Fabrication of Biocompatible Polycaprolactone–Hydroxyapatite Composite Filaments for the FDM 3D Printing of Bone Scaffolds

Abstract

Recently, three-dimensional printing (3DP) technology has been widely adopted in biology and biomedical applications, thanks to its capacity to readily construct complex 3D features. Using hot-melt extrusion 3DP, scaffolds for bone tissue engineering were fabricated using a composite of biodegradable polycaprolactone (PCL) and hydroxyapatite (HA). However, there are hardly any published reports on the application of the fused deposition modeling (FDM) method using feed filaments, which is the most common 3D printing method. In this study, we report on the fabrication and characterization of biocompatible filaments made of polycaprolactone (PCL)/hydroxyapatite (HA), a raw material mainly used for bone scaffolds, using FDM 3D printing. A series of filaments with varying HA content, from 5 to 25 wt.%, were fabricated. The mechanical and electrical properties of the various structures, printed using a commercially available 3D printer, were examined. Specifically, mechanical tensile tests were performed on the 3D-printed filaments and specimens. In addition, the electrical dielectric properties of the 3D-printed structures were investigated. Our method facilitates the fabrication of biocompatible structures using FDM-type 3DP, creating not only bone scaffolds but also testbeds for mimicking bone structure that may be useful in various fields of study.

Fabrication and Characterization of PCL/HA Filament as a 3D Printing Material Using Thermal Extrusion Technology for Bone Tissue Engineering

“…Surprisingly, the material extrusion method has rarely been used for scaffold fabrication, probably due to the lack of suitable materials and control methods [21]. Historically, solvent casting has been the main method, with only a few studies focusing on hot-melt extrusion, although using higher HA contents which, in return, influences printability parameters, involves the use of more expensive printers, and increases the presence of cell byproducts [26][27][28][29]33].…”

“…The project was supported by a grant from the Osteology Foundation, Switzerland, grant number (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Bilateral Science and Technology cooperation program with Asia, grant number (IPG 01-112019) and (IPG 07-052020).…”

“…Filament fabrication favorably uses a thermal procedure, having the advantage of producing solvent-free and eco-friendly filaments with no harmful effects (such as cell death) derived from solvent residuals [24,25]. Although solvent-casting techniques are commonly used to fabricate PCL composite filaments, these techniques suffer from inherent limitations, such as the challenging fabrication process associated with the leaching of solvent residues in the fabricated scaffolds; thus, it might not be suitable for scaffold fabrication in hospital settings [26][27][28][29]. A hot-melt filament extrusion machine would include HA and fabricate the composite filament in a cost-contained situation [30,31].…”

Regression Analysis of the Dielectric and Morphological Properties for Porous Nanohydroxyapatite/Starch Composites: A Correlative Study

“…In tissue engineering, numerous efforts have been made in research to find alternative materials with similar microstructural features as a natural bone for bone defect reconstruction [ 1 , 2 ]. The microstructural features (pore size, pore distribution, porosity, and pore interconnectivity) of a bone scaffold are the main factors that lead to biological activities (cell adhesion, cell migration, cell proliferation, and cell differentiation) during bone regeneration [ 3 , 4 ]. Several characterization techniques (microscopy, micro-computed tomography, density determination, and ultrasonic testing) are available for evaluating bone scaffold microstructures, but most of the techniques are destructive, costly, and time-consuming.…”

“…Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ), a bioceramic, shows excellent biodegradability, bioactivity, biocompatibility, and osteoconductivity. Consequently, it is versatile in diverse biomedical applications, e.g., gene therapy, regenerative medicine, drug delivery, and tissue/implant engineering [ 3 , 7 ]. Hydroxyapatite is commonly used as an artificial bone substitute because of its physical, chemical, and biological similarities with the natural bone.…”