Modeling of the Mechanical Behavior of 3D Bioplotted Scaffolds Considering the Penetration in Interlocked Strands

Abstract

Three-dimensional (3D) bioplotting has been widely used to print hydrogel scaffolds for tissue engineering applications. One issue involved in 3D bioplotting is to achieve the scaffold structure with the desired mechanical properties. To overcome this issue, various numerical methods have been developed to predict the mechanical properties of scaffolds, but limited by the imperfect representation of one key feature of scaffolds fabricated by 3D bioplotting, i.e., the penetration or fusion of strands in one layer into the previous layer. This paper presents our study on the development of a novel numerical model to predict the elastic modulus (one important index of mechanical properties) of 3D bioplotted scaffolds considering the aforementioned strand penetration. For this, the finite element method was used for the model development, while medium-viscosity alginate was selected for scaffold fabrication by the 3D bioplotting technique. The elastic modulus of the bioplotted scaffolds was characterized using mechanical testing and results were compared with those predicted from the developed model, demonstrating a strong congruity between them. Once validated, the developed model was also used to investigate the effect of other geometrical features on the mechanical behavior of bioplotted scaffolds. Our results show that the penetration, pore size, and number of printed layers have significant effects on the elastic modulus of bioplotted scaffolds; and also suggest that the developed model can be used as a powerful tool to modulate the mechanical behavior of bioplotted scaffolds.

3D Bioprinted Scaffolds for Bone Tissue Engineering: State-Of-The-Art and Emerging Technologies

“…B. et al, 2016 ). Although the resulting elastic moduli were much lower than that of native trabecular bone (E ≈ 100–5000 MPa ( Wu et al, 2014 )), it was higher than that of pure cell-laden alginate (E ≈ 3.6–32.1 kPa ( Naghieh et al, 2018b )). A research including both in-vitro and in-vivo studies on hybrid PCL scaffolds loaded with bioprinted HAp-modified alginate suggested such hybrid system for osteochondral regeneration; however, no mechanical evaluation was done in this study ( You et al, 2018 ).…”

Preparation and Use of Decellularized Extracellular Matrix for Tissue Engineering

“…This shear-thinning behaviour helps to cushion cells during dispensing, and, after dispensing, the dECM hydrogel returns to a higher viscosity that holds cells in place rather than allowing them to settle out [ 82 , 114 , 333 ]. The printability and ultimate structural stability of dECM colloidal dispersions will depend on the viscosity of the suspension following dispensing, as well as how rapidly the dECM can gel to stabilize the strands, which might necessitate the use of a plotting bath [ 334 , 335 ].…”

Cellular Membranes, a Versatile Adaptive Composite Material

“…In contrast, an omnidirectional assembly of the same structures will produce isotropic mechanical properties. Besides the form of the supporting structure, the spacing between individual subunits also influences the bending stiffness (Naghieh et al, 2018). One such example is agarose gel, which exhibits substantially higher resistance to shear stresses than its primary component water.…”