Correia Carreira, S.Armstrong, J. P.K.Seddon, A. M.Perriman, A. W.Hartley-Davies, R.Schwarzacher, W.2026-03-272026-03-272040-3364PubMed:26822466ORCID:/0000-0003-2205-9364/work/209602514https://hdl.handle.net/1885/733807952Magnetic 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 laborious surface functionalisation are often employed, which can adversely affect cell function. Here, we demonstrate that chemical cationisation of magnetoferritin produces a highly membrane-active nanoparticle that can magnetise human mesenchymal stem cells (hMSCs) using incubation times as short as one minute. 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 membrane integrity, proliferation and multi-lineage differentiation capacity of hMSCs, which provides the first detailed evidence for the biocompatibility of magnetoferritin. The combination of synthetic ease and flexibility, the rapidity of labelling and absence of cytotoxicity make this novel nanoparticle system an easily accessible and versatile platform for a range of cell-based therapies in regenerative medicine.This work was financed through the Bristol Centre for Functional Nanomaterials, sponsored by the Engineering and Physical Sciences Research Council (EPSRC grant code EP/G036780/1). We are grateful to the staff of the Wolfson Bioimaging Facility (Paul Verkade, Judith Mantell, Gini Tilly) and Monika Jakimowicz for electron microscopy support at the University of Bristol, and to the Clinical Research and Imaging Centre (CRIC) at University Hospitals Bristol NHS Foundation Trust, particularly Sian Curtis, for MRI support.10enPublisher Copyright: © 2016 The Royal Society of Chemistry.2016-04-1410.1039/c5nr07144e84963561202