Bionic Design Of Artificial Cartilage Scaffold Based On Mechanical Properties Of Natural Cartilage And Its Properties

Articular cartilage is an important part of human joints.It has low elastic modulus and high deformability.It can effectively transfer load,buffer and absorb shock.Because articular cartilage needs to bear repeated compressive loads,these loads will cause creep deformation of cartilage,and the continuous accumulation of creep deformation will eventually lead to the damage of articular cartilage.Based on the research on the mechanical properties of natural cartilage under uniaxial and biaxial tensile load,this paper bionically designs a new artificial cartilage scaffold that fits the mechanical properties of articular cartilage,which is of great significance to solve the mechanical properties of existing artificial cartilage scaffold materials and improve their service life.This paper takes the Achyranthes bidentata articular cartilage as the research object,carries out the creep recovery experiments under uniaxial and biaxial tensile loads,analyzes the creep recovery behavior of articular cartilage,and explores the relationship between the quasi-static mechanical properties of articular cartilage under uniaxial and biaxial loads.The results showed that under uniaxial tensile load,the cartilage showed rate correlation.Under the same tensile strain,the tensile stress of cartilage increased with the increase of strain rate.In addition,the creep strain of articular cartilage increases with the increase of stress level under uniaxial tensile load.The change trend of creep strain of articular cartilage under biaxial tensile load is similar to that under uniaxial tensile load.With the increase of stress level,the creep strain increases,but the creep strain under biaxial load is less than that under uniaxial load,indicating that the biaxial stress state has a restrictive effect on the accumulation of creep of articular cartilage.Finally,the creep recovery behavior of articular cartilage is predicted by establishing a nonlinear viscoelastic creep recovery model.The results show that the predicted values are in good agreement with the experimental values.Based on the study of mechanical properties of natural articular cartilage,a new type of collagen Ⅱ silk fibroin hyaluronic acid artificial cartilage scaffold was prepared by low temperature biological 3D printing technology.Firstly,the physical properties such as porosity and hydrophilicity of the scaffold were explored.Secondly,carry out quasi-static mechanical experiments(rate correlation,stress relaxation and creep experiments)and dynamic compression experiments(ratchet experiments)on the support.The results show that the young’s modulus and stress-strain curve of the scaffold show rate correlation,which is similar to the mechanical properties of natural articular cartilage and belongs to viscoelastic materials.With the increase of the number of cycles,the ratchet strain of the support continues to accumulate,indicating that the damage degree of the support is also accumulating,indicating that the damage degree of the support is also accumulating.Finally,the biocompatibility of the composite scaffold was detected by CCK-8,live/dead cell staining and scanning electron microscope.The results showed that the scaffold had good biocompatibility and weak toxicity,which met the living conditions of cells on the scaffold material.Considering the poor interface integration during cartilage repair,we prepared the osteochondral integrated scaffold by freeze-drying technology on the basis of the developed artificial cartilage scaffold,and tested the mechanical properties and interface integration of the scaffold.The results show that the mechanical properties of the integrated scaffold are good,and the scaffold can be well integrated with subchondral bone,which solves the problem of interface separation between scaffold and cancellous bone.