Dartmouth Engineering Team Receives $2.5M NIH Grant for Scaffold Innovations that Accelerate Bone Repair

3D-printed biomaterial scaffold in the Hixon Lab. (Photo by Rob Strong '04)

Poor bone quality in the jaw is a debilitating problem that can cause pain, fractures, and infection. Two of the leading causes are osteoporosis and osteonecrosis following radiation therapy (RT). Osteoporosis affects more than 200 million people worldwide, while RT—the standard treatment for head and neck cancer, the sixth most common cancer globally—often leaves bone brittle and unable to heal.

Awarded by the NIH's National Institute of Dental & Craniofacial Research, the five-year grant will support Hixon's lab in the design and creation of a cost-effective, biologically-improved scaffold treatment option with potential applications far beyond the jaw.

"When you take out a tumor and irradiate the bone to make sure there's no residual cancer, it basically prematurely ages your cells," said Hixon. "We are trying to prevent the cells from aging so they can function correctly. The materials we're developing seem to act like a shield, such that if you remove a tumor, implant this scaffold, and then deliver radiation, you see less of that damaging aging effect."

The team’s scaffold is designed not only to protect bone from destructive structural and cellular modulations following radiation, but also to actively induce new bone formation.

"Bone is a highly mineralized tissue. What’s exciting is that even though our scaffold has no cells when implanted, bone cells in the body are naturally drawn to the mineral. Once they attach, they begin depositing more mineral and building new bone—creating a positive feedback loop." explained Hixon.

The process starts with 3D printing a mineral scaffold that can be customized to any shape. The framework is then infused with the lab's "secret sauce"—a chitosan/gelatin-based cryogel that stimulates bone cells, fills defect gaps, and provides large pores that allow both bone cells and blood vessels to infiltrate.

"It's literally like a sponge that can be made into patient-specific shapes and has cell-binding sites that stimulate tissue growth," said Hixon. "Then over time, the scaffold will actually break down and degrade while the cells are laying down new tissue. So it's an implant, but it's temporary."

According to Hixon, that's the long-term goal of tissue engineering—to help tissue become healthy again and replace whatever scaffold guide was implanted. "It's like when you scaffold a building. You use it to build up the new structure, but once the walls and windows are in place, you remove it."

Professor Katie Hixon (left) with PhD Innovation Program fellows Peter Bertone and Adelaide Cagle in the Hixon Lab.

For now, Hixon's team is focused only on applications for the jaw, or mandible. "It's so important for communication," she said. "I’ve always had a soft spot for anything craniofacial because it just helps people feel like themselves."

In the future, however, Hixon says this approach could easily translate to other areas. "This could be applied to any situation where a bone needs to heal—helping patients reduce pain and restore function more quickly."

The project benefits from a strong collaboration with Adjunct Associate Professor of Engineering Eric Henderson, clinician and medical director of the Sarcoma Oncology Program at Dartmouth Cancer Center, ensuring the technology can integrate smoothly into standard treatment. Doctors would need only a routine CT scan to generate patient-specific scaffolds, which can be fabricated quickly and cost-effectively. "Dr. Henderson has been incredibly helpful for clinical context and making sure everything fits the workflow of how a doctor would treat a patient."

Two of Hixon's students aim to use entrepreneurship to help further facilitate clinician and patient access. PhD Innovation Program Fellow Peter Bertone and PhD candidate Levi Olevsky recently founded GyroGel Inc. with a mission to "revolutionize oncologic maxillofacial reconstruction."

"My students have gotten really into it," Hixon said with a smile. "Peter and Levi have led a lot of the work, but it's been very much a group effort. Many of my students have been with me since the beginning, and their contributions have been truly invaluable." 

Learn more about the Hixon Lab: