November 23, 2012
Researchers Create Printed Cartilage For Potential Use In Human Patients
Lawrence LeBlond for redOrbit.com - Your Universe Online
Printers have come a long way over the years. From the early days of keyed typewriters to the dot-matrix printers of the 1970s and the modern laser printers and plotters, printing has dramatically evolved. And that is no more true than as seen in new research, published in the latest issue of IOP Publishing´s journal Biofabrication.Researchers from Wake Forest Institute for Regenerative Medicine (WFIRM) have developed a way to print cartilage that could be used to treat joint diseases and sporting injuries. The process of printing 3D tissue has been around for a while, but the team involved in the latest approach turned to a novel hybrid printing format that simplifies the process of creating implantable cartilage.
The team said their efforts have led to production of new material that is more robust and hardwearing than previous attempts to create artificial tissue. They combined a traditional ink-jet printer with a specialized spinning-machine to make the new synthetic material. Synthetic materials ensure the strength of the construct and natural gel materials provide an environment that promotes cell growth, the researchers said.
Previous attempts to create tissue used gel material alone. The new system, adding synthetic material to the mix, proved the cartilage was more mechanically stable. The printed material maintained its functionality in both lab experiments and in the real-life system.
Their electro-spinning machine used an electric current to generate very fine fibers from a polymer solution. Electro-spinning allows the composition of polymers to be easily controlled and therefore produces porous structures that encourage cells to integrate into surrounding tissue.
"This is a proof of concept study and illustrates that a combination of materials and fabrication methods generates durable implantable constructs," said study author James Yoo, M.D., Ph.D., Professor at the Wake Forest Institute for Regenerative Medicine. "Other methods of fabrication, such as robotic systems, are currently being developed to further improve the production of implantable tissue constructs."
Yoo and his colleagues constructed the cartilage from a polymer coated with cartilage cells from a rabbit´s ear. The researchers, who tested the printed cartilage on mice, said the tissue developed properties of real cartilage after just eight weeks, suggesting it has the potential for use in human patients.
Currently, one of the best options available to doctors treating cartilage damage is microfracture surgery. This involves drilling small holes into the bone in the cartilage´s gap to encourage bleeding. Scar tissue then forms over the gap, acting as a replacement for the missing cartilage. Of course, this is rarely suitable in older or more obese patients, and doesn´t work if the lesion is too large.
While there is hope that this innovation could lead to new treatments for patients, at least one expert is warning that it is too early to be confident in the technology.
The new innovation could potentially offer patients a wider range of options, but it is doubtful the technology would ever be used, remarked Dr. Richard Weiler, a consultant in sport and exercise medicine at University College London Hospitals.
"Certainly with sport there are injuries that cause damage to cartilage - we have seen this with some famous footballers, cyclists and other athletes who have had traumatic injuries where the cartilage has been damaged and then drops off and doesn't grow back very well in the affected area," Weiler told the BBC in an interview.
"However, there have been lots of previous cartilage replacement technologies that were shown to have had an effect in animals but have proved not to be as good as hoped when used long-term by humans,” he explained. "This technology sounds an interesting development, we would just want to make sure it's safe [sic]."