A biphasic calcium phosphate ceramic scaffold loaded with oxidized cellulose nanofiber-gelatin hydrogel with immobilized simvastatin drug for osteogenic differentiation

Abstract

A novel bone scaffold containing bioceramic and biopolymer materials with an osteoinductive simvastatin molecule was developed to enhance bone regeneration. An oxidized cellulose nanofiber (OCNF)-Gelatin (Gel) hydrogel was loaded into a biphasic calcium phosphate (BCP) ceramic in which simvastatin was entrapped, resulting in a scaffold with both osteoconductive and osteoinductive properties. The fabricated scaffold showed interconnected porosity with micro- and macroporous orientation. After loading the OCNF-Gel (HG), the mechanical stability of the ceramic BCP scaffold was increased suitable for the application of hard tissue regeneration. Fourier-transform infrared spectroscopy showed that simvastatin was successfully coated on the BCPHG scaffolds. OCNF, with its slower degradation, may contribute to the sustained release of drug from the scaffold. Initially simvastatin was released from the scaffold at high levels, then was constantly and gradually released for up to 4 weeks. Pre-osteoblast MC3T3E1 cells were seeded on the scaffolds to investigate cell viability, morphology, and differentiation. The simvastatin-loaded BCPHG-S scaffolds showed better cell proliferation and spreading compared to other scaffolds. Immunostaining assays showed the expression of proteins responsible for osteogenic differentiation. Alkaline phosphatase and osteopontin were more highly expressed in the BCPHG-S scaffold than in other scaffolds. These results suggest that simvastatin-loaded BCPHG scaffolds provided physiological environments suitable for better osteogenic differentiation.