New technique may help severely damaged nerves regrow and restore function
Engineers at the University of Sheffield have developed a method of assisting nerves damaged by traumatic accidents to repair naturally, which could improve the chances of restoring sensation and movement in injured limbs.
Scanning electron microscopy images of the structures fabricated by (left) 2PP and (right) microreplication techniques
In a collaborative study with Laser Zentrum Hannover (Germany) published today (23 April 2012) in the journal Biofabrication
, the team describes a new method for making medical devices called nerve guidance conduits or NGCs.
The method is based on laser direct writing, which enables the fabrication of complex structures from computer files via the use of CAD/CAM (computer aided design/manufacturing), and has allowed the research team to manufacture NGCs with designs that are far more advanced than previously possible.
Currently patients with severe traumatic nerve damage suffer a devastating loss of sensation and/or movement in the affected limb. The traditional course of action, where possible, is to surgically suture or graft the nerve endings together. However, reconstructive surgery often does not result in complete recovery.
"When nerves in the arms or legs are injured they have the ability to re-grow, unlike in the spinal cord; however, they need assistance to do this," said University of Sheffield Professor of Bioengineering, John Haycock. "We are designing scaffold implants that can bridge an injury site and provide a range of physical and chemical cues for stimulating this regrowth."
The new conduit is made from a biodegradable synthetic polymer material based on polylactic acid and has been designed to guide damaged nerves to re-grow through a number of small channels.
"Nerves aren't just like one long cable, they're made up of lots of small cables, similar to how an electrical wire is constructed," said lead author Frederik Claeyssens, of the University's Department of Materials Science and Engineering. "Using our new technique we can make a conduit with individual strands so the nerve fibres can form a similar structure to an undamaged nerve."
Once the nerve is fully regrown, the conduit biodegrades naturally. The team hopes that this approach will significantly increase recovery for a wide range of peripheral nerve injuries.
In laboratory experiments, nerve cells added to the polymer conduit grew naturally within its channelled structure and the research team is now working towards clinical trials.
"If successful we anticipate these scaffolds will not just be applicable to peripheral nerve injury, but could also be developed for other types of nerve damage too. The technique of laser direct writing may ultimately allow production of scaffolds that could help in the treatment of spinal cord injury" said Claeyssens.
"What's exciting about this work is that not only have we designed a new method for making nerve guide scaffolds which support nerve growth, we´ve also developed a method of easily reproducing them through micromolding.
"This technology could make a huge difference to patients suffering severe nerve damage," he added.
s: 1. This study, entitled "Two-photon polymerization-generated and micromolding-replicated 3-D scaffolds for peripheral neural tissue engineering applications is published in the current issue of Biofabrication. A copy of the paper is available.
2. John Haycock is a Professor in the Department Materials Science and Engineering, Associate Director of the Kroto Research Institute and Director of the Centre for Biomaterials & Tissue Engineering. Frederik Claeyssens is a Lecturer in Biomaterials at the Department of Materials Science and Engineering
3. The Faculty of Engineering at the University of Sheffield - the 2011 Times Higher Education´s University of the Year - is one of the largest in the UK. Its seven departments include over 4,000 students and 900 staff and have research-related income worth more than £50M per annum from government, industry and charity sources. The 2008 Research Assessment Exercise (RAE) confirmed that two thirds of the research carried out was either Internationally Excellent or Internationally Leading.
The Faculty has a long tradition of working with industry, including Rolls-Royce, Network Rail and Siemens. Its industrial successes are exemplified by the award-winning Advanced Manufacturing Research Centre (AMRC) and the new £25 million Nuclear Advanced Manufacturing Research Centre (NAMRC). To find out more, visit the link below.
4. The Laser Zentrum Hannover eV (LZH), based in Germany, is an association which supports applied research in laser technology on a non-profit basis. To find out more, visit the link below.
5. The Engineering and Physical Sciences Research Council (EPSRC) is the UK's main agency for funding research in engineering and physical sciences. EPSRC invests around £800m a year in research and postgraduate training, to help the nation handle the next generation of technological change.
The areas covered range from information technology to structural engineering, and mathematics to materials science. This research forms the basis for future economic development in the UK and improvements for everyone's health, lifestyle and culture. EPSRC works alongside other Research Councils with responsibility for other areas of research. The Research Councils work collectively on issues of common concern via research Councils UK.