Gold Nanowire Heart Patch Helps Cardiac Tissue Rebuild Itself

Posted on Wednesday, September 28, 2011 by Unknown

Ischaemic heart disease is one of the leading cause of death all over the world causing more than 7 million deaths every year according to WHO. So it's no wonder that scientist all over the world are trying to find ways to combat against it and now Scientists at MIT may be on the best track for the solution.

Fixing cardiac tissue damaged in a heart attack is one of the great current challenges in tissue engineering. Heart cells are particularly hard to make in the lab, requiring special care to develop into the proper type of beating cells. Once they’re made, it’s difficult to seed them into a broken heart. Other efforts have also been made that encourage surrounding heart cells to grow into Heart Muscle Cells.

Electrical signals shared among calcium ions dictate when cardiomyocytes contract, making the heart beat. But tissue scaffolds are often made with materials like polylactic acid or alginate, which act as insulators, so the signals are blocked. This makes it difficult to get all the cells in a piece of tissue to coordinate their signals and beat in time, which in turn makes it difficult to build a very big or very effective heart patch.

The Cambridge-based team, led by Daniel Kohane, a professor in the Harvard-MIT Division of Health Sciences and Technology, went around this problem by creating a sponge-like matrix made from alginate, a gummy organic substance that is frequently used for such tissue scaffolds. Mixed with that alginate, however, was a solution containing billions of tiny gold nanowires. As with "traditional" tissue scaffolds, it was then seeded with heart cells.

Although the alginate itself acted as an insulator, the nanowires were able to bridge the gaps between the cells, allowing electrical signals to pass between them. While heart tissue grown on pure alginate has been shown to have a conductivity of only a few hundred micrometers, the nanowire-enhanced tissue was able to conduct electricity over "many millimeters." Compared to a typical scaffold system, the gold nanowire cells’ conductivity improved by three orders of magnitude. Kohane said it was “night and day.”

The MIT researchers believe that the technology could be used not only for heart patches, but also for addressing problems with other types of muscle tissue, vascular constructs, or in neural systems.

The video below shows how tissue grown in the nanowire-alginate composite (right) is able to conduct electricity better than tissue grown using pure alginate (left).