Nanofibers have potential as orthopedic biomaterials

PHILADELPHIA – Scientists from the Perelman School of Medicine at the University of Pennsylvania have developed and validated a new technology that has the potential for use as orthopedic biomaterials. The composite nanofibers provide a loose enough structure for cell colonization without impediment, but are still capable of instructing cells how to lay down new tissue.

The findings of Robert L. Mauck, Ph.D., professor of Orthopedic Surgery and Bioengineering at the Perelman School of Medicine, and Brendon M. Baker, Ph.D., were published in the Proceedings of the National Academy of Sciences.

“These are tiny fibers with a huge potential that can be unlocked by including a temporary, space-holding element,” says Mauck. The fibers are on the order of nanometers in diameter. A nanometer is a billionth of a meter.

Using a method called electrospinning, the team made composites containing two distinct fiber types: a slow-degrading polymer and a water-soluble polymer. This causes the solution to erupt as a fine spray of fibers which fall like snow onto a rotating drum and collect as a stretchable fabric. This can then be shaped for medical applications, including as a patch for damaged tissue.

Increasing the proportion of the dissolving fibers enhances host cell ability to colonize the nanofiber mesh and eventually form a truly three-dimensional tissue. This led to a biologic material that nearly matches human meniscus tissue in terms of tensile properties, in lab tests of tissue mechanics.

“This approach transforms what was once an interesting biomaterials phenomenon -- cells on the surface of nanofibrous mats -- into a method by which functional, three-dimensional tissues can be formed,” says Mauck.

The materials are currently being tested in a large animal model of meniscus repair and for other orthopedic applications.