Additive Manufacturing of Porous Biominerals

Nature fabricates hard functional materials from soft organic scaffolds that are mineralized. To enable an energy-efficient locomotion of these creatures while maintaining their structural stability, nature often renders parts of these minerals porous. Unfortunately, methods to produce synthetic minerals with a similar degree of control over their multi length scale porous structure remain elusive. This level of control, however, would be required to design lightweight yet robust biominerals. Here, a room temperature process is presented that combines a localized mineralization with emulsion-based 3D printing to form cm sized biominerals possessing pores whose diameters range from the 100 s of nm up to the mm length scale. The samples encompass up to 80 wt% of CaCO3 and display a specific compressive strength that is significantly higher than that of previously reported 3D printed porous biominerals and close to those of trabecular bones. The universality of this approach by forming different types of bioactive minerals, including calcite, aragonite, and brushite is demonstrated. The ability to 3D print these materials under benign conditions renders this energy-efficient process well-suited to construct cm-sized lightweight yet load-bearing structures that might find applications, for example, in the design of the next generation of flying or motile objects.

Automated summary

Nature creates hard functional materials from soft organic scaffolds that are mineralized, often making parts of these minerals porous to achieve energy-efficient locomotion. However, methods to produce synthetic minerals with a similar level of control over their porous structure remain elusive. This study presents a room temperature process that combines localized mineralization with emulsion-based 3D printing to create cm-sized biominerals with pores ranging from the 100 nm to mm length scale. These biominerals have high compressive strength and can form different types of bioactive minerals. The ability to 3D print these materials under benign conditions makes this energy-efficient process suitable for constructing lightweight yet load-bearing structures for various applications.