Gentamycin-loaded halloysite-based hydrogel nanocomposites for bone tissue regeneration: fabrication, evaluation of the antibacterial activity and cell response

Abstract

Biocompatible hydrogels are promising approaches for bone repair and engineering. A novel therapeutic nanocomposite hydrogel was designed based on triblock copolymer PCL-PEG-PCL and natural gelatin (PCEC/GEL) and reinforced with halloysite nanotube (HNT). Gentamicin (GM) loaded HNT was immobilized in polymeric hydrogel matrix to fabricate scaffolds using the freeze-drying method. Scaffolds were characterized via FT-IR, XRD, and SEM methods. The swelling ratio, density, porosity, degradation, and mechanical behavior were evaluated to investigate the effects of HNT on the physicochemical properties of the composite. Cell viability and cell attachment were investigated by MTT assay and SEM. Cell proliferation was observed without any cytotoxicity effect on h-DPSCs. Alizarin red staining (ARS) and real-time QRT-PCR assay were carried out to monitor the osteoconductivity of scaffolds on human dental pulp-derived mesenchymal stem cells (h-DPSCs) which were seeded drop wise onto the top of scaffolds. The quantification of the mRNA expression of osteogenic marker genes, BMP2, SPARK, BGLAP and RUNEX2 over a period of 21 days of cell seeding, demonstrated that cell-encapsulating PCEC/GEL/HNT-GM hydrogel scaffolds supported osteoblast differentiation of hDPSCs into osteogenic cells through the up-regulation of related genes along with moderate effects on cell viability. Moreover, the antibiotics loading reduced bacterial growth while maintaining the osteogenic properties of the scaffold. Therefore, the bactericidal PCEC/gelatin/HNT-GM hydrogel nanocomposite, with enhanced durability, maintenance the functionality of seeded cells in vitro that can be a remarkable dual-functional candidate for hard tissue reconstruction and customized bone implants fabrication via the direct incorporation of bactericidal drug to prevent infection.

Clindamycin-Loaded Halloysite Nanotubes as the Antibacterial Component of Composite Hydrogel for Bone Repair

“…There are few reports on using HNTs as a scaffold component to deliver antibiotics locally. Gentamycin-loaded HNTs were used in PCEC/Gel material [ 23 ], while vancomycin-loaded HNTs were used in silk fibroin scaffolds [ 24 ]. To the best of our knowledge, however, clindamycin-loaded HNTs were not used as a component of the materials for bone repair.…”