Sports enthusiasts the world over will be the first to tell you about the dangers of injuring your joints; these injuries can be some of the most painful, and treatments for the area are often incapable of restoring joint movement back to how it was prior to the injury.
Luckily, science is on the case, and much like the efforts in restoring damaged spinal cords and damage to tendons, fully healing knee cartilage damage is now a pursuit made possible by the wonders of fields like optical and materials engineering.
Such is certainly the case with novel technology from the University of Connecticut (UConn) researchers Thanh Nguyen and Yang Liu, who together with a team created a novel concept for “tissue scaffolds,” which are materials that are specially designed so as to facilitate and promote tissue healing by allowing neighboring cells to nestle within their structures and reproduce.
Thing is, soft tissue that regenerates using scaffolds has a tendency to be weaker than the original tissue, according to the researchers in their paper that was published in the journal Science Translational Medicine.
To overcome these limitations, the research team instead worked on synthesizing their tissue scaffolds while incorporating nanofibers of a polymer called poly-L lactic acid (PLLA), a polymer known for its piezoelectric properties. These piezoelectric materials, in essence, generate an electric current when their internal structures are deformed. (For additional reading about piezoelectric materials, read further with our previous piece on self-powered materials that may be a battery-free alternative to hearing aids.)
In a similar way, deforming these tissue scaffolds causes them to generate tiny amounts of current—current that, according to the team, may be used to “stimulate” nearby cells into healing soft tissue damage. Nguyen, Liu, and the team tested just that by implanting their novel scaffolds into the injured knee of a rabbit, which they allowed to exercise on a treadmill after the scaffold was implanted. As predicted, the rabbit eventually had its knee restored to normal function.
And, much like other tissue scaffold materials, this particular one made use of biocompatible polymers that simply broke down and dissolve safely within the body.
“Piezoelectricity is a phenomenon that also exists in the human body. Bone, cartilage, collagen, DNA, and various proteins have a piezoelectric response. Our approach to healing cartilage is highly clinically translational, and we will look into the related healing mechanism,” said lead author Liu in a statement released by UConn.
Nguyen, who handles the research group Liu studies under, calls their findings “[…] a fascinating result,” while also recognizing the need to test their novel material on subjects much closer to the body mass of a human. The research team also needs time to examine the long-term effects of the healed cartilage. FInally, the team recognizes the need to test the material on older animals—a need made apparent by the fact that arthritis is a condition that commonly affects the older human population.
References
- Coxworth, B. (2022, January 13). Piezoelectric material shown to help regrow knee-joint cartilage. New Atlas. https://newatlas.com/medical/piezoelectric-scaffolding-regrows-cartilage/
- Krieger, K. (2022, January 12). Regrowing cartilage in a damaged knee gets closer to fixing arthritis. UConn Today. https://today.uconn.edu/2022/01/regrowing-cartilage-in-a-damaged-knee-gets-closer-to-fixing-arthritis/
- Liu, Y., Dzidotor, G., Le, T. T., Vinikoor, T., Morgan, K., Curry, E. J., Das, R., McClinton, A., Eisenberg, E., Apuzzo, L. N., Tran, K. T. M., Prasad, P., Flanagan, T. J., Lee, S.-W., Kan, H.-M., Chorsi, M. T., Lo, K. W. H., Laurencin, C. T., & Nguyen, T. D. (2022). Exercise-induced piezoelectric stimulation for cartilage regeneration in rabbits. Science Translational Medicine. https://doi.org/10.1126/scitranslmed.abi7282
