Advancements in 3D-Printed Carbon Scaffolds for Bone Regeneration

In a significant breakthrough for regenerative medicine, researchers at the IMDEA Materials Institute have unveiled the potential of 3D-printed carbon microlattices as structurally tunable scaffolds for bone tissue engineering. This innovative study, published on July 22, 2025, in the journal Small Structures, highlights how these scaffolds can address longstanding challenges in bone regeneration by combining mechanical robustness, biocompatibility, and precise geometrical design.

The scaffolds are crafted using polyethylene glycol diacrylate (PEGDA), a photo-sensitive resin that is subsequently converted into pyrolytic carbon (PyC) through a high-temperature pyrolysis process. Dr. Monsur Islam, a lead researcher at IMDEA Materials, emphasized that this study represents the first comprehensive in vitro evaluation of 3D-printed PyC scaffolds specifically designed for bone regeneration.

"Our goal was to move beyond conventional scaffold materials and explore carbon as a fully architected, tunable platform for tissue engineering," stated Dr. Islam. He noted that while other carbon forms, such as graphene or carbon nanotubes, have shown promise, they often require embedding in polymers, which can obscure their potential benefits.

This research presents a novel approach by utilizing pure carbon, which can be shaped entirely through 3D printing and pyrolysis. The resulting scaffolds are designed to promote cellular behavior, facilitating either cell proliferation or osteogenesis without the need for surface coatings or bioactive additives.

The team, which includes researchers Wei Tang, Dr. Miguel Monclús, Dr. Mónica Echeverry Rendón, Prof. De-Yi Wang, and former researcher Dr. Jesús Ordoño, conducted this study as part of the European Marie Skłodowska Curie Actions project known as 3D-CARBON.

Pyrolysis, a process where organic materials undergo decomposition at high temperatures in the absence of oxygen, played a crucial role in this research. The intricate 3D PEGDA structures that were initially created through UV-light-based resin 3D printing experienced a significant shrinkage (up to ~80%) during pyrolysis, while maintaining their original geometry. This allowed for a higher printing resolution, resulting in pore geometries that closely resemble those of native bone.

Furthermore, the researchers found that by varying the pyrolysis temperature between 500 and 900 °C, they could effectively tune the physical and biological properties of the carbon microlattices. Higher temperatures led to increased conductivity and mechanical robustness, with elasticity and hardness values approaching those of natural bone. The study's findings suggest these scaffolds could have promising applications in clinical settings for bone repair.

Interestingly, scaffolds created at lower pyrolysis temperatures retained more oxygen-containing surface groups, which correlated with increased metabolic activity and enhanced cell proliferation. This indicates that researchers could manipulate pyrolysis parameters to direct cellular behavior, a significant advancement over existing scaffold materials that often lack strength or are difficult to process to the geometrical scale of native bone.

The PyC microlattices not only offer a rare combination of processability, biocompatibility, mechanical resilience, and surface tunability but also present the potential for compatibility with MRI-based monitoring, an advantage over traditional metal-based implants.

As the field of regenerative medicine continues to evolve, this innovative approach to scaffold design and fabrication promises to open new avenues for effective and efficient bone tissue engineering, setting the stage for future research and clinical applications. The implications of this work could significantly enhance the quality of life for patients requiring bone repair and regeneration, marking a potential turning point in the use of carbon-based materials in medicine.