She sewed the sheets together using surgical sutures as thread, with the perforated sheet on the inside. The suture seams create a series of pockets, left open at what would be the top and bottom of the device. The device is sutured to the healthy tissue like a patch and provides a path for movement of cells and bone building materials upward, downwards and inwards.
The researchers filled the pockets of one set of the devices with membranes made of collagen, which is a natural component of the periosteum; a second set was filled with collagen membranes seeded with cells that reside in the periosteum , and a third set with strips of periosteum. Both the collagen seeded sheets and the periosteum strips tucked into the pockets showed the most promising results for bridging of critical sized defects that do not heal on their own.
The pockets filled with natural periosteal strips, although no longer connected to a blood supply, provided the ingredients to grow bone quickly, densely, and completely in a group of five adult sheep, Knothe Tate said.
In addition to providing the ingredients at the right place and time, the device, along with the nail, act as a template for the new growth.
"This really blurs the line between an implant and a delivery system," Knothe Tate said.
Depending on how she directs growth, the device can grow bone two ways found in nature. Much of the skeleton forms as cartilage first then turns to bone before birth, while the skull grows directly from stem cells into bone.
Beyond bone, the device is flexible enough to be used in a broad array of applications, Knothe Tate said. Potential uses include growing cartilage for orthopedics, to fuse vertebrae, as a delivery system for stem cells, antibiotics, transcription factors and more.
|Contact: Kevin Mayhood|
Case Western Reserve University