Construction Of Van/DFO/Dex Liposome-hydrogel Complex And Osteogenic Studies

Objective: Liposomes were used as sustained-release carriers of vasogenic small molecule deferoxamine(DFO)and osteogenic small molecule dexamethasone(Dex),and sodium alginate hydrogel was used as sustained-release carriers of vancomycin(Van)To explore the ability of the injectable liposome-hydrogel composite to promote the regeneration and repair of bone tissue.Methods: DFO/Dex liposomes were fabricated by a thin film dispersion method,and mixed with Van sodium alginate solution to form Van/DFO/Dex liposome-hydrogel composite under the action of calcium ions.Particle size,polydispersity index(PDI)and Zeta potential of the liposomes were measured by Zeta particle size analyzer.The microstructure and mechanical properties of Van/DFO/Dex liposome-hydrogel composites were evaluated by scanning electron microscopy(SEM)and universal material testing machine.The encapsulation efficiency of liposomes and the sustained release curves of Van DFO and Dex in the composite were measured by UV-vis spectrophotometer.CCK-8 and Cell live/dead fluorescence staining were used to evaluate the cytocompatibility of the composites.In vitro antibacterial activity of the composite was quantitatively detected by bacteriostatic zone and WST-8.Real-time fluorescence quantitative PCR(RT-PCR)was used to detect the angiogenesis promoting effect of composite materials.ALP activity quantification,staining and RT-PCR were used to evaluate the effect of Van/DFO/Dex liposome-hydrogel complex on promoting bone differentiation in vitro.Bacterial colony count and mouse hematoxylin-eosin(HE)staining were used to detect the in vivo antibacterial activity of the composite material.The pro-angiogenic and bone-producing abilities of Van/DFO/Dex liposome-hydrogel composites were evaluated in vivo by HE staining and immunohistochemical(IHC)staining of rabbit maxillary sinus bone tissue.Results: An injection Van/DFO/Dex liposome-hydrogel composite was successfully constructed.The particle size of the liposome was 121.76±6.35 nm,PDI was 0.2～0.3,Zeta potential of about-5.7 m V,and DFO encapsulation rate was 73.5%,Dex encapsulation rate was 20.2%.SEM and compression experiments show that the Van/DFO/Dex liposome-hydrogel composite has porous structure and good mechanical properties.The sustained release curve showed that Van DFO and Dex were released continuously in stages,with the release time of Van reaching 5 days,DFO exceeding 7days and Dex exceeding 14 days.CCK-8 and Cell live/dead fluorescence staining showed that Van/DFO/Dex liposome-hydrogel composite had good cytocompatibility.The inhibition zone and WST-8 quantitative detection showed that the composite material had good antibacterial activity in vitro.The expression of angiogenesis related genes indicated that Van/DFO/Dex liposome-hydrogel complex had the ability to promote angiogenesis in vitro compared with blank liposome-hydrogel.ALP activity assay,ALP staining,and RT-PCR showed that Van/DFO/Dex liposome-hydrogel complex could improve osteogenic differentiation activity in vitro compared with blank liposome-hydrogel.Colony count and mouse HE staining showed that the composite material could release Van to achieve in vivo bacteriostatic effect.HE staining and IHC staining of rabbit maxillary sinus bone tissue that Van/DFO/Dex liposome-hydrogel composite could promote angiogenesis and bone regeneration in vivo.Conclusion: Van/DFO/Dex liposome/hydrogel composite is a multifunctional bone regeneration material with osteogenesis,angiogenesis promotion and anti-infection.Its good injectable property is conducive to the repair of irregular jaw defects,which highlights its clinical potential as an ideal bone graft material.