Structural monitoring and modeling of the mechanical deformation of three-dimensional printed poly( ε -caprolactone) scaffolds

Abstract

Three-dimensional (3D) printed poly(ε-caprolactone) (PCL) based scaffolds have being proposed for different tissue engineering applications. This study addresses the design and fabrication of 3D PCL constructs with different struts alignments at 90°, 45° and 90° with offset. The morphology and the mechanical behavior under uniaxial compressive load were assessed at different strain percentages. The combination of a new compressionCT device and micro computed tomography (micro-CT) allowed understanding the influence of pore geometry under controlled compressive strain in the mechanical and structural behavior of PCL constructs. Finite element analysis (FEA) was applied using the micro-CT data to modulate the mechanical response and compare with the conventional uniaxial compression tests. Scanning electron microscopic analysis showed a very high level of reproducibility and a low error comparing with the theoretical values, confirming that the alignment and the dimensional features of the printed struts are reliable. The mechanical tests showed that the 90° architecture presented the highest stiffness. With the compressionCT device was observed that the 90° and 90° with offset architectures presented similar values of porosity at same strain and similar pore size, contrary to the 45° architecture. Thus, pore geometric configurations affected significantly the deformability of the all PCL scaffolds under compression. The prediction of the FEA showed a good agreement to the conventional mechanical tests revealing the areas more affected under compression load. The methodology proposed in this study using 3D printed scaffolds with compressionCT device and FEA is a framework that offers great potential in understanding the mechanical and structural behavior of soft systems for different applications, including for the biomedical engineering field.

Bioprinting: From Tissue and Organ Development to in Vitro Models

“…Traditionally, FDM techniques have used polymer thermoplastics, such as PCL and PLA, which are stiff and show poor resilience upon compression, unlike the mechanical properties of native articular cartilage. 355 − 360 Moreover, cell culture on these types of materials generally results in cell morphologies that are not representative of chondrocytes (spread vs rounded), promoting dedifferentiation of the cells. 361 − 363 In comparison, fabrication of hydrogel-based scaffolds, where chondrogenic differentiation is more likely to occur, results in mechanical properties that are rather low compared to the native tissue.…”

Selection of the optimum 3D‐printed pore and the surface modification techniques for tissue engineering tracheal scaffold in vivo reconstruction

“…Many natural materials, such as fibrin and collagen, have good biocompatibility and biodegradability, but the mechanical properties are poor and do not meet the needs of tissue engineering . The ester groups on PCL's molecular chains are biocompatible, and the melting point of PCL is low (only 60°C); in addition, its thermoplasticity is good, making it easy to process and form . It has been approved by the Food and Drug Administration (FDA) of the United States and is widely used as the perfect material source for 3D printing.…”

“…24 The ester groups on PCL's molecular chains are biocompatible, and the melting point of PCL is low (only 60 C); in addition, its thermoplasticity is good, making it easy to process and form. 25 It has been approved by the Food and Drug Administration (FDA) of the United States and is widely used as the perfect material source for 3D printing. The biomechanical properties of the scaffold are an important indicator of whether it can be used for in vivo reconstruction.…”

Biodegradable polymers: an update on drug delivery in bone and cartilage diseases

“…Bone grafts are usually based on biodegradable polymer composites [e.g. silk fibroin [170], PCL [171], gellan-gum [172], chitosan [173] and/or hyaluronic acid] with calcium phosphate materials (e.g. hydroxyapatite and tricalcium phosphate).…”