The world’s largest land mammal has just inspired one of the smallest 3D bioprinters ever created. Developed by researchers at McGill University in Canada, the device measures just 2.7 mm wide, about the width of a grain of rice, and uses a flexible, trunk-like nozzle to print healing hydrogels directly onto the vocal cords during surgery.
Like an elephant’s trunk, the bioprinter’s soft robotic arm can bend, twist, and move with precision in tight spaces. Mounted to a surgical microscope, it allows surgeons to manually deposit biomaterials inside the throat without blocking visibility, something traditional injection tools struggle to achieve.
Schematic overview of suspension laryngoscopy with the MIISB. (Photo credit: Cell Press)
Published in Device on October 29, this new approach adds precision to in situ tissue repair and could help reduce the post-operative scarring that often limits a patient’s ability to speak.
Why Vocal Fold Repair Is Uniquely Challenging
Between 3% and 9% of people will experience a voice disorder in their lifetime, often due to cysts, polyps, or cancerous growths on the vocal cords. While these can be surgically removed, the healing process can leave behind fibrosis, stiff scar tissue that restricts vocal fold vibration and makes speaking difficult.
Surgeons currently use hydrogels to soften this scarring and promote tissue regeneration. However, injecting biomaterials by hand in such a tight space makes it difficult to control placement and shape. This is the limitation the McGill team set out to solve.
How the Device Works
The team’s solution is a miniature bioprinter with a flexible printhead mounted on a tendon-driven robotic arm that surgeons control in real time. Its nozzle can deliver thin, 1.2 mm lines of hyaluronic acid-based hydrogel across a 20 mm workspace, allowing it to reconstruct the curved and layered structure of the vocal folds with precision.
To demonstrate its precision, the researchers first used the device to “draw” simple shapes such as spirals, letters, and hearts on a flat surface. They then moved to simulated vocal fold models used in surgical training. In both cases, the bioprinter accurately traced and filled in the required areas, including recreating full vocal fold geometry ranging from small cavities left after lesion removal to complete tissue reconstruction.
“Our device is designed not only for accuracy and printing quality but also for surgeon usability,” said Swen Groen, the study’s first author and biomedical engineer at McGill University. “Its compact and flexible design integrates with standard surgical workflows and provides real-time manual control in a restricted work environment.”
Toward Bioprinting in the Operating Room
While other bioprinting devices have been designed to deliver hydrogels to internal organs such as the colon or liver, few have been small or flexible enough to work inside the throat without obstructing a surgeon’s view. The McGill bioprinter offers a miniature, handheld solution that could be used directly during vocal cord surgery, bringing additive manufacturing closer to real-time clinical care.
The next step is testing the device in animal studies to evaluate how the printed hydrogels integrate with live tissue. If successful, the team hopes to bring the tool into human clinical trials to measure safety, usability, and healing outcomes. Beyond vocal cords, researchers believe this approach could be adapted for other areas in the body that require delicate and targeted tissue repair. To learn more, check out the press release.
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