2D‐Material‐Integrated Micromachines: Competing Propulsion Strategy and Enhanced Bacterial Disinfection

Abstract

powered by chemical reactions encounters an arduous challenge, that is, the translocation speed is often compromised grievously in ionic suspension; [6] the alleviation of such an issue requires investigating new materials, schemes, and understanding of the complex mechanisms of locomotion. Furthermore, this far, the materials employed in chemical micro/ nanomotors that can operate continuously largely rely on noble metals such as Pt and Au combined with semiconductor oxides, for example, TiO 2 and ZnO, [1a,7] which are either expensive or are restricted in the UV region for light-powered chemical propulsion. It is highly desirable to explore new materials that can enhance the performance of chemical motors in an inexpensive, broadly applicable, and functional manner. [8] In the last decade, 2D materials, such as graphene, boron nitride, and transitionmetal-dichalcogenides have emerged as a promising class of materials owing to their 2D stacking atomic structures, high environmental stability, low cost, and the associated unique chemical and physical properties. [9] For instance, the 2D-structured molybdenum disulfide (MoS 2 ) possesses distinct semiconductor properties. The bandgap can be facilely tuned by its thickness from 1.2 eV (in bulk) to 1.8 eV (monolayer structure), accompanied by a transition from indirect to direct semiconductor bandgap structure, [10] which corresponds to an absorption edge of 1033.3 to 688.9 nm, mainly in the visible region. As a result, MoS 2 can respond to visible light with rapid optoelectric switching with a rise and decay time of 8 and 16 ms, respectively. [9a] Due to the 2D crystal structure, MoS 2 can be routinely made into van der Waals terminated thin films with lowdensity surface defects, ideal for flexible electronics. [11] Of paramount importance, when engineered with high-density defects, MoS 2 nanostructures demonstrate excellent chemical catalysis for hydrogen-evolution reduction, with a theoretical value close to that of Pt while at a much lower cost. [12] Furthermore, by leveraging the chemical properties of their defects, MoS 2 can readily react with mercury and be chemically functionalized for click-chemistry reactions. [9a] When applied in an aqueous medium, MoS 2 nanostructures are chemically stable even in an acid environment. [13] All these properties made the 2D MoS 2 a highly potential material that could make a remarkable impact on the field of micro/nanomachines, motors, and robots. For instance, MoS 2 was integrated into Pt nanotubes and demonstrated the controllable loading and release of doxorubicin. [14] 2D transition-metal-dichalcogenide materials, such as molybdenum disulfide (MoS 2 ) have received immense interest owing to their remarkable structureendowed electronic, catalytic, and mechanical properties for applications in optoelectronics, energy storage, and wearable devices. However, 2D materials have been rarely explored in the field of micro/nanomachines, motors, and robots. Here, MoS 2 with anatase TiO 2 is successfully integrated into an...

Portable Bulk-Water Disinfection by Live Capture of Bacteria with Divergently Branched Porous Graphite in Electric Fields

“…[15,16] Notably, the recent advances in micro/nanomachines powered by external stimuli, such as light and magnetic fields, demonstrate the feasibility in decontaminating bacteria, organic molecules, toxic metal ions, and microplastics. [17][18][19][20][21][22] However, most research works only treat water of a fraction of a milliliter confined in a microwell, are still at the concept-proof stage.…”

Drug-Free Antimicrobial Nanomotor for Precise Treatment of Multidrug-Resistant Bacterial Infections

“…Bacterial infections are seriously threatening human life and health worldwide, and people must pay great attention to them. − Currently, commonly used antimicrobial therapy is reliant on a broad-spectrum strategy, namely, the use of commercially available antibiotics, which, if overused, may generate multidrug-resistant bacteria or resistant biofilms. − As such, innovative antimicrobial research has become extremely significant . Despite drastic advances in developing different antibacterial agents (e.g., metal nanomedicine, − strong oxidant, , heat, ,, antimicrobial peptides, ,, or catalytic treatment − ) to avoid drug resistance, infections still often cannot be effectively treated, primarily because of the passive diffusion of these agents leading to poor or even no matter–bacteria interactions. − Therefore, improving the mobility of antibacterial agents to break the bottleneck in infection treatment is challenging.…”

Portable Bulk-Water Disinfection by Live Capture of Bacteria with Divergently Branched Porous Graphite in Electric Fields

“…Notably, the recent advances in micro/nanomachines powered by external stimuli, including light, magnetic fields, and chemical fuels, have been applied in water treatment, including decontaminating bacteria. , The designed structures and actuation mechanisms of micro/nanomachines demonstrate enhanced efficiency in interacting with substances in water compared to their static counterparts. , Although such an approach is still largely at the proof-of-concept stage, e.g., treating water of a milliliter confined in a microwell, it inspires a different way of water purification.…”

“…32,33 The designed structures and actuation mechanisms of micro/nanomachines demonstrate enhanced efficiency in interacting with substances in water compared to their static counterparts. 32,34 Although such an approach is still largely at the proof-of-concept stage, e.g., treating water of a milliliter confined in a microwell, it inspires a different way of water purification.…”