Spun-sugar fibers spawn sweet technique for nerve repair

February 26, 2009 Emil Venere
Researchers at Purdue have developed a technique using sugar filaments spun like cotton candy and coated with a polymer to create a scaffold of tiny synthetic tubes that might serve as conduits to regenerate nerves severed in accidents or damaged by disease. These images, taken with fluorescent-dyed samples, show nerve-insulating cells called Schwann cells (on left) growing on a tubule, and a combination of Schwann cells and neurons aligned lengthwise along the tubes (on right). This alignment is critical for the fast growth of nerves. Credit: Weldon School of Biomedical Engineering, Department of Basic Medical Sciences, and the Center for Paralysis Research, Purdue University

Researchers at Purdue University have developed a technique using spun-sugar filaments to create a scaffold of tiny synthetic tubes that might serve as conduits to regenerate nerves severed in accidents or blood vessels damaged by disease.

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.

Purdue researchers have developed a technique using sugar filaments spun like cotton candy and coated with a polymer to create a scaffold of tiny synthetic tubes that might serve as conduits to regenerate nerves severed in accidents or damaged by disease. The image on the left, taken with a scanning electron microscope and artificially colored, shows the sugar strands in yellow and the polymer coating in blue. Images on the right, taken with the same instrument, show a side view of the tubes and tiny pores that are ideal for supplying nutrients to growing nerve cells and removing waste products from the cells. Credit: Weldon School of Biomedical Engineering

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.

Source: Purdue University

Explore further: Stem cells pave the way for new treatment of diabetes

Related Stories

Stem cells pave the way for new treatment of diabetes

November 6, 2017
A new stem cell study conducted at the University of Copenhagen shows how we may increase the vital production of insulin in patients suffering from diabetes. The discovery helps to more efficiently at less cost make insulin-producing ...

New drug enables infants with genetic disorder to live longer, gain motor function

November 1, 2017
Infants with the most severe form of spinal muscular atrophy (SMA) were more likely to show gains in motor function and were 47 percent more likely to survive without permanent assisted ventilation support when treated with ...

Gene therapy helps boys with 'Lorenzo's Oil' disease

October 4, 2017
The fledgling field of gene therapy has scored another win: An experimental treatment seemed to help boys with the inherited nerve disease featured in the movie "Lorenzo's Oil."

Longtime antidepressant could slow Parkinson's

September 5, 2017
Michigan State University scientists now have early proof that an antidepressant drug that's been around for more than 50 years could slow the progression of Parkinson's.

Two agents deliver knockout punches to Ewing sarcoma

October 3, 2017
When combined with an already FDA-approved chemotherapy, a novel agent developed by researchers at Georgetown Lombardi Comprehensive Cancer Center, appears to halt the ability of Ewing sarcoma to grow and progress.

Stem cells injected into nerve guide tubes repair injured peripheral nerve

January 9, 2014
Using skin-derived stem cells (SDSCs) and a previously developed collagen tube designed to successfully bridge gaps in injured nerves in rat models, the research team in Milan, Italy that established and tested the procedure ...

Recommended for you

New breast cell types discovered by multidisciplinary research team

November 20, 2017
A joint effort by breast cancer researchers and bioinformaticians has provided new insights into the molecular changes that drive breast development.

Brain cell advance brings hope for Creutzfeldt-Jakob disease

November 20, 2017
Scientists have developed a new system to study Creutzfeldt-Jakob disease in the laboratory, paving the way for research to find treatments for the fatal brain disorder.

Hibernating ground squirrels provide clues to new stroke treatments

November 17, 2017
In the fight against brain damage caused by stroke, researchers have turned to an unlikely source of inspiration: hibernating ground squirrels.

Molecular guardian defends cells, organs against excess cholesterol

November 16, 2017
A team of researchers at the Harvard T. H. Chan School of Public Health has illuminated a critical player in cholesterol metabolism that acts as a molecular guardian in cells to help maintain cholesterol levels within a safe, ...

Prototype ear plug sensor could improve monitoring of vital signs

November 16, 2017
Scientists have developed a sensor that fits in the ear, with the aim of monitoring the heart, brain and lungs functions for health and fitness.

Ancient enzyme could boost power of liquid biopsies to detect and profile cancers

November 16, 2017
Scientists are developing a set of medical tests called liquid biopsies that can rapidly detect the presence of cancers, infectious diseases and other conditions from only a small blood sample. Researchers at The University ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

El_Nexus
3 / 5 (2) Feb 26, 2009
This is terrific. First grow new nerve cells from stem cells, when we get that right, and then guide them to grow in the right places using these new polymer tubes.
menkaur
not rated yet Feb 27, 2009
that's good indeed. but somehow it feels like old news... i believe, i was reading a similar article for few weeks

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.