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Intracellular processing of silica-coated superparamagnetic iron nanoparticles in human mesenchymal stem cells

Harrison, Richard P.; Chauhan, Veeren M.; Onion, David; Aylott, Jonathan W.; Sottile, Virginie


Richard P. Harrison

Advanced Technical Specialist (Flow Cytometry)

Virginie Sottile


Silica-coated Superparamagnetic Iron Nanoparticles (SiMAGs) are an exciting biomedical technology capable of targeted delivery of cell-based therapeutics and disease diagnosis. However, in order to realise their full clinical potential, their intracellular fate must be determined. The analytical techniques of super-resolution fluorescence microscopy, particle counting flow cytometry and pH-sensitive nanosensors were applied to elucidate mechanisms of intracellular SiMAG processing in human mesenchymal stem cell (hMSCs). Super-resolution microscopy showed SiMAG fluorescently-tagged nanoparticles are endocytosed and co-localised within lysosomes. When exposed simulated lysosomal conditions SiMAGs were solubilised and exhibited diminishing fluorescence emission over 7 days. The in vitro intracellular metabolism of SiMAGs was monitored in hMSCs using flow cytometry and co-localised pH-sensitive nanosensors. A decrease in SiMAG fluorescence emission, which corresponded to a decrease in lysosomal pH was observed, mirroring ex vivo observations, suggesting SiMAG lysosomal exposure degrades fluorescent silica-coatings and iron cores. These findings indicate although there is a significant decrease intracellular SiMAG loading, sufficient particles remain internalised (>50%) to render SiMAG treated cells amenable to long-term magnetic cell manipulation. Our analytical approach provides important insights into the understanding of the intracellular fate of SiMAG processing, which could be readily applied to other particle therapeutics, to advance their clinical translation.


Harrison, R. P., Chauhan, V. M., Onion, D., Aylott, J. W., & Sottile, V. (2019). Intracellular processing of silica-coated superparamagnetic iron nanoparticles in human mesenchymal stem cells. RSC Advances, 9(6), 3176-3184.

Journal Article Type Article
Acceptance Date Dec 21, 2018
Publication Date Jan 23, 2019
Deposit Date Jan 23, 2019
Publicly Available Date Jan 24, 2019
Journal RSC Advances
Electronic ISSN 2046-2069
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 9
Issue 6
Pages 3176-3184
Public URL
Publisher URL!divAbstract
Additional Information : This document is Similarity Check deposited; : Supplementary Information; : Veeren M. Chauhan (ORCID); : Virginie Sottile (ORCID); : Single-blind; : Received 2 November 2018; Accepted 21 December 2018; Version of Record published 23 January 2019


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