3D printing bones at the nano level achieved

3D printing of synthetic bone is now possible in detail never seen before, with University of Sydney led research successfully developing a new printing technique that can mimic nanosized structures found in natural bone. 

Researchers have achieved a new milestone in the mission to create replacement bones by developing the first nanoscale 3D printing technique for synthetic bone substitutes.

The method makes it possible to mimic bone anatomy in unprecedented detail, with researchers able to precisely control the grain size and how porous it can be during printing. 

The development was co-led by Professor Hala Zreiqat, the Payne-Scott Professor of Biomedical Engineering at the University of Sydney, and Associate Professor Iman Roohani, now at the University of Technology Sydney's School of Biomedical Engineering. 

“The technology brings us a step closer to transforming bone graft surgeries in the future,” said Professor Zreiqat, who this week was appointed as a 2025 Fellow of the American Institute for Medical and Biological Engineering for her work in musculoskeletal regeneration and successful technology commercialisation.

The material used closely mimics the mineral composition of natural bone, allowing human cells to recognise and interact with them effectively, with the goal of creating synthetic bone with the same strength and biological properties of natural bone. 

“This reduces the risk of long-term complications and future surgeries and offers a more natural restoration of bone defects,” said Professor Zreiqat, whose team specialises in creating bio-ceramic materials that aim to recreate the structure and properties of real bone. 

“While the technology is still evolving, it represents a significant step in reconstructive surgery," she said. 

According to the Australian Orthopaedic Association National Joint Replacement Registry, in 2023 there were 58,529 hip replacement surgeries, 78,125 knee replacement surgeries and 10,141 shoulder replacement surgeries. 

An Australian Institute of Health and Welfare statistics report showed that in 2021-22 there were 53,500 knee replacements (210 per 100,000 population) and 35,500 hip replacements (140 per 100,000 population) to treat osteoarthritis.

The technology uses specialised inks from biocompatible materials, such as calcium phosphate, which closely resemble the mineral composition of natural bone. 

The team were able to print at 300 nanometres resolution, which they say is one thousand times stronger than existing techniques. 

Although human bone looks deceptively simple on the surface, within the bone mineral is a complex architecture of micro- and nano-sized shapes and forms. This gives bones their strength, durability, and ability to support the weight of multiple layers of dense human muscle and tissue. 

“Bone’s complex architecture is a masterpiece of nature,” said Professor Zreiqat, based at the School of Biomedical Engineering in the Faculty of Engineering.

Aiming to mimic and 3D print natural bone architecture was no easy feat, especially at the nano level. 

“Our bioceramic scaffolds aim to mimic the structure and properties of real bone. Just looking like bone is not enough – it needed to have similar strength and integrity. We were able to do it at the macro and micro level but achieving it at the nano level was the final piece of the puzzle,” said Professor Zreiqat. 

How could researchers mimic the same nano sized structures during the natural bone formation process? 

Associate Professor Roohani and PhD candidate Shuning Wang cracked the code by using prenucleation clusters. These clusters, naturally found in the bone, play an important role in bone formation by guiding the mineralisation process that makes bone so strong. 

By incorporating these clusters into a highly transparent and printable calcium phosphate resin, the researchers have been able to mimic the micro and nano scale features of natural bone. 

The approach not only reflects a deep understanding of the bone’s biological processes but also showcases the potential of using materials inspired by biology to revolutionise medical treatments. 

The findings were published in Advanced Materials. The 3D printing machine used to print bone substitutes is located at Research and Prototype Foundry, a Core Research Facility at the University of Sydney.

“This study demonstrates the potential to create bone-mimicking structures, paving the way for advanced bone grafts and implants,” said lead author Associate Professor Roohani, who completed the work at University of Sydney as part of Professor Zreiqat’s team and now leads the Advanced Biomaterials and Fabrication laboratory at UTS.

“This could revolutionise bioceramic implants, regenerative medicine and high-performance biomaterials," he said.

Traditionally, metal implants such as titanium plates and screws are used. Although they provide structural support, they do not participate in the healing process. There is also the risk of the body rejecting the foreign object or infection. 

The goal of bioceramic materials developed by Professor Zreiqat’s team is to provide the support but also to gradually integrate with the body and encourage new bone formation. 

One of the team members, Ms Shuning Wang, said the study is a major leap toward creating bone implants that truly mimic natural bone, down to the nanoscale. 

“Next, we’re advancing this technology by enhancing the scalability of our printed structures, accelerating their path to clinical application,” she said.

Declaration: The authors declare no conflict of interest. 

Main image: A close up of 3D printed synthetic bone mimicking trabeculae, a major part of natural bone. Credit: Roohani et al.