A recent study published in Advanced Materials introduced a new approach to 3D printing calcium phosphate (CaP) structures using bone prenucleation clusters (PNCs). By using bioinspired chemistry, researchers overcame previous limitations in resolution, opening up new possibilities for biomedical applications.
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Background
Current additive manufacturing methods can create complex geometries but struggle to achieve fine feature sizes for CaP structures, typically limited to around 120 μm. These challenges stem from light scattering, difficulty maintaining precise calcium-to-phosphorus ratios, and the reactivity of CaP nanoparticles with water, which affects particle size and crystallinity. Many direct-printing methods rely on photocurable solutions, but these often face shrinkage and instability issues when used with CaPs.
To address these challenges, researchers focused on PNCs, which serve as intermediates in calcium phosphate formation. By integrating these nanoscale clusters into a photosensitive resin, they developed a highly effective material for high-resolution 3D printing.
Developing a Nanoscale Printing Method
The study centered on synthesizing PNCs with an average size of 5 nm to enhance printing precision. These nanoclusters were designed to remain stable and minimize light scattering, which is crucial for two-photon polymerization (2PP)—a technique that enables nanoscale 3D printing.
Researchers formulated a novel photosensitive resin incorporating PNCs, creating a material that was highly transmissive and well-suited for precision printing. The 2PP process was tested in both dip-in and immersion modes to optimize print quality. Through detailed experiments, they determined the ideal PNC concentration in the resin, ensuring structural stability during printing and post-processing.
After printing, the structures underwent post-printing sintering to improve mechanical properties and crystallinity. Scanning electron microscopy (SEM) was used to analyze printed features, such as a 100 × 100 array of CaP submicron grains, while transmission measurements assessed how PNC content influenced resin transparency.
Furthermore, the use of controlled environmental conditions during synthesis and printing was essential to prevent unwanted particle agglomeration and maintain precise calcium-to-phosphorus ratios. These measures ensured high reproducibility and material consistency, which are critical for biomedical applications.
Key Findings: Higher Precision and Stability
The study successfully printed CaP structures with feature sizes as small as 300 nm, surpassing the limitations of previous techniques. The incorporation of PNCs into the photoresist enhanced the material’s transparency, making it highly compatible with the 2PP process. Printed structures closely matched their intended designs, demonstrating high resolution and accuracy.
Beyond resolution improvements, the method offers potential applications in bioinspired materials, cell-modulating interfaces, and engineered coatings. However, the process still requires post-printing sintering at high temperatures, which prevents direct integration of heat-sensitive biological components during fabrication.
Researchers also noted that while nanoscale precision was achieved, printing speed remained a challenge for scaling up production. Despite this, advancements in scanning technology and fabrication workflows could help improve efficiency in future applications.
What’s Next for Nanoscale 3D Printing?
This study represents a major step forward in nanoscale 3D printing of calcium phosphates, demonstrating how bioinspired chemistry can improve resolution and material properties.
While challenges remain—particularly in post-processing and scalability—this method opens new possibilities for advanced biomaterials in tissue engineering, regenerative medicine, and precision manufacturing.
Future research may focus on integrating biological components post-sintering and refining the printing process to enhance speed and efficiency.
Journal Reference
Roohani I., et al. (2025). Bioinspired nanoscale 3D printing of calcium phosphates using bone prenucleation clusters. Advanced Materials, 2413626. DOI: 10.1002/adma.202413626, https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.202413626
