Manipulation and navigation of micro and nanoswimmers in different fluid environments can be achieved by chemicals, external fields, or even motile cells. Many researchers have selected magnetic fields as the active external actuation source based on the advantageous features of this actuation strategy such as remote and spatiotemporal control, fuel-free, high degree of reconfigurability, programmability, recyclability, and versatility. This review introduces fundamental concepts and advantages of magnetic micro/nanorobots (termed here as “MagRobots”) as well as basic knowledge of magnetic fields and magnetic materials, setups for magnetic manipulation, magnetic field configurations, and symmetry-breaking strategies for effective movement. These concepts are discussed to describe the interactions between micro/nanorobots and magnetic fields. Actuation mechanisms of flagella-inspired MagRobots (i.e., corkscrew-like motion and traveling-wave locomotion/ciliary stroke motion) and surface walkers (i.e., surface-assisted motion), applications of magnetic fields in other propulsion approaches, and magnetic stimulation of micro/nanorobots beyond motion are provided followed by fabrication techniques for (quasi-)spherical, helical, flexible, wire-like, and biohybrid MagRobots. Applications of MagRobots in targeted drug/gene delivery, cell manipulation, minimally invasive surgery, biopsy, biofilm disruption/eradication, imaging-guided delivery/therapy/surgery, pollution removal for environmental remediation, and (bio)sensing are also reviewed. Finally, current challenges and future perspectives for the development of magnetically powered miniaturized motors are discussed.

The trade-offs between photoelectrode efficiency and stability significantly hinder the practical application of silicon-based photoelectrochemical devices. Here, we report a facile approach to decouple the trade-offs of silicon-based photocathodes by employing crystalline TiO2 with graded oxygen defects as protection layer. The crystalline protection layer provides high-density structure and enhances stability, and at the same time oxygen defects allow the carrier transport with low resistance as required for high efficiency. The silicon-based photocathode with black TiO2 shows a limiting current density of ~35.3 mA cm−2 and durability of over 100 h at 10 mA cm−2 in 1.0 M NaOH electrolyte, while none of photoelectrochemical behavior is observed in crystalline TiO2 protection layer. These findings have significant suggestions for further development of silicon-based, III–V compounds and other photoelectrodes and offer the possibility for achieving highly efficient and durable photoelectrochemical devices.

The efficiency and stability of narrow-gap semiconductor-based photoelectrodes are two fundamental factors for realizing their industrial solar-to-fuel conversion.

Ubiquitous pollution by microplastics is causing significant deleterious effects on marine life and human health through the food chain and has become a big challenge for the global ecosystem. It is of great urgency to find a cost‐efficient and biocompatible material to remove microplastics from the environment. Mimicking basic characteristics of the adhesive chemistry practiced by marine mussels, adhesive polydopamine (PDA)@Fe3O4 magnetic microrobots (MagRobots) are prepared by coating Fe3O4 nanoparticles with a polymeric layer of dopamine via one‐step self‐polymerization. In addition, lipase is loaded on the PDA@Fe3O4 MagRobots’ surface to perform microplastic enzymatic degradation. The synthesized MagRobots, which are externally triggered by transversal rotating magnetic field, have the capacity to clear away the targeted microplastics due to their strong sticky characteristics. With the adhesive PDA@Fe3O4 MagRobots on their surfaces, the microplastics can be navigated along an arbitrarily predefined path by a rotating field and removed using a directional magnetic field. Such adhesive MagRobots are envisioned to be used in swarms to remove microplastics from aqueous environments.

A novel thermochromic WO3/VO2/WO3 sandwich structure was deliberately designed and deposited by a reactive magnetron sputtering technique.

Silicon (Si) requires a protection layer to maintain stable and long-time photoanodic reaction. However, poor charge separation and transfer are key constraint factors in protection layer/Si photoanodes that reduce their water-splitting efficiency. Here, a simultaneous enhancement of charge separation and transfer in Nb-doped NiO /Ni/black-Si photoanodes induced by plasma treatment is reported. The optimized photoanodes yield the highest charge-separation efficiency (η ) of ≈81% at 1.23 V versus reversible hydrogen electrode, corresponding to the photocurrent density of ≈29.1 mA cm . On the basis of detailed characterizations, the concentration and species of oxygen defects in the NiO -based layer are adjusted by synergistic effect of Nb doping and plasma treatment, which are the dominating factors for forming suitable band structure and providing a favorable hole-migration channel. This work elucidates the important role of oxygen defects on charge separation and transfer in the protection layer/Si-based photoelectrochemical systems and is encouraging for application of this synergistic strategy to other candidate photoanodes.

The increasing prevalence of implant-associated infections (IAIs) imposes a heavy burden on patients and medical providers. Bacterial biofilms are recalcitrant to antiseptic drugs and local immune defense and can attenuate host proinflammatory response to interfere with bacterial clearance. Zinc oxide nanoparticles (ZnO NPs) play a dual role in antibacterial and immunomodulatory activities but compromise the cytocompatibility because of their intracellular uptake. Here, ZnO NPs were immobilized on titanium to form homogeneous nanofilms (from discontinuous to continuous) through magnetron sputtering, and the possible antimicrobial activity and immunomodulatory effect of nano-ZnO films were investigated. Nano-ZnO films were found to prohibit sessile bacteria more than planktonic bacteria in vitro, and the antibacterial effect occurred in a dose-dependent manner. Using a novel mouse soft tissue IAI model, the in vivo results revealed that nano-ZnO films possessed outstanding antimicrobial efficacy, which could not be ascribed solely to the intrinsic anti-infective activity of nano-ZnO films observed in vitro. Macrophages and polymorphonuclear leukocytes (PMNs), two important factors in innate immune response, were cocultured with nano-ZnO and bacteria/lipopolysaccharide in vitro, and the nano-ZnO films could enhance the antimicrobial efficacy of macrophages and PMNs through promoting phagocytosis and secretion of inflammatory cytokines. This study provides insights into the anti-infective activity and mechanism of ZnO and consolidates the theoretical basis for future clinical applications of ZnO.

The semiconductor–metal transition temperature of a VO2 film can be decreased to 330 K through electron transfer in the VO2–graphene–Ge structure.