Create new heart patch

Scanning electron microscope (SEM) image of patch with gold and alginate nanofibers. Star clusters of gold nanowires can be seen in these images.

A group of researchers at MIT and Children's Hospital Boston, USA, have built heart patches using tiny gold-made wires that are used to create tissue samples that all wear. They both have the ability to contract simultaneously, mimicking the natural dynamics of the heart muscle. The results of this study in the future will help treat heart attack patients.

The new heart patch, using gold nanowires to boost electrical signals between cells , is a promising step in more effective treatment for heart attack patients.

The results of this study, published in the journal Nature Nanotechnology , promise to provide better therapeutic efficacy than currently used heart patches, which do not meet the required level of enhancement. Circulating electrical signals between cells to ensure smooth muscle, continuous contraction.

"The heart is a rather sophisticated structure including electrical signals, " said Professor Daniel Kohane, working at the Department of Health and Technology Science (HST), Harvard-MIT and the lead author of this study. . "It is important that the heart muscle cells have to contract smoothly, otherwise the tissues will not function properly."

The new and unique approach uses gold nanowires scattered among cardiac muscle cells as these cardiac muscle cells are growing in vitro, a technique "significantly enhancing the performance of patches Kohane said. Researchers believe that this technology can eventually lead to the introduction of heart patches, which will be implanted to replace damaged tissue after a heart attack.

Scanning electron microscope (SEM) image of nanowires

Co-authors of this study include: Dr. Brian Timko, working at MIT and Dr. Tal Dvir, alumnus, currently working at Tel Aviv University in Israel, other authors are their colleagues from the Department of Health and Technology Science (HST), Children's Hospital Boston and the Department of Chemistry of MIT including Robert Langer, the David H. Koch Institute Professor.

To build new tissue, biological engineers often use pieces of sponge-like material to organize cells into functional shapes as they grow. Traditionally, however, these pieces of material have been made from materials with poor electrical conductivity, while cardiac muscle cells, based on electrical signals to coordinate the simultaneous contraction, is a big problem.

"In the case of cardiac muscle cells characteristic: the junction between cells must be able to transmit good electrical signals between cells" , according to Timko. However, the piece of material acts as an insulator, preventing signals from circulating between cells and making nearly all tissue tissues unable to coordinate smoothly.

To solve the problem, Timko and Dvir collaborated on each other: Timko designed semiconductor gold (gold) nanowires, Dvir in myocardial tissue transplantation techniques - to design a heart patch that would give allow electrical signals to pass.

"We started brainstorming, and I realized that it was quite easy to develop nanowires that transmit electrical signals, made of gold, and of course gold has high electrical conductivity , " Timko added. . "As long as there are two nanotubes of signal transmission made of gold, several microns long are the signal transmitting."

The team mixed alginate (an organic substance like gum) with a solution containing gold nanowires to create a synthetic patch with billions of tiny metal structures running through it.

They then implanted cardiac muscle cells into alginate-gold patch, testing the conductivity of the developed tissue on this mixed patch compared to the developed tissue on the patch made of pure alginate. Because the signal is guided by calcium ions and among the cells, the researcher can check how far the electrical signal travels between cells by observing how much calcium is present in different areas of the tissue. .

"Essentially, calcium is the way that heart muscle cells communicate with each other, so we look at cells with signs of calcium specificity and place patches on the microscope , " Timko said. Here, the research team observed: an impressive improvement in cell growth on the mixed patch: a series of conduction signals improves by about three conventions in the form of powers 10.

"In healthy congenital heart tissue, there is transmission through many centimeters," Timko said. Previously, the tissue developed on pure alginate patched only about a few hundred (measured by micrometers) or several thousand millimeters. But in the patch with gold nanoparticles and alginate achieved signal transmission across many millimeter scales, Timko said.

"This is a limp comparison. The use of heart patches made from nanomaterials is much better , " Kohane said.

Charles Lieber, a professor of chemistry at Harvard University, said: "It's great." "I think the results are quite clear, and very interesting, basically: show that the team has improved the electrical conductivity of the patches and then obviously made a difference in the increase. enhance the ability of simultaneous contraction of cardiac muscle tissue ".

Researchers plan to pursue human body studies to determine how complex tissue functions continue to develop after being transplanted into living organisms. In addition, for heart attack patients, Kohane added that successful trials "will open a series of doors for other types of tissue-related techniques." Lieber agrees with this statement.

"I think: scientists in other fields can take advantage of this idea for other systems: In other muscle cells, other vascular structures, perhaps even in the nervous system. Sutra, this is a simple way to have a major impact on the collective communication forms of cells, " Lieber said. "A lot of people will take advantage of the results of this study."