Bioprocess-Inspired Room-Temperature Synthesis of Enamel-like Fluorapatite/Polymer Nanocomposites Controlled by Magnesium Ions

Abstract

Tooth enamel is composed of arrayed fluorapatite (FAP) or hydroxyapatite nanorods modified with Mg-rich amorphous layers. Although it is known that Mg2+ plays an important role in the formation of enamel, there is limited research on the regulatory role of Mg2+ in the synthesis of enamel-like materials. Therefore, we focus on the regulatory behavior of Mg2+ in the fabrication of biomimetic mineralized enamel-like structural materials. In the present study, we adopt a bioprocess-inspired room-temperature mineralization technique to synthesize a multilayered array of enamel-like columnar FAP/polymer nanocomposites controlled by Mg2+ (FPN-M). The results reveal that the presence of Mg2+ induced the compaction of the array and the formation of a unique Mg-rich amorphous-reinforced architecture. Therefore, the FPN-M array exhibits excellent mechanical properties. The hardness (2.42 ± 0.01 GPa) and Young’s modulus (81.5 ± 0.6 GPa) of the as-prepared FPN-M array are comparable to those of its biological counterparts; furthermore, the enamel-like FPN-M array is translucent. The hardness and Young’s modulus of the synthetic array of FAP/polymer nanocomposites without Mg2+ control (FPN) are 0.51 ± 0.04 and 43.5 ± 1.6 GPa, respectively. The present study demonstrates a reliable bioprocess-inspired room-temperature fabrication technique for the development of advanced high-performance composite materials.

Advanced materials for enamel remineralization

“…As the concentration of Mg 2+ on the enamel surface increases, the nano-hardness of the enamel rises dramatically ( Kis et al, 2021 ). Layer by layer mineralization process is used to create multilayer arrays of enamel-like FAP/polymer nanocomposites controlled by Mg 2+ (FPN-M) at room temperature ( Li Y. et al, 2021 ) ( Figure 3 ). In the presence of Mg 2+ , the single nanorods are refined in size and a highly compact array is formed, eventually, (FPN-M) n exhibits excellent mechanical strength and transparency.…”

“…(E) Interlayer structure and amorphous-reinforced architecture schematic diagram. Reprinted with permission from [ ( Li Y. et al, 2021 ) ]. Copyright © 2021 American Chemical Society.…”

Room-temperature growth of fluorapatite/CaCO3heterogeneous structured composites inspired by human tooth

“…† Since the FAP arrays are arranged more closely, the mechanical properties of these synthetic FAP/CaCO 3 heterogeneous structured composites are lower than that of FAP arrays. 31 Table S1 † presents other synthetic calcium phosphate and calcium carbonate materials.…”

Mechanically Reinforced Artificial Enamel by Mg2+-Induced Amorphous Intergranular Phases

“…1 Nature provides us with many interesting examples for the design of materials. 1−4 Some typical natural biomaterials, including tooth enamel 5,6 and shell nacre, 7−9 utilize limited inorganic and organic substances achieving excellent mechanical properties. 10,11 This is mainly attributed to their complex hierarchically ordered microstructure.…”