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BACKGROUND:Previous research by the research team found that domestically produced porous tantalum is beneficial for early adhesion and proliferation of MG63 cells,and can be used as a scaffold material for bone tissue engineering. OBJECTIVE:To investigate the effect of domestic porous tantalum modified by osteogenic induction factor slow-release system on the adhesion,proliferation,and differentiation of MG63 cells. METHODS:Osteogenic induction factor slow-release system was constructed by adding 15%volume fraction of osteogenic factor solution to poly(lactic-co-glycolic-acid)gel.The passage 3 MG63 cells were inoculated on a porous tantalum surface(control group),porous tantalum surface coated with poly(lactic-co-glycolic-acid)copolymer gel(gel group),and porous tantalum surface coated with osteoblastic induction factor slow-release system(slow-release system group),and co-cultured for 5 days.The surface cytoskeleton of the material was observed by phalloidine staining.Cell proliferation was detected by flow cytometry.Western blot assay and RT-qPCR were used to detect the protein and mRNA expressions of type Ⅰ collagen,osteopontin,and RUNX-2 on the surface cells of the material. RESULTS AND CONCLUSION:(1)Phalloidine staining showed that MG63 cells adhered to and grew on the surface and inside of the three groups of porous tantalum,and the matrix secreted by the cells covered the surface of the material.(2)Flow cytometry showed that the cell proliferation in the slow-release system group was faster than that in the control group and the gel group(P<0.05).(3)Western blot assay and RT-qPCR showed that the protein and mRNA expressions of type Ⅰ collagen,osteopontin,and RUNX-2 in the slow-release system group were higher than those in the control group and gel group(P<0.05).(4)The results showed that the domestic porous tantalum modified by the osteogenic induction factor slow-release system was beneficial to the adhesion,proliferation,and differentiation of MG63 osteoblasts.
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We constructed and optimized the plasmid DNA (pDNA) Opt-S encoding the gene of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein, using poly (lactic-co-glycolic acid) copolymer (PLGA) as a delivery carrier for pDNA. PLGA-pDNA NPs were loaded by nanoprecipitation and its properties in vitro were preliminary evaluated. The results showed that the prepared PLGA-pDNA NPs were regular morphology, clear edges, with an average particle size of (184.2 ± 2.4) nm, polydisperse index (PDI) of 0.093 ± 0.013, zeta potential of (-68.10 ± 0.36) mV, and encapsulation rate of (98.92 ± 0.22)%. The PLGA-pDNA NPs were stable at -20 ℃ for 7 months and could protect pDNA against nuclease degradation. And they also exhibited sustained release of pDNA in vitro. The PLGA-pDNA NPs have low cytotoxicity and high safety. In addition, in vitro transfection experiments showed that the SARS-CoV-2 S gene could enter cells and be expressed. These results indicate that PLGA-pDNA NPs non-viral gene vector have simple preparation process and good performance, which are expected to provide a new idea for the research and development of SARS-CoV-2 vaccine.
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Objective: To prepare a bacterial outer membrane vesicle (OMV) coated poly (lactic-co-glycolic acid) copolymer (PLGA) nanoparticle loaded with ovalbumin (OVA) and evaluate its intranasal immune effect in mice. Methods: OMV was prepared by ultrafiltration concentration method. OVA loaded PLGA nanoparticle (NP) was prepared by emulsion-solvent evaporation method. OMV coated PLGA nanoparticle (OMV-PLGA NP) loaded with OVA was prepared by extrusion method and characterized. BALB/c mice were intranasally immunized and specific sIgA levels in nasal wash, jejunum and fecal pellet were determined by ELISA. Results: Size of OVA loaded OMV-PLGA NP was (234.4±22.9) nm. The shell-core structure of OVA loaded OMV-PLGA NP was proved by transmission electron microscope. After 14 d of administration, sIgA antibody levels in nasal wash, jejunum and fecal pellet of OVA loaded OMV-PLGA NP treated group were the highest in all treated groups. Compared with the group treated with OMV and OVA, OVA-specific sIgA antibody level in nasal wash, jejunum and fecal pellet of OVA loaded OMV-PLGA NP treated group was increased 1.6, 2.1 and 1.7 times, respectively. Compared with the group treated with OMV and OVA, OMV-specific sIgA antibody level in nasal wash, jejunum and fecal pellet of OVA loaded OMV-PLGA NP treated group was all increased 1.5 times. Conclusion: This novel nanoparticle drug delivery system can simultaneously delivery OVA and OMV to antigen presenting cells, resulting in stronger mucosal immune response in mice.
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Objective·To prepare a bacterial outer membrane vesicle (OMV) coated poly (lactic-co-glycolic acid) copolymer (PLGA) nanoparticle loaded with ovalbumin (OVA) and evaluate its intranasal immune effect in mice.Methods· OMV was prepared by ultrafiltration concentration method.OVA loaded PLGA nanoparticle (NP) was prepared by emulsion-solvent evaporation method.OMV coated PLGA nanoparticle (OMV-PLGA NP) loaded with OVA was prepared by extrusion method and characterized.BALB/c mice were intranasally immunized and specific sIgA levels in nasal wash,jejunum and fecal pellet were determined by ELISA.Results· Size of OVA loaded OMV-PLGA NP was (234.4±22.9) nm.The shell-core structure of OVA loaded OMV-PLGA NP was proved by transmission electron microscope.After 14 d of administration,sIgA antibody levels in nasal wash,jejunum and fecal pellet of OVA loaded OMV-PLGA NP treated group were the highest in all treated groups.Compared with the group treated with OMV and OVA,OVA-specific sIgA antibody level in nasal wash,jejunum and fecal pellet of OVA loaded OMV-PLGA NP treated group was increased 1.6,2.1 and 1.7 times,respectively.Compared with the group treated with OMV and OVA,OMV-specific sIgA antibody level in nasal wash,jejunum and fecal pellet of OVA loaded OMV-PLGA NP treated group was all increased 1.5 times.Conclusion· This novel nanoparticle drug delivery system can simultaneously delivery OVA and OMV to antigen presenting cells,resulting in stronger mucosal immune response in mice.