title: Tailoring the surface charge of dextran-based polymer coated SPIONs for modulated stem cell uptake and MRI contrast.
abstract: Tracking stem cells in vivo using non-invasive techniques is critical to evaluate the efficacy and safety of stem cell therapies. Superparamagnetic iron oxide nanoparticles (SPIONs) enable cells to be tracked using magnetic resonance imaging (MRI), but to obtain detectable signal cells need to be labelled with a sufficient amount of iron oxide. For the majority of SPIONs, this can only be obtained with the use of transfection agents, which can adversely affect cell health. Here, we have synthesised a library of dextran-based polymer coated SPIONs with varying surface charge from -1.5 mV to +18.2 mV via a co-precipitation approach and investigated their ability to be directly internalised by stem cells without the need for transfection agents. The SPIONs were colloidally stable in physiological solutions. The crystalline phase of the particles was confirmed with powder X-ray diffraction and their magnetic properties were characterised using SQUID magnetometry and magnetic resonance. Increased surface charge led to six-fold increase in uptake of particles into stem cells and higher MRI contrast, with negligible change in cell viability. Cell tracking velocimetry was shown to be a more accurate method for predicting MRI contrast of stem cells compared to measuring iron oxide uptake through conventional bulk iron quantification.
authors.affiliation: Department of Chemistry, University of Liverpool, Liverpool, UK. d.j.adams@liverpool.ac.uk.
authors.forename: Michael
authors.initials: M
authors.lastname: Barrow
authors.forename: Arthur
authors.initials: A
authors.lastname: Taylor
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Nieves
authors.forename: Lara K
authors.initials: LK
authors.lastname: Bogart
authors.forename: Pranab
authors.initials: P
authors.lastname: Mandal
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Collins
authors.forename: Lee R
authors.initials: LR
authors.lastname: Moore
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Chalmers
authors.forename: Raphaël
authors.initials: R
authors.lastname: Lévy
authors.forename: Steve R
authors.initials: SR
authors.lastname: Williams
authors.forename: Patricia
authors.initials: P
authors.lastname: Murray
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rosseinsky
authors.forename: Dave J
authors.initials: DJ
authors.lastname: Adams
mesh_terms: D058948:Cell Tracking / Q000379:methods; D003287:Contrast Media / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D013234:Stem Cells; D014961:X-Ray Diffraction
chemical_list: D003287:Contrast Media; D003911:Dextrans; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D007501:Iron; C065507:ferumoxides