Study on antibacterial properties and cytocompatibility of EPL coated 3D printed PCL/HA composite scaffolds

Biomaterial scaffolds play a critical role in bone tissue engineering. Moreover, 3D printing technology has enormous advantage in the manufacture of bioengineering scaffolds for patient-specific bone defect treatments. In order to provide an aseptic environment for bone regeneration, ε-poly-l-lysine (EPL), an antimicrobic cationic polypeptide, was used for surface modification of 3D printed polycaprolactone/hydroxyapatite (PCL/HA) scaffolds which were fabricated by fused deposition modeling (FDM) technology. The scaffold morphology and micro-structure were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transform infrared spectroscopy (FT-IR). The release profile surface roughness, open porosity, and mechanical properties of the scaffolds were evaluated. Cell adhesion, proliferation, differentiation potential and antibacterial properties were also examined. As a result, 3D printed PCL/HA scaffolds with interconnected pores showed a slightly rough surface and improved mechanical properties due to adding hydroxyapatite (HA) particles. After being modified by EPL, favorable biocompatibility and osteoconductivity of ε-poly-l-lysine/polycaprolactone/hydroxyapatite (EPL/PCL/HA) scaffolds were observed. Moreover, antibacterial activity of the EPL/PCL/HA scaffolds was apparent. As a consequence, the EPL/PCL/HA scaffolds had great potential for bone regeneration and prevention of infections. This would yield a patient-specific bioactive and antibacterial composite scaffold for advanced bone tissue engineering applications.