Controlled Rare Earth Ions Release From Ca-P Coating Fabricated By Wide-band Laser Cladding And Its Inhibition Effects On The Activity Of Osteoclast

Artificial joint osteolysis（debris disease）is a major cause of prosthesis loosening.The inhibitory activity of osteoclasts will effectively prevent osteolysis by rare earth ions.In this paper,the surface of biomedical metal material（Ti-6Al-4V）was modified by laser cladding technology,Ca-P bioceramic coating with rare earth was prepared.Using the precipitation of rare earth ions from coating in physical environment to achieve the purpose of preventing osteolysis.The bonding interface,micro morphology,precipitation of rare earth ion,phase analysis,microhardness,bioactivity and inhibition effect of rare earth ions concentration on the activity of osteoclasts of Ca-P ceramic coating were characterized by metallographic microscope（OM）,scanning electron microscope（SEM）,plasma mass spectrometer（ICP-AES）,X-ray diffractometer（XRD）,microhardness tester,MTT assay,inverted fluorescence microscope,TRAP staining and other detection methods.The following conclusions are obtained:（1）The effects of different content of La₂O₃ and ratio of Ca:P on the properties and bioactivity of Ca-P ceramic coating was investigated.The results indicate: the phases of Ca-P ceramic coating is mainly composed of CaTiO₃、HA、β-TCP、TiO₂ etc.The higher the Ca:P ratio in ceramic coating is,the higher the average hardness is.When the content of La₂O₃ is 0.6 wt.%,Ca:P=1.40,Ca-P ceramic coating has excellent properties and bioactivity（2）The rule of degradation and precipitation of Ca-P ceramic coating in the simulated body fluid was investigated.The results indicate: the quality of Ca-P ceramic coating exhibits dynamic change in simulated body fluid,which is thedeposition of bone like apatite and the degradation of β-TCP.The average concentration of La³⁺ changes dynamically between 9.5¹2 PPB every day.The formula of La³⁺ precipitation concentration C and soaking time t was obtained:（?）（PPB/mm²）.（3）The inhibitory effect of controlled precipitation of rare earth ions of Ca-Pceramic coating on osteoclast activity was investigated.The results indicate: when the cells inducer factor concentration RANKL was 100 ng/m L and M-CSF was 50 ng/mL,the number of induced positive multinucleated osteoclasts was the largest.Setting 3 days,6 days and 9 days three time points,compared with the blank group,it can be seen from statistics that the number of induced osteoclasts increases significantly when La³⁺ concentration was 21 PPB,P<0.05.Other concentrations of La³⁺significantly inhibits the formation of induced osteoclasts.It can be concluded that when the content of La₂O₃ is 0.6 wt.%,Ca:P=1.40,Ca-P ceramic coating not only has excellent properties and bioactivity,but also has the effect of inhibiting the activity of osteoclast and inhibition time can be as long as 16.5 years or so,which can provide a new idea for prevention and treatment of debris disease in clinical practice.