Magnetic nanocomposites for tissue regeneration therapies

Abstract

Event Abstract Back to Event Magnetic nanocomposites for tissue regeneration therapies Rebecca Zhiyu Yuan1, Kaveh Memarzadeh1, Robert A. Brown2 and Jie Huang1 1 University College London, Mechanical Engineering, United Kingdom 2 University College London, Faculty of Medical Sciences, United Kingdom Introduction: The use of tissue engineering scaffolds to repair and promote bone formation has received much clinical attention over the past decades. However, to guide and stimulate cells towards the target site remains challenging. There are increasing efforts to promote current cell therapies by developing new methodologies to target, monitor, and control cells. Recently, magnetic nanoparticles (MNPs) have been identified as being capable of promoting the proliferation and differentiation of osteoblast under static magnetic field (SMF)[1]. Iron oxide nanoparticles (IONPs) are clinically approved and can be injected intravenously, however, the majority of the IONPs are rapidly cleared from the bloodstream by the reticuloendothelial system. IONPs have been encapsulated in a gel matrix; there are concerns of toxic side-effects of organic solvents. Encapsulated electrospun nanofibre web has offered an attractive alternative solution[2]. In this study, IONPs were synthesised and their nanofiber mesh were produced by eletrospinning (ES). A device to support cell culture under SMF was prepared by 3D printing, and used for in vitro study. Materials and Methods: IONPs were prepared by precipitation of iron (III) chloride hexahydrate and Iron (II) chloride tetrahydrate with an addition of ammonia[3]. The microstructure of IONPs was examined by Transmission Electron Microscopy (TEM) and phase purity was determined by X-ray diffraction (XRD). The biocompatibility of IONPs was assessed by in vitro culture using a human osteoblast MG63 cell model. IONPs / polyvinylpyrrolidone (PVP) / ethanol / water suspensions were formulated for ES, and various parameters were employed to control the size of fibres. The microstructure of the nanofibre mesh was examined by Scanning Electron Microscopy (SEM) and Scanning Probe Microscopy (SPM). Results and Discussion: By using TEM examination, the image analysis showed that the average diameter of the IONPs was 30∓ 20 nm. Phase purity was further confirmed by XRD; IONP nanofibre meshes were produced with size of 100 nm to 2 μm. An uniform distribution of IONPs in the nanocomposites was revealed form SPM (Fig. 1). Figure 1. (A) TEM micrograph of IONPs (B) SEM and (C) SPM micrographs of IONPs nanofibre mesh. Alamar Blue assay showed that MG63 cells were able to proliferate when in contact with IONPs coated substrates during 7 days culture. The cell activity was increased significantly under SMF (Fig. 2) indicating a stimulating effect. Figure 2. A comparison of the proliferation of MG63 cells under SMF and non-static magnetic field (NSMF) from alamar blue assay (n=3). Conclusion: Biocompatible iron oxide nanoparticles were successfully prepared and tested. The size and morphology of electrospun IONP nanofibres can be controlled by varying solution properties and processing parameters. With the aid of external static magnetic field, the three-dimensional magnetic nanocomposites scaffolds can offer great potential in magnetic cell guiding applications.