1 October 2014
Research at the Tel Aviv University (TAU) has developed a cardiac patch that could negate the need for heart transplants in the future. The team, led by Dr Tal Dvir, used gold nanoparticles to engineer a novel biocompatible device.
Dr Dvir and his graduate student Michal Shevach of TAU's Department of Biotechnology, Department of Materials Science and Engineering, and Center for Nanoscience and Nanotechnology, have been developing substitutes to replace damaged heart tissue.
After a cardiac trauma, such as a heart attack, the organ is unable to repair itself as the organ contains few stem cells and cannot multiply. This means damaged hearts are vulnerable for the long term.
Because of this Dr Dvir's team have been looking for innovative methods that would restore the heart's vital function, with particular attention being focused on creating a 'cardiac patch'. In theory, these would be transplanted in the body to replace the damaged heart tissue. The TAU researchers discovered that gold particles are able to increase the conductivity of biomaterials.
Published by Nano Letters, the team have developed a model for a superior hybrid cardiac patch, using biomaterial taken from patients and gold nanoparticles.
Dr Dvir said their goal was "twofold" as they needed to engineer tissue that would not be rejected by the immune system and also create a functional patch that would not have problems with signalling or conductivity.
Cardiac tissue is engineered by allowing cells, harvested from patients or another source, to grow on a three-dimensional scaffold. This is similar to the collagen grid that naturally supports the cells in the heart. Over time, the cells come together to form a tissue that generates its own electrical impulses and expands and contracts of its own will, which can then be transplanted into a patient to restore heart function.
Previous attempts at creating such a device has failed because immune cells detect and try to fight off the 'foreign' cells, which are usually harvested from animals. To overcome this issue, Dr Dvir's team tried a new approach, which saw them take fatty tissue from a patient's stomach. These can be easily, efficiently and quickly harvested, and does not trigger an immune response.
Another obstacle was to ensure that there were functional network signals, which is often inhibited by the complexity of the human extracellular matrix.
"Engineered patches do not establish connections immediately," said Dr Dvir. "Biomaterial harvested for a matrix tends to be insulating and thus disruptive to network signals."
Research at his Laboratory for Tissue Engineering and Regenerative Medicine, found that including gold nanoparticles into cardiac tissue was able to encourage electrical signalling between cells.
"To address our electrical signalling problem, we deposited gold nanoparticles on the surface of our patient-harvested matrix, 'decorating' the biomaterial with conductors," said Dr Dvir. "The result was that the nonimmunogenic hybrid patch contracted nicely due to the nanoparticles, transferring electrical signals much faster and more efficiently than non-modified scaffolds."
Initial findings have shown that the hybrid patch works, but the team will now have to prove that it is able to improve heart function after a heart attack, while not triggering a destructive immune response, according to Dr Dvir.
Posted by Philip Briggs
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