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 degrees Celsius, cool enough to protect surrounding tissue while forming a custom-fit framework for new bone growth.