Benedikt Steitz

Enhancement of the efficiency of non-viral gene delivery by application of pulsed magnetic field

New approaches to increase the efficiency of non-viral gene delivery are still required. Here we report a simple approach that enhances gene delivery using permanent and pulsating magnetic fields. DNA plasmids and novel DNA fragments (PCR products) containing sequence encoding for green fluorescent protein were coupled to polyethylenimine coated superparamagnetic nanoparticles (SPIONs). The complexes were added to cells that were subsequently exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency 40 times more than in cells not exposed to the magnetic field. The transfection efficiency was highest when the nanoparticles were sedimented on the permanent magnet before the application of the pulsating field, both for small (50 nm) and large (200–250 nm) nanoparticles. The highly efficient gene transfer already within 5 min shows that this technique is a powerful tool for future in vivo studies, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs.

Superparamagnetic Nanoparticles as a Powerful Systems Biology Characterization Tool in the Physiological Context

Recently, functionalized superparamagnetic iron oxide nanoparticles (SPIONs) have been utilized for protein separation and therapeutic delivery of DNA and drugs. The development of new methods and tools for the targeting and identification of specific biomolecular interactions within living systems is of great interest in the fields of systems biology, target and drug identification, drug delivery, and diagnostics. Magnetic separation of organelles and proteins from complex whole-cell lysates allows enrichment and elucidation of intracellular interaction partners for a specific immobilized protein or peptide on the surface of SPIONs.

PRODUCTION AND BIOFUNCTIONALIZATION OF MAGNETIC NANOBEADS FOR MAGNETIC SEPARATION OF MESSENGER RNA

The synthesis of nanosized beads of superparamagnetic iron oxide nanoparticles coated with 3-(aminopropyl)triethoxysilane is reported in this paper. The resulting beads are agglomerates of SPIONs with an open fractal like structure. These beads have been examined by means of transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and attenuated total reflection Fourier transformation infrared spectroscopy (ATR-FTIR). The resulting beads with a size of 88 nm have been further biofunctionalized with avidin and biotinylated oligo(dT).