Identification of toxin inhibitors using a magnetic nanosensor-based assay.

A magnetic nanosensor-based method is described to screen a library of drugs for potential binding to toxins. Screening is performed by measuring changes in the magnetic relaxation signal of the nanosensors (bMR nanosensors) in aqueous suspension upon addition of the toxin. The Anthrax lethal factor (ALF) is selected as a model toxin to test the ability of our bMR nanosensor-based screening method to identify potential inhibitors of the toxin.

Assessment of molecular interactions through magnetic relaxation.

The dissociation constant (K) of various molecular interactions was determined using a novel competition assay with binding magnetic relaxation nanosensors (bMRs). In this assay, changes in the magnetic relaxation of an aqueous suspension of the nanosensors facilitate the fast determination of K values using nanomolar protein concentrations.

Cell-specific, activatable, and theranostic prodrug for dual-targeted cancer imaging and therapy.

Herein we describe the design and synthesis of a folate-doxorubicin conjugate with activatable fluorescence and activatable cytotoxicity. In this study we discovered that the cytotoxicity and fluorescence of doxorubicin are quenched (OFF) when covalently linked with folic acid. Most importantly, when the conjugate is designed with a disulfide bond linking the targeting folate unit and the cytotoxic doxorubicin, a targeted activatable prodrug is obtained that becomes activated (ON) within the cell by glutathione-mediated dissociation and nuclear translocation, showing enhanced fluorescence and cellular toxicity.

Identification of molecular-mimicry-based ligands for cholera diagnostics using magnetic relaxation.

When covalently bound to an appropriate ligand, iron oxide nanoparticles can bind to a specific target of interest. This interaction can be detected through changes in the solution's spin-spin relaxation times (T2) via magnetic relaxation measurements. In this report, a strategy of molecular mimicry was used in order to identify targeting ligands that bind to the cholera toxin B subunit (CTB).