Molecular dynamics exploration of ion association mechanism of apatite controlled by a nanogrooved hydroxyapatite surface

Abstract

Surface topography modification is a promising tissue engineering technology that provides an adjustable geometric microenvironment for the implant-tissue interface. Nanogrooves can affect the amount and arrangement of apatite deposition, which plays a crucial role in the formation of bionic bone tissue in the preferred direction. The effects of grooved topography on the ion association must be understood for designing and optimizing bone implant materials. We performed molecular dynamics and metadynamics simulations to explore the effect of grooves with different slope angles on the ion association of Ca2+ and PO43- ions. The ion deposition degree could be controlled by regulating the slope angle of the nanogrooves. The groove model with a 60° slope angle has the greatest biological activity for ion deposition. Ions were selectively adsorbed at the sharp corners of the groove. This phenomenon was attributed to relative differences in binding thermostability in different regions of the groove, which could partially explain why a grooved topography can improve the production of a well-organized apatite structure. Our results provide a molecular mechanism to understand the effects of the grooved topography on the ion association, which can aid in optimizing the biological activity of materials through topography-modified tissue engineering technology.