A biocompatible conducting polymer stimulates the changes needed for nerve regeneration

October 31, 2014, RIKEN
Figure 1: Nerve cells showing the extended neurite outgrowths (dark bands) stimulated by application of the electrically conducting polymer. Credit: B. Zhu et al.

Promoting the guided regeneration of nerve cells could transform the treatment of a vast range of debilitating conditions, including brain injuries, nerve damage and degenerative neurological diseases. Electrically stimulating the outgrowth of 'neurites'—new projections from nerve cells—is a promising avenue of research, but it has been hampered by immune rejection and scar tissue insulating the electrodes from the targeted cells. Progress has reached a bottleneck because traditional electronic materials, mostly metals and semiconductors, are unable to provide the biocompatibility and mechanical strength needed for stable electrical transmission.

Researchers in Japan, China and Taiwan, led by Hsiao-hua Yu of the RIKEN Responsive Organic Materials Laboratory (now at the Institute of Chemistry, Academia Sinica, Taiwan), have now potentially broken through this bottleneck with the development of a targeted, electrically conducting polymer that mimics the .

The researchers used polyethylenedioxythiophene polymers assembled from two monomer units, each carrying a chemical component designed to mimic a crucial aspect of cell membranes. One monomer has a peptide group that replicates the selective binding between cells and the extracellular matrix outside cells. The other monomer carries a mixture of hydrophilic and hydrophobic parts mimicking the phospholipid molecules of cell membrane lipid bilayers.

When a mixture of and was added to a layer of the polymer in a culture dish, the peptide component allowed the nerve cells to bind preferentially to the polymer. Applying electrical stimulation to the cells through the conducting polymer promoted significantly more neurite outgrowths from the nerve cells than achieved using alternative methods (Fig. 1).

Crucially, the system avoided the nonspecific interactions with other cells and biomolecules that can cause the problems found with existing methods. In tests with Schwann cells, which support nerve cell growth and development, the polymer also stimulated increased secretion of proteins required for nerve regeneration. Altering the peptide carried by the polymer could allow a variety of cell types to be targeted, greatly extending the range of applications.

"The ultimate goal of our research is to promote tissue regeneration, particularly neuron regeneration, including within the brain," says Yu. In addition to regenerating for grafting into patients, Yu also envisages creating bioimplanted devices that could stimulate in situ nerve regeneration in a patient. "Our conducting polymer could also be used to coat the materials in neuroprosthetic devices to provide an electrical interface capable of more specific interactions toward cells and proteins while preventing the problems of rejection by the patient's immune system."

Explore further: Targeted nanoparticles that combine imaging with two different therapies could attack cancer, other conditions

More information: Zhu, B., Luo, S.-C., Zhao, H., Lin, H.-A., Sekine, J., Nakao, A., Chen, C., Yamashita, Y. & Yu, H.-h. "Large enhancement in neurite outgrowth on a cell membrane-mimicking conducting polymer." Nature Communications 5, 4523 (2014). DOI: 10.1038/ncomms5523

Related Stories

Protein glue shows potential for use with biomaterials

August 28, 2014

Researchers at the University of Milan in Italy have shown that a synthetic protein called AGMA1 has the potential to promote the adhesion of brain cells in a laboratory setting. This could prove helpful in improving cell ...

New tissue engineering breakthrough encourages nerve repair

July 8, 2013

A new combination of tissue engineering techniques could reduce the need for nerve grafts, according to new research by The Open University. Regeneration of nerves is challenging when the damaged area is extensive, and surgeons ...

Team improves solar-cell efficiency

September 19, 2014

New light has been shed on solar power generation using devices made with polymers, thanks to a collaboration between scientists in the University of Chicago's chemistry department, the Institute for Molecular Engineering, ...

Recommended for you

Tiny 'water bears' can teach us about survival

March 20, 2019

Earth's ultimate survivors can weather extreme heat, cold, radiation and even the vacuum of space. Now the U.S. military hopes these tiny critters called tardigrades can teach us about true toughness.

A decade on, smartphone-like software finally heads to space

March 20, 2019

Once a traditional satellite is launched into space, its physical hardware and computer software stay mostly immutable for the rest of its existence as it orbits the Earth, even as the technology it serves on the ground continues ...

Researchers find hidden proteins in bacteria

March 20, 2019

Scientists at the University of Illinois at Chicago have developed a way to identify the beginning of every gene—known as a translation start site or a start codon—in bacterial cell DNA with a single experiment and, through ...

Turn off a light, save a life, says new study

March 20, 2019

We all know that turning off lights and buying energy-efficient appliances affects our financial bottom line. Now, according to a new study by University of Wisconsin-Madison researchers, we know that saving energy also saves ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.