Zein/ZnO-Modified 3D-Printed PCL/Sphene Scaffolds with Improved Bacterial Inhibition and Osteoblast Activity for Bone Regeneration Applications

3D printing offers a significant advantage in creating bioengineering scaffolds for patient-specific treatments of bony defects. In this study, a 3D-printed polycaprolactone (PCL)/sphene (SP, CaTiSiO5) scaffold coated with zein/ZnO was fabricated to provide a suitable environment for bone regeneration. SP nanoparticles were synthesized using a mechanochemical method and characterized by SEM-EDS, FTIR, and XRD. 0-30 wt % of prepared SP nanoparticles was used to fabricate 3D-printed PCL-based scaffolds. Incorporation of SP into PCL scaffolds (up to 20 wt %) significantly increased compressive strength (from 37.5 to 65.2 MPa) and modulus (from 0.33 to 0.63 MPa). <i>In vitro</i> bioactivity evaluation in simulated body fluid demonstrated the apatite formation ability of PCL/SP scaffolds, as confirmed by SEM-EDS analysis. Compared to PCL/SP, the zein/ZnO-modified scaffold showed increased surface hydrophilicity and significantly higher values of bactericidal potency against <i>S. aureus</i> and <i>E. coli</i>. Additionally, MTT assay, cell attachment, and alkaline phosphatase activity revealed that zein and ZnO coexistence on PCL/SP scaffolds resulted in significantly higher cell proliferation, improved cell adhesion, and enhanced osteogenic differentiation of MG-63 cells compared to unmodified samples. Overall, zein/ZnO-modified 3D-printed PCL/SP nanocomposite scaffolds with desirable physicochemical, mechanical, and biological characteristics can serve as superior platforms for bone regeneration applications.