The sugar filaments are coated with a corn-based degradable polymer, and then the sugar is dissolved in water, leaving behind bundles of hollow polymer tubes that mimic those found in nerves, said Riyi Shi, an associate professor in Purdue's Weldon School of Biomedical Engineering and Department of Basic Medical Sciences.
The scaffold could be used to promote nerve regeneration by acting as a bridge placed between the ends of severed nerves, said biomedical engineering doctoral student Jianming Li, who is a member of Shi's research team that developed the technique.
The researchers are initially concentrating on the peripheral nerves found in the limbs and throughout the body because nerve regeneration is more complex in the spinal cord. About 800,000 peripheral nerve injuries are reported annually in the United States, with about 50,000 requiring surgery.
The approach also might have applications in repairing blood vessels damaged by trauma and disease such as atherosclerosis and diabetes, Shi said.
The new approach represents a potential alternative to the conventional surgical treatment, which uses a nerve "autograft" taken from the leg or other part of the body to repair the injured nerves. Researchers are trying to develop artificial scaffolds to replace the autografts because removing the donor nerve causes a lack of sensation in the portion of the body where it was removed.
"The autograft is the lesser of two evils because you have to sacrifice a healthy nerve to repair a damaged segment," said Li, who led the research.
New findings were published online in December and this month in the print edition of the journal Langmuir. The paper was written by Li, biomedical engineering doctoral student Todd A. Rickett and Shi. Rickett also is attending the Indiana University School of Medicine in an MD-Ph.D. program.
Researchers from Cornell University published similar findings online Feb. 9 in the journal Soft Matter. Those findings focused on using the technique to create vascular networks for providing blood and nutrients to tissues and grafts.
The synthetic scaffold resembles the structural assembly of natural nerves, which are made of thousands of small tubes bundled together. These tubes act as sheaths that house the conducting elements of the nerve cell.
The first step in making the tubes is to spin sugar fibers from melted sucrose.
"It's basically like making cotton candy," Li said.
The sugar filaments were coated with a polymer called poly L-lactic acid. After the filaments were dissolved, hollow tubes of the polymer remained. The researchers then grew nerve-insulating cells called Schwann cells on these polymer tubes. These cells automatically aligned lengthwise along the tubes, as did nerve cells grown on top of the Schwann cells.
This alignment is critical for the fast growth of nerves, Shi said.
Nerve cells grew not only inside the hollow tubes but also around the outside of the tubes.
"This finding is important because the increased surface area may accelerate the regeneration process following an accident," Li said.
The scaffolds are designed specifically to regenerate a portion of a nerve cell called the axon, a long fiber attached to the cell body that transmits signals. Fast regeneration is essential to prevent the atrophy of muscles and organs connected to severed nerves.
The researchers also discovered that the polymer tubes contain pores that are ideal for supplying nutrients to growing nerve cells and removing waste products from the cells.
Images of the polymer-coated sugar strands were taken using a scanning electron microscope. Another instrument, called an atomic force microscope, was used to obtain images of the hollow tubes and pores in the walls of the tubules. Other images using fluorescent dyes revealed the nerve cell alignment along the tubes.
The work was done using cell cultures in petri dishes, but ongoing work focuses on implanting the scaffolds in animals.
The method for creating the scaffolds is relatively simple and inexpensive and does not require elaborate laboratory equipment, Shi said.
"This is low-tech," he said. "We used the same kind of sugar found in candy and a cheap polymer to make samples of these scaffolds for a few dollars. The process easily lends itself to mass production. It is a unique idea, and the simplicity and efficiency of this technology distinguish it from other approaches for nerve repair."
A provisional patent application on the material has been filed.
This study was conducted at Purdue's Center for Paralysis Research, which receives funding support from the state of Indiana. Shi's lab is supported by both the National Institutes of Health and the National Science Foundation. Li was supported by the NSF's Graduate Teaching Fellows in K-12 Education Program, which strives to help graduate students bring their research and practice into the K-12 classrooms and inspire students to pursue careers in science and engineering. Li used knowledge gained in the laboratory to teach middle school students and worked on curriculum development. Rickett is supported through the Indiana Clinical and Translational Sciences Institute, which funds research on developing new technologies into effective medical therapies.Writer: Emil Venere, (765) 494-4709, firstname.lastname@example.org
Emil Venere | EurekAlert!
Further reports about: > Diabetes > K-12 > Schwann cells > Science TV > Spun-sugar fibers > atherosclerosis > biomedical engineering > blood vessel > conventional surgical treatment > nerve cells > nerve regeneration > nerve repair > poly L-lactic acid > polymer tubes > spun-sugar filaments > sweet technique > tiny synthetic tubes > waste products
Atomic-level motion may drive bacteria's ability to evade immune system defenses
24.04.2017 | Indiana University
Two-dimensional melting of hard spheres experimentally unravelled after 60 years
24.04.2017 | University of Oxford
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences