TimmyHNatural Polymer Brain Implants
July 18th 2008 02:20
New approaches could more seamlessly integrate medical devices into the body.
Early studies by researchers at the University of Michigan have revealed that conductive polymer coatings could be used to improve the performance of medical implants. These polymers that weave their way into implanted tissue might one day be able to improve the performance of brain stimulators and cochlear implants.
Tests have suggested that the conductive polymer coatings will perform much better than their metal counterparts. Researchers have found that the material's novel properties could lessen tissue damage which is often caused by medical implants and boost long-term function.
The use of artificial metallic devices to assist brain and nervous function is on the increase. They work by stimulating nerve cells via an implanted electrode. But many of these devices have been linked to neural tissue damage. When the rigid metal is inserted into soft tissue it inflames the surrounding area, damaging and killing neurons and forming a scar.
“We hope to come up with a way to communicate across the scar layer and send information to and from the device in a way that is as friendly as possible,” says David Martin, a materials scientists at the University of Michigan, in Ann Arbor, who is leading the research into the polymer coatings.
The polymer coatings allow for messages to pass more easily across the scar tissue. “If you have lots of surface area, you can inject current more efficiently,” says Douglas McCreery, director of the Neural Engineering Program at the Huntington Medical Research Institute, in Pasadena, CA. “That means less demand on batteries, but, probably more importantly, you're not recruiting the nasty electrochemical reactions that might be hazardous to surrounding tissue.”
The researchers deposit polymer strands onto the electrode to create a hairy texture that mimics nature. The numerous alveoli in the lungs react the same way by increasing the surface area available for oxygen exchange between air and blood. Nanofibres loaded with controlled-release drugs can also be used to inhibit the inflammatory reaction and reduce scarring.
Tests on animals have revealed that coated electrodes perform better than their bare metal counterparts, particularly in the short term. But without long-term testing having been complete, the results are open to interpretation. “Recording quality deteriorates over time with all existing electrodes,” says Andrew Schwartz, a neuroscientist at the University of Pittsburgh.
Martin’s goal is to integrate the electrodes with the tissue. “Imagine the cells are like M&Ms suspended in Jell-O,” says Martin. “We're growing the polymer around the M&Ms and through the Jell-O.”
Early studies by researchers at the University of Michigan have revealed that conductive polymer coatings could be used to improve the performance of medical implants. These polymers that weave their way into implanted tissue might one day be able to improve the performance of brain stimulators and cochlear implants.
Tests have suggested that the conductive polymer coatings will perform much better than their metal counterparts. Researchers have found that the material's novel properties could lessen tissue damage which is often caused by medical implants and boost long-term function.
The use of artificial metallic devices to assist brain and nervous function is on the increase. They work by stimulating nerve cells via an implanted electrode. But many of these devices have been linked to neural tissue damage. When the rigid metal is inserted into soft tissue it inflames the surrounding area, damaging and killing neurons and forming a scar.
“We hope to come up with a way to communicate across the scar layer and send information to and from the device in a way that is as friendly as possible,” says David Martin, a materials scientists at the University of Michigan, in Ann Arbor, who is leading the research into the polymer coatings.
The polymer coatings allow for messages to pass more easily across the scar tissue. “If you have lots of surface area, you can inject current more efficiently,” says Douglas McCreery, director of the Neural Engineering Program at the Huntington Medical Research Institute, in Pasadena, CA. “That means less demand on batteries, but, probably more importantly, you're not recruiting the nasty electrochemical reactions that might be hazardous to surrounding tissue.”
The researchers deposit polymer strands onto the electrode to create a hairy texture that mimics nature. The numerous alveoli in the lungs react the same way by increasing the surface area available for oxygen exchange between air and blood. Nanofibres loaded with controlled-release drugs can also be used to inhibit the inflammatory reaction and reduce scarring.
Tests on animals have revealed that coated electrodes perform better than their bare metal counterparts, particularly in the short term. But without long-term testing having been complete, the results are open to interpretation. “Recording quality deteriorates over time with all existing electrodes,” says Andrew Schwartz, a neuroscientist at the University of Pittsburgh.
Martin’s goal is to integrate the electrodes with the tissue. “Imagine the cells are like M&Ms suspended in Jell-O,” says Martin. “We're growing the polymer around the M&Ms and through the Jell-O.”
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