Immobilization of plant-derived osteopontin on bacterial cellulose membrane for bone tissue regeneration

Abstract

Bacterial cellulose (BC) membrane is recognized as a potential material to be developed into Guided Tissue Regeneration (GTR) membrane due to its sufficient mechanical strength, biocompatibility, and ease for surface functionalization. Here in this research, plant-produced osteopontin (pOPN) was selected to be immobilized on BC surface in order to promote cell adhesion and osteogenic differentiation. BC membrane was first grafted with poly(acrylic acid) (PAA) brushes via surface-initiated reversible addition fragmentation chain transfer (RAFT) polymerization. pOPN was subsequently immobilized on the PAA-grafted BC via amidation reaction between carboxyl groups of PAA and amino groups of pOPN. ATR-FTIR and XPS analysis were used to verify the success of stepwise modification. Surface morphology of the modified BC was evaluated by FE-SEM and AFM techniques. pOPN immobilized on the BC membrane was quantified by ELISA assay. Biological functions of the pOPN immobilized PAA-grafted BC membrane (pOPN-BC) were tested against human mesenchymal stem cells (hMSCs) in comparison with commercial available recombinant OPN from mammalian cells (rOPN). Results from immunofluorescent staining assay, mineralization assay and quantitative real-time polymerase chain reaction (qPCR) subsequently suggested the potential of pOPN-BC to promote bone tissue regeneration.