镁锶共掺杂羟基磷灰石矿化胶原的构建与体外促成骨活性研究OA

Objective To investigate the efficacy of magnesium-strontium co-doped hydroxyapatite mineralized col-lagen(MSHA/Col)in improving the bone repair microenvironment and enhancing bone regeneration capacity,providing a strategy to address the insufficient biomimetic composition and limited bioactivity of traditional hydroxyapatite miner-alized collagen(HA/Col)scaffolds.Methods A high-molecular-weight polyacrylic acid-stabilized amorphous calcium magnesium strontium phosphate precursor(HPAA/ACMSP)was prepared.Its morphology and elemental distribution were characterized by high-resolution transmission electron microscopy(TEM)and energy-dispersive spectroscopy.Re-combinant collagen sponge blocks were immersed in the HPAA/ACMSP mineralization solution.Magnesium-strontium co-doped hydroxyapatite was induced to deposit within collagen fibers(experimental group:MSHA/Col;control group:HA/Col).The morphological characteristics of MSHA/Col were observed using scanning electron microscopy(SEM).Its crystal structure and chemical composition were analyzed by X-ray diffraction and Fourier transform infrared spectros-copy,respectively.The mineral phase content was evaluated by thermogravimetric analysis.The scaffold's porosity,ion release,and in vitro degradation performance were also determined.For cytological experiments,CCK-8 assay,live/dead cell staining,alkaline phosphatase staining,alizarin red S staining,RT-qPCR,and western blotting were used to evaluate the effects of the MSHA/Col scaffold on the proliferation,viability,early osteogenic differentiation activity,late mineralization capacity,and gene and protein expression levels of key osteogenic markers[runt-related transcription fac-tor 2(Runx2),collagen type Ⅰ(Col-Ⅰ),osteopontin(Opn),and osteocalcin(Ocn)]in mouse embryonic osteoblast precur-sor cells(MC3T3-E1).Results HPAA/ACMSP appeared as amorphous spherical nanoparticles under TEM,with en-ergy spectrum analysis showing uniform distribution of carbon,oxygen,calcium,phosphorus,magnesium,and strontium elements.SEM results of MSHA/Col indicated successful complete intrafibrillar mineralization.Elemental analysis showed the mass fractions of magnesium and strontium were 0.72%(matching the magnesium content in natural bone)and 2.89%,respectively.X-ray diffraction revealed characteristic peaks of hydroxyapatite crystals(25.86°,31°-34°).Infrared spectroscopy results showed characteristic absorption peaks for both collagen and hydroxyapatite.Thermogravi-metric analysis indicated a mineral phase content of 78.29%in the material.The scaffold porosity was 91.6%±1.1%,close to the level of natural bone tissue.Ion release curves demonstrated sustained release behavior for both magnesium and strontium ions.The in vitro degradation rate matched the ingrowth rate of new bone tissue.Cytological experiments showed that MSHA/Col significantly promoted MC3T3-E1 cell proliferation(130%increase in activity at 72 h,P<0.001).MSHA/Col exhibited excellent efficacy in promoting osteogenic differentiation,significantly upregulating the ex-pression of osteogenesis-related genes and proteins(Runx2,Col-Ⅰ,Opn,Ocn)(P<0.01).Conclusion The MSHA/Col scaffold achieves dual biomimicry of natural bone in both composition and structure,and effectively promotes osteo-genic differentiation at the genetic and protein levels,breaking through the functional limitations of pure hydroxyapatite mineralized collagen.This provides a new strategy for the development of functional bone repair materials.