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We produced poro-us poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) composite scaffolds for bone regeneration, which can have a tailored macro/micro-porous structure with high mechanical properties and excellent in vitro bioactivity using non-solvent-induced phase separation (NIPS)-based 3D plotting. This innovative 3D plotting technique can create highly microporous PCL/HA composite filaments by inducing unique phase separation in PCL/HA solutions through the non-solvent-solvent exchange phenomenon. The PCL/HA composite scaffolds produced with various HA contents (0 wt %, 10 wt %, 15 wt %, and 20 wt %) showed that PCL/HA composite struts with highly microporous structures were well constructed in a controlled periodic pattern. Similar levels of overall porosity (~78 vol %) and pore size (~248 µm) were observed for all the PCL/HA composite scaffolds, which would be highly beneficial to bone tissue regeneration. Mechanical properties, such as ultimate tensile strength and compressive yield strength, increased with an increase in HA content. In addition, incorporating bioactive HA particles into the PCL polymer led to remarkable enhancements in in vitro apatite-forming ability. [ABSTRACT FROM AUTHOR]

This study demonstrates the utility of the newly developed self-assembly-induced gelation technique for the synthesis of porous collagen/hydroxyapatite (HA) composite microspheres with a nanofibrous structure. This new approach can produce microspheres of a uniform size using the droplets that form at the nozzle tip before gelation. These microspheres can have a highly nanofibrous structure due to the immersion of the droplets in a coagulation bath (water/acetone), in which the collagen aggregates in the solution can self-assemble into fibrils due to pH-dependent precipitation. Bioactive HA particles were incorporated into the collagen solutions, in order to enhance the bioactivity of the composite microspheres. The composite microspheres exhibited a well-defined spherical morphology and a uniform size for all levels of HA content (0 wt %, 10 wt %, 15 wt %, and 20 wt %). Collagen nanofibers--several tens of nanometers in size--were uniformly present throughout the microspheres and the HA particles were also well dispersed. The in vitro apatite-forming ability, assessed using the simulated body fluid (SBF) solution, increased significantly with the incorporation of HA into the composite microspheres. [ABSTRACT FROM AUTHOR]

This study proposes a new type of calcium phosphate (CaP) scaffolds with a continuously gradient macro/microporous structure using the ceramic/camphene-based 3D extrusion process. Green filaments with a continuously gradient core/shell structure were successfully produced by extruding a bilayered feedrod comprised of a CaP/camphene mixture lower part and a pure camphene upper part. The extruded filaments were then deposited in a controlled manner to construct triangular prisms, followed by the assembly process for the production of CaP scaffolds with a gradient core/shell structure. In addition, a gradient microporous structure was created by heat-treating the green body at 43 °C to induce the overgrowth of camphene dendrites in the CaP/camphene walls. The produced CaP scaffold showed a highly macroporous structure within its inner core, where the size of macrochannels increased gradually with an increase in the distance from the outer shell, while relatively larger micropores were created in the outer shell. [ABSTRACT FROM AUTHOR]