The applications of nanomotors in the biomedical field have been attracting extensive attention. However, it remains a challenge to fabricate nanomotors in a facile way and effectively load drugs for active targeted therapy. In this work, we combine the microwave heating method and chemical vapor deposition (CVD) to fabricate magnetic helical nanomotors efficiently. The microwave heating method can accelerate intermolecular movement, which converts kinetic energy into heat energy and shortens the preparation time of the catalyst used for carbon nanocoil (CNC) synthesis by 15 times. Fe3O4 nanoparticles are in situ nucleated on the CNC surface by the microwave heating method to fabricate magnetically driven CNC/Fe3O4 nanomotors. In addition, we achieved precise control of the magnetically driven CNC/Fe3O4 nanomotors through remote manipulation of magnetic fields. Anticancer drug doxorubicin (DOX) is then efficiently loaded onto the nanomotors via π–π stacking interactions. Finally, the drug-loaded CNC/Fe3O4@DOX nanomotor can accurately accomplish cell targeting under external magnetic field control. Under short-time irradiation of near-infrared light, DOX can be quickly released onto target cells to effectively kill the cells. More importantly, CNC/Fe3O4@DOX nanomotors allow for single-cell or cell-cluster-targeted anticancer drug delivery, providing a dexterous platform to potentially perform many medically relevant tasks in vivo. The efficient preparation method and application in drug delivery are beneficial for future industrial production and provide inspiration for advanced micro/nanorobotic systems using the CNC as a carrier for a wide range of biomedical applications.

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Developing highly flexible, mechanically strong, and highly efficient microwave absorption materials is urgently needed to solve the electromagnetic (EM) wave pollution problems in the areas of fast-growing electronic devices. Herein, poly(vinylidene difluoride) (PVDF) composite nanofibrous mats combined with functionalized carbon nanotubes (CNTs) were fabricated by a facile electrospinning process. The hydrogen-bonding heterointerfaces between PVDF and acidified CNTs (a-CNTs) favored interfacial polarization relaxation compared with the covalent heterointerfaces between PVDF and aminated CNTs (NH 2 − CNTs), resulting in better microwave absorption performance. Furthermore, 4,4′-diaminodiphenylsulfone (DDS) was adopted as the chemical cross-linking agent. The PVDF nanocomposite nanofibrous mats with 0.25 wt % DDS exhibited excellent microwave absorbing properties with a minimum reflection loss (RL min ) of −30.4 dB at 7.2 GHz and a thickness of 3.4 mm as well as an effective absorption bandwidth of 5.0 GHz at a thickness of 1.6 mm. More importantly, the mechanical properties were improved simultaneously, because of the cross-linking reaction occurring within the PVDF nanofibers. A tensile strength and a modulus of 1.2 and 21.7 MPa were achieved, respectively. The provided strategy would facilitate the design of highly flexible and mechanically strong electrospun nanofibrous mats for microwave absorption applications.

Here, the authors propose a switchable all‐dielectric frequency selective surface (ADFSS), which is composed of two periodically placed high‐permittivity dielectric resonator (DR) arrays. If the two DR arrays are laminated together, the FSS presents band‐stop property; while if the two DR arrays are separated by a narrow gap, the FSS exhibits band‐pass property. The switching characteristic of the device can be explained with DR theory and effective medium theory. The experimental results of the switchable ADFSS demonstrate a fractional bandwidth of 22.2% and a large field of view in a wide band (from 11.9 to 14.8 GHz), which is consistent with the simulated results. The method can be readily extended to the design of on/off ADFSS at other frequencies.

Although NO2 detection based on metal oxide semiconductors (MOS) has received continuous attention, the sensing properties of MOS still need to be further improved for practical application. Carbon nanocoils (CNCs)...