Using Biofunctional Magnetic Nanoparticles to Capture Vancomycin-Resistant Enterococci and Other Gram-Positive Bacteria at Ultralow Concentration

Abstract

Covalently linked to vancomycin (Van), chemically stable and highly magnetic anisotropic FePt magnetic nanoparticles (3−4 nm) become water-soluble and capture vancomycin-resistant enterococci (VRE) and other Gram-positive bacteria at concentrations ∼10¹ cfu/mL via polyvalent ligand−receptor interactions. When a pyramidal end of a magnet “focuses” the nanoparticles into ∼1 mm² area, the bacteria can be observed by an optical microscope and further identified by electron micrograph (EM). Compared to the conventional use of magnetic particles (with the sizes of 1−5 μm) in biological separation or drug delivery, magnetic nanoparticles, combined with specific receptor−ligand interactions, promise a sensitive and rapid protocol to detect pathogens.