Fabrication Of Nano-hydroxyapatite/Collagen Scaffolds Loaded MAG-PLGA Microspheres And Their Physicochemical Properties

Objective:Insufficient blood supply in a large bone defect area can easily lead to oxidative stress reaction in cells,making the failure of bone defect repair treatment.Mangiferin exhibits strong antioxidant effects,so a Nanohydroxyapatite / collagen scaffold loaded with mangiferin(MAG)-poly(lactic co glycolic acid)(PLGA)sustained-release microspheres(MAG-PLGA/n HAC)was prepared in this study,and the physicochemical properties,drug release capacity of the material were examined,thus providing a theoretical basis for the combined use of MAG-PLGA/n HAC materials in the field of oral medicine and bone defect regeneration and repair.Methods:1.Preparation of MAG-PLGA drug loaded microspheres by single emulsification(O / W)emulsification solvent volatilization method;Two groups of drug loaded bone scaffolds were obtained by loading MAG-PLGA microspheres and MAG solution with Nanohydroxyapatite / collagen(n HAC),respectively.The average particle size of the prepared microspheres and their size distribution were measured by SEM images using nano measurer 1.2.5 software.2.Materials characterization including n HAC,MAG,MAG-PLGA microspheres and MAG-PLGA / n HAC were observed by scanning electron microscopy(SEM).3.Measuring the mass in dry and wet weight states of scaffold materials by dry wet weight method,the porosity was calculated and compared whether the scaffold porosity was affected after drug loading treatment.4.Gradient concentration of MAG solution was taken by ultraviolet spectrophotometer,after absorbance draw standard straight line regression equation and measure the drug loading rate and encapsulation efficiency of drug in microspheres.5.In vitro drug release experiments of PLGA drug loaded microspheres and scaffold materials were measured by PBS slow release,and a contrast curve was drawn.PH value determination of scaffold materials.6.Soaked scaffold materials in PBS,the mass and volume swelling ratio of scaffold materials were measured to observe water absorption and deformability.7.The mass degradation changes of the scaffold materials in the medium for a certain time were measured.8.Cell proliferation curves the absorbance of MAG-PLGA / n HAC group was higher than that of the control group after 1,3,and 5 days of culture,indicating that the surface of MAG-PLGA / n HAC scaffold had better proliferation activity.Results:1.Material characterization: as shown under SEM,PLGA drug loaded microspheres showed good sphere forming rate,smooth surface,round morphology,no irregular crystal like structure of MAG on the surface,completely dissolved,the average diameter of microspheres was 2.70 μ m,particle size showed normal distribution and uniform.Nhacs have high porosity with well defned pore walls.SEM images of MAG / n HAC bone scaffolds revealed a small number of loaded MAG crystals.MAG-PLGA / n HAC bone scaffolds it can be seen that a large number of PLGA drug loaded microspheres were adsorbed on the pore walls of the scaffolds,the connection was compact,the morphology was basically round and there was no MAG crystal like structure on the surface of the microspheres,indicating that MAG was completely dissolved,the macroscopic contrast of the three bone scaffolds,n HAC was creamy white macroscopically,cylindrical discs with multiple micro holes on the surface,and the drug loaded group bone scaffolds all exhibited yellowish color.Average particle size and distribution: the average particle size of the microspheres is 2.70 μ m,and the particle size is normally distributed,with a relatively uniform distribution.2.Porosity: the scaffold material porosity is all > 70%.The porosity of n HAC,MAG-PLGA / n HAC and MAG / n HAC groups was approximately 74.61% ± 2.15%,73.31% ± 2.27% and 74.06% ± 2.29%,respectively,and the porosity of the drug loaded scaffolds was not changed in either group.3.Drug loading efficiency and entrapment efficiency of MAG-PLGA microspheres: the optimal formulation obtained after orthogonal test the drug loading efficiency of PLGA microspheres prepared was 10.98% and entrapment efficiency was 75.75%,and the results were in a better level in orthogonal test and stable and reproducible.4.In vitro drug release: the average release was about 14.54% in the first 30 min from PLGA drug loaded microspheres.The bulk release reached around 65% in the first 2 days.The average release was about 32.66% in the first 30 min for MAG / n HAC scaffolds and6.12% for MAG-PLGA / n HAC scaffolds.The mean release was about 78% on the first day and about 88% on the third day,while there was almost no release in the subsequent period in the MAG / n HAC group,and about 40% on the first day and about 55% on the third day,and it could be released slowly for more than a week.Combining microspheres with scaffolds can retard drug release.The p H test results showed that the p H value of the degradation solution of PLGA drug loaded microspheres was significantly decreased,and the p H values of MAG-PLGA / n HAC and MAG / n HAC groups were slightly decreased in the pre phase and subsequently rebounded back.None of the materials in each group obviously caused an acidic environment.5.Swelling ratio detection: it was found that the water absorption of scaffold materials was better,and a small amount of swelling occurred in the volume after water absorption.6.Weight loss ratio detection: results it can be seen that scaffold materials will undergo a certain slow degradation with time in the medium.7.Cell proliferation curves the absorbance of MAG-PLGA / n HAC group was higher than that of the control group after 1,3,and 5 days of culture,indicating that the surface of MAG-PLGA / n HAC scaffold had better proliferation activity.Conclusions: 1.The optimal PLGA drug loaded microspheres were prepared by the following process: PLGA concentration of 30 mg / ml,PVA concentration of 1%,and medicinal material ratio of 435 μ G / ml and the phacoemulsification power was 50%.2.The MAG-PLGA / n HAC group was significantly superior to the MAG / n HAC group in both drug loading capacity and drug controlled release capacity.3.MAG-PLGA/nhac scaffold materials are nontoxic and can promote cell proliferation.