Metallic Fe-Au Barcode Nanowires as a Simultaneous T Cell Capturing and Cytokine Sensing Platform for Immunoassay at the Single-Cell Level.

Barcode nanowires (BNWs) composed of multiple layered segments of different materials are attractive to bioengineering field due to their characteristics that allow the adjustment of physicochemical properties and conjugation with two or more types of biomolecules to facilitate multiple tasks. Here, we report a metallic Fe (iron)-Au (gold) BNW-based platform for capturing CD8 T cells and the interferon-γ (γ) they secrete, both of which play key roles in controlling infectious diseases such as tuberculosis, at the single-cell level. We also describe an efficient approach for conjugating distinct antibodies, which recognize different epitopes to appropriate materials. The platform achieved detection even with 4.45-35.6 µg mL-1 of BNWs. The T cell capture efficiency was close to 100% and the detection limit for interferon-γ was 460 pg mL-1. This work presents a potential guideline for the design of single-cell immunoassay platforms for eliminating diagnostic errors by unambiguously identifying disease-relevant immune mediators.

Magnetization reversal of ferromagnetic nanosprings affected by helical shape.

Helicity, a natural property of macro-, micro-, and nano-objects, potentially offers a new dimension to mechanical and electromagnetic applications for creating emerging nanodevices, such as nanorobots, nanomagnets, nanosensors, and high-density magnetic memory. Helical magnetic nanosprings are unique objects with remarkable magnetic properties, including the absence of stray fields in remanence owing to the chiral geometry, which makes them promising for data storage devices, nanoelectromechanical systems, and biomedical usage. Here, we investigated Co and CoFe nanospring arrays electrodeposited in highly ordered nanoporous templates. We report helical-shape-driven magnetization reversal of the nanosprings in comparison with the behavior of dipolarly coupled nanowires. We reveal two magnetization reversal modes depending on the orientation of the external magnetic field: coherent rotation of magnetization in the longitudinal geometry and three-dimensional vortex domain wall motion in the transverse geometry. The experimental findings are supported by analytical calculations and micromagnetic simulations that help to explain the field-dependent spin configurations observed by magnetic force microscopy.

Synthesis of Co nanotubes by nanoporous template-assisted electrodeposition via the incorporation of vanadyl ions.

We report a facile fabrication concept for nanotubes (NTs) based upon template-assisted electrodeposition, which is widely applied for metallic nanowire (NW) synthesis. Co NTs have been synthesized into nanoporous anodized aluminum oxide (AAO) templates via electrodeposition by simply adding a small amount of chemicals including vanadyl ions (VO2+).