A new medical technology has been developed that can print and attach implants directly to the damaged areas of a patient's bone during surgery. It has been proven safe and effective in rabbit experiments and is expected to expand into clinical trials involving humans in the future.
A research team from Sungkyunkwan University, Korea University, and the Massachusetts Institute of Technology (MIT) announced on the 6th that they successfully extracted customized bone implants directly at the fracture or defect sites of patients using a device similar to a glue gun that melts plastic adhesives. The research findings were published that day in the international academic journal Cell's sister journal, "Device."
Previously, when bones were damaged, implants made of metal or donated bones were used for transplantation. Recently, three-dimensional (3D) printers have been used to create three-dimensional bone tissue. However, when the fracture sites are irregular or complex, pre-imaging, modeling, and production processes are essential for customized transplants. This increases time and expense and decreases surgical efficiency. Donated bones also carried risks of infection or immune rejection.
Professor Lee Jeong-seung of the Department of Global Biomedical Engineering at Sungkyunkwan University, who led the research, said, "The research idea came from the opinions of actual doctors." According to doctors, even if implants are pre-made using 3D printing, once opened during surgery, they may not fit well with the defect site, necessitating additional processing.
The research team devised a device that prints implants directly at the surgical site. The material used is a filament mixed with hydroxyapatite (HA), which helps bone regeneration, and polycaprolactone (PCL), a plastic that safely decomposes in the body.
PCL can melt at just 60 degrees Celsius, allowing it to be used safely during surgery without damaging surrounding tissues. Additionally, the melted PCL can flow into the gaps of bones and fully fill the irregularly fractured areas. By adjusting the HA ratio in the filament, its hardness or strength can be altered according to the situation.
Doctors can hold the implant printing device like a glue gun and stack the material in the desired direction and depth within a few minutes to match the shape of the broken bone, the research team noted. Custom bone implants that fit perfectly can be created without the complicated CT (computed tomography), modeling, or processing procedures.
An infection prevention function has also been added. The research team incorporated antibiotic components, vancomycin and gentamicin, into the filament to be released gradually over several weeks post-surgery. This significantly reduces the risk of infection around the bone while also lowering the risk of side effects and resistance compared to taking antibiotics orally or via injection.
As a result of applying this technology to fractures in rabbit femurs, the bones rapidly regenerated without infection or tissue necrosis within 12 weeks. The research team explained that "it outperformed existing bone cement in key indicators such as bone surface area and strength," adding that "the printed bone substitute gradually decomposes over time, and new bone naturally fills the space left behind."
Professor Lee stated, "Being able to produce and apply bone implants in real time in the operating room can shorten surgery time and increase accuracy," and added, "We plan to expand the application range by adding various functions in the future." However, he noted that trials on large animals such as pigs and humans are necessary for commercialization.
References
Device(2025), DOI: https://doi.org/10.1016/j.device.2025.100873