A new handheld biopen may be used to 3d print cartilaginous tissue during surgery. The device has been successfully demonstrated to work in animal trials, as well as with human cells in a more controlled environment, however more extensive experimentation is required before surgeons can start to use it professionally.
Similar to a large 3D bioprinter, the biopen extrudes a solution of stem cells immersed in a semi liquid hydrogel that looks and behaves like natural articular tissue.
“Thanks to a series of sophisticated histological, molecular and imaging techniques, we confirmed that the tissue that developed within the constructs forms, appears, and behaves like articular cartilage,” say the researchers. “This material is expected to be as durable as real cartilage.”
“This is in stark contrast to conventional reparative cartilage made of fibrocartilage, which is very different in structure to physiological cartilage, inferior in quality and not durable,” say the researchers, a multidisciplinary team that includes surgeons, biologists, physicists and engineers. “Our technique and the scaffolds we are able to produce provide much hope for treating patients suffering from cartilage injuries and osteoarthritis.”
Since cartilage contains only a few distinct cells and no blood vessels injuries to the joint are difficult to heal and treat. Current modern day procedures require two separate surgical operations – one to remove the damaged cartilage and one to graft another scaffold back on to the joint.
This is part and parcel to why joint surgeries have such a high failure rate. Either the fabricated scaffolds don’t match the patients injury or they’re just not similar enough to natural cartilage for the transplantation to last.
In this study published in the journal biofabricaton, an interdisciplinary team of experts ranging from the University of Melbourne, University of Wollongong, and St Vincents Hospital of Melbourne provide in vitro evidence that their new biopen can form patient specific scaffolds in real-time, during the first surgery, eliminating the need for two separate operations.
In other words the device can be used to “edit” damaged tissue rather then extracting from and then re-transplanting a less accurate tissue sample later on. Experts claim that this could improve the probability of success by increasing the accuracy of the procedure and reducing the amount of operations required.
The multidisciplinary team tested their biopen with human derived mesenchymal stem cells harvested from infra patellar fat pads of people with osteoarthritis, combining the cells with a hydrogel material bio-ink. A specialized nozzle allows bio-materials from separate cartridges to be extruded coaxially (in nested cylindrical layers). The stem cells are contained within a central core while the outer shell is filled with cross-linking material that supports the final product.
With that being said – their device is not quite ready for application. They’ve only tested it on animals and isolated human tissue samples, so more extensive experimentation is required before it can make the transition to clinical application.
“We are refining our methodology to upscale the production of the inks used in the device, and to fine-tune how to harvest and prepare the mesenchymal stem cells,” they say. “We are also aiming to develop a protocol that will enable one-step harvesting, preparation and delivery of the cells during surgery.”