24 May 2011
Researchers from India and the US have created a band-aid for the heart with carbon nanofibres that can bring back dead cardiac cells to life
It’s as if when confronted with a road riddled with potholes, you abandon what’s there and build a new road instead.
Needless to say, this is a grossly inefficient way to treat arguably the single most important organ in the human body.
The best approach would be to figure out how to resuscitate the deadened area, and in this quest, a group of researchers at IIT Kanpur and Brown University, US, may have an answer.
Nano-Tech to the Rescue
The scientists turned to nanotechnology. In a lab, they built a scaffold-looking structure consisting of carbon nanofibers and a governmentapproved polymer.
Tests showed the synthetic nanopatch regenerated natural heart tissue cells – called cardiomyocytes –as well as neurons. In short, the tests showed that a dead region of the heart can be brought back to life.
"This whole idea is to put something where dead tissue is to help regenerate it, so that you eventually have a healthy heart," said David Stout, lead author of the paper published with Bikramjit Basu from IIT Kanpur in the journal Acta Biomaterialia.
A third of women and a fifth of men who have experienced a heart attack will have another one within six years, linked to weakness caused by the scarred cardiac muscle from a previous heart attack, according to the American Heart Association.
What is unique about the experiments at the India Institute of Technology Kanpur and Brown is the engineers employed carbon nanofibres, helical-shaped tubes with diametres between 60 and 200 nanometres.
The carbon nanofibres work well because they are excellent conductors of electrons, performing the kind of electrical connections the heart relies upon for keeping a steady beat.
The researchers stitched the nanofibres together using a polymer to form a mesh about 22 millimetres long and 15 microns thick and resembling "a black Band Aid," Stout said. They laid the mesh on a glass substrate to test whether cardiomyocytes would colonise the surface and grow more cells.
Successful Lab Tests
In tests with the carbon nanofibres seeded with cardiomyocytes, five times as many heart-tissue cells colonised the surface after four hours than with a control sample consisting of the polymer only.
After five days, the density of the surface was six times greater than the control sample, the researchers reported. Neuron density had also doubled after four days, they added.
The scaffold works because it is elastic and durable, and can thus expand and contract much like heart tissue, said Thomas Webster, the corresponding author on the paper.
It’s because of these properties and the carbon nanofibres that cardiomyocytes and neurons congregate on the scaffold and spawn new cells, in effect regenerating the area.
The scientists want to tweak the scaffold pattern to better mimic the electrical current of the heart, as well as build an in-vitro model to test how the material reacts to the heart’s voltage and beat regime.
They also want to make sure the cardiomyocytes that grow on the scaffolds are endowed with the same abilities as other heart-tissue cells.