Nanovibrational stimulation for 3D osteogenesis in biphasic 3D scaffold; a new option for bone tissue engineering

[摘要] In our centre, we had developed nanovibrational bioreactor generating nanoscale vibration by piezo actuator for bone tissue engineering. Recently, nanovibrational stimulation (NS; 30 nm at 1000 Hz) showed the success of osteogenic induction in mesenchymal stem cells (MSCs) seeded collagen hydrogel without chemical supplement. However, culturing MSCs in the collagen hydrogel for long term NS stimulation in NS bioreactor is challenging due to its mechanical properties. The principle aim of this thesis is to develop the scaffold for nanovibrational bioreactor which is suitable for surgical application. Three strategies including ingel scaffolds, collagen concentration optimization and genipin crosslinking were trialled which aimed to improve hydrogel stiffness and handleability, possess biocompatibility and allow NS force transmission. The role of high amplitude stimulation (90 nm at 1000 Hz) on 3D osteogenesis was also studied. Interestingly, increasing NS amplitude successfully enhanced 3D osteogenesis through multiple pathways and it was biologically safe. Metabolomics during NS revealed the evidence of low level of reactive oxygen species production and inflammation which was controlled in physiological level through multiple intracellular signals such as redox balancing, NFkB and MAPK pathways. To propose the technique how to use NS induced MSCs for clinics, MSCs seeded biphasic scaffolds compositing collagen hydrogels and freeze dried collagen sponges were developed. Cell-hydrogel-sponge composite (CHSC) was reproducible, handleable and biologically safe. CHSC allowed a good fidelity of NS. NS with high amplitude stimulation successfully induced 3D osteogenesis. NS protocol in CHSC was optimized in order to identify a stimulating duration which can induce osteogenesis without phenotypic reversibility. Interestingly, two-week stimulation possibly committed MSCs in the preosteoblast stage.

[发布机构] University:University of Glasgow;Department:Institute of Molecular Cell and Systems Biology

[关键词] Nanovibration, nanoscale, vibration, osteogenesis, scaffold, hydrogel, bone, tissue engineering.