|Assisting Nerve Repairs With Fabricated Structures|
|SciMed - Neuroscience|
|TS-Si News Service|
|Thursday, 03 May 2012 08:00|
Sheffield, UK. A method for assisting nerves to repair naturally could improve the chances of restoring sensation and movement in injured or regenerated limbs and appendages.
An engineering team has describes a new method for making medical devices called nerve guidance conduits (NGCs). Their study that appears in the journal Biofabrication.
A collaborative team from the University of Sheffield and Laser Zentrum Hannover (LZH) has described a new method for making medical devices called nerve guidance conduits (NGCs). "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," says 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 method for nerve repair is based on laser direct writing, which enables the fabrication of complex structures from computer files via the use of computer aided design/manufacturing (CAD/CAM).
This has has allowed the research team to manufacture designs that are far more advanced than previously possible.
The immediate application is for patients with severe traumatic nerve damage. Other potential treatments are emerging from the field of regenerative medicine, which can involve the attachment of nerves during reconstructive surgery.
Patients who suffer a devastating loss of sensation and/or movement in the affected limb have limited courses of action.
Traditionally, there may be an attempt, where possible, to surgically suture or graft the nerve endings together. However, reconstructive surgery often does not result in complete recovery.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," says lead author Dr Frederik Claeyssens, of the Sheffield 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," says Dr 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," he adds. "This technology could make a huge difference to patients suffering severe nerve damage."
FundingThis research was funded by the Engineering and Physical Sciences Research Council.
CitationTwo-photon polymerization-generated and micromolding-replicated 3D scaffolds for peripheral neural tissue engineering applications. A Koroleva, A A Gill, I Ortega, J W Haycock, S Schlie, S D Gittard, B N Chichkov, F Claeyssens. Biofabrication 2012; 4(2): 025005. doi:10.1088/1758-5082/4/2/025005
In this study, we explore the production of well-defined macroscopic scaffolds with two-photon polymerization (2PP) and their use as neural tissue engineering scaffolds. We also demonstrate that these 3D scaffolds can be replicated via soft lithography, which increases production efficiency. Photopolymerizable polylactic acid (PLA) was used to produce scaffolds by 2PP and soft lithography. We assessed the biocompatibility of these scaffolds using an SH-SY5Y human neuronal cell line and primary cultured rat Schwann cells (of direct relevance to the repair of nerve injuries). A Comet assay with SH-SY5Y human neuronal cells revealed minimal DNA damage after washing the photocured material for 7 days in ethanol. Additionally, thin films and 3D scaffolds of the photocured PLA sustained a high degree of Schwann cell purity (99%), enabled proliferation over 7 days and provided a suitable substrate for supporting Schwann cell adhesion such that bi-polar and tri-polar morphologies were observed. Evidence of orthogonally aligned and organized actin thin filaments and the formation of focal contacts were observed for the majority of Schwann cells. In summary, this work supports the use of PLA as a suitable material for supporting Schwann cell growth and in turn use of 3D soft lithography for the synthesis of neural scaffolds in nerve repair.
|Last Updated on Thursday, 03 May 2012 07:35|