Rapid cell magnetisation using cationised magnetoferritin

• Main Author: Carreira, Sara Correia
• Published: University of Bristol 2015
• Subjects: 610
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686244

Magnetic cell labelling with superparamagnetic iron oxide nanoparticles (SPIONs) facilitates many important biotechnological applications, such as cell imaging and remote manipulation. However, to achieve adequate cellular loading of SPIONs, long incubation times (24 hours and more) or high exposure concentrations are often employed, which can adversely affect cell function. This work aimed at developing a facile surface functionalisation strategy that enables rapid and versatile cell magnetisation using low exposure concentrations. It was found that chemical cationisation of magnetoferritin produced a novel, highly membrane-active SPION that magnetised human mesenchymal stem cells (hMSCs) and two bacterial species using incubation times as short as one minute. In hMSCs, magnetisation persisted for several weeks in culture and provided significant T2 contrast enhancement during magnetic resonance imaging. Exposure to cationised magnetoferritin did not adversely affect the viability, membrane integrity, proliferation and multi-lineage differentiation capacity of hMSCs. Significantly, chondrogenesis was not inhibited, which is a differentiation pathway that is often affected by SPION exposure. A one minute incubation with cationised magnetoferritin also magnetised the gram-negative bacterium Escherichia coli and the gram-positive Staphylococcus aureus, such that these bacteria could be captured in a magnetic column with an efficiency of at least 99.97%. Importantly, Escherichia coli could be concentrated from a very dilute suspension (‹ 10² cfu mL-¹), which is an important pre-processing step for rapid, microfluidics-based pathogen detection. The combination of synthetic ease and flexibility, the rapidity of labelling and absence of cytotoxicity make this novel SPION system an easily accessible and versatile platform for a range of cell-based therapies in regenerative medicine, as well as an attractive tool for rapid pathogen isolation.