Bio-inspired 3D-printing of Layered Amorphous Calcium Carbonate Composites

In nature, composites are often formed in the course of biomineralization, composed of a brittle mineral reinforcement joined by a ductile organic matrix. The formed composites often originate from an amorphous precursor such as amorphous calcium carbonate (ACC), and obtain a layered structure. In this study, we utilized robocasting, a 3D-printing technique to print models inspired by the Ophiomastix wendtii and the Odontodactylus scyllarus layered structures. We compared various bio-degradable organic matrices with a high percentage (>94%) of ACC reinforcements and studied their mechanical properties. With the organic matrix protection, ACC was stabilized for long periods of time, exceeding two years, when stored at ambient conditions. The layered models were printed and tested to evaluate their strength. The breakage interface was examined as well, to weigh the benefits an amorphous precursor may offer in 3D printing processes of ceramic materials. The breakage interface presented bulk behavior with no distinct layering, resembling the formation of single crystalline organs in nature, and overcoming one of the most burning problems in 3D printing, the layers’ interfaces. Herein we present a bio-inspired, ecological formation of layered structures, resulting in a bulk material after low-temperature sintering, composed of stabilized ACC and biodegradable, environmentally friendly matrices.