Accelerated Degradation of Poly-ε-caprolactone Composite Scaffolds for Large Bone Defects

Abstract

This research investigates the accelerated hydrolytic degradation process of both anatomically designed bone scaffolds with a pore size gradient and a rectangular shape (biomimetically designed scaffolds or bone bricks). The effect of material composition is investigated considering poly-ε-caprolactone (PCL) as the main scaffold material, reinforced with ceramics such as hydroxyapatite (HA), β-tricalcium phosphate (TCP) and bioglass at a concentration of 20 wt%. In the case of rectangular scaffolds, the effect of pore size (200 μm, 300 μm and 500 μm) is also investigated. The degradation process (accelerated degradation) was investigated during a period of 5 days in a sodium hydroxide (NaOH) medium. Degraded bone bricks and rectangular scaffolds were measured each day to evaluate the weight loss of the samples, which were also morphologically, thermally, chemically and mechanically assessed. The results show that the PCL/bioglass bone brick scaffolds exhibited faster degradation kinetics in comparison with the PCL, PCL/HA and PCL/TCP bone bricks. Furthermore, the degradation kinetics of rectangular scaffolds increased by increasing the pore size from 500 μm to 200 μm. The results also indicate that, for the same material composition, bone bricks degrade slower compared with rectangular scaffolds. The scanning electron microscopy (SEM) images show that the degradation process was faster on the external regions of the bone brick scaffolds (600 μm pore size) compared with the internal regions (200 μm pore size). The thermal gravimetric analysis (TGA) results show that the ceramic concentration remained constant throughout the degradation process, while differential scanning calorimetry (DSC) results show that all scaffolds exhibited a reduction in crystallinity (Xc), enthalpy (Δm) and melting temperature (Tm) throughout the degradation process, while the glass transition temperature (Tg) slightly increased. Finally, the compression results show that the mechanical properties decreased during the degradation process, with PCL/bioglass bone bricks and rectangular scaffolds presenting higher mechanical properties with the same design in comparison with the other materials.

Poly-ε-Caprolactone 3D-Printed Porous Scaffold in a Femoral Condyle Defect Model Induces Early Osteo-Regeneration

“…The results showed that PCL/Bioglass exhibited higher degradation kinetics than PCL, PCL/HA, and PCL/TCP. Additionally, the degradation processes increased with increasing pore size [ 46 ].…”

The effect of graphene and graphene oxide induced reactive oxygen species on polycaprolactone scaffolds for bone cancer applications

“…1 , scaffolds with a 0°/90° lay-down pattern architecture, 330 μm fibre diameter, and 350 μm top view and 210 μm side view pore size, were fabricated using 3D Discovery (regenHU, Switzerland), a screw-assisted material-extrusion additive manufacturing system, at room temperature and with the optimal processing parameters previously reported (nozzle diameter of 330 μm, printing temperature of 90 °C, air pressure of 6 bars, deposition velocity of 13 mm/s, and screw rotational velocity of 8 rpm, and layer thickness of 270 μm) [ [40] , [41] , [42] ]. The geometrical characteristics of the considered scaffolds were based on previous studies from our group that investigated the effect of filament diameter, pore size, and porosity on mechanical and biological properties [ [42] , [43] , [44] , [45] ]. As reported the considered values are the ones that allow both high mechanical properties and cell attachment, proliferation, and differentiation.…”

Research Progress of Bone Repair Materials for Bone Defects

“…Recent studies have shown that. The degradation kinetics of PCL/ BG bone scaffold was enhanced when the pore size increased from 500 μm to 200 μm [11] . Degradable scaffolds can release chemicals to stimulate cell growth and differentiation during degradation, thereby promoting tissue regeneration.…”

“…[9] Qiao Yongjie, Zhang Lvdan, Li Xusheng, et al β-tricalcium phosphate filled with drug-loaded microspheres for the treatment of infectious bone defects in rabbits [J]. Orthopedic Journal of China, 2021, 29 (11):1013-1018.…”