Abstract: Disclosed are nanofluidic analytical devices. The devices employ a sample processing region that includes a plurality of fluidically connected sample handling elements that, in combination, affect a physical change on a sample introduced into the sample processing region. This physical change can include, for example, purification of an analyte of interest present in the sample, concentration of an analyte of interest present in the sample, chemical modification (e.g., cleavage and/or chemical derivatization) of an analyte of interest present in the sample, or a combination thereof. The analytical devices further include a nanochannel comprising a plurality of in-plane nanopores in series fluidically coupled to the sample processing region. The in-plane nanopores can be used to detect and/or analyze analyte(s) present in the sample following processing by the sample processing region. These analytical devices can advantageously provide for the label-free detection of single molecules.

Abstract: A method is disclosed for synthesizing core-shell nanoparticles or microparticles in an aqueous solution. A displacement reaction produces a protective, noble metal shell around nanoparticles or microparticles, for example a copper shell around cobalt nanoparticles. In an electroless displacement reaction in an aqueous solution, a less noble metal core is oxidized by cations of a more noble metal in solution, and the noble metal ions are reduced by the less noble atoms of the metal core, forming a thin layer of the reduced noble metal on the surface of the core metal. The formation of the nanoscale shell is self-terminating once the core is fully covered, because the core metal is then inaccessible for further redox reaction with ions in solution. The magnetic core is preferably a ferromagnetic metal, e.g., Co, Fe, Ni. The shell is a more noble metal, e.g., Cu, Ag, Au, Pt, or Pd.