Remote Actuation of Magnetic Nanoparticles For Cancer Cell Selective Treatment Through Cytoskeletal Disruption.

Motion of micron and sub-micron size magnetic particles in alternating magnetic fields can activate mechanosensitive cellular functions or physically destruct cancer cells. However, such effects are usually observed with relatively large magnetic particles (>250 nm) that would be difficult if at all possible to deliver to remote sites in the body to treat disease. Here we show a completely new mechanism of selective toxicity of superparamagnetic nanoparticles (SMNP) of 7 to 8 nm in diameter to cancer cells.

Diffusion of Drug Delivery Nanoparticles into Biogels Using Time-Resolved MicroMRI.

Nanoparticle-based therapeutic agents can in some cases provide selective delivery to tumors, yet this field would greatly benefit from more detailed understanding of particle transport into and within tumor tissue. To provide fundamental information for optimizing interstitial transport of polymeric nanoparticles, we have developed a quantitative approach employing real-time analysis of nanoparticle diffusion into bulk biological hydrogels using microMRI. We use two distinct imaging approaches to probe the migration of two novel "theranostic" polymeric agents (combining drug delivery and contrast agent functions) into bulk hydrogels.

Manganese graft ionomer complexes (MaGICs) for dual imaging and chemotherapy.

Novel manganese graft ionomer complexes (MaGICs) that contain Mn ions complexed with a polyaminobisphosphonate-g-poly(ethylene oxide) (PEO) copolymer were developed for use as T-weighted contrast agents for MRI. The complexes exhibited good colloidal stability without release of free manganese and did not result in any in vitro toxicity against mouse hepatocytes. T relaxivities of the MaGICs at physiological pH were 2-10 times higher than that of a commercial manganese-based positive contrast agent.

Magnetic Nanoclusters with Hydrophilic Spacing for Dual Drug Delivery and Sensitive Magnetic Resonance Imaging.

Magnetic Block Ionomer Clusters () with hydrophilic ionic cores and nonionic coronas have been prepared that have ultrahigh transverse NMR relaxivities together with capacities for incorporating high concentrations of polar antibiotic payloads. Magnetite-polymer nanoparticles were assembled by adsorbing the polyacrylate block of an aminofunctional poly(ethylene oxide--acrylate) (HN-PEO--PAA) copolymer onto magnetite nanoparticles. The PEO blocks extended into aqueous media to keep the nanoparticles dispersed.

Changing the enzyme reaction rate in magnetic nanosuspensions by a non-heating magnetic field.

werden Enzyme, die auf magnetischen Nanopartikeln (MNPs) immobilisiert sind, beim Anlegen von magnetischen Feldern. Diese Veränderungen resultieren aus der erneuten Ausrichtung der MNPs im AC-Magnetfeld, die mit den MNP verknüpfte Polymerketten unter Belastung setzt. Für immobilisierte Enzymmoleküle auf einem MNP-Aggregat ergeben sich dadurch Deformationen und irreversible (oder lange anhaltende) Konformationsän-derungen.