Replacing damaged knee ligaments with lab-grown tissues is the aim of research by Keith Baar, a newly arrived assistant professor in the UC Davis Department of Neurobiology, Physiology and Behavior, and his collaborators in the United Kingdom.

Ligaments are the tough tissues that connect bones together and stop, for example, your knee going sideways instead of backwards and forwards. They can be vulnerable to injuries, such as tears of the anterior cruciate ligament, that can take about a year to heal.

The artificial ligaments in Baar's laboratory are grown from a gel of fibrin, the protein that forms blood clots, seeded with cells called fibroblasts. The cells grow and generate the collagen matrix that makes a ligament strong.

But a real ligament is only as strong as the anchor points connecting it to bone. In two papers published recently in the journals Tissue Engineering and Annals of Biomedical Engineering, Baar and colleagues at the University of Birmingham, England, describe using brushite, a calcium/phosphate material, to anchor the artificial ligaments to pieces of bone.

The brushite-anchored artificial ligaments are not yet as strong as real ligaments, but the work shows promise, Baar said.

Ultimately the goal is to take cells from a patient, use them to grow a new ligament and transplant it back into the patient to replace a torn or injured ligament, Baar said.

"The goal is to be back to full activity in four to eight weeks (the time it takes for the bone to fuse with the brushite) instead of the four to eight months that it takes now," he said.

The work was supported by grants from the British government's Engineering and Physical Sciences Research Council and the Biotechnology and Biological Sciences Research Council.