The material was applied to the damaged knee cartilage of the animals and, following a period of six months, the team observed significant repair improvements wherein new cartilage, which was rich in natural biopolymers like collagen II and proteoglycans, developed.

Source: Northwestern University

“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,” said Northwestern’s Samuel I. Stupp, the study’s lead author.

The researchers explained that the rubbery substance is a network of molecular components that simulate the environment of cartilage in the body.

The new biomaterial features two elements — the first, a bioactive peptide that adheres to transforming growth factor beta-1 (TGFb-1), a protein critical for cartilage growth and maintenance, and the second, a modified hyaluronic acid, which is a natural polysaccharide found in both cartilage and the lubricating synovial fluid of joints.

To create nanoscale fiber bundles similar to the structure of cartilage, the team combined the bioactive peptide with the chemically modified hyaluronic acid particles. This resulted in a scaffold designed to attract the body’s cells that regenerate the tissue. The material’s bioactive signals prompt the cells to repair cartilage by populating the scaffold.

During trials, the biomaterial was applied to cartilage defects in the stifle joints of sheep, which are similar to human knees in both structure and mechanical load. The team injected the paste-like material into the defects of the joints where it formed a rubbery matrix that encouraged the growth of new cartilage as the scaffold degraded gradually.

The team believes that one day, the material could potentially prevent the need for full knee replacements, be used to treat degenerative diseases like osteoarthritis and repair sports-related injuries like ACL tears.

The study has been published in Proceedings of the National Academy of Sciences.