Fluorescence-based sensing is a straightforward and powerful technique with high sensitivity for the detection of a wide range of chemical and biological analytes. Integrating the high sensing capabilities of fluorescent probes with wireless navigation systems can enable the extension of their operational range, even in challenging scenarios with limited accessibility or involving hazardous substances. This study presents the development of molecularly engineered magneto-fluorescent microrobots based on the push-pull quinonoids by incorporating magnetic nanoparticles using a reprecipitation approach with the aim of detecting high-energy explosives and antibiotics in aqueous environments. The magnetic components in the microrobots offer remotely controlled navigability toward the intended target areas under the guidance of external magnetic fields. Upon interactions with either explosives (picric acid) or antibiotics (tetracycline), the microrobots' intrinsic fluorescence switches to a "fluorescence off" state, enabling material-based intelligence for sensing applications. The molecular-level interactions that underlie "on-off" fluorescence state switching upon engagement with target molecules are elucidated through extensive spectroscopy, microscopy, and X-ray diffraction analyses. The microrobots' selectivity toward target molecules is achieved by designing microrobots with amine functionalities capable of intermolecular hydrogen bonding with the acidic hydroxyl group of picric acid, leading to the formation of water-soluble charge transfer picrate complexes through proton transfer. Similarly, proton transfer interactions play a key role in tetracycline detection. The selective fluorescence switching performance of microrobots in fluidic channel experiments illustrates their selective sensing intelligence for target molecules in an externally controlled manner, highlighting their promising characteristics for sensing applications in real-world scenarios.

• Keywords
• charge transfer complexes, environmental monitoring, fluorescence sensing, magnetic microrobots, organic pollutants,
• MeSH
• Anti-Bacterial Agents * analysis   MeSH
• Fluorescent Dyes * chemistry   MeSH
• Magnetite Nanoparticles * chemistry   MeSH
• Picrates MeSH
• Tetracycline * analysis   MeSH
• Water chemistry   MeSH
• Explosive Agents * analysis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents * MeSH
• Fluorescent Dyes * MeSH
• Magnetite Nanoparticles * MeSH
• picric acid MeSH Browser
• Picrates MeSH
• Tetracycline * MeSH
• Water MeSH
• Explosive Agents * 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.

• Keywords
• biofilm, collective motion, magnetically driven, micromotors, microrobots, photocatalysis,
• MeSH
• Anti-Bacterial Agents * pharmacology   chemistry   MeSH
• Biofilms * drug effects   MeSH
• Escherichia coli * drug effects   physiology   MeSH
• Microspheres MeSH
• Platinum chemistry   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Robotics * instrumentation   MeSH
• Ultraviolet Rays MeSH
• Ferric Compounds chemistry   pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents * MeSH
• Platinum MeSH
• Reactive Oxygen Species MeSH
• Ferric Compounds MeSH

Quantum dot-based materials have been found to be excellent platforms for biosensing and bioimaging applications. Herein, self-propelled microrobots made of graphene quantum dots (GQD-MRs) have been synthesized and explored as unconventional dynamic biocarriers toward the optical "on-the-fly" monitoring of DNA. As a first demonstration of applicability, GQD-MRs have been first biofunctionalized with a DNA biomarker (i.e., fluorescein amidite-labeled, FAM-L) via hydrophobic π-stacking interactions and subsequently exposed toward different concentrations of a DNA target. The biomarker-target hybridization process leads to a biomarker release from the GQD-MR surface, resulting in a linear alteration in the fluorescence intensity of the dynamic biocarrier at the nM range (1-100 nM, R2 = 0.99), also demonstrating excellent selectivity and sensitivity, with a detection limit as low as 0.05 nM. Consequently, the developed dynamic biocarriers, which combine the appealing features of GQDs (e.g., water solubility, fluorescent activity, and supramolecular π-stacking interactions) with the autonomous mobility of MRs, present themselves as potential autonomous micromachines to be exploited as highly efficient and sensitive "on-the-fly" biosensing systems. This method is general and can be simply customized by tailoring the biomarker anchored to the GQD-MR's surface.

• Keywords
• DNA biosensor, FRET, fluorescence, microrockets, self-propelled micromotors,
• MeSH
• Biomarkers MeSH
• Biosensing Techniques * methods   MeSH
• DNA chemistry   MeSH
• Graphite * chemistry   MeSH
• Nucleic Acid Hybridization MeSH
• Quantum Dots * chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biomarkers MeSH
• DNA MeSH
• Graphite * MeSH

The brewing industry will amass a revenue above 500 billion euros in 2022, and the market is expected to grow annually. This industrial process is based on a slow sugar fermentation by yeast (commonly Saccharomyces cerevisiae). Herein, we encapsulate yeast cells into a biocompatible alginate (ALG) polymer along Fe3O4 nanoparticles to produce magneto/catalytic nanostructured ALG@yeast-Fe3O4 BioBots. Yeast encapsulated in these biocompatible BioBots keeps their biological activity (growth, reproduction, and catalytic fermentation) essential for brewing. Catalytic fermentation of sugars into CO2 gas caused a continuous oscillatory motion of the BioBots in the solution. This BioBot motion is employed to enhance the beer fermentation process compared to static-free yeast cells. When the process is finished, magnetic actuation of BioBots is employed for their retrieval from the beer samples, which avoids the need of additional filtration steps. All in all, we demonstrate how an industrial process such as beer production can be benefited by miniaturized autonomous magneto/catalytic BioBots.

• Keywords
• beer, biohybrid, brewing, driven, fermentation, hydrogel, magnetic, robots,
• MeSH
• Fermentation MeSH
• Beer * analysis   MeSH
• Saccharomyces cerevisiae * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The recent COVID-19 pandemic has resulted in the massive discard of pandemic-related plastic wastes, causing serious ecological harm and a high societal burden. Most single-use face masks are made of synthetic plastics, thus their careless disposal poses a direct threat to wildlife as well as potential ecotoxicological effects in the form of microplastics. Here, we introduce a 1D magnetic photoactive microswarm capable of actively navigating, adhering to, and accelerating the degradation of the polypropylene microfiber of COVID-19 face masks. 1D microrobots comprise an anisotropic magnetic core (Fe3O4) and photocatalytic shell (Bi2O3/Ag), which enable wireless magnetic maneuvering and visible-light photocatalysis. The actuation of a programmed rotating magnetic field triggers a fish schooling-like 1D microswarm that allows active interfacial interactions with the microfiber network. The follow-up light illumination accelerates the disruption of the polypropylene microfiber through the photo-oxidative process as corroborated by morphological, compositional, and structural analyses. The active magnetic photocatalyst microswarm suggests an intriguing microrobotic solution to treat various plastic wastes and other environmental pollutants.

• MeSH
• COVID-19 * prevention & control   MeSH
• Humans MeSH
• Masks * MeSH
• Pandemics prevention & control   MeSH
• Plastics MeSH
• Polypropylenes MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Plastics MeSH
• Polypropylenes MeSH

Hybrid biological robots (biobots) prepared from living cells are at the forefront of micro-/nanomotor research due to their biocompatibility and versatility toward multiple applications. However, their precise maneuverability is essential for practical applications. Magnetotactic bacteria are hybrid biobots that produce magnetosome magnetite crystals, which are more stable than synthesized magnetite and can orient along the direction of earth's magnetic field. Herein, we used Magnetospirillum magneticum strain AMB-1 (M. magneticum AMB-1) for the effective removal of chlorpyrifos (an organophosphate pesticide) in various aqueous solutions by naturally binding with organic matter. Precision control of M. magneticum AMB-1 was achieved by applying a magnetic field. Under a programed clockwise magnetic field, M. magneticum AMB-1 exhibit swarm behavior and move in a circular direction. Consequently, we foresee that M. magneticum AMB-1 can be applied in various environments to remove and retrieve pollutants by directional control magnetic actuation.

• Keywords
• magnetic actuation, magnetotactic bacteria, micromotors, microrobots, nanorobots,
• MeSH
• Bacteria metabolism   MeSH
• Bacterial Proteins metabolism   MeSH
• Decontamination MeSH
• Magnetospirillum * metabolism   MeSH
• Ferrosoferric Oxide * MeSH
• Robotics methods   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Ferrosoferric Oxide * MeSH

Less than 1% of Earth's freshwater reserves is accessible. Industrialization, population growth and climate change are further exacerbating clean water shortage. Current water-remediation treatments fail to remove most pollutants completely or release toxic by-products into the environment. The use of self-propelled programmable micro- and nanoscale synthetic robots is a promising alternative way to improve water monitoring and remediation by overcoming diffusion-limited reactions and promoting interactions with target pollutants, including nano- and microplastics, persistent organic pollutants, heavy metals, oils and pathogenic microorganisms. This Review introduces the evolution of passive micro- and nanomaterials through active micro- and nanomotors and into advanced intelligent micro- and nanorobots in terms of motion ability, multifunctionality, adaptive response, swarming and mutual communication. After describing removal and degradation strategies, we present the most relevant improvements in water treatment, highlighting the design aspects necessary to improve remediation efficiency for specific contaminants. Finally, open challenges and future directions are discussed for the real-world application of smart micro- and nanorobots.

• Keywords
• Molecular machines and motors,
• Publication type
• Journal Article MeSH
• Review MeSH

The coronavirus disease 2019 (COVID-19) has prompted an urgent demand for nanotechnological solutions towards the global healthcare crisis, particularly in the field of diagnostics, vaccines, and therapeutics. As an emerging tool for nanoscience and technology, micro/nanorobots have demonstrated advanced performances, such as self-propelling, precise maneuverability, and remote actuation, thus hold great potential to provide breakthroughs in the COVID-19 pandemic. Here we show a plasmonic-magnetic nanorobot-based simple and efficient COVID-19 detection assay through an electronic readout signal. The nanorobots consist of Fe3O4 backbone and the outer surface of Ag, that rationally designed to perform magnetic-powered propulsion and navigation, concomitantly the probe nucleic acids transport and release upon the hybridization which can be quantified with the differential pulse voltammetry (DPV) technique. The magnetically actuated nanorobots swarming enables enhanced micromixing and active targeting, thereby promoting binding kinetics. Experimental results verified the enhanced sensing efficiency, with nanomolar detection limit and high selectivity. Further testing with extracted SARS-CoV-2 viral RNA samples validated the clinical applicability of the proposed assay. This strategy is versatile to extend targeting various nucleic acids, thus it could be a promising detection tool for other emerging pathogens, environmental toxins, and forensic analytes.

• Keywords
• Biosensing, COVID-19, Iron oxides, Micromotors, Transversal rotating magnetic field,
• Publication type
• Journal Article MeSH

Herein, a general procedure for the synthesis of multifunctional MRs, which simultaneously exhibit i) chiral, ii) magnetic, and iii) fluorescent properties in combination with iv) self-propulsion, is reported. Self-propelled Ni@Pt superparamagnetic microrockets have been functionalized with fluorescent CdS quantum dots carrying a chiral host biomolecule as β-cyclodextrin (β-CD). The "on-the-fly" chiral recognition potential of MRs has been interrogated by taking advantage of the β-CD affinity to supramolecularly accommodate different chiral biomolecules (i.e., amino acids). As a proof-of-concept, tryptophan enantiomers have been discriminated with a dual-mode (optical and electrochemical) readout. This approach paves the way to devise intelligent cargo micromachines with "built-in" chiral supramolecular recognition capabilities to elucidate the concept of "enantiorecognition-on-the-fly", which might be facilely customized by tailoring the supramolecular host-guest encapsulation.

• Keywords
• Chiral Analysis, Cyclodextrin, Magnetic Micromotors, Nickel Microrockets, Quantum Dots,
• MeSH
• Amino Acids * MeSH
• Stereoisomerism MeSH
• Tryptophan * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Amino Acids * MeSH
• Tryptophan * MeSH

Mobile self-propelled micro/nanorobots are mobile binding surface that improved the sensitivity of many biosensing system by "on-the-fly" identification and isolation of different biotargets. Proteins are powerful tools to predict infectious disease progression such as COVID-19. The main methodology used to COVID-19 detection is based on ELISA test by antibodies detection assays targeting SARS-CoV-2 virus spike protein and nucleocapside protein that represent an indirect SARS-CoV-2 detection with low sentitivy and specificity. Moreover ELISA test are limited to used external shaker to obtain homogenously immobilization of antibodies and protein on sensing platform. Here, we present magnetic microrobots that collective self-assembly through immuno-sandwich assay and they can be used as mobile platform to detect on-the-fly SARS-CoV-2 virus particle by its spike protein. The collective self-assembly of magnetic microrobots through immuno-sandwich assay enhanced its analytical performance in terms of sensitivity decreasing the detection limit of SARS-CoV-2 virus by one order of magnitude with respect to the devices previously reported. This proof-of-concept of microrobotics offer new ways to the detection of viruses and proteins of medical interest in general.

• Keywords
• Biosensor, Covid19, Microrobots,
• Publication type
• Journal Article MeSH