Help could be on the way for people who don't have enough bone to support dental implants, who are missing bone due to a birth defect, or who have suffered bone-damaging injuries. Scientists at the University of Iowa have created an implantable collagen patch seeded with particles containing synthetic DNA, that instructs the patient's own cells to produce the protein that leads to bone growth.

As with other bone-growing patches, this "bio-patch" has a scaffolding-like interior structure, and is shaped to the size of the area where the new bone is needed. Contained within that scaffolding are synthetically-created plasmids (DNA molecules) that are encoded for a growth factor known as PDGF-B. When cells from the adjacent existing bone grow into the patch, the healing process begins.

"The delivery mechanism is the scaffold loaded with the plasmid," says Prof. Aliasger Salem. "When cells migrate into the scaffold, they meet with the plasmid, they take up the plasmid, and they get the encoding to start producing PDGF-B, which enhances bone regeneration."

In laboratory tests, the bio-patches were implanted onto 5 x 2-mm holes in the skulls of test animals. After four weeks, the results were compared to those of tests in which patches with no plasmids were used, or no action was taken at all. According to the university, "The plasmid-seeded bio patch grew 44 times more bone and soft tissue in the affected area than with the scaffold alone, and was 14-fold higher than the affected area with no manipulation."

The plasmid is said to be unlikely to cause an immune response, and should be relatively easy to produce in large amounts.

A paper on the research was recently published in the journal Biomaterials.