Doctors perform hundreds of thousands of knee surgeries every year, often to replace damaged or worn cartilage. The techniques for performing these surgeries today may be about to change, thanks to new research.
In the not-too-distant future, orthopedic surgeons may simply draw new cartilage inside your knee, using a 3D printing, stem-cell-extruding device called the “BioPen.”
The device is still in the research and development stage and not yet approved for medical use, but it’s an example of how 3D printing technologies may usher in new ways of treating common human ailments.
In a study published last month in the journal Biofabrication, scientists from the Australian Research Council’s Center of Excellence for Electromaterials Science (ACES) detailed experiments with their custom-built, 3D printing pen, known as the BioPen, a device they’ve been working for almost three years.
Its new capability, though, is what they’re calling a breakthrough: the ability to effectively print viable human stem cells into damaged joints to regrow cartilage.
The pen was developed by Peter Choong, director of orthopedics at St. Vincent’s Hospital in Melbourne, along with ACES director Gordon Wallace.
According to Wallace, it was Choong, an orthopedic surgeon, who first come up with the idea.
Why drawing beats printing
While researchers acknowledged the benefits of emerging bio-printing techniques for cartilage reconstruction, especially for tailoring implants to the needs of specific patients, they noted that cartilage surgery often requires removal of damaged tissue, which means the surgeon can’t pre-print replacement material.
A handheld 3D printing pen, on the other hand, allows them to perform what they’re calling “in-situ biofabrication.” Other emerging knee cartilage replacement methods, like NeoCart, use the patient’s own cells to grow cartilage on a scaffold outside the knee. It’s then trimmed and implanted into the patient.
According to the study, the BioPen “allows for surgical sculpting of the substitute tissue to achieve the desired structure.”
In other words, the surgeon sculpts the material as he or she draws. Using a small, handheld device also means they can deposit materials, via two channels and a titanium tip, in areas that pre-printed material would not cover, like crevices and under overhangs of existing tissue.
The scientists contend that their 3D-printed BioPen will also cost less than conventional bio-printing machinery.
“The hardware can be assembled for a low cost — maybe $10,000,” Wallace wrote in an email to Mashable. As with all printers though, Wallace wrote, “the magic is in the ink — this time the bio ink.”
If the BioPen’s printing methods look somewhat familiar, that’s because they are. It uses a printing method quite similar to that of the CreoPop 3D printing pen. Like the latter device, BioPen uses a polymer-based hydrogel, extruded through a nozzle and insta-hardened by UV light focused on a point just in front of the extruder.
Scientists control the extrusion of the gel through the use of foot pedals.
Unlike Creopop day-glo-colored gel, though, the BioPen’s extrusion material is infused with adipose stem cells, which are collected in a routine surgical procedure from human fat cells.
The study claims that the cells drawn using the pen have undergone chondrogenesis, which is essentially new cartilage growth. The researchers claim that the cells printed using the BioPen have shown up to 97% viability.
A work in progress
There are limitations to the new BioPen, however. According to the study, the temperature of the hospital room and the heat coming from the surgeon’s hand onto the BioPen can impact the bio material flow. In addition, the pressure-driven extrusion system can be somewhat inconsistent.
For BioPen version 2, the scientists plan to introduce both a temperature control system into the BioPen and back it with a mechanical extrusion system to maintain flow consistency. Wallace said the researchers are also refining the bio ink and ergonomics of the BioPen.
While the BioPen is unlikely to end up in surgeons’ hands in the near term, Wallace told Mashable that veterinarians could be using the 3D printing pen “in a handful of years.” As for humans, that timeline will be dictated by how quickly the researchers can perfect the hardware and, of course, gain approval of regulatory agencies.
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