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Updated: May 26, 2026
Polyethyleneimine-coated Iron Oxide Nanoparticles as a Vehicle for the Delivery of Small Interfering RNA to Macrophages In Vitro and In Vivo
Published on: February 5, 2019
Silica-iron oxide magnetic nanoparticles modified for gene delivery: a search for optimum and quantitative criteria
Olga Mykhaylyk1, Titus Sobisch, Isabella Almstätter
1Institute of Experimental Oncology and Therapy Research, Klinikum rechts der Isar der Technischen Universität München, Ismaningerstrasse 22, 81675 Munich, Germany. olga.mykhaylyk@lrz.tu-muenchen.de
Purpose:
To optimize silica-iron oxide magnetic nanoparticles with surface phosphonate groups decorated with 25-kD branched polyethylenimine (PEI) for gene delivery.
Methods:
Surface composition, charge, colloidal stabilities, associations with adenovirus, magneto-tranduction efficiencies, cell internalizations, in vitro toxicities and MRI relaxivities were tested for the particles decorated with varying amounts of PEI.
Results:
Moderate PEI-decoration of MNPs results in charge reversal and destabilization. Analysis of space and time resolved concentration changes during centrifugation clearly revealed that at >5% PEI loading flocculation gradually decreases and sufficient stabilization is achieved at >10%. The association with adenovirus occurred efficiently at levels over 5% PEI, resulting in the complexes stable in 50% FCS at a PEI-to-iron w/w ratio of ≥7%; the maximum magneto-transduction efficiency was achieved at 9-12% PEI. Primary silica iron oxide nanoparticles and those with 11.5% PEI demonstrated excellent r(2)* relaxivity values (>600 s(-1)(mM Fe)(-1)) for the free and cell-internalized particles.
Conclusions:
Surface decoration of the silica-iron oxide nanoparticles with a PEI-to-iron w/w ratio of 10-12% yields stable aqueous suspensions, allows for efficient viral gene delivery and labeled cell detection by MRI.
