity and mimics the rough surface of natural tissue. The more nanotubes the Brown researchers added to the patch, the more cells around it were able to regenerate.
During a heart attack, areas of the heart are deprived of oxygen, killing muscle and nerve cells used to keep the heart beating strongly and rhythmically. The tissue cannot regenerate on its own, which disrupts the heart’s rhythm, weakens it, and sometimes leads to a repeat heart attack. Tissue engineers around the globe are searching for ways to regenerate or repair this damaged tissue using different types of scaffolds and stem cells.
Thomas Webster, an associate professor of engineering and orthopedics at Brown and senior author of the study, says his work is distinctive because he examined not just the muscle cells that beat, but also the nerve cells that help them contract and the endothelial cells that line the blood vessels leading to and from the heart. The fact that the patch helped regenerate all three types of cells, which function interdependently in the heart, suggests the newly grown tissue is similar to normal heart tissue. The research was published today in Acta Biomaterialia.
Jeff Karp, codirector of the Regenerative Therapeutics Research Center at Brigham and Women’s Hospital, says he’s impressed by Webster’s idea. But Karp cautions that the work is still preliminary. “It will be some time before we know how promising this approach truly is,” he says, because it has not yet been tested in animals.
Webster’s nanotube patch is just one of many approaches underway to help repair the heart. Many involve injecting stem cells collected from the patient into the damaged heart or implanting patches of muscle derived from these stem cells. He says the nanotubes could be used on their own, or as scaffolds for stem cells.
Webster’s team is now fine-tuning the nanomaterial to create a linear pattern to more closely mimic the pattern in natural tissue. Others have shown that creating this kind of structure can provide a natural scaffold that supports tissue strength and growth. The team is also working to make the patch as precisely as conductive as heart tissue, to see if that improves its function. The next step will be to figure out how to deliver the patch, which could be rolled up and transported to the heart via a catheter.
Of course, researchers need to do extensive safety testing before the technology can be used in patients. Unlike other materials used in tissue engineering, the carbon nanotube patch would not naturally degrade in the body. “The idea would be that the heart tissue would grow around these carbon nanotubes and they would continue to provide electrical stimulus to the heart,” Webster says.
To avoid regulatory delays, Webster says, he may try his carbon nanotube patch first on pets. Right now, heart attacks are usually fatal for the family dog, Webster says, because most animals don’t get diagnostic medical care or treatment, and have smaller hearts that have a harder time than human hearts compensating for damage. Treating pets “could be a way to get this technology out earlier,” he says.