The important component in joints, cartilage, is notoriously difficult to repair. This presents medical complications. To address this, a new material has been developed by scientists from Northwestern University that can serve as a cartilage surrogate.
This new material comprises peptides, proteins and polysaccharides that mimic the microstructure of natural cartilage. So far, researchers have tested the material on cartilage defects in the knee joints of a large-animal model. Within six months, researchers observed new cartilage growth
The new material resembles nothing more than a rubbery goo; however, the material is actually a complex network of molecular components, which work together to mimic cartilage’s natural environment in the body.
In the new study, the researchers applied the material to damaged cartilage in the animals’ knee joints. Within six months, the researchers observed evidence of enhanced repair, including the growth of new cartilage containing the natural biopolymers (collagen II and proteoglycans), which enable pain-free mechanical resilience in joints.
The study follows recently published work from the Stupp laboratory, in which the team used “dancing molecules” to activate human cartilage cells to boost the production of proteins that build the tissue matrix.
Instead of using dancing molecules, the new study evaluates a hybrid biomaterial. The new biomaterial comprises two components: a bioactive peptide that binds to transforming growth factor beta-1 (TGFb-1) — an essential protein for cartilage growth and maintenance — and modified hyaluronic acid, a natural polysaccharide present in cartilage and the lubricating synovial fluid in joints.
It is hoped the material can potentially be used to prevent full knee replacement surgeries, treat degenerative diseases like osteoarthritis and repair sports-related injuries like ACL tears.
The scientists successfully integrated the bioactive peptide and chemically modified hyaluronic acid particles to drive the self-organization of nanoscale fibres into bundles that mimic the natural architecture of cartilage.
This formed a scaffold for the body’s own cells to regenerate cartilage tissue. Using bioactive signals in the nanoscale fibres, the material encourages cartilage repair by the cells, which populate the scaffold.
Commenting on the study, lead researcher Samuel I. Stupp says: “Cartilage is a critical component in our joints. When cartilage becomes damaged or breaks down over time, it can have a great impact on people’s overall health and mobility.”
Clarifying this, Stupp observes: “The problem is that, in adult humans, cartilage does not have an inherent ability to heal. Our new therapy can induce repair in a tissue that does not naturally regenerate. We think our treatment could help address a serious, unmet clinical need.” The study is to appear in the journal Proceedings of the National Academy of Sciences. The research is titled “A bioactive supramolecular and covalent polymer scaffold for cartilage repair in a sheep model”.
