Regulation of cell migration and differentiation using iron oxide nanoparticle

Abstract

Regulation of cell behavior and function is crucial to understand biological phenomena and overcome its functional disorder. Cell behavior includes cellular morphogenesis, proliferation, migration, and differentiation, etc. Because these cellular processes contribute to the underlying causes of many diseases, many researchers have investigated cellular responses by biochemical, physical and mechanical factors. Traditionally, chemicals such as signal transfer molecules have been used to induce various changes in intracellular level. Recently, many researchers have been trying to use physical stimulation or develop material-based system, which have nanoscale structures or features induce cellular changes by cell-matrix interactions. These systems include microfabricated system, nanoparticles and carbon nanotubes, etc., which mimic the biological microenvironments and were favorable to concisely manipulate the cellular behaviors. Therefore, it was needed to understand the cell-matrix interaction and surface characteristics of these nanoplatforms. The objective of this research is to develop the iron oxide nanoparticle system for controlling cellular behavior and to apply this system to the regenerative therapeutics. In this study, iron oxide nanoparticles were isolated from the magnetic bacteria, Magnetospirillum sp. AMB-1, which were covered by the lipid bilayer. This particle has ferromagnetic property, so it is useful for the control of cell mobility by external magnetic field. First, iron oxide nanoparticles were isolated from AMB-1 and characterized to deliver into cells. To investigate cellular uptake pathway of nanoparticles, qualitative and quantitative analysis were used. Nanoparticles were delivered to cells via an energy-dependent endocytosis pathway. Second, cells incorporating these particles were magnetically activated and can be used for targeting cells at a specific location within a microfluidic channel. A common problem in the in vivo therapeutic applications of cells is that cells can rapidly disappear into the circulatory system after an injection. Magnetic property of these nanoparticles can solve this problem. The environment of a human blood vessel was simulated using a microfluidic channel. Iron oxide nanoparticle-incorporated EPCs (endothelial progenitor cells) were injected into a microchannel and their flow rate was uniformly controlled by use of syringe pump. EPCs were effectively targeted to a specific location within the microchannel by an external magnetic force (about 400 mT). About 40% of EPCs were efficiently targeted with a flow rate of 5 μl min-1 when 10 μg of magnetic nanoparticles per 104 cells were used. This microfluidic system provides a useful tool towards a better understanding of the behavior of magnetic nanoparticle-incorporated cells within the human circulatory system for clinical use. Third, iron oxide magnetic nanoparticles can be utilized for the generation of three-dimensional cellular structure such as multicellular spheroid. Generally, spheroids were generated by the hanging drop method or miropatterning techniques. Using iron oxide nanoparticle, cells were spontaneously aggregated by a focused magnetic force. This system makes it possible to fast generate uniform size of spheroids and regulate their size by control of cell concentration. This system can be used for the anti-cancer drug screening or the efficient embryoid body (EB) formation in stem cell research. Fourth, we investigated the effect of iron oxide nanoparticles on neurite outgrowth. Despite the various potential therapeutic applications of iron oxide nanoparticle, its biological effects have not yet been extensively characterized. In this study, PC12 cells exposed to both iron oxide nanoparticles and nerve growth factor (NGF) synergistically increased the efficiency of neurite outgrowth in a dose-dependent manner. This might result from the activation of cell adhesion molecules that are associated with cell-matrix interactions through iron. Immunoblotting assays also revealed that both neural specific marker protein and cell adhesion protein expression were upregulated by iron oxide nanoparticles compared with non-treated cells via activation of the mitogen-activated protein kinase (MAPK) signaling pathway. These findings point to the possibility that iron oxide nanoparticles can affect cell-substrate interactions and regulate cell behaviors, which provides clinical insights into potential neurologic and therapeutic applications of iron oxide nanoparticles. In this research, we have used physical and chemical properties of iron oxide nanoparticles for control of cellular behavior and have suggested a several biological and therapeutic applications. These suggested systems provide much potential for the biological study and therapeutic applications in regenerative medicine using stem cells.