Researchers have developed electronic artificial blood vessels that can continue to work after implantation in the body to help provide novel treatments for vascular diseases as well as other potential health-monitoring technology.
A team of scientists in China and Switzerland developed the vessels, which are made from a flexible and biodegradable metal-polymer conductor membrane. The technology mimics natural blood vessels and can conduct electricity, paving the way for novel functions inside the body.
Conventional tissue-engineered blood vessels (TEBVs) already exist to help treat vascular diseases—typically providing mechanical support for hard-to-treat blockages of tiny blood vessels in patients with cardiovascular disease.
However, they have limitations in that they can’t proactively assist in regenerating blood vessel tissue and, unlike natural tissue, often cause inflammation in response to blood flow, said Xingyu Jiang, a researcher at Southern University of Science and Technology and the National Center for NanoScience and Technology in China.
"None of the existing small-diameter TEBVs has met the demands of treating cardiovascular diseases," he said in a press statement.
The electronically conductive vessels go much further to this end. After implantation, the new vessels can be actively tuned to address changes in the body and coordinate with other electronic devices to deliver genetic material, enable controlled drug release, and facilitate the formation of new endothelial blood vessel tissue.
"We take the natural blood vessel-mimicking structure and go beyond it by integrating more comprehensive electrical functions that are able to provide further treatments, such as gene therapy and electrical stimulation," Jiang said in a press statement.
Fabrication and Testing
To develop the vessels, the team used a cylindrical rod to roll up a metal-polymer conductor membrane made from poly(L-lactide-co-ε-caprolactone), demonstrating in the lab that electrical stimulation from the blood vessel increased the proliferation and migration of endothelial cells for wound healing. This finding suggests that electrical stimulation could help drive the formation of new endothelial blood vessel tissue and thus potentially help repair vessels.
The researchers also integrated the blood vessels' flexible circuitry with a device that applies an electrical field to make cell membranes more permeable, which is called an electroporation device. The result of these combined technologies was the delivery of green fluorescent protein DNA into three kinds of blood vessel cells in the lab.
To test their results more conclusively, the team replaced the carotid arteries of New Zealand rabbits with electronic vessels. These arteries supply blood to the brain, neck, and face. Researchers monitored the implants for three months using Doppler ultrasound imaging, finding that the device consistently allowed for sufficient blood flow during that time.
Other tests to look inside the artificial arteries revealed that they showed no signs of narrowing, signaling to the team that they functioned as well as a natural one. Moreover, an examination of the rabbits’ internal organs after the three-month period showed no evidence of the artificial vessels producing an inflammatory response.
The team published a paper on its work in the journal Matter.
Though the initial tests are promising, researchers said they realize there is a long way and many clinical tests and trials to go before the artificial vessels can be used in humans. Moreover, the team must design a smaller companion electronic device than the one used in the study for the solution to be viable, Jiang said.
"In the future, optimizations need be taken by integrating it with minimized devices, such as minimized batteries and built-in control systems, to make all the functional parts fully implantable and even fully biodegradable in the body," he said in a press statement.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco, and New York City. In her free time, she enjoys surfing, traveling, music, yoga, and cooking. She currently resides in a village on the southwest coast of Portugal.