Gold nanowires used in promising new heart patches
By Ben Coxworth
September 27, 2011
Around the world, scientists have been working on ways of replacing the heart tissue that dies when a heart attack occurs. These efforts have resulted in heart "patches" that are made from actual cardiomyocytes (heart muscle cells), or that encourage surrounding heart cells to grow into them. One problem with some such patches, however, lies in the fact that that they consist of cardiomyocytes set within a scaffolding of poorly-conductive materials. This means that they are insulated from the electrical signals sent out by the heart, so they don't expand and contract as the heart beats. Scientists at MIT, however, may be on the way to a solution.
The team created 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" (if such a word can be used) 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."
While this range still isn't up there with natural heart tissue, which has a conductivity that is measured in centimeters, it's definitely a step in the right direction.
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.
A paper on the research was published this week in the journal Nature Nanotechnology.
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).