Bone-like microtextures of HA coatings prepared by nanosecond laser and their properties

Abstract

Although the hydroxyapatite (HA) coating implant prepared by laser cladding exhibits good biological activity due to its chemical composition similar to biological bone, the original surface roughness of the laser-clad coating is high, which is unfavorable for long-term cell adhesion and proliferation. In order to improve the biological activity of HA coating implants and increase the adhesion and proliferation rate of osteoblasts on their surface, microtextures with different length-diameter ratios and depth gradients were prepared on the HA coating surface by nanosecond laser with reference to the microscopic morphology characteristics of the biological bone surface. By investigating the effects of microtexture aspect ratio and depth gradient on osteoblast adhesion characteristics, it was found that bone-like microtextures better controlled and simulated cell-material surface interactions. The geometric morphology of microtextured bone with a wide front end and narrow rear end and a depth gradient from front to back was an important signal for osteoblast proliferation. When the aspect ratio of bone microtexture was 2.5:1 and the maximum depth gradient was 15.7 μm, osteoblasts within the microtexture showed optimal growth, proliferation, and adhesion. Additionally, due to induction by microtexture contour shape and depth gradient morphology, cell morphology showed varying adhesion morphology from the front to the back of the microtexture. The results demonstrated that HA coatings with bone-like microtextures had superior osteoblast proliferation and adhesion properties compared to the original cladded coating surface, beneficial for enhancing the application of HA-coated bone implants in large segment bone repair.