A team of bioengineers from the University of Connecticut (UConn, USA) managed to reconstruct a rabbit’s knee cartilage using a ‘scaffold’ made from a nanomaterial which has piezoelectric properties. The advance, published in Science Translational Medicine, opens new avenues for the treatment of joints in humans.

THE arthritis It is a common and painful disease caused by damage to our joints. They are normally protected by cartilage ‘cushions’, but injury or age can wear them down. Available treatments try to replace the damaged cartilage with a healthy piece taken from another part of the body or from a donor, but these are complex procedures and can lead to rejection.

According to the authors, the best therapy would be regenerate healthy cartilage in the damaged joint itself. Some researchers have tried to amplify chemical growth factors to induce the body to grow cartilage on its own, and other attempts have relied on a bioengineering scaffold to give the body a model for fresh fabric. “But none of these approaches worked, not even in combination,” they emphasize.

Regular movement of a joint can cause the PLLA scaffold to generate a weak but constant electrical field that encourages cells to colonize it and turn into cartilage.

“Regenerated cartilage does not behave like native cartilage. It breaks under normal joint stresses,” he explains. Thanh nguyen, co-author of the work.

Now Nguyen’s lab, which has also worked on cartilage regeneration, has discovered that electrical signals are essential for normal growth.

Piezoelectric Nanomaterials

Nguyen and his team designed a fabric scaffold made from poly-L lactic acid nanofibers (PLLA), a biodegradable polymer commonly used to suture surgical wounds. The nanomaterial has a very interesting property, called piezoelectricity. When squeezed, it produces a small burst of electrical current.

Regular movement of a joint, such as a person walking, can cause the PLLA scaffold to generate a weak but constant electrical field that stimulates cells to colonize it and turn into cartilage. No external growth factors or stem cells (which are potentially toxic or at risk of unwanted adverse effects) are needed, and above all, the cartilage that grows is mechanically robust.

The researchers tested the piezoelectric scaffold on the knee of an injured rabbit. They then placed the animal on a treadmill and, as expected, the cartilage grew back normally.

The authors tested the scaffolding on the knee of an injured rabbit. They then placed the animal on a treadmill and, as expected, the cartilage grew back normally.

as explained Yang read, lead author of the research, “piezoelectricity is a phenomenon that also exists in the human body. Bone, cartilage, collagen, DNA and various proteins have a piezoelectric response”.

He also points out that the approach they followed has “a good chance of being transferred to the clinic in the future.”

stay cautious

However, Nguyen prefers to remain cautious: “It is a fascinating result, but we have to test it on a larger animal“With size and weight more similar to those of a human being”, he emphasizes.

His lab plans to observe the treated animals for at least a year, probably two, to ensure the cartilage is durable. The team also wants to test PLLA scaffolding in older animals.

“In humans, arthritis is usually a disease of the elderly. Young animals heal more easily. If piezoelectric scaffolding also helps older animals heal, it could be a real breakthrough in bioengineering,” the researchers conclude.

Rights: Creative Commons.

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