WEB Characterization of 3D printed PHBV+BG scaffolds for bone regeneration
To repair bone damage, tissue engineering combine biomaterials that can stimulate the body response to promote healing. Biomaterials are used to design scaffolds that act as support for the cells involved in bone tissue regeneration. Scaffolds should promote the adhesion, proliferation, differentiation and organization of the cells involved in the process of bone generation, originating a normal and healthy bone tissue as the material is biodegraded. The aim of this work was to obtain bioresorbable 3D printed scaffolds that mimic the bone extracellular matrix with suitable mechanical properties that actively participate in bone healing. In this regard, 3D printed scaffold were obtained by the solid fusion deposition technique (FFD) in a 3D printer. This technique is a rapid and reproducible process to obtain a complex structure in a layer by layer deposition fashion. It allows to reproduce custom-made scaffolds from medical images obtained by CT or/and MRI of the own patient.
The filament was made of a biocompatible and resorbable polymer, polyhydroxybutyrate-co-valerate (PHBV) combined with Bioglass 45s5 (BG), in a Parallel Twin-Screw Extruder, and used to 3D printing. This process conduct to a biodegradable composite that stimulates the response of the organism to regenerate bone. PHBV+BG filaments were suitable for FFD and shown a good printability. Adjusting the printer parameters, porous structures with highly interconnected macro-channels, ranging from 100 µm up to 500 µm of diameter, were produced. The obtained structures have a strand size of 230800 m tuned by the nozzle inner diameter. Filaments and scaffolds morphology was observed by SEM. Mechanical properties were measured in a Dynamical Mechanical Analyzer and a Mechanical Testing Machine. The elastic modulus of the printed scaffolds depended on the printing pattern and the elastic response was similar to the trabecular bone one. HA-like layer formation was observed when immersed in simulated body fluid, its formation is fundamental in the bonding process of the scaffold to the tissue. The biological evaluation of the scaffolds was performed including preosteoblastic cells adhesion and cytotoxicity assay.
The morphological characteristics, mechanical properties and biocompatibility of Bioglass/PHBV 3D printed scaffolds are promising to use them in medical applications.