Spatial charge manipulated set-selective apatite deposition on micropatterned piezoceramic

Mineralization plays a crucial role in the formation and remodeling of bone and charge has a positive influence on the mineralization by manipulating apatite deposition. In this paper, micropatterned piezoelectric K0.5Na0.5NbO3 (MPK) was constructed via laser-irradiation induced micro-zonal phase transition to manipulate set-selective apatite deposition. Two types of piezoelectric micro-zones on polarized MPK showed different charge densities, namely, higher charge density zone (H-zone) and lower charge density zone (L-zone). The micro-zonal piezoelectric difference on negatively polarized MPK (N-MPK) was ascertained by scanning Kelvin probe force microscopy (SKPM). With the manipulation of spatial charge, apatite selectively deposited on H-zone rather than L-zone, forming stripped zonal distribution. The furry platelet morphology of apatite was observed by scanning electron microscopy (SEM). Energy-dispersive spectroscopy (EDS) mapping observation indicated selective distribution of Ca and P elements in apatite. Phase composition of deposited apatite also can be regulated effectively via X-ray diffraction (XRD), which confirmed the existence of hydroxyapatite phase. Meanwhile, the apatite was further identified as carbonated hydroxyapatite by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The feasible and convenient way of manipulating apatite deposition selectively with spatial charge realized by micro-zonal piezoelectric materials will inspire future development in biomimetic materials designation for biomedical applications.