Calcium carbonate thin films as biomaterial coatings using DNA as crystallization inhibitor

Abstract

Synthetic, bio-inspired organic–inorganic composites are emerging as new materials for bone regeneration, offering more possibilities to tune biocompatibility, biodegradability and mechanical properties. Also thin films of calcium carbonate have been shown to have potential as models for bone replacement biomaterials. These calcium carbonate thin films can be formed using anionic macromolecules as a crystallization inhibitor. Here we demonstrate that also DNA is a powerful inhibitor of calium carbonate crystallization which can be used to prepare amorphous films that slowly crystallize to form calcite with a preferred (11.0) orientation. We show that the DNA-based hybrid material can be grown as inorganic coatings on polymer substrates of high molecular weight polyethylene and poly(caprolactone). The layer-by-layer deposition of a DNA-surfactant double layer was used as an interfacial layer minimizing the observed polymer specific surface roughness. This coating increased the crystallization rate but did not affect the preferred (11.0) orientation. Using this technique we were able to apply this coating as a smooth calcium carbonate coating on the surface of a porous 3D polycaprolactone scaffold.