Genetically programmed superparamagnetic behavior of mammalian cells

• Published in: Journal of biotechnology Vol. 162; no. 2-3; pp. 237 - 245
• Main Authors: Kim, Taeuk, Moore, David, Fussenegger, Martin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 31.12.2012
• Subjects: Biogenic magnetization; Biomagnetism; biotechnology; Cation Transport Proteins - chemistry; Cation Transport Proteins - genetics; Cation Transport Proteins - metabolism; Cell separation; Cell Separation - methods; Cell Survival; culture media; Culture Media - chemistry; diagnostic techniques; engineering; evolution; ferritin; Ferritins - chemistry; Ferritins - genetics; Ferritins - metabolism; Genetic Engineering - methods; HEK293 Cells; Humans; Intracellular Space; Iron - metabolism; Magnetic Fields; magnetic separation; Magnetics - methods; Metabolic engineering; mineralization; nanoparticles; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Reproducibility of Results; Superparamagnetism; Synthetic biology; Synthetic Biology - methods; Metabolic engineering; Biomagnetism; Superparamagnetism; Synthetic biology; Cell separation; Biogenic magnetization
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2012.09.019

► First genetically engineered superparamagnetic mammalian cells. ► First magnetic cell separation using superparamagnetically engineered cells. ► Unprecedented iron loading of mammalian cells using ectopic expression of the DMT1 iron-import protein. ► Elaboration of special iron-loading cell culture media to allow for maximum ferritin-based intracellular iron storage. Although magnetic fields and paramagnetic inorganic materials were abundant on planet earth during the entire evolution of living species the interaction of organisms with these physical forces remains a little-understood phenomenon. Interestingly, rather than being genetically encoded, organisms seem to accumulate and take advantage of inorganic nanoparticles to sense or react to magnetic fields. Using a synthetic biology-inspired approach we have genetically programmed mammalian cells to show superparamagnetic behavior. The combination of ectopic production of the human ferritin heavy chain 1 (hFTH1), engineering the cells for expression of an iron importer, the divalent metal ion transferase 1 (DMT1) and the design of an iron-loading culture medium to maximize cellular iron uptake enabled efficient iron mineralization in intracellular ferritin particles and conferred superparamagnetic behavior to the entire cell. When captured by a magnetic field the superparamagnetic cells reached attraction velocities of up to 30μm/s and could be efficiently separated from complex cell mixtures using standard magnetic cell separation equipment. Technology that enables magnetic separation of genetically programmed superparamagnetic cells in the absence of inorganic particles could foster novel opportunities in diagnostics and cell-based therapies.