Handheld 3D printing BioPen can 'draw' human stem cells for cartilage repair

Handheld 3D printing BioPen can 'draw' human stem cells for cartilage repair

A team of Australian surgeons and researchers has developed a 3D printing pen that allows surgeons to draw and sculpt customized cartilage implants made from actual human stem cells during the live surgery. Dubbed the ‘BioPen’, this lightweight, handheld device gives surgeons unprecedented control as it 3D prints a mixture of hydrogel bioink and human stem cells directly into the patient’s body, ‘filling’ damaged cartilage with fresh cells that have a proven 97% survival rate and can actually heal the body over time.

Developed by researchers from the ARC Centre of Excellence for Electromaterials Science (ACES) and orthopaedic surgeons at St Vincent’s Hospital, Melbourne, this landmark, proof-of-concept mobile 3D bioprinting device could help reduce the hundreds of thousands of arthritis-related knee and hip replacement surgeries that take place every year, reducing medical expenses and eliminating the need for patients to undergo painful and invasive surgical procedures.

Arthritis is an extremely common and debilitating condition, affecting close to 350 million people worldwide. As their cartilage breaks down, arthritis sufferers can experience excruciating pain, but since cartilage—which has no nerves or blood supply—cannot re-grow itself, invasive surgeries that involve drilling into the bone or implanting pre-fabricated implants, is often the only solution.

Luckily, the fact that cartilage has no nerves or blood supply also makes it a relatively simple tissue for 3D bioprinting applications. In fact, several universities and research institutions worldwide have already been exploring 3D bioprinted nose and ear reconstructions, 3D printed hydrogels, and even 3D bioprinted cartilage implants that have been successfully tested in mice.

The major advantage of the 3D printing BioPen, however, is that it gives surgeons an unprecedented level of control and allows them to sculpt bespoke, 3D scaffolds directly into the wounded area. Often, the exact geometry of a cartilage implant cannot be known prior to the surgery actually taking place—but with the BioPen, that won’t matter, since surgeons can 'draw' the implant on-the-spot.

The BioPen was designed by a team of cell biologists, electromaterial scientists, and 3D printing specialists specifically with the “practical constraints of the operating theatre” in mind. It is made from medical grade plastic and titanium, and is small, lightweight and ergonomic—much like the scalpels and forceps surgeons are already used to using. On the more technical, 3D printing side, it features custom titanium nozzles that allow the 3D printing of multiple ink formulations side-by-side.

Essentially, the cartilage-repairing BioPen works just like the 3Doodler or any other 3D printing pen, but rather than plastic filament, it extrudes human stem cells from the patient’s own body, surrounded by a protective hydrogel bioink. The hydrogel is made from a mixture of gelatin and hyaluronic acid that is hardened into a 3D scaffold with a low-powered UV light.

The hydrogel works to protect the stem cells as they begin to multiply and grow new cartilage. Over time, the scaffold dissolves back into the body, leaving only a “thriving community” of healthy, functional tissue behind. In lab tests, the researchers found that more than 97% of the human cells were still alive one week after being 3D printed.

“The development of this type of technology is only possible with interactions between scientists and clinicians—clinicians to identify the problem and scientists to develop a solution,” said Professor Peter Choong, Director of Orthopaedics at St Vincent’s Hospital and one of the lead concept developers.

“The BioPen project highlights both the challenges and exciting opportunities in multidisciplinary research. When we get it right we can make extraordinary progress at a rapid rate,” added Professor Gordon Wallace, ACES Director.

As a “personalized intervention that encourages the body to heal itself,” the 3D printing BioPen could pave the way for the use of freeform 3D bioprinting during a range of surgical processes. In addition to 3D printing cartilage directly into arthritis patients, it could potentially be configured to 3D print other tissues, such as skin, muscles, or bone structures. Despite its small size, this 3D printing BioPen could represent one of the biggest breakthroughs in 3D printed medicine to date.

The research was recently published in the journal Biofabrication. A second prototype is currently being tested by Professor Choong and experts at the University of Wollongong (UOW) to optimize the cell materials for use in clinical trials. Watch the video below to see Professor Choong explain the BioPen and demonstrate it in action: