Metal grafts and titanium-based implants remain the standard for stabilizing severe bone fractures, but they are expensive to produce and difficult to customize for individual patients. And while 3D printing has opened the door to more personalized solutions, it still demands significant time and resources.
Seeking a faster, more affordable option, researchers at Sungkyunkwan University in Korea are developing a technique that can create patient-specific bone implants without the high costs or delays of traditional methods.
Their “bone-healing gun” resembles a handheld 3D printer, but instead of plastic, it extrudes biodegradable polymer scaffolds directly onto broken bones during an operation. The device melts special polymer “bullets” at a safe 60 °C, cool enough to protect surrounding tissue while forming a custom-fit framework for new bone growth.
Targeting patient-specific bone implants without high expense
Jung Seung Lee, a biomedical engineering researcher at Sungkyunkwan University in Korea, and his team built a tool which extrudes a biocompatible filament that quickly hardens into a scaffold, holding the bone in place and supporting natural healing without the cost and delay of traditional implants.
Creating a glue-gun stick that could repair bones proved tricky for Lee’s team. Standard hot glue melts at more than 100 °C – far too hot for living tissue. The material also had to harden with strength similar to natural bone and gradually break down so new bone could replace it. These three challenges – safe temperature, bone-like strength, and controlled biodegradation – guided the design of their bone-healing scaffold, Ars Technica writes.
As Lee explains further, his team tested several mixtures before finding the right one. They combined polycaprolactone, an FDA-approved thermoplastic that safely breaks down in the body within months, with hydroxyapatite, a mineral that helps new bone grow. After adjusting the proportions, they achieved a blend that melts at a mild 60 °C, bonds securely to bone, stays strong during healing, and gradually degrades as natural tissue replaces it.
Gun speeds fracture repair but needs faster degradation
With the bone-healing pellets perfected, Lee’s team moved to animal trials, testing the device on rabbits with broken femurs. Those treated with the healing gun recovered more quickly than rabbits treated with standard bone cement, a common commercial option.
Yet the material’s slow breakdown kept the fractures from fully restoring, highlighting the need for further refinement before human trials can begin. Lee now aims to speed degradation and add antibiotics to the mix so the implant can gradually release infection-fighting drugs during healing.
Another challenge is load bearing. Rabbits are light, so what works for them may not hold up in humans. Therefore, Lee notes that testing in larger animals will be needed to ensure long-term safety. There’s also the question of skill, as the healing gun works like an advanced hot glue gun, but precision is critical. Therefore, researchers note that surgeons will need training to use the tool effectively and consistently before it can be applied in human procedures.