3D-printed polycaprolactone-bioactive glass composite scaffolds for bone tissue engineering: the effect of filler content on different surface modifications

Composite material technology and advanced surface modifications are the two most substantial components in designing an effective bone scaffold. In this study, the extrusion of polycaprolactone (PCL)-45S5 Bioglass® (BG) composite filaments using a dry-mix hot-melt extrusion method was investigated. PCL-45S5 BG (PCL-BG) composite filaments of three different filler contents, 1, 2, and 5 wt%, and their three-dimensional (3D)-printed constructs were studied and compared to an industrial-grade PCL filament and its 3D-printed constructs. Following the composite material study, the PCL and PCL-BG composite scaffolds were treated with three surface modifications: subtractive chemical etching, conventional biomimetic calcium phosphate (CaP) coating, and bioinspired polydopamine (PDA) modification. A collective, comparative, and comprehensive analysis package comprising microstructure and morphology observation, topography characterization, mechanical performance, and a series of in vitro studies were conducted. The results showed considerable changes in mechanical performance and osteogenic properties across different combinations of substrate materials and surface modification strategies. Adding to the current general understanding that surface-modified scaffolds follow the substrate’s properties, varying filler contents of composite substrates in interaction with surface modification strategies certainly influenced the essential properties of bone scaffolds. These findings emphasize the considerable details involved in designing and engineering patient-specific bone scaffolds.