Non-Destructive Evaluation of Thermal Aging in EPDM Rubber Using Electromagnetic Techniques.

This study investigates the use of eddy-current technology and impedance spectroscopy in sensing the change in rubber properties after it is exposed to accelerated thermal aging. The thermal aging process, by application of temperature and pressure over time, of ethylene propylene diene monomer (EPDM) rubbers containing both carbon black (CB) and graphene are investigated. Both eddy-current sensing and electrical impedance measurement techniques were used for electromagnetic analysis.

Remote Sensing of the Nano-Rheological Properties of Soft Materials Using Magnetic Nanoparticles and Magnetic AC Susceptometry.

We have developed a nano-rheological characterization tool to extract the frequency- and scale-dependent rheological properties of soft materials during oral processing. Taking advantage of AC susceptometry, the dynamic magnetization of magnetic nanoparticles blended in the matrix material is measured. The magnetic AC susceptibility spectra of the particles are affected by the viscosity and mechanical modulus of the matrix material and provide the rheological properties of the matrix.

Characterization of Binding of Magnetic Nanoparticles to Rolling Circle Amplification Products by Turn-On Magnetic Assay.

The specific binding of oligonucleotide-tagged 100 nm magnetic nanoparticles (MNPs) to rolling circle products (RCPs) is investigated using our newly developed differential homogenous magnetic assay (DHMA). The DHMA measures ac magnetic susceptibility from a test and a control samples simultaneously and eliminates magnetic background signal. Therefore, the DHMA can reveal details of binding kinetics of magnetic nanoparticles at very low concentrations of RCPs.

Homogeneous Differential Magnetic Assay.

Assays are widely used for detection of various targets, including pathogens, drugs, and toxins. Homogeneous assays are promising for the realization of point-of-care diagnostics as they do not require separation, immobilization, or washing steps. For low concentrations of target molecules, the speed and sensitivity of homogeneous assays have hitherto been limited by slow binding kinetics, time-consuming amplification steps, and the presence of a high background signal.

Development of a Sensitive Induction-Based Magnetic Nanoparticle Biodetection Method.

We developed a novel biodetection method for influenza virus based on AC magnetic susceptibility measurement techniques (the DynoMag induction technique) together with functionalized multi-core magnetic nanoparticles. The sample consisting of an incubated mixture of magnetic nanoparticles and rolling circle amplified DNA coils is injected into a tube by a peristaltic pump. The sample is moved as a plug to the two well-balanced detection coils and the dynamic magnetic moment in each position is read over a range of excitation frequencies.

Volume-amplified magnetic bioassay integrated with microfluidic sample handling and high- SQUID magnetic readout.

A bioassay based on a high- superconducting quantum interference device (SQUID) reading out functionalized magnetic nanoparticles (fMNPs) in a prototype microfluidic platform is presented. The target molecule recognition is based on volume amplification using padlock-probe-ligation followed by rolling circle amplification (RCA). The MNPs are functionalized with single-stranded oligonucleotides, which give a specific binding of the MNPs to the large RCA coil product, resulting in a large change in the amplitude of the imaginary part of the ac magnetic susceptibility.

Electrical properties of GaSb/InAsSb core/shell nanowires.

Temperature dependent electronic properties of GaSb/InAsSb core/shell and GaSb nanowires have been studied. Results from two-probe and four-probe measurements are compared to distinguish between extrinsic (contact-related) and intrinsic (nanowire) properties. It is found that a thin (2-3 nm) InAsSb shell allows low barrier charge carrier injection to the GaSb core, and that the presence of the shell also improves intrinsic nanowire mobility and conductance in comparison to bare GaSb nanowires.