Broken bones often heal naturally with time, a cast, or a brace. But when fractures are complex or severe, doctors rely on implants or surgical devices.
Now, researchers at Penn State say they have created a biodegradable scaffold that could speed recovery while reducing complications.
The new implant, called CitraBoneQMg, combines magnesium and glutamine with citric acid to stimulate bone regrowth.
“By integrating magnesium and glutamine — two small molecules found naturally in the body and in food — with citric acid, we found that the molecules work together to promote bone growth by encouraging increased intracellular energy metabolism,” said Hui Xu, doctoral student and first author of the study.
The scaffold does more than replace missing tissue. It activates cellular energy systems that push stem cells to become bone cells, leading to faster and stronger regrowth.
Fueling bones with energy
The researchers compared CitraBoneQMg to existing scaffolds made only from citric acid — already approved by the U.S. Food and Drug Administration — and to a traditional bone material implant.
Adding magnesium and glutamine changed the game. The molecules regulate two key energy pathways in cells, AMPK and mTORC1. Usually, these act like a seesaw, one rising while the other falls. But in the new scaffold, they worked together.
“The scaffold essentially powers up a bone cell: both nutrients act in a synergistic relationship with the citric acid to give stem cells more energy to grow and differentiate to bone cells, leading to better bone regrowth,” Xu explained.
When tested in rats with cranial bone defects, the results were striking.
After 12 weeks, CitraBoneQMg boosted bone growth by 56% compared with citric acid scaffolds, and by 185% compared with traditional implants.
Beyond bones, broader healing
The benefits extended beyond bone repair. “The three molecules work as a healing recipe for the bone, paving the way for a new way of thinking of bone repair,” said Su Yan, co-corresponding author and assistant research professor.
“Alongside rapid bone growth, we also saw nerve regeneration and anti-inflammation properties at the site of the scaffold, two elements that are important to long-term healing of the bone,” Yan added.
Delivering the molecules directly at the injury site through the scaffold ensured a high concentration where it was most needed. Oral supplements, by contrast, reach the bone in only small amounts.
The team also discovered a built-in imaging advantage. CitraBoneQMg has photoluminescent and photoacoustic properties, meaning it can be detected by ultrasound inside deep tissue. “With photoacoustic properties, CitraBoneQMg has great potential for in vivo tracking,” Xu said.
The Penn State researchers believe their scaffold could redefine how surgeons approach bone repair in the future. Their work blends materials science with biology to create a treatment that encourages the body to heal itself faster.
The team, working with orthopedic surgeons, has filed a U.S. patent application and published their findings in Science Advances.