Cardiac 'patch' to replace damaged heart tissue

A cardiac patch which incorporates biomaterial harvested from patients and gold nanoparticles could be transplanted into the body to replace damaged tissue after a heart attack, scientists say.
Tel Aviv University researchers have been developing sophisticated micro- and nanotechnological tools to develop functional substitutes for damaged heart tissues.
Dr Tal 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 now discovered that gold particles are able to increase the conductivity of biomaterials.
In a study published in the journal Nano Letters, Dvir's team described their model for a superior hybrid cardiac patch, which incorporates biomaterial harvested from patients and gold nanoparticles.

Cardiac tissue is engineered by allowing cells, taken from the patient or other sources, to grow on a three-dimensional scaffold, 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 spontaneously.

The tissue can then be surgically implanted as a patch to replace damaged tissue and improve heart function in patients.
According to Dvir, recent efforts in the scientific world focus on the use of scaffolds from pig hearts to supply the collagen grid, called the extracellular matrix, with the goal of implanting them in human patients.

However, due to residual remnants of antigens such as sugar or other molecules, the human patients' immune cells are likely to attack the animal matrix.
In order to address this immunogenic response, Dvir's group suggested a new approach. Fatty tissue from a patient's own stomach could be easily and quickly harvested, its cells efficiently removed, and the remaining matrix preserved. This scaffold does not provoke an immune response.
The second dilemma, to establish functional network signals, was complicated by the use of the human extracellular matrix.
"Engineered patches do not establish connections immediately. Biomaterial harvested for a matrix tends to be insulating and thus disruptive to network signals," said Dvir.

Dvir explored the integration of gold nanoparticles into cardiac tissue to optimise 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 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," Dvir added.