Fabrication of biocompatible and bioabsorbable polycaprolactone/magnesium hydroxide 3D printed scaffolds: Degradation and in vitro osteoblasts interactions

Biodegradable polymeric 3D implants are of considerable interest for biomedical applications, however the degradation profile and bioactivity are important considerations for many clinical applications. In this context, bioresorbable magnesium hydroxide (MH) nanoparticles (NPs) (<50 nm) were blended with the degradable polymer poly (epsilon-caprolactone) (PCL) at concentrations of 5 and 20 wt%, and the composite was manufactured by 3D printing technology. Efficient load transfer was found between the nanofiller and matrix PCL, which was reflected in changes in the tensile properties of the MH-based composite. A statistically significant 44.3% increase in tensile modulus was achieved by the addition of 5 wt% MH, which was in agreement with the Halpin-Tsai theoretical model. The incorporation of MH in the PCL scaffolds accelerated the weight loss of the scaffolds and decreased the molecular weight of PCL over a prolonged soaking period (150 days) in PBS solution (pH 7.37, 37 +/- 0.5 degrees C). The PCL/MH composite scaffolds were shown to be non-cytotoxic in vitro, and ion diffusion into the cell culture media promoted osteoblast metabolic activity, attachment, and proliferation, as compared to PCL-only scaffolds. Moreover, osteoblastic activity, as assessed by the expression of alkaline phosphatase, was significantly higher on the composite PCL/MH scaffold after 14 and 21 days. In summary, the 3D PCL/MH composite scaffolds could enhance osteoblastic activity and demonstrated a moderately accelerated degradation profile, which are characteristics that can be considered favorable for bone regeneration applications.