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As one of the most important parameters of the nanomotors’ motion, precise speed control of enzyme-based nanomotors is highly desirable in many bioapplications. However, owing to the stable physiological environment, it is still very difficult to in situ manipulate the motion of the enzyme-based nanomotors. Herein, inspired by the brakes on vehicles, the near-infrared (NIR) “optical brakes” are introduced in the glucose-driven enzyme-based mesoporous nanomotors to realize remote speed regulation for the first time. The novel nanomotors are rationally designed and fabricated based on the Janus mesoporous nanostructure, which consists of the SiO2@Au core@shell nanospheres and the enzymes-modified periodic mesoporous organosilicas (PMOs). The nanomotor can be driven by the biofuel of glucose under the catalysis of enzymes (glucose oxidase/catalase) on the PMO domain. Meanwhile, the Au nanoshell at the SiO2@Au domain enables the generation of the local thermal gradient under the NIR light irradiation, driving the nanomotor by thermophoresis. Taking advantage of the unique Janus nanostructure, the directions of the driving force induced by enzyme catalysis and the thermophoretic force induced by NIR photothermal effect are opposite. Therefore, with the NIR optical speed regulators, the glucose-driven nanomotors can achieve remote speed manipulation from 3.46 to 6.49 μm/s (9.9–18.5 body-length/s) at the fixed glucose concentration, even after covering with a biological tissue. As a proof of concept, the cellar uptake of the such mesoporous nanomotors can be remotely regulated (57.5–109 μg/mg), which offers great potential for designing smart active drug delivery systems based on the mesoporous frameworks of this novel nanomotor.

Nanofibers have been attracting growing attention owing to their outstanding physicochemical and structural properties as well as diverse and intriguing applications. Electrospinning has been known as a simple, flexible, and multipurpose technique for the fabrication of submicro scale fibers. Throughout the last two decades, numerous investigations have focused on the employment of electrospinning techniques to improve the characteristics of fabricated fibers. This review highlights the state of the art of melt electrospinning and clarifies the major categories based on multitemperature control, gas assist, laser melt, coaxial, and needleless designs. In addition, we represent the effect of melt electrospinning process parameters on the properties of produced fibers. Finally, this review summarizes the challenges and obstacles connected to the melt electrospinning technique.

Graphitic carbon nitrides (gCNs) are promising materials for multidisciplinary catalytic applications due to their inimitable physicochemical merits, thermal-physical-chemical stability, and rich electron density. The catalytic properties of gCNs are determined by their structure and composition; therefore, various methods have been developed for the rational synthesis of gCNs with different morphologies and compositions. Unlike other gCN nanostructures, one-dimensional (1D) nanostructures possess an outstanding accessible surface area, multiple adsorption sites, active catalytic sites, aspect ratio, and short electron-diffusion that enable their utilization in various gas conversion reactions. The thermal CO oxidation reaction (CO OR) on either gCNs or other catalysts is important in industrial, fundamental, and environmental issues; however, the reviews on 1D gCNs for CO oxidation is not yet reported. This chapter highlights the fabrication methods of 1D gCN nanostructures (i.e., nanotubes, nanorods, nanofibers, and needles) and their mechanisms and utilization in thermal CO ORs. Lastly, the current challenges and future prospects on gCNs for CO ORs are also discussed.

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