Characterization and biological properties of nanostructured clinoenstatite scaffolds for bone tissue engineering applications

Abstract

With the enhancement of bone-tissue regeneration technologies, there is an increment request for perfect bio-ceramic scaffolds with multifunctional properties, including high mechanical strength as well as biological and controlled drug-release potential. In the present work, extremely porous clinoenstatite (CLEN; MgSiO3) scaffolds with different micropore sizes and great interconnectivity were fabricated for the first time via the space holder method and subsequent sintering. The NaCl particle size escalation as spacer results in an increase of the pore size and interconnectivity and reduction of the compressive strength. According to the results, nanostructured CLEN scaffolds contain pore sizes in the range of ~450–650 µm and porosity more than ~77–81%, which offered greater compressive strength (0.9 MPa) in comparison with the other CLEN scaffolds. Favorable burst release was noticed throughout the first 8 h, and right after the early burst, the dose was progressively reduced until 35 h, and subsequently, a sustained release was noticed. In vitro examinations verified the antimicrobial performance of the metronidazole (MTZ)-embedded CLEN scaffolds towards the Fusobacterium nucleatum (Fn) and Aggregatibacter actinomycetemcomitans (Aa) bacteria. In this context, the antibacterial performance is enhanced with escalating MTZ loading into scaffolds, which is directly linked with the increase of MTZ concentration. The results exhibited that both CLEN and MTZ-embedded CLEN scaffolds presented apatite formation capability in SBF. The biological test showed that the MG63 cell adhesion and proliferation on the CLEN scaffold were comparable with their counterpart loaded with low MTZ concentration. Also, the scaffold's ALP activity with low MTZ concentration was considerably greater than that of the scaffold with high MTZ concentration. The results presented here demonstrate that the fabricated CLEN scaffold with 1–3 wt% MTZ concentration has a great potential to be utilized as a bone repair material for tissue engineering applications.