Bone is deceptively complex. It is light, porous, and strong at the same time, a combination that has long challenged engineers and clinicians trying to replace or repair it. Metal implants and bone grafts remain standard solutions, but they rarely behave the way real bone does once inside the body.
Researchers at UNSW Canberra are exploring whether 3D printing can help close that gap. Their work focuses on biodegradable bone scaffolds designed to better match bone’s internal structure and mechanical response, rather than simply filling a defect.
PhD student Kaushik Raj Pyla (center), with supervisors Juan Pablo Escobedo-Diaz (left) and Paul Hazell (right). (Photo credits: UNSW Canberra)
Moving Beyond Uniform Scaffold Designs
The team developed 3D printed scaffolds that replicate key characteristics of natural bone, including strength and porosity. Once implanted, the structures act as temporary supports, allowing new tissue to form before gradually dissolving. In principle, this could reduce the need for additional surgeries.
Much of the difference lies in how the scaffolds are designed. Instead of using uniform, repeating patterns, the researchers turned to stochastic lattice structures. These irregular architectures more closely resemble bone, which varies in density depending on location and function. The scaffolds were printed in polylactic acid (PLA), a biodegradable polymer already widely studied in medical applications.
A 3D-printed stochastic lattice structure designed to mimic the internal architecture of natural bone. (Photo credit: Kaushik Raj Pyla)
Testing Strength Under Real-World Conditions
To assess performance, the team printed scaffolds with different internal grading directions, including lengthwise, transverse, and diagonal layouts. Mechanical testing showed that the structures resisted sudden impacts better than slow, steady loading. Fracture behavior also changed depending on orientation, suggesting that internal architecture plays a larger role than previously assumed.
“Under fast loads, the material behaves more brittle, but it also absorbs energy more efficiently. This is particularly important for real-world scenarios such as falls or accidents,” said Kaushik Raj Pyla, lead author of the study.
Why Fluid Flow Matters for Healing
Mechanical strength, however, is only part of the equation. The researchers also examined how fluids move through the scaffolds, a critical factor for healing. Blood and nutrients must be able to circulate freely to support cell growth and regeneration.
“We found that certain designs performed especially well in both strength and fluid flow. This suggests that implants can be tailored depending on the stresses different bones experience,” Pyla added.
The scaffolds are not yet ready for clinical use, and further biological testing and regulatory work will be required. Still, the results point toward more patient-specific approaches to bone repair. As medical additive manufacturing advances, studies like this underline how design choices can be just as important as material selection.
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*Cover Photo Credits: UNSW Canberra