Superparamagnetic iron oxide nanoparticles (SPIONs) as non-viral

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					European Cells and Materials Vol. 10. Suppl. 5, 2005 (page 10)                                   ISSN 1473-2262
 Superparamagnetic iron oxide nanoparticles (SPIONs) as non-viral vectors for
                            gene delivery in vitro
        Kamau, Sarah, W.; 2Schulze, Katja; 3Steitz, Benedikt; 3Petri-Fink, Alke; 1Hassa, Paul, O.; 1Hottiger,
             Michael, O.; 3Hofmann, Heinrich; 4Hofmann Margarethe; 2von Rechenberg, Brigitte.
     Institute of Veterinary Biochemistry and Molecular Biology, University of Zurich, Zurich,
   Switzerland. 2Musculoskeletal Research Unit, Equine Hospital, University of Zurich, Zurich,
 Switzerland, 3Laboratory of Powder Technology, EPFL, Lausanne, Switzerland, 4MAT SEARCH,
                                        Pully, Switzerland.

                                                             particle uptake by the cells or gene release from
INTRODUCTION: The treatment and control of
                                                             these polymers. Although PVA-SPIONs were less
acute and chronic inflammatory processes of the
                                                             toxic to the cells, these results showed that PEI-
bone and cartilage remain a major goal in
                                                             SPIONs were more efficient gene vectors. This
orthopedic research. Gene therapy would be an
                                                             was confirmed in synovial cells where up to 96.2%
attractive alternative to chemotherapy which is
                                                             of the cells expressed GFP after transfection with
accompanied often by various side effects that are
                                                             PEI-SPIONs. Gene transfection using of PEI-
detrimental to the patient. The true benefits of
                                                             SPIONs in presence of magnet for 5 min resulted
these approaches can only be realized when
                                                             in significantly higher proportion of cells
delivery methods are perfected or new ones
                                                             expressing GFP when compared with conventional
                                                             transfection system with lipofectamine, calcium
METHODS: Superparamagnetic nanoparticles                     phosphate and PEI alone.
(SPIONs) were synthesized according to
                                                             DISCUSSION & CONCLUSIONS: Our results
Chastellain et al.1 SPIONs were coated either with
                                                             show that PEI-coated SPIONs are very efficient for
polyvinyl alcohol (PVA) (Mowiol® 3-83, Clariant)
                                                             non-viral gene delivery, resulting in high
and further functionalized with amino-groups and
                                                             transfection efficiency in vitro. High transfection
fluorochromes Cy3.5 or Texas red, or alternatively
                                                             efficiency was achieved within minutes and the
coated with 25 kDa polyethylenimine (PEI)
                                                             transfection rates achieved were significantly
(Aldrich). Intracellular uptake of PVA-SPIONs
                                                             higher than those achieved with conventional
into cells was evaluated by confocal microscopy
                                                             transfection methods. The PVA-coated particles
and flow cytometry. The feasibility of using
                                                             were less efficient in gene delivery, however their
SPIONs coated with PVA (PVA-SPIONs), for the
                                                             efficient uptake and low toxicity is to be explored
delivery of a DNA expression plasmid encoding
                                                             for protein delivery. Preliminary studies by our
the green fluorescent protein (GFP) gene (pEGFP-
                                                             group have shown that the use of PEI-coated
C1 plasmid, Clontech), into different cell lines
                                                             SPIONs is also feasible in gene delivery in vivo.
within a magnetic field, was subsequently
                                                             Further studies will evaluate the toxicology and in
explored, and evaluated using fluorescent
                                                             vivo efficiency of these transfection systems. This
microscopy and flow cytometry. The gene
                                                             study will serve as a basis for further studies with
expression after delivery with PVA-SPIONs was
                                                             plasmids, peptides and proteins targeted at
further compared with that of particles coated with
                                                             inhibiting joint inflammation and cartilage matrix
polyethylenimine (PEI), PEI-SPIONs.
RESULTS: Flow cytometric analysis showed that                REFERENCES: 1 M. Chastellain, A. Petri, H.
the PVA coated particles were taken up, resulting            Hofmann: Particle size investigations on a multi-
in more than 80% of the synovial cells being                 step synthesis of PVA coated superparamagnetic
labelled with Cy3.5. Gene delivery was also                  nanoparticles, J. Colloid and Interface Science,
achieved using PVA-SPIONs, and 17.7% of 293T                 278 (2004) 353-360.
cells expressed GFP. In contrast, in cells
transfected with PEI-SPIONs, 43.5 % of 293T                  ACKNOWLEDGEMENTS: This work was
cells expressed GFP. The green fluorescence in               supported by Vetsuisse-Faculty of the Universities
cells transfected with PVA-SPIONs was faint and              of Berne and Zurich, Switzerland, and by the
seen clearly after 48 hrs of incubation, while in            European Community, 5th Framework Program,
cells transfected with PEI-SPIONs the fluorescence           “Magnanomed“ G5RD-2000-00375
intensity was high and seen clearly after 24 hrs of
incubation. This indicated a difference in either