Heart attacks may be less deadly in the future, thanks to micro-technology and nanotechnology research that has just begun in Ohio State University.
Researchers are investigating ways to culture tiny blood vessels to keep damaged heart tissue alive after a heart attack, by a process called therapeutic angiogenesis (neovascularization).
"Our bodies already contain cells that trigger the growth of new blood vessels. We want to use those same cells to create seeds for blood vessels in the laboratory and transplant them into the body," said Nicanor Moldovan, research scientist and assistant professor in Ohio State's Biomedical Engineering Center, and Heart and Lung Institute.
He relayed the researchers' initial results in a presentation on 25 September in Columbus at the BioMEMS and Biomedical Nanotechnology World Conference 2000, co-sponsored by Ohio State.
Moldovan admits that his plan of growing capillaries in tissue culture and implanting them into the body is very complex. It relies on ideas about blood vessel formation that are just beginning to emerge.
"We've had to deal with a lot of speculation or supposition, but our approach appears to be a very promising one," he said. "Of course, this is just our dream, but we are working on it."
In these earliest results, Moldovan and his colleagues have demonstrated that these 'seed cells,' called endothelial cells, will grow in grooves carved in the surface of a soft transparent gel in the laboratory.
The researchers' ultimate plan is to grow endothelial cells inside or on the surface of silicon moulds resembling capillaries. If the cells could assume the shape of capillaries under those conditions, they could be transplanted - either alone or with some kind of carrier - into the heart to start the replacement of blood vessels that died during a heart attack.
Moldovan continued by saying that showing that the cells can grow two-dimensionally following the shape of grooves in the gel is a necessary first step.
To demonstrate that the cells were indeed following the shape of the grooves, Moldovan and his colleagues first had to develop a method that allowed them to view the shape of the tiny grooves accurately, which measure only a few micrometers across - less than the width of a human hair. Normal viewing instruments would have torn the delicate surface of the gel, he said.
They developed a method Moldovan characterizes as fast and inexpensive. After they scrape the tiny grooves into the gel, they spray the gel with even more minute fluorescent beads, which spill along the surface and fill the grooves. A quick look through the microscope reveals the location of the grooves.
The researchers then literally wash the beads from the gel, leaving its delicate surface intact.
Moldovan envisions that one day, capillaries will be carried into the heart tissue by micro-machines called 'angiochips.' Once inside the heart, the implants will begin to undo the damage of a heart attack.
This is in relation to his other work in the Biomedical Engineering Center at Ohio State, Moldovan said. There the aim is to stimulate capillary growth by angiogenic drugs released from silicon capsules that are unable to be planted.
"We probably couldn't bring tissue back to its original form, but we could try to re-vascularize it to make a heart beat again. Otherwise, we could keep the heart tissue from dying by creating new capillaries that would provide blood and oxygen as soon as possible," he said.
When the time comes time to create three-dimensional moulds to shape the capillaries, the researchers will turn from gel to silicon. Methods already exist to create complex 3D shapes in the element, he said, and his previous research demonstrates that endothelial cells could grow on silicon.
"Once we have proof that we can grow cells in specific three-dimensional shapes on or inside silicon, then we hope to come back to the tissue," he said.
You can visit the following site for details.
http://www.acs.ohio-state.edu/units/research/
