مدل‌سازي مكانيكي داربست الكترواكتيو پلي كاپرولاكتون - نانوذرات گرافن به روش چاپ سه بعدي براي مهندسي بافت استخوان

With scientific advances in the field of tissue engineering, the use of nanocomposite scaffolds to improve the regeneration of damaged tissues, especially bone tissue, has become of great importance.One of these scaffolds that has attracted a lot of attention is electroactive polycaprolactone scaffolds with the addition of graphene nanoparticles. In this research, by reducing the distances between the stran‎ds of the structure, its elastic modulus increases.This means that more force is required to deform the structure. On the other han‎d, as the string spacing increases, the modulus of elasticity of the structure decreases an‎d less force is required to deform the structure[5]. The results of this study showed that increasing porosity has a significant effect on the mechanical properties of polycaprolactone (PCL) an‎d polycaprolactone reinforced with graphene oxide (PCL+G) scaffolds. By increasing the distance between the rods from 1 mm to 2.5 mm, larger pores were created in the structure, which led to a decrease in the load-bearing cross-section an‎d an increase in stress concentration in critical areas.This increase in stress, along with the increase in displacement an‎d strain, indicated structural weakness at higher porosities. In the pure PCL samples, the von Mises stress increased significantly, reaching a maximum value of 380.8 MPa at a porosity of 2.5 mm. The increase in stress at higher porosities indicates that the pure PCL structure is more susceptible to plastic deformation an‎d mechanical failure under higher loading.In the graphene oxide reinforced samples (PCL+G), despite the increase in porosity, the von Mises stress was significantly reduced, an‎d the maximum stress at 2.5 mm porosity was 363 MPa. This stress reduction can be attributed to the more uniform stress distribution an‎d greater structural strength due to the presence of graphene oxide.Finally, it can be concluded that although increasing porosity led to a decrease in the stiffness of the structure, the addition of graphene oxide was able to largely prevent the negative effects of larger porosity an‎d maintain the mechanical stability of the scaffold. With increasing porosity, displacement an‎d strain increased in both PCL an‎d PCL+G groups, which was due to a decrease in structural resistance to deformation.The displacement in pure PCL samples increased from 0.4561 mm at 1 mm porosity to 0.814 mm at 2.5 mm porosity. The strain also increased at higher porosities an‎d reached a maximum value of 0.5776.This increase in displacement an‎d strain indicated a decrease in the stiffness of the structure an‎d an increase in the deformation potential in larger pores. In the graphene oxide reinforced samples (PCL+G), the displacement an‎d strain were significantly reduced compared to pure PCL.At 2.5 mm porosity, the displacement decreased to 0.5769 mm an‎d the strain decreased to 0.3893, indicating an improvement in structural stability in the presence of graphene oxide. As a result, graphene oxide reduced the displacement an‎d strain at all porosity levels, which was due to increased stiffness, improved interfacial bonding, an‎d reduced polymer chain motion.The aim of this research is to model an‎d analyze the mechanical properties of polycaprolactone-graphene nanoparticles electroactive scaffolds using 3D printing for bone tissue engineering.

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