Engineers pioneer use of 3D printer to create new bones

A 3D printer is being used to create "bone-like" material which researchers claim can be used to repair injuries. The engineers say the substance can be added to damaged natural bone where it acts as a scaffold for new cells to grow. It ultimately dissolves with "no apparent ill-effects", the team adds. The researchers say doctors should be able to use the process to custom-order replacement bone tissue in a few years time.

Prof Susmita Bose helped carry out the work at Washington State University and co-authored a report in the Dental Materials journal.

"You can use the bone-like ceramic powder as a feed material and it can make whatever you draw on the computer," she says.

"It is mostly [suitable for] low load bearing applications. However, what we are trying to develop is the controlled degradation... of these scaffolds where as the scaffold dissolves in the body the bone tissue grows over it."

Binder
Prof Bose's team have spent four years developing the bone-like substance.

Prof Bose hopes the material will be used for orthopaedic and dental work
Their breakthrough came when they discovered a way to double the strength of the main ceramic powder - calcium phosphate - by adding silica and zinc oxide.

To create the scaffold shapes they customised a printer which had originally been designed to make three-dimensional metal objects.

It sprayed a plastic binder over the loose powder in layers half as thick as the width of a human hair.

The process was repeated layer by layer until completed, at which point the scaffold was dried, cleaned and then baked for two hours at 1250C (2282F).

Repairs
Tests carried on immature foetal bone cells in the laboratory found that new bone cells started growing over the scaffold within the first week of it being attached.

The team say they have also had promising results from tests involving live rabbits and rats.

"The way I envision it is that 10 to 20 years down the line, physicians and surgeons should be able to use these bone scaffolds along with some bone growth factors, whether it is for jaw bone fixation or spinal fusion fixation," says Dr Bose.


The US-team believe that the substance they have created does not pose any health risks.

Read more at link http://www.bbc.co.uk/news/technology-15963467

Adult Stem Cells Use Special Pathways to Repair Damaged Muscle, Researchers Find
http://www.sciencedaily.com/releases/2011/12/111201163624.htm
ScienceDaily (Dec. 1, 2011) — When a muscle is damaged, dormant adult stem cells called satellite cells are signaled to "wake up" and contribute to repairing the muscle. University of Missouri researchers recently found how even distant satellite cells could help with the repair, and are now learning how the stem cells travel within the tissue. This knowledge could ultimately help doctors more effectively treat muscle disorders such as muscular dystrophy, in which the muscle is easily damaged and the patient's satellite cells have lost the ability to repair.

"When your muscles are injured, they send out a 'mayday' for satellite cells to come and fix them, and those cells know where to go to make more muscle cells, and eventually new muscle tissue," said D Cornelison, an associate professor of biological sciences in the College of Arts and Science and a researcher in the Bond Life Sciences Center. "There is currently no effective satellite cell-based therapy for muscular dystrophy in humans. One problem with current treatments is that it requires 100 stem cell injections per square centimeter, and up to 4,000 injections in a single muscle for the patient, because the stem cells don't seem to be able to spread out very far. If we can learn how normal, healthy satellite cells are able to travel around in the muscles, clinical researchers might use that information to change how injected cells act and improve the efficiency of the treatment."

In a new study, researchers in Cornelison's lab used time-lapse microscopy to follow the movement of the satellite cells over narrow "stripes" of different proteins painted onto the glass slide. The researchers found that several versions of a protein called ephrin had the same effect on satellite cells: the cells that touch stripes made of ephrin immediately turn around and travel in a new direction.

"The stem cell movement is similar to the way a person would act if asked to walk blindfolded down a hallway. They would feel for the walls," Cornelison said. "Because the long, parallel muscle fibers carry these ephrin proteins on their surface, ephrin might be helping satellite cells move in a straighter line towards a distant 'mayday' signal."

If researchers gave the satellite cells the signals to differentiate and form muscle fibers in culture, the group also found that they could use stripes of ephrins to get them to arrange themselves in parallel, the way muscle fibers always do in living beings, but have never been persuaded to do in a culture dish. This leads researchers to think that ephrins might actually be regulating several of the different steps that are needed to get from a population of stem cells spread out all over the muscle, to an organized and patterned new muscle fiber.

Read more at http://www.sciencedaily.com/releases/2011/12/111201163624.htm