Research On Melt Electrospinning Direct Writing Composite Bone-cartilage Multilevel Gradient Structure Scaffold And Its Properties

There are nearly ten million new cases of cartilage damage in China every year,and many of them suffer huge pains because they have not received effective treatment.Although existing clinical treatment technologies such as microfracture technology,autologous or allograft technology,and periosteal transplantation technology have achieved certain medical results in cartilage repair,there are still limited repair scopes,poor clinical prognosis,and weakened tissue function after repair,etc.A problem that cannot be ignored.As a potential biotechnology in the 21st century,tissue engineering technology not only makes up for the shortcomings of current technology to a certain extent,but also shows a broad prospect in cartilage repair.In this project,medical grade polycaprolactone(m-PCL),a high-molecular material with good biocompatibility,polyethylene glycol(PEG),a high-molecular material with good hydrophilicity,and a natural material shell that helps cartilage repair are selected.Polysaccharides(CS),inorganic particles that are beneficial to the growth and calcification of mast chondrocytes,micron-sized hydroxyapatite(μmHA)and inorganic particles with good bone conductivity,nano-sized hydroxyapatite(nmHA)are used as raw materials.Self-developed melt electrospinning direct writing controllable molding device,using Melt Electrospinning Direct Writing technology to complete the process technology and structure of composite bone-cartilage multi-level gradient structure Preliminary research on design and performance,material properties and overall support performance and application.The main research contents and conclusions are as follows:(1)A method for preparing a disordered structure with higher controllability is proposed,and a high-performance m-PCL bone-cartilage composite structure scaffold is prepared by MEW technology:the average diameter of the scaffold is in the range of 20.4μm～36.2 μ m,The porosity is up to 90.4%,and the combination of ordered and disordered structure not only improves the efficiency of scaffold preparation but also ensures a good cell growth environment.By controlling the number of layers of disordered structure and the pore size of ordered structure,it can be changed The growth environment of the cells,and the tensile strength of the 10-layer fiber is in the range of 3.44MPa～5.75MPa,and the compressive strength reaches 0.032MPa.In summary,the scaffold structure has broad application prospects in the field of tissue engineering repair and biomedicine.(2)The crystalline properties,direct writing properties,hydrophilic properties,tensile properties of m-PCL/PEG,m-PCL/CS,m-PCL/μ mHA and m-PCL/nmHA of 10%,20%and 30%composite materials were studied The performance and compression performance determine the best mixture ratio of the material performance,and prepare the high-performance MEW fiber:composite materials m-PCL/PEG,m-PCL/CS,m-PCL/μ mHA and The blending ratio of the best performance of m-PCL/nmHA is 20%;the water contact angle of composite m-PCL/PEG(20wt%)sample is 63“;composite m-PCL/CS(20wt%)sample Compared with pure m-PCL,the tensile performance is increased by 81.74%,and the compression resistance is increased by 146.16%;the composite m-PCL/μ mHA(20wt%)sample tensile performance is increased by 35.65%compared to pure m-PCL,The compression performance was improved by 46.15%;the tensile properties of the composite m-PCL/nmHA(20wt%)sample were improved by 35.65%and the compression performance by 130.77%compared to pure m-PCL.(3)Proposes a scaffold design scheme based on the bone-cartilage microstructure,and a high-performance composite bone-cartilage multi-level gradient structure scaffold is prepared by MEW:The average diameter of the composite m-PCL/CS(20wt%),m-PCL/μmHA(20wt%),and m-PCL/nmHA(20wt%)fibers was 213.4 μm.,The average diameter of composite m-PCL/PEG(20wt%)fibers is 14.7μm,the porosity of the scaffold is 83.2%,the composite materials m-PCL/CS(20wt%),m-PCL/μmHA(20wt%),and m-PCL/nmHA(20wt%)fibers have average tensile strengths of 15.38 MPa,20.96 MPa,and 11.07 Mpa,respectively.The compressive strength of composite materials and pure m-PCL bone-cartilage multi-level gradient structure scaffolds are 0.134 MPa and 0.128 MPa,the former improved 4.69%compared with the latter.It can be seen that the optimization of the material has achieved the desired effect.Although the compressive strength of the structural scaffold may be weaker than that of the normal Y-shaped scaffold,its integrated bionic structure has a broad field of prospects of bone-cartilage tissue engineering repair.With the increase of time,the weight loss rate of the composite bone-cartilage multi-level gradient structure scaffold is obviously greater than that of the pure m-PCL bone-cartilage multi-level gradient structure scaffold,which is 11.83%higher,which shows that the degradation rate is obtained The improvement improves the defect that the pure m-PCL scaffold has a slow degradation rate,can better fit the growth state of the cells,and provides a suitable growth space for it,thereby being more suitable as a carrier for engineering culture.