Out of all the body parts replacement surgical procedures, knee replacement is one of the most performed surgeries. Despite, there still remains high level of dissatisfaction accounting to post surgeries pain and discomfort. This is primarily due to the fact that the lab-developed replacements or the similar alternatives fail to provide as good strength and flexibility as of that of a human knee cartilage.
To resolve this issue, the chemistry and materials scientists at Duke University, namely Ben Wiley and Ken Gall have come up with the idea of synthetic hydrogel. This equally possess the quality of being both- soft and strong, providing the much needed strength as well as the flexibility simultaneously. This hydrogel comprises 60% of water and a quarter-sized disc that can withstand the load of a 100-pound kettlebell without tearing or losing its shape.
To simulate collagen, the researchers used cellulose nanofibers that are strong in tension however, unlike the collagen properties, do not degrade in humans. They then added a negatively charged polymer—PAMPS— to resist compression. Finally, thee two components were combined with a strong polyvinyl alcohol hydrogel that provides an elastic restoring force, energy dissipation and prevents stress concentration.
The research team knows this is true as they performed mechanical tests on more than 40 combinations of different hydrogel components in order to find the ones that correctly mimic the structure of cartilage when combined.
In one experiment of the winning hydrogel, the researchers subjected it to 100,000 cycles of repeat pulling—and the material held up just as well as porous titanium used for bone implants.
They also rubbed the new material against natural cartilage a million times, concluded that its smooth, slippery, self-lubricating surface is as wear-resistant as the real thing. Just one hydrogel has been approved by the US Food and Drug Administration (USFDA) for the purpose of replacing knee cartilage, and that is only for the joint of the big toe.
