Three-dimensional cellulose-hydroxyapatite nanocomposite enriched with dexamethasone loaded metal–organic framework: a local drug delivery system for bone tissue engineering

Abstract: Three-dimensional cellulose-hydroxyapatite nanocomposite integrated with dexamethasone loaded metal organic framework (HA/DMOF) has been synthesized as a local drug delivery system for bone tissue engineering. Initially, in situ dexamethasone encapsulated metal–organic frameworks (DMOFs) were developed and characterized. The synthesized DMOFs are 60–80 nm in size with rhombohedral morphology. Results showed that nearly 16% dexamethasone (Dex) was loaded in DMOFs. These synthesized DMOF nanoparticles were efficiently integrated with carboxymethyl cellulose-hydroxyapatite nanocomposite for the development of three dimensional localized drug delivery system, namely, HA/DMOF. The synthesized HA/DMOF nanocomposite was structurally characterized using various techniques. The mechanical properties of HA/DMOFs were also measured by means of compression test. It was found that the compressive strength and compressive modulus of HA/DMOF nanocomposite are 16.3 ± 1.57 MPa and 0.54 ± 0.073 GPa respectively, which are in the range of cancellous bone. In-vitro release behaviour of Dex from both DMOFs and HA/DMOFs was examined in phosphate buffered solution. It was found that Dex molecules have been released very slowly from HA/DMOF nanocomposite compared to DMOF nanoparticles, and it was sustained for 4 weeks. Cytocompatibility of HA/DMOF nanocomposite was evaluated against pre-osteoblast MC3T3 cells. It was found that the synthesized HA/DMOF nanocomposite is compatible to MC3T3 cells. Moreover, the ALP activity and extracellular mineralization capability of cells were enhanced when cultured with HA/DMOF nanocomposite. Results showed that the synthesized HA/DMOF nanocomposite is a promising material for possible therapeutic as well as load-bearing orthopedic applications. Graphic abstract: [Figure not available: see fulltext.].