The successful isolation of single layers from two-dimensional (2D) van der Waals (vdW)-layered materials has opened new frontiers in condensed matter physics and materials science. Their discovery and unique properties laid the foundation for exploring 1D counterparts. However, the isolation of 1D vdW-wired materials has thus far remained a challenge, and effective techniques are demanded. Here we report the facile synthesis of isolated transition-metal monochalcogenide MoTe nanowires by using carbon nanotubes (CNTs) as molds. Individual nanowires are perfectly separated by CNTs with a minimal interaction, enabling detailed characterization of the single wires. Transmission electron microscopy revealed unusual torsional motion of MoTe nanowires inside CNTs. Confinement of 1D vdW-wired materials to the nanotest tubes might open up possibilities for exploring unprecedented properties of the nanowires and their potential applications such as electromechanical switching devices.

We report a near-infrared (NIR) fluorescence and magnetic resonance (MR) dual-modal probe composed of fluorescent carbon nanotubes (CNTs) filled with paramagnetic Gd ions. The Gd-filled CNTs are synthesized by means of a vapor-phase technique using gadolinium halides as precursors, and host CNTs exhibit the strong photoluminescence even after Gd filling. We have investigated the NIR fluorescence and MR imaging in vivo as well as in vitro, and demonstrated that the Gd-filled CNTs can be used for the dual-modal imaging of tissues and vessels in the living mice.