OBJECTIVES: This study aimed to compare the osteogenic performance differences of titanium surface coatings modified by dopamine or silanized graphene oxide, and to provide a more suitable modification scheme for titanium surface graphene oxide coatings. METHODS: Titanium was subjected to alkali-heat treatment and then modified with dopamine and silanization, respectively, followed by coating with graphene oxide. Control and experimental groups were designed as follows: pure titanium (Ti) group; titanium after alkali-heat treatment (Ti-NaOH) group; titanium after alkali-heat treatment and silanization modification (Ti-APTES) group; titanium after alkali-heat treatment and dopamine modification (Ti-DOPA) group; titanium with silanization-modified surface decorated with graphene oxide (Ti-APTES/GO) group; titanium with dopamine-modified surface decorated with graphene oxide (Ti-DOPA/GO) group. The physical and chemical properties of the material surfaces were analyzed using scanning electron microscopy (SEM), contact angle goniometer, X-ray photoelectron spectroscopy (XPS), and Raman spectrometer. The proliferation and adhesion morphology of mouse embryonic osteoblast precursor cells MC3T3-E1 on the material surfaces were observed by cell viability detection and immunofluorescence staining followed by laser confocal microscopy. The effects on the osteogenic differentiation of MC3T3-E1 cells were studied by alkaline phosphatase (ALP) staining, alizarin red staining and quantification, and real-time quantitative polymerase chain reaction. RESULTS: After modification with graphene oxide coating, a thin-film-like structure was observed on the surface under SEM. The hydrophilicity of all experimental groups was improved, among which the Ti-DOPA/GO group had the best hydrophilicity. XPS and Raman spectroscopy analysis showed that the modified materials exhibited typical D and G peaks, and XPS revealed the presence of a large number of oxygen-containing functional groups on the surface. CCK8 assay showed that all groups of materials had no cytotoxicity, and the proliferation level of the Ti-APTES/GO group was higher than that of the Ti-DOPA/GO group. Under the laser confocal microscope, the cells in the Ti-DOPA/GO and Ti-APTES/GO groups spread more fully. The Ti-DOPA/GO and Ti-APTES/GO groups had the deepest ALP staining, and the Ti-APTES/GO group had the most alizarin red-stained mineralized nodules and the highest quantitative result of alizarin red staining. In the Ti-DOPA/GO and Ti-APTES/GO groups, the expression of the early osteogenic-related gene RUNX2 reached a relatively high level, while in the expression of the late osteogenic-related genes OPN and OCN, the Ti-APTES/GO group performed better than the Ti-DOPA/GO group. CONCLUSIONS Ti-APTES/GO significantly outperformed Ti-DOPA/GO in promoting the adhesion, proliferation, and in vitro osteogenic differentiation of MC3T3-E1 cells.
Titanium/chemistry* ; Graphite/chemistry* ; Dopamine/chemistry* ; Animals ; Mice ; Osteogenesis ; Osteoblasts/cytology* ; Surface Properties ; Cell Proliferation ; Silanes/chemistry* ; Cell Adhesion ; Coated Materials, Biocompatible/chemistry* ; Cell Differentiation ; Alkaline Phosphatase/metabolism* ; Microscopy, Electron, Scanning

Objective:To compare the effects of gelatin(Gel)and polydopamine(PDA)modification of polycaprolactone(PCL)on the biological behaviour and osteogenic function of osteoblasts.Methods:PCL electrospun membranes were prepared by electrostatic spinning technique,PCL surface was modified by Gel and PDA respectively as G/PCL and D/PCL with chemical self-assembly tech-nique,and the physicochemical properties of the electrospun membranes were characterized by scanning electron microscopy(SEM),Fourier infrared spectroscopy(FTIR),X-ray photoelectron spectroscope(XPS)and contact angle measurement.The MC3T3-E1 cell adhesion morphology was observed by SEM,immunofluorescence staining followed by confocal microscopy(CLSM),cell proliferation at 1,3 and 5 d was tested by CCK-8 assay,alkaline phosphatase(ALP)staining,alizarin red staining and qRT-PCR were used to detect osteogenic gene expression of the cells.Results:A coating of PDA particles was observed on the surface of D/PCL film.FTIR and XPS showed that the characteristic peaks of Gel and PDA,and there was no obvious droplets on the surface of G/PCL and D/PCL ob-served by contact angle test.Cell density of G/PCL group was higher,the adhesion morphology was good and pseudopods were obvi-ous.CCK-8 assay showed the highest proliferation of the cells on G/PCL(P＜0.05).ALP and alizarin red staining of the cells were stronger in D/PCL group than in the other 2 groups.qRT-PCR results showed that the mRNA expression of ALP,COL-1,RUNX2 and OCN was higher in the D/PCL group than in the other 2 groups.Conclusion:Both Gel and PDA modification can enhance the cell adhesion,proliferation and osteogenic properties of PCL scaffolds,Gel modification may induce a more pronounced proliferative effect and PDA modification more pronounced osteogenic effect.

OBJECTIVE:To study the absorption features of Silymarin enteric coated-polyllactic-co-glycolic acid (PLGA) nanoparticles in rat in situ intestine perfusion model and colonic adenoma Caco-2 cell model. METHODS:HPLC method was used to determine the content of silymarin. The absorption rate constant(Ka)and apparent absorption coefficient(Kapp)of Silymarin sus-pension,Silymarin PLGA nanoparticles and Silymarin enteric coated-PLGA nanoparticles were investigated in duodenum,jejunum, ileum and colon of rat in situ intestine perfusion model;the apparent permeability coefficient (Papp) of those drugs containing low-concentration,medium-concentration and high-concentration(20,40,60 μg/mL)of silymarin in Caco-2 cell model were also investigated. RESULTS:Compared with Silymarin suspension,Ka and Kapp of Silymarin PLGA nanoparticles and Silymarin enteric coated-PLGA nanoparticles were all increased in duodenum,jejunum,ileum and colon(P<0.05);compared with the correspond-ing concentration Silymarin suspension,two-way Papp of Silymarin PLGA nanoparticles and Silymarin enteric coated-PLGA nanopar-ticles containing low-concentration,medium-concentration and high-concentration of silymarin were all increased in Caco-2 cell model (P<0.05);there was no statistical significance between Silymarin PLGA nanoparticles and Silymarin enteric coated-PLGA nanoparticles (P>0.05). CONCLUSIONS:Silymarin enteric coated-PLGA nanoparticles can effectively increase the intestinal ab-sorption,cellular uptake and transmembrane transport rate of silymarin.