Study On Trace Element Doped Hydroxyapatite For Antibacterial And Antitumor Activity

Hydroxyapatite[Ca10?PO4?6?OH?2,HA]has excellent biocompatibility and is the main mineral of biological hard tissues.Synthetic hydroxyapatite is a widely used clinical hard tissue replacement material.Especially in bone and tooth mineralized tissue.However,the synthetic hydroxyapatite encountered many problems in the process of use:bacterial infection,loosening of the implant,etc.The second operation brought secondary pain to the patient.The research found that the structure and composition of synthetic hydroxyapatite and natural hydroxyapatite are significantly different.Natural hydroxyapatite is non-stoichiometric and contains a large number of other ions CO₃^2-,Mg²⁺,K⁺,Na⁺,Mn²⁺,HPO₄^2-and SiO₄^4-.In response to these problems,we hope to introduce biologically active ions and explore the effects of trace elements on the crystal structure,biological activity,bacteriostasis and anti-tumor activity of natural hydroxyapatite.The main results obtained so far are as follows:Preparation of Trace Gallium Doped Hydroxyapatite and Study of Its Biological Effects.A gallium-doped hydroxyapatite was successfully prepared by hydrothermal synthesis.The peak position shift of XRD confirmed that Ga ions entered the hydroxyapatite lattice to replace the positions of calcium ions,and did not affect the inherent phase composition and main chemical groups of hydroxyapatite.With the increase of the doping concentration,the lattice parameters a and c of the Ga-doped hydroxyapatite continue to decrease,which may be the reason why the radius of the calcium ion is larger than the radius of the gallium ion.Cytotoxicity studies showed no significant cytotoxicity of gallium-doped hydroxyapatite.Ga-HA containing 0.01%,0.1%,and 1%reduced the cell viability of 143b in a dose-dependent manner.After 143b cells were co-cultured with 0.1Ga-HA ceramic sheets for 72 hours,the cell viability was reduced by more than 55%.RT-PCR showed that gallium-doped hydroxyapatite can activate the caspase-8 signaling apoptotic pathway.MTT and alkaline phosphatase?ALP?activity measurements also confirmed that trace-doped Ga-HA promoted osteoblast proliferation and differentiation.Antibacterial experimental research found that 0.1Ga has good antibacterial properties.Antibacterial experiment research found that 0.1Ga has good antibacterial properties.This is because the gallium ions and iron ions know each other chemically.Gallium ions replace the position of iron ions in the bacterial respiratory chain,block bacterial breathing,and eventually kill bacteria.This material offers opportunities for bone tumor treatment and postoperative bone repair regeneration,as well as prognosis infection prevention.Preparation of trace copper-doped hydroxyapatite and research on antibacterial and biocompatibility.Cu-doped hydroxyapatite nanocrystalline aggregates with different concentration gradients were successfully prepared by hydrothermal synthesis.The peak position shift of XRD confirmed that copper ions entered the hydroxyapatite lattice to replace the positions of calcium ions,and did not affect the inherent phase composition and main chemical groups of hydroxyapatite.With the increase of the doping concentration,the lattice parameters a and c of the copper-doped hydroxyapatite continue to decrease,which may be the reason why the radius of the calcium ion is larger than the radius of the same ion.With the increase of the same ion concentration,the grain size of copper-doped hydroxyapatite becomes smaller and the ordered structure also changes.A small amount of copper-doped hydroxyapatite had no obvious cytotoxicity after co-culture with L929 cells.With the increase of copper concentration?0.01%¹0%[Cu/?Ca+Cu?]?,the antibacterial rate of copper-doped hydroxyapatite increased?16.4%⁷4.5%?.This provides ideal prospects for the research and development of bone defect treatment materials.