Novel class of radially-aligned nanofibers promising for tissue regeneration

(Nanowerk Spotlight) Nanotechnology-enabled tissue engineering is a rapidly growing field. At the core of tissue engineering is the construction of scaffolds out of biomaterials to provide mechanical support and guide cell growth into new tissues or organs. In particular, electrospun biodegradable polymeric nanofibers are being used in scaffolds for engineering various tissues such as nerves,cartilages or bone (read more: "One day doctors will grow new bones with nanotechnology"). Electrospinning is a fabrication technique which can produce nanoscale fibers from more than 100 different polymers. The electrospun nanofibers are typically collected as nonwoven mats with random orientation.
A new study by researchers at Washington University in St. Louis has now demonstrated the fabricationof a novel class of nanofiber scaffold composed of radially-aligned, electrospun nanofibers and also demonstrated the unique application of these materials as effective biomedical patches/scaffolds that could prove to be beneficial during neurosurgery.
"Such a scaffold represents a significant departure from existing scaffolds fabricated through traditional electrospinning techniques," YounanXia, the the James M. McKelvey Professor for Advanced Materials in the Department of Biomedical Engineering, tells Nanowerk. "Specifically, individual nanofibers within these novel scaffolds are not limited to simple orthogonal patterns imparted by uniaxial-alignment, but instead are capable of achieving any number of organized radial orientations around a central point electrode."
Essentially, thenovel method of electrospinning described in a paper in the August 9, 2010 online issue of ACS Nano ("Radially Aligned, Electrospun Nanofibers as Dural Substitutes for Wound Closure and Tissue Regeneration Applications") extends nanofiber patterning techniques beyond simple Cartesian patterns, and enables the creation of advanced radial patterns of organized, aligned nanofibers.

SEM image of aradially aligned, electrospun nanofiber scaffold. (Image: Xia Lab, Washington University in St. Louis)
"Additionally," says Jingwei Xie, first author of the ACS Nano paper, "our study demonstrates that radially-aligned nanofibers provide an optimal substrate capable of directing and enhancing wound healing and tissue regeneration. Radial-alignment of individual nanofibers within these novelscaffolds offers a unique method of presenting organized topographical cues useful in directing cellular migration from the periphery of native tissue directly to the center of the nanofiber patch."
As a result, it has been hypothesized that radially-aligned nanofiber scaffolds would increase the speed of cellular ingrowth, and as a result support faster wound healing and recovery. In their work, theWashington University team confirms this hypothesis by applying these novel scaffolds within ex vivo duraplasty models (dura is the outermost of the three layers of the meninges surrounding the brain and spinal cord and is responsible for keeping in the cerebrospinal fluid).
The researchers showed that patches composed of radially-aligned nanofibers promoted faster ingrowth of dural fibroblastsinto induced dural defects than either patches composed of randomly oriented nanofibers or random collagen matrices.
Overall, this new study suggests that this novel class of radially-aligned nanofiber scaffolds represents a unique advancement in the design of biomedical patches useful in repairing wounds and defects in many types of tissue throughout the human body.
"Ideally, furtherinvestigation into these scaffolds may lead to the creation of nano-patterned scaffolds, dressings, and patches capable of modulating cellular migration and function as a means of enhancing wound healing and improving patient outcomes" says Xia.
Xie recounts how this present study was motivated by a recent collaboration established between the Department of Biomedical Engineering at Washington University...