• A new study has demonstrated how 3D-printed carbon scaffolds can overcome the challenges of mechanical mismatch and processing constraints of existing materials used in bone tissue regeneration.
• The study shows how high-temperature pyrolysis enables tunable properties of 3D-printed carbon, optimised for bone regeneration.

In a breakthrough for regenerative medicine, a new study from IMDEA Materials Institute researchers has demonstrated the potential of 3D-printed carbon microlattices as structurally tunable scaffolds for bone tissue engineering.  

Specifically, the scaffolds were fabricated using 3D-printed polyethylene glycol diacrylate (PEGDA) structures that are transformed into pyrolytic carbon (PyC) through high-temperature treatment.

Their findings, published in Small Structures, open up promising avenues for the use of carbon-based materials in bone tissue engineering, a field long in search of biomaterials that combine mechanical robustness, biocompatibility, and tailored design with geometrical precision.

“This study presents the first comprehensive in vitro evaluation of 3D-printed PyC scaffolds for bone regeneration,” said Dr. Monsur Islam from IMDEA Materials. “Our goal was to move beyond conventional scaffold materials and explore carbon as a fully architected, tunable platform for tissue engineering”.

“While other forms of carbon like graphene or carbon nanotubes have shown promise in bone regeneration, they typically require embedding in polymers, which often mask their true potential”.

“We were excited by the idea of using pure carbon, shaped entirely through 3D printing and pyrolysis, to create scaffolds with programmable mechanical and chemical properties. What’s truly remarkable is that these structures can guide cell behaviour, promoting either proliferation or osteogenesis, without any surface coatings or bioactive additives. That’s what makes this work feel like a turning point for carbon in regenerative medicine,” he added.

The team behind the publication, led by Dr. Islam, also includes IMDEA Materials researchers Wei Tang, Dr. Miguel Monclús, Dr. Mónica Echeverry Rendón, Prof. De-Yi Wang, and former IMDEA Materials researcher Dr. Jesús Ordoño.

Pyrolysis is a process in which organic materials are decomposed at high temperatures in the absence of oxygen.

In the study, carried out as part of the European Marie Skłodowska Curie Actions project 3D-CARBON, PEGDA, an organic photo-sensitive resin, was first used for UV-light-based resin 3D printing, where intricate 3D PEGDA structures were fabricated in a layer-by-layer photopolymerisation process.

These structures were later subject to a high-temperature pyrolysis process, resulting in the formation of a carbon-based framework exhibiting enhanced mechanical, electrical, or thermal properties depending on the processing conditions.

Importantly, the original structures experienced a significant geometrical shrinkage (up to ~80%), while retaining the original geometry. This shrinkage enabled a higher printing resolution compared to the UV 3D printing process, leading to the fabrication of pore geometries similar to native bone.

Researchers also demonstrated how varying the pyrolysis temperature from 500 to 900 °C effectively tuned both the physical and biological properties of the resulting carbon microlattices.

At higher temperatures, the carbon becomes more conductive and mechanically robust, with elasticity and hardness values approaching those of natural bone, making them particularly promising for clinical applications in bone repair.

Interestingly, the study shows that PyC scaffolds created at lower pyrolysis temperatures retain more oxygen-containing surface groups, leading to greater metabolic activity and enhanced cell proliferation. This suggests that adjusting the pyrolysis parameters offers a powerful tool to direct cellular behaviour.

Unlike many existing scaffold materials, such as polymers that lack strength or ceramics that are extremely challenging to process to the geometrical scale of native bone, these PyC microlattices offer a rare combination of processability, biocompatibility, mechanical resilience, and surface tunability.

 In addition, their potential compatibility with MRI-based monitoring presents a notable advantage over metal-based implants.

This research received funding from the European Union’s Marie Skłodowska-Curie Actions under grant agreement number 101106022 (3D-CARBON). The views expressed are those of the authors and do not necessarily reflect those of the European Union or its agencies.