ABSTRACT
The repair of irregular and complex critical bone defects remains a challenge in clinical practice. The application of 3D-printed bioceramics particle/polymer composite scaffolds in bone tissue engineering has been widely studied. At present, the inorganic particle content of the composite scaffolds is generally low, resulting in poor osteogenic activity. However, scaffold with high inorganic content are highly brittle, difficult to operate during surgery, and cannot be in close contact with surrounding bones. Therefore, it is of great significance to design a 'surgery-friendly' scaffold with high bioceramic content and good ductility. In this study, we used the solvent method to add high concentration (wt% 70%) bioglass (BG) into polycaprolactone (PCL), and polyethylene glycol was used as plasticizer to prepare 70% BG/PCL composite scaffolds with high ductility using 3D printing technology.In vitroexperiments showed that the scaffold had good mechanical properties: easy extension, easy folding and strong compressive resistance. It also showed good performance in biocompatibility and osteogenic activity. It was further observed that compared with pure BG or PCL implantation, the scaffold with higher BG content could have more new bone tissue appeared after 12 weeks. All these results indicate that 3D-printed 70% BG/PCL scaffolds have great potential for personalized repair of bone defects.
Subject(s)
Ceramics , Tissue Scaffolds , Polyesters , Tissue Engineering/methods , Bone and Bones , Printing, Three-DimensionalABSTRACT
3D printed bioactive glass or bioceramic particle reinforced composite scaffolds for bone tissue engineering currently suffer from low particle concentration (<50 wt%) hence low osteoconductivity. Meanwhile, composites with very high inorganic particle concentrations are very brittle. Scaffolds combining high particle content and ductility are urgently required for bone tissue engineering. Herein, 3D printed PCL/hydroxyapatite (HA) scaffolds with high ceramic concentration (up to 90 wt%) are made ductile (>100% breaking strain) by adding poly(ethylene glycol) which is biocompatible and FDA approved. The scaffolds require no post-printing washing to remove hazardous components. More exposure of HA microparticles on strut surfaces is enabled by incorporating higher HA concentrations. Compared to scaffolds with 72 wt% HA, scaffolds with higher HA content (90 wt%) enhance matrix formation but not new bone volume after 12 weeks implantation in rat calvarial defects. Histological analyses demonstrate that bone regeneration within the 3D printed scaffolds is via intramembranous ossification and starts in the central region of pores. Fibrous tissue that resembles non-union tissue within bone fractures is formed within pores that do not have new bone. The amount of blood vessels is similar between scaffolds with mainly fibrous tissue and those with more bone tissue, suggesting vascularization is not a deciding factor for determining the type of tissues regenerated within the pores of 3D printed scaffolds. Multinucleated immune cells are commonly present in all scaffolds surrounding the struts, suggesting a role of managing inflammation in bone regeneration within 3D printed scaffolds.
Subject(s)
Durapatite , Tissue Scaffolds , Animals , Bone Regeneration , Ceramics , Polyesters , Printing, Three-Dimensional , Rats , Tissue EngineeringABSTRACT
In this study, the double-layered nHA and PCL/nHA coatings were prepared on the substrate of Mg66Zn28Ca6 amorphous alloy. The phase composition and morphological were analyzed by Scanning electron microscopy, Energy dispersive spectrometry and X-ray diffraction. The electrochemical properties of these samples were measured on electrochemical workstation. The degradation rate was evaluated by measuring the pH value and weight loss. Experiment results show that the outer composite PCL/nHA coating is a porous structure, where the porosity and pore size could be easily controlled by adding nHA. The combined properties of double-layered nHA and PCL/nHA coating can control the degradation of the Mg66Zn28Ca6 amorphous alloy in the scheduled time. Moreover,the cell co-culture and cell adhesion tests show that the double-layered nHA and PCL/2%nHA coating possesses the best cytocompatibility with cell organization. The above experiments have demonstrated that the Mg66Zn28Ca6 amorphous alloy which was coated with PCL/nHA composite coating have good mechanical properties, good corrosion resistance and perfect cytocompatibility. It can be used as a potential novel biomaterial for bone tissue engineering.
