Preparation And In Vitro Bioactivity Of Copper-doped Bioactive Glass Composite Scaffold By Polydopamine Functionalization

Bone tissue engineering scaffolds are used to repair bone defects mainly caused by tumors,trauma,osteoporosis and infections.Due to the limited number of donor sites in autologous transplantation,bone tissue engineering aims to produce functional bone scaffolds as an alternative to clinical treatment.Biomaterial produced by electrospinning techniques have been made for the tissue engineering field,the material having a nano-scale structure and high porosity,to mimic natural extracellular matrix(ECM).In this study,bioactive glass was used as the inorganic part,and polylactic acid was used as the organic part,and inorganic/organic composite materials were prepared by electrospinning technology.At the same time,the excellent biological characteristics of polydopamine are used to modify the surface of the bioglass to prepare a biological scaffold material with good biological activity.The essay has been organised in the following way.(1)Preparation and in vitro activity of copper-doped bioglassThe sol-gel method was used to prepare copper-doped mesoporous bioglass.Test methods such as TEM,FTIR and nitrogen adsorption were used to characterize the surface morphology,chemical structure and physical and chemical properties of the glass material.And the effect of different doses of copper doping gradient on the biological activity of mesoporous bioglass powder was explored.The experimental results show that by choosing different ratios of glass precursors,controllable copper-doped mesoporous bioglass nanospheres can be obtained.With the increase of Cu content,the pore volume and average pore diameter of Cu-MBGs samples increase.All sample particles show larger specific surface area,pore volume and pore size,and the incorporation of a suitable amount of copper source can improve the in vitro biological activity of the bioglass.(2)Preparation and in vitro activity of polydopamine modified copper-doped bioglassAiming at the problems of poor compatibility and weak adhesion of inorganic nanoparticles(Cu-MBG)in polymer(PLA)matrix,the Cu-MBG@PDA nanocomposite was prepared by oxidative self-polymerization method.The effects of dopamine concentration and solution pH on the morphology,thermal stability,hydrophilicity and in vitro biological activity of nanocomposites were studied,and the prepared samples were tested by SEM,EDS,TEM,XRD,TGA,etc.Experimental results show that polydopamine has been successfully attached to the surface of bioglass by oxidative self-polymerization.The change of pH value affects the physical and chemical properties of nanocomposite materials.When the pH value of the solution is 8.5,the thermal stability and hydrophilic properties of the material are better.As the concentration of dopamine increases,the particle size of the material is more uniform,and the hydrophilicity and thermal stability are improved.In vitro biological activity tests show that polydopamine-modified bioglass has a better ability to induce the formation of hydroxyapatite.To stand out,the material has good biological activity.(3)Construction of PLA-based biomimetic composite bone scaffold and its in vitro activityThe PLA/Cu-MBG@PDA bionic composite fiber scaffold was prepared by electrospinning technology.By changing the relative content of functional mesoporous bioglass in the fiber scaffold,the effect on the composite fiber scaffold material was studied.The experimental results show that the addition of inorganic substances can increase the conductivity of the spinning solution.A certain concentration of Cu-MBG@PDA nanoparticles can be uniformly distributed in PLA.When the concentration is higher than a certain value,the particles in the spinning solution are prone to agglomeration,thereby reducing the mechanical properties of the electrospun membrane.The thermal stability and hydrophilicity of PLA/Cu-MBG@PDA composite membrane material are greatly improved compared with PLA/Cu-MBG composite membrane and pure PLA membrane.As the relative content of mesoporous bioglass increases,the hydrophilicity of the biomimetic composite fiber membrane has improved,and the ability to generate hydroxyapatite in simulated body fluids has gradually improved.