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.

• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Ammonia (NH₃) production is a critical industrial process, as ammonia is a key component in fertilizers, essential for global agriculture and food production. However, the current method of synthesizing ammonia, the Haber-Bosch process, is highly energy-intensive, and relies on fossil fuels, contributing substantially to greenhouse gas emissions. Moreover, the centralized nature of the Haber-Bosch process limits its accessibility in remote or resource-limited areas. Photochemical synthesis of ammonia, provides an alternate lower energy, carbon-free pathway compared to the prevailing industrial methods. The photoconversion of nitrate anions, often present in wastewater, offers a greener, more sustainable, and energy-efficient route for both ammonia-generation and wastewater treatment. Photochemical and chemical synthesis of ammonia requires intensive mass-transfer processes, which limits the efficiency of the method. To change the game, in this work, a key new technology of ammonia-generation, a catalytic ammonia generation (AmmoGen) microrobot, which converts nitrate to ammonia using renewable light energy is reported. The magnetic propulsion of the AmmoGen microrobots significantly enhances mass-transfer, and expedites the photosynthesis of ammonia. Overall, this "proof-of-concept" study demonstrates that microrobots can aid in catalytic small molecule activation and generation of value-added products; and are envisaged to pave the way toward new sustainable technologies for catalysis.

• Klíčová slova
• ammonia, magnetically driven, microrobots, nitrate reduction, photosynthesis,
• Publikační typ
• časopisecké články MeSH

Magnetic La(0.75)Sr(0.25)MnO(3) nanoparticles possessing an approximately 20-nm-thick silica shell (LSMO(0.25)@SiO(2) ) were characterised and tested for the isolation of PCR-ready bacterial DNA. The results presented here show that the nanoparticles do not interfere in PCR. DNA was apparently reversibly adsorbed on their silica shell from the aqueous phase system (16% PEG 6000-2 M NaCl). The method proposed was used for DNA isolation from complex food samples (dairy products and probiotic food supplements). The isolated DNA was compatible with PCR. The main advantages of the nanoparticles tested for routine use were their high colloidal stability allowing a more precise dosage and therefore high reproducibility of DNA isolation.

• MeSH
• DNA bakterií chemie   izolace a purifikace   MeSH
• Lactobacillus cytologie   genetika   MeSH
• lanthan chemie   MeSH
• magnetické jevy * MeSH
• magnetismus MeSH
• nanočástice chemie   MeSH
• oxid křemičitý chemie   MeSH
• oxidy chemie   MeSH
• polymerázová řetězová reakce MeSH
• sloučeniny manganu chemie   MeSH
• stroncium chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA bakterií MeSH
• lanthan MeSH
• manganese oxide MeSH Prohlížeč
• oxid křemičitý MeSH
• oxidy MeSH
• sloučeniny manganu MeSH
• stroncium MeSH

Prostate cancer is the most commonly diagnosed tumor disease in men, and its treatment is still a big challenge in standard oncology therapy. Magnetically actuated microrobots represent the most promising technology in modern nanomedicine, offering the advantage of wireless guidance, effective cell penetration, and non-invasive actuation. Here, new biodegradable magnetically actuated zinc/cystine-based microrobots for in situ treatment of prostate cancer cells are reported. The microrobots are fabricated via metal-ion-mediated self-assembly of the amino acid cystine encapsulating superparamagnetic Fe3 O4 nanoparticles (NPs) during the synthesis, which allows their precise manipulation by a rotating magnetic field. Inside the cells, the typical enzymatic reducing environment favors the disassembly of the aminoacidic chemical structure due to the cleavage of cystine disulfide bonds and disruption of non-covalent interactions with the metal ions, as demonstrated by in vitro experiments with reduced nicotinamide adenine dinucleotide (NADH). In this way, the cystine microrobots served for site-specific delivery of Zn2+ ions responsible for tumor cell killing via a "Trojan horse effect". This work presents a new concept of cell internalization exploiting robotic systems' self-degradation, proposing a step forward in non-invasive cancer therapy.

• Klíčová slova
• cysteine, magnetic actuation, micromotors, nanorobots, self-propulsion, tumors,
• MeSH
• cystin * MeSH
• lidé MeSH
• nádory prostaty * MeSH
• zinek MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cystin * MeSH
• zinek MeSH

The forefront of micro- and nanorobot research involves the development of smart swimming micromachines emulating the complexity of natural systems, such as the swarming and collective behaviors typically observed in animals and microorganisms, for efficient task execution. This study introduces magnetically controlled microrobots that possess polymeric sequestrant "hands" decorating a magnetic core. Under the influence of external magnetic fields, the functionalized magnetic beads dynamically self-assemble from individual microparticles into well-defined rotating planes of diverse dimensions, allowing modulation of their propulsion speed, and exhibiting a collective motion. These mobile microrobotic swarms can actively capture free-swimming bacteria and dispersed microplastics "on-the-fly", thereby cleaning aquatic environments. Unlike conventional methods, these microrobots can be collected from the complex media and can release the captured contaminants in a second vessel in a controllable manner, that is, using ultrasound, offering a sustainable solution for repeated use in decontamination processes. Additionally, the residual water is subjected to UV irradiation to eliminate any remaining bacteria, providing a comprehensive cleaning solution. In summary, this study shows a swarming microrobot design for water decontamination processes.

• Klíčová slova
• collective motion, magnetically driven, micromotors, microplastics, self-assembly, swarming behavior, water purification,
• MeSH
• Bacteria izolace a purifikace   MeSH
• Escherichia coli izolace a purifikace   MeSH
• magnetické pole MeSH
• mikroplasty * chemie   MeSH
• polymery chemie   MeSH
• robotika * přístrojové vybavení   MeSH
• velikost částic MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Adsorption and advanced oxidation processes, especially photocatalysis, are amongst the most common water treatment methodologies. Unfortunately, using each of these techniques independently does not fully eliminate the pollutants of diverse nature, which are present in wastewater. Here, an avenue for multifunctional materials for water treatment is opened by reporting for the first time the preparation, characterization, and study of the properties of a novel multifunctional nanocomposite with both adsorption and visible-light-driven photocatalysis abilities. These multifunctional nanocomposites, namely iron (II, III) oxide/poly(N-isopropylacrylamide-co-methacrylic acid)/silver-titanium dioxide (Fe3O4/P(NIPAM-co-MAA)/Ag-TiO2), are prepared by combining magnetic polymeric microspheres (Fe3O4/P(NIPAM-co-MAA)) with silver-decorated titanium dioxide nanoparticles (Ag-TiO2 NPs). Cationic dyes, such as basic fuchsin (BF), can be adsorbed by the nanocomposites thanks to the carboxylic groups of Fe3O4/P(NIPAM-co-MAA) microspheres. Concomitantly, the presence of Ag-TiO2 NPs endows the system with the visible-light-driven photocatalytic degradation ability toward antibiotics such as ciprofloxacin (CIP) and norfloxacin (NFX). Furthermore, the proposed nanocomposites show antibacterial activity toward Escherichia coli (E. coli), thanks to the presence of silver nanoparticles (Ag NPs). Due to the superparamagnetic properties of iron (II, III) oxide nanoparticles (Fe3O4 NPs), the nanocomposites can be also recycled and reused, after the cleaning process, by using an external magnetic field.

• Klíčová slova
• adsorption, dyes and antibiotics, multifunctionality, recycling, visible‐light‐driven photocatalysis,
• Publikační typ
• časopisecké články MeSH

Micro/nanomotors are capable of a wide variety of tasks related, i.e., to biomedical or environmental applications. Light-driven semiconductor-based micromotors are especially appealing, as they can split surrounding water via light irradiation, and therefore, they can move infinitely. However, their motion is typically limited to in-plane motion with four degrees of freedom (4DoF) or even pseudo-1D motion with 2DoF. Herein, magnetically steerable tubular TiO2 /Fe3 O4 /CdS micromotors, termed microsubmarines, with 6DoF motion, based on a fuel-free design where surrounding water acts as fuel upon visible light irradiation, are presented, with an average velocity of 7.9 µm s-1 . Besides, the generation of radicals via such water splitting aids the photocatalytic chemicals degradation with the potential to use solar radiation. A light-induced self-electrophoretic mechanism is responsible for the self-propulsion and can be used to predict the motion direction based on the structure and composition. Finally, the TiO2 /Fe3 O4 /CdS microsubmarines are tested in a proof-of-concept application of high-energy explosive, e.g., picric acid, photocatalytic degradation, with the best performance owing to the versatility of 6DoF motion, the surface coating with amorphous TiO2 layer, and UV light. The results can help optimize light-active micromotor design for potential national security and environmental application, hydrogen evolution, and target cargo delivery.

• Klíčová slova
• explosive decontamination, micromotor, six degrees of freedom, visible-light-driven, water fuel,
• MeSH
• dekontaminace MeSH
• světlo MeSH
• voda * MeSH
• vodík MeSH
• výbušné látky * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda * MeSH
• vodík MeSH
• výbušné látky * MeSH

Bacterial biofilms are complex multicellular communities that adhere firmly to solid surfaces. They are widely recognized as major threats to human health, contributing to issues such as persistent infections on medical implants and severe contamination in drinking water systems. As a potential treatment for biofilms, this work proposes two strategies: (i) light-driven ZnFe2O4 (ZFO)/Pt microrobots for photodegradation of biofilms and (ii) magnetically driven ZFO microrobots for mechanical removal of biofilms from surfaces. Magnetically driven ZFO microrobots were realized by synthesizing ZFO microspheres through a low-cost and large-scale hydrothermal synthesis, followed by a calcination process. Then, a Pt layer was deposited on the surface of the ZFO microspheres to break their symmetry, resulting in self-propelled light-driven Janus ZFO/Pt microrobots. Light-driven ZFO/Pt microrobots exhibited active locomotion under UV light irradiation and controllable motion in terms of "stop and go" features. Magnetically driven ZFO microrobots were capable of maneuvering precisely when subjected to an external rotating magnetic field. These microrobots could eliminate Gram-negative Escherichia coli (E. coli) biofilms through photogenerated reactive oxygen species (ROS)-related antibacterial properties in combination with their light-powered active locomotion, accelerating the mass transfer to remove biofilms more effectively in water. Moreover, the actuation of magnetically driven ZFO microrobots allowed for the physical disruption of biofilms, which represents a reliable alternative to photocatalysis for the removal of strongly anchored biofilms in confined spaces. With their versatile characteristics, the envisioned microrobots highlight a significant potential for biofilm removal with high efficacy in both open and confined spaces, such as the pipelines of industrial plants.

• Klíčová slova
• biofilm, collective motion, magnetically driven, micromotors, microrobots, photocatalysis,
• MeSH
• antibakteriální látky * chemie   farmakologie   MeSH
• biofilmy * účinky záření   MeSH
• Escherichia coli * fyziologie   MeSH
• fotolýza účinky záření   MeSH
• mikrosféry MeSH
• platina chemie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• robotika přístrojové vybavení   MeSH
• ultrafialové záření MeSH
• železité sloučeniny chemie   MeSH
• zinek chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky * MeSH
• platina MeSH
• reaktivní formy kyslíku MeSH
• železité sloučeniny MeSH
• zinek MeSH

Modern micro/nanorobots can perform multiple tasks for biomedical and environmental applications. Particularly, magnetic microrobots can be completely controlled by a rotating magnetic field and their motion powered and controlled without the use of toxic fuels, which makes them most promising for biomedical application. Moreover, they are able to form swarms, allowing them to perform specific tasks at a larger scale than a single microrobot. In this work, they developed magnetic microrobots composed of halloysite nanotubes as backbone and iron oxide (Fe3 O4 ) nanoparticles as magnetic material allowing magnetic propulsion and covered these with polyethylenimine to load ampicillin and prevent the microrobots from disassembling. These microrobots exhibit multimodal motion as single robots as well as in swarms. In addition, they can transform from tumbling to spinning motion and vice-versa, and when in swarm mode they can change their motion from vortex to ribbon and back again. Finally, the vortex motion mode is used to penetrate and disrupt the extracellular matrix of Staphylococcus aureus biofilm colonized on titanium mesh used for bone restoration, which improves the effect of the antibiotic's activity. Such magnetic microrobots for biofilm removal from medical implants could reduce implant rejection and improve patients' well-being.

• Klíčová slova
• collective behavior, ribbons, swarms, vortices,
• MeSH
• biofilmy * MeSH
• fyzikální jevy MeSH
• lidé MeSH
• magnetické pole MeSH
• pohyb těles MeSH
• titan * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• titan * MeSH

A microtube implosion driven by ultraintense laser pulses is used to produce ultrahigh magnetic fields. Due to the laser-produced hot electrons with energies of mega-electron volts, cold ions in the inner wall surface implode towards the central axis. By pre-seeding uniform magnetic fields on the kilotesla order, the Lorenz force induces the Larmor gyromotion of the imploding ions and electrons. Due to the resultant collective motion of relativistic charged particles around the central axis, strong spin current densities of [Formula: see text] peta-ampere/[Formula: see text] are produced with a few tens of nm size, generating megatesla-order magnetic fields. The underlying physics and important scaling are revealed by particle simulations and a simple analytical model. The concept holds promise to open new frontiers in many branches of fundamental physics and applications in terms of ultrahigh magnetic fields.

• Publikační typ
• časopisecké články MeSH