Trapping and detecting nanoplastics by MXene-derived oxide microrobots

Size-dependent internalization of polystyrene microplastics as a key factor in macrophages and systemic toxicity

Microplastics are emerging pollutants with a wide range of ecological and biological effects, including the ability to accumulate in organisms and induce toxicity. Although numerous studies have investigated the distribution and toxicity of microplastics in murine models and cell lines, the conclusions are inconsistent owing to variations in experimental designs, particle sizes, exposure methods, and dose quantifications. To address these gaps, we systematically evaluated the size-dependent internalization and toxicity of polystyrene microplastics (PS-MPs) using in vitro and in vivo models. Fluorescently labeled PS-MPs were used to confirm the negligible toxicity of fluorophores on macrophages, demonstrating their suitability for tracking particle accumulation. In vitro experiments using RAW 264.7 cell lines and primary peritoneal macrophages revealed size-dependent phagocytosis and cytotoxicity, with smaller particles (0.5 µm) demonstrating higher internalization and causing greater mitochondrial depolarization, reactive oxygen species generation, and apoptosis compared to that with larger particles (5 µm). Acute in vivo experiments comparing oral administration and tail-vein injection revealed that the absorbed dose and toxicity were significantly influenced by particle size, with smaller PS-MPs showing higher organ retention and alterations in hematological and metabolic parameters. Additionally, a 28-day subacute oral exposure study highlighted systemic toxicity, including weight loss, disrupted food intake, elevated oxidative stress markers, and reduced antioxidant enzyme activity. By integrating multiple exposure routes, macrophage models, and fluorescence toxicity evaluations, this study provided a comprehensive and realistic assessment of microplastic toxicity, offering valuable insights for advancing toxicological evaluations and regulatory frameworks. However, this study did not address the influence of other plastic types, shapes, or environmental factors on toxicity. Future studies are thus needed to explore these variables and the long-term implications of real-world microplastic exposure.

Recent advances in the detection of microplastics in the aqueous environment by electrochemical sensors: A review

Microplastics (MPs), as an emerging contaminant, have become a serious threat to marine ecosystems due to their small size, widespread distribution and easy ingestion by organisms. Therefore, it is necessary to develop various analytical techniques to detect MPs in real water environment. Among these detection techniques, the advantages of electrochemical sensors, such as easy operation, high sensitivity and low cost, provide the possibility of online real-time detection of MPs in real water environment. The aim of this article is to analyze and compare the advantages and disadvantages of different MPs detection techniques. Compilation of various electrochemical sensors, we compiled various electrochemical sensors, evaluated the recent advances in carbon materials, metals and their oxides, biomass materials, composite materials, and microfluidic chips in electrochemical sensors for detecting MPs, and in-depth investigated their detection mechanisms and sensing performances, proposed hotspot nanomaterials for electrochemical sensors that could be used to detecting MPs and gave an outlook on the last years of electrochemical sensors in the area of microplastic detection. Finally, the challenges of electrochemical sensors for the detection of MPs are discussed and perspectives for this area are presented.

Machine learning-driven optical microfiltration device for improved nanoplastic sampling and detection in water systems

The rising presence of nanoplastics in water poses toxicity risks and long-term ecological and health impacts. Detecting nanoplastics remains challenging due to their small size, complex chemistry, and environmental interference. Traditional filtration combined with Raman spectroscopy is time-consuming, labor-intensive, and often lacks accuracy and sensitivity. This study presents an agarose-based microfiltration device integrated with machine learning-assisted Raman analysis for nanoplastic capture and identification. The 1 % agarose microfluidic channel features circular micropost arrays enabling dual filtration: nanoplastics diffuse into the porous matrix, while larger particles (>1000 nm) are blocked by the microposts. Unlike conventional systems, this design achieves both physical separation and preconcentration, enhancing nanoplastic detectability. Upon dehydration, the agarose forms a transparent film, significantly improving Raman compatibility by minimizing background interference. This transformation enables direct Raman analysis of retained nanoparticles with enhanced signal clarity and sensitivity. Using 100-nm polystyrene nanoparticles (PSNPs) as a model, we evaluated device performance in distilled water and seawater across concentrations (6.25-50 µg/mL) and flow rates (2.5-100 µL/min). Maximum capture efficiencies of 80 % (seawater) and 66 % (distilled water) were achieved at 2.5 µL/min. A convolutional neural network (CNN) further enhanced spectral analysis, reducing mapping time by 50 % and enabling PSNP detection in seawater at 6.25 µg/mL. This agarose-based system offers a scalable, cost-effective platform for nanoplastic sampling, demonstrating the potential of combining microfluidics with machine learning-assisted Raman spectroscopy to address critical environmental and public health challenges.

Combining computational and experimental approaches: a novel pH-responsive PVA-stabilized MXene nanocarriers/doxorubicin delivery system with enhanced efficacy for targeted lung cancer therapeutics

While advancements have been made in cancer treatment, achieving effective localized therapy remains a significant challenge. Major obstacles include the inefficiency of drug delivery methods and the side effects linked to traditional chemotherapeutics. In this study, we present an innovative delivery system designed to transport doxorubicin (DOX) directly to the lungs. This system employs PVA-stabilized DOX-loaded MXene, aiming to improve targeted delivery and drug efficacy while minimizing toxicity. Our approach represents a promising advancement in the optimization of cancer therapeutics. Using in silico and computational methods, we evaluated the interactions between PVA, DOX, and MXene. Characterization techniques demonstrated that the synthesized PVA@Mxene/DOX exhibited favorable physicochemical properties. We assessed the anticancer potential of PVA@Mxene/DOX through the MTT assay, in vitro migration assay, and apoptosis assay. The findings revealed that the developed anticancer PVA@Mxene/DOX displayed a layered structure with controlled release kinetics. Notably, it significantly reduced cancer cell growth (P < 0.05), induced apoptosis in cancer cells, and inhibited their migration. These results suggest that PVA@Mxene/DOX holds promise as an effective anticancer agent to enhance lung cancer treatment and improve patient care.

Cell Response to Nanoplastics and Their Carrier Effects Tracked Real-Timely with Machine Learning-Driven Smart Surface-Enhanced Raman Spectroscopy Slides

Research on nanoplastic (NP) toxicity and their "carrier effects" on human health remains nascent, especially for real-time, in situ monitoring of metabolic reactions in live cells. Herein, we developed smart surface-enhanced Raman spectroscopy (SERS) slides using a cyclic centrifugation-enhanced electrostatic loading (CCEL) method to facilitatively track live-cell metabolic signals. The designed core-shell polystyrene NPs (mPS) with embedded Raman probes successfully identified intracellular accumulation via a distinct Raman-silent peak. The smart SERS slide effectively monitored the metabolic changes induced by mPS at the molecular level, distinguishing different stages of membrane interaction, the endocytosis process, endosomal aggregation, and cell apoptosis. Besides, this platform was employed to perform a real-time, in situ comparison of cell cycle alterations induced by bare NPs and their "carrier effects", revealing that NPs extended both the S and G2 phases in BEAS-2B cells, while the "carrier effects" further prolonged G2 and disrupted S-phase progression. Additionally, we integrated machine learning algorithms to accurately predict the cell cycle impacts associated with mPS and their "carrier effects". This study provides a label-free, in situ, real-time method for monitoring NP-induced metabolic changes in live cells, laying the groundwork for further investigation into cytotoxic behaviors and strategies to mitigate NP toxicity.

Smart MXene-based microrobots for targeted drug delivery and synergistic therapies

MXenes and their composites exhibit remarkable electrical conductivity, mechanical flexibility, and biocompatibility, making them ideal candidates for microrobot fabrication. Their tunable surface chemistry allows for easy functionalization, which enhances their interaction with biological environments, thereby facilitating targeted therapies. Such smart microrobots can be engineered to navigate through complex biological systems with precision via the integration of responsive elements, such as stimuli-sensitive polymers or magnetic components. MXene-based microrobots are able to actively seek out specific tissues or cells. This capability is crucial for applications in cancer treatment, where localized drug delivery minimizes side effects and enhances therapeutic efficacy. The primary advantage of MXene-based microrobots lies in their ability to deliver therapeutic agents directly to diseased cells. Utilizing ligand-receptor interactions, these microrobots can bind to target cells and release their payload in a controlled manner. This targeted delivery system not only improves the effectiveness of the drug but also reduces the required dosage, thus mitigating potential side effects. Moreover, smart MXene-based microrobots can facilitate synergistic therapies by co-delivering multiple therapeutic agents. For instance, combining chemotherapy drugs with immunotherapeutic agents could enhance treatment outcomes in cancer therapy. The ability to simultaneously deliver different types of drugs allows for more comprehensive treatment strategies that can tackle tumor heterogeneity. Significant advancements are anticipated in synergistic therapies, particularly in chemo-photothermal, chemodynamic, and photothermal/photodynamic therapies. These strategies leverage multiple therapeutic modalities to enhance cancer treatment outcomes. Despite their outstanding potential, several challenges remain in the development of MXene-based microrobots namely matters pertaining to scalability, stability in biological environments, and associated regulatory hurdles which ought to be addressed. Future research should focus on optimizing the design and functionality of these microrobots, including enhancing their navigation capabilities and ensuring their safety and effectiveness in vivo. By presenting the innovative capabilities of MXene-based microrobots, this perspective aims to inspire additional explorations in the field of advanced targeted drug delivery systems and synergistic therapies, ultimately contributing to the future of personalized medicine and oncology.

Magneto-Fluorescent Microrobots with Selective Detection Intelligence for High-Energy Explosives and Antibiotics in Aqueous Environments

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.

Innovative materials that behave like robots to combat plastic pollution

The growing plastic pollution crisis demands novel approaches, with innovative materials that mimic robotic behaviors emerging as a promising solution. This approach explores the development and application of smart materials that can autonomously engage in plastic waste removal, functioning like robots under various environmental conditions. We focus on materials activated by light, magnetic fields, chemical fuels, and ion exchange, which are designed to target and remove plastic waste efficiently. The key properties of these materials, such as self-activation, adaptability, and precision that enable them to function autonomously in waste management systems, are examined. The integration of these innovative materials offers significant advantages, including faster waste processing, reduced human exposure to hazardous waste, and enhanced sorting accuracy. Additionally, this review evaluates the environmental impact, scalability, and cost-effectiveness of these materials in comparison to traditional methods. Finally, the potential of these materials to play a central role in sustainable plastic waste management and contribute to a circular economy is discussed.

Research Progress in Electroactive Polymers for Soft Robotics and Artificial Muscle Applications

Soft robots, constructed from deformable materials, offer significant advantages over rigid robots by mimicking biological tissues and providing enhanced adaptability, safety, and functionality across various applications. Central to these robots are electroactive polymer (EAP) actuators, which allow large deformations in response to external stimuli. This review examines various EAP actuators, including dielectric elastomers, liquid crystal elastomers (LCEs), and ionic polymers, focusing on their potential as artificial muscles. EAPs, particularly ionic and electronic varieties, are noted for their high actuation strain, flexibility, lightweight nature, and energy efficiency, making them ideal for applications in mechatronics, robotics, and biomedical engineering. This review also highlights piezoelectric polymers like polyvinylidene fluoride (PVDF), known for their flexibility, biocompatibility, and ease of fabrication, contributing to tactile and pressure sensing in robotic systems. Additionally, conducting polymers, with their fast actuation speeds and high strain capabilities, are explored, alongside magnetic polymer composites (MPCs) with applications in biomedicine and electronics. The integration of machine learning (ML) and the Internet of Things (IoT) is transforming soft robotics, enhancing actuation, control, and design. Finally, the paper discusses future directions in soft robotics, focusing on self-healing composites, bio-inspired designs, sustainability, and the continued integration of IoT and ML for intelligent, adaptive, and responsive robotic systems.

Uncovering layer by layer the risk of nanoplastics to the environment and human health

Nanoplastics (NPs), defined as plastic particles with dimensions less than 100 nm, have emerged as a persistent environmental contaminant with potential risk to both environment and human health. Nanoplastics might translocate across biological barriers and accumulate in vital organs, leading to inflammatory responses, oxidative stress, and genotoxicity, already reported in several organisms. Disruptions to cellular functions, hormonal balance, and immune responses were also linked to NPs exposure in in vitro assays. Further, NPs have been found to adsorb other pollutants, such as persistent organic pollutants (POPs), and leach additives potentially amplifying their advere impacts, increasing the threat to organisms greater than NPs alone. However, NPs toxic effects remain largely unexplored, requiring further research to elucidate potential risks to human health, especially their accumulation, degradation, migration, interactions with the biological systems and long-term consequences of chronic exposure to these compounds. This review provides an overview of the current state-of-art regarding NPs interactions with environmental pollutants and with biological mechanisms and toxicity within cells.

MXene-based materials for enhanced water quality: Advances in remediation strategies

Two-dimensional MXenes are promising candidates for water treatment because of their large surface area (e.g., exceeding 1000 m²/g for certain structures), high electrical conductivity (e.g., >1000 S/m), hydrophilicity, and chemical stability. Their strong sorption selectivity and effective reduction capacity, exemplified by heavy metal adsorption efficiencies exceeding 95 % in several studies, coupled with facile surface modification, make them suitable for removing diverse contaminants. Applications include the removal of heavy metals (e.g., achieving >90 % removal of Pb(II)), dye removal (e.g., demonstrating >80 % removal of methylene blue), and radioactive waste elimination. Furthermore, 3D MXene architecture exhibit enhanced performance in antibacterial activities (e.g., against bacteria), desalination rejection percentage, and photocatalytic degradation of organic contaminants. However, several challenges have remained, which necessitate further investigation into toxicity (e.g., assessing effects on aquatic organisms), scalability, and cost-effectiveness of large-scale production. This review summarizes recent advancements in 3D MXene-based functional materials for wastewater treatment and water remediation, critically analyzing their both potential and limitations.

Light-Programmable g-C3N4 Microrobots with Negative Photogravitaxis for Photocatalytic Antibiotic Degradation

Microrobots enhance contact with pollutants through their movement and flow-induced mixing, substantially improving wastewater treatment efficiency beyond traditional diffusion-limited methods. g-C3N4 is an affordable and environmentally friendly photocatalyst that has been extensively researched in various fields such as biomedicine and environmental remediation. However, compared to other photocatalytic materials like TiO2 and ZnO, which are widely used in the fabrication of micro- and nanorobots, research on g-C3N4 for these applications is still in its early stages. This work presents microrobots entirely based on g-C3N4 microtubes, which can initiate autonomous movement when exposed to ultraviolet and visible light. We observed distinct motion behaviors of the microrobots under light irradiation of different wavelengths. Specifically, under ultraviolet light, the microrobots exhibit negative photogravitaxis, while under visible light, they demonstrate a combination of 3-dimensional motion and 2-dimensional motion. Therefore, the wavelength of the light can be used for programming the motion style of the microrobots and subsequently their application. We show that the microrobots can effectively degrade the antibiotic tetracycline, displaying their potential for antibiotic removal. This exploration of autonomous motion behaviors under different wavelength conditions helps to expand research on g-C3N4-based microrobots and their potential for environmental remediation.

Active Microrobots for Dual Removal of Biofilms via Chemical and Physical Mechanisms

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.

Chlorella-Based Biohybrid Microrobot for Removing Both Nutrient and Microalgae toward Efficient Water Eutrophication Treatment

Excessive nutrients and explosive growth of harmful microalgae in water environments are key challenges in the treatment of eutrophication. The development of a low-cost, time-saving, and small-space-suitable research method that can simultaneously remove nutrients and microalgae is highly anticipated. This work first proposed applying microrobots to eutrophication treatment. Phosphate and Microcystisaeruginosa (M. aeruginosa) were selected as representative nutrients and harmful microalgae, respectively, to investigate the efficient removal effect of the microrobots on the two. The Chlorella@Fe3O4@ZIF-8 biohybrid microrobot can not only perform the dual removal of phosphates and M. aeruginosa but also take advantage of its small size and controllable motion to achieve targeted treatment of eutrophication of water in microenvironments such as microchannels, thereby achieving the effect of fundamentally treating the eutrophication. The Chlorella@Fe3O4@ZIF-8 microrobot reveals a new strategy for the treatment of eutrophication and also exploits a new perspective for application research of microrobots.

Selective on-site detection and quantification of polystyrene microplastics in water using fluorescence-tagged peptides and electrochemical impedance spectroscopy

In this study, we developed a method for the on-site selective detection and quantification of microplastics in various water matrices using fluorescence-tagged peptides combined with electrochemical impedance spectroscopy (EIS). Among the types of plastics found in seawater, polystyrene (PS) microplastics were selected. Fluorometry, scanning electron microscopy (SEM), and Raman spectroscopy were used to verify the specific interaction of these peptides with PS spherical particles of different sizes (ranging from 0.1 to 250 µm). Principal component analysis (PCA) was employed to determine the effects of temperature (25-65 °C), incubation time (5 and 10 min), and particle size on plastic-peptide bonding efficiency, based on fluorescence intensity. For each water type (pure, tap, NaCl (0.5 M), and seawater), EIS plots (Nyquist and Bode) were generated. Significant factors affecting the EIS response, including particle size, shape, and material, were analyzed by measuring electrical parameters for different microplastic concentrations (50 ppb to 20 ppm). The EIS parameters changed with increasing plastic concentration, determining a limit of detection (LOD) of 50 ppb (ng/mL) for pure and tap water and 400 ppb for saline water, as the lowest concentration producing a significant change in EIS parameters compared to the baseline. The sensor proved highly effective for detecting microplastics in low ionic strength environments such as pure and tap water. However, in high ionic strength environments like saline and seawater, the detection capability diminished, likely due to the masking effect of ions on the EIS response.

Application of Micro/Nanomotors in Environmental Remediation: A Review

The advent of self-propelled micro/nanomotors represents a paradigm shift in the field of environmental remediation, offering a significant enhancement in the efficiency of conventional operations through the exploitation of the material phenomenon of active motion. Despite the considerable promise of micro/nanomotors for applications in environmental remediation, there has been a paucity of reviews that have focused on this area. This review identifies the current opportunities and challenges in utilizing micro/nanomotors to enhance contaminant degradation and removal, accelerate bacterial death, or enable dynamic environmental monitoring. It illustrates how mobile reactors or receptors can dramatically increase the speed and efficiency of environmental remediation processes. These studies exemplify the wide range of environmental applications of dynamic micro/nanomotors associated with their continuous motion, force, and function. Finally, the review discusses the challenges of transferring these exciting advances from the experimental scale to larger-scale field applications.

Label-free impedimetric analysis of microplastics dispersed in aqueous media polluted by Pb2+ ions

The rapid differentiation between polluted and unpolluted microplastics (MPs) is critical for tracking their presence in the environment and underpinning their potential risks to humans. However, the quantitative analysis of polluted microplastics on the field is limited by the lack of rapid methods that do not need optical analysis nor their capture onto sophisticated electrochemical sensor platforms. Herein, a simple analytical approach for MPs dispersed in aqueous media leveraging electrochemical impedance spectroscopy (EIS) analysis on screen-printed sensors is presented. This method is demonstrated by the EIS-based analysis of two standards of microplastics beads (MPs), one of polystyrene (PS) and one of polystyrene carboxylated (PS-COOH), when exposed to aqueous solutions containing Pb2+ ions. The adsorption of Pb2+ ions on the MPs was quantitatively determined by voltammetric analysis. EIS permitted to rapidly (about 2 minutes) differentiate clean MPs from the Pb2+ polluted ones. These results could constitute a first-step towards the realization of a portable impedimetric sensor for the quantification of microplastics polluted by metal ions in aqueous solutions.

Low-Energy Photoresponsive Magnetic-Assisted Cleaning Microrobots for Removal of Microplastics in Water Environments

In the global ecosystem, microplastic pollution pervades extensively, exerting profound and detrimental effects on marine life and human well-being. However, conventional removal methods are usually limited to chemical flocculation and physical filtration but are insufficient to remove extremely small microplastics. Therefore, developing a comprehensive strategy to address the threat posed by microplastics is imperative. Here, we report a low-energy photoresponsive magnetic-assisted cleaning microrobot (LMCM) composed of photocatalytic material (Ag@Bi2WO6) and magnetic nanoparticles (Fe3O4), which can be used for the active removal of microplastics from water environments. Due to the diffusion electrophoresis effect, the low-energy photoresponsive cleaning microrobots (LCMs) are formed by spontaneous assembly of Ag@Bi2WO6, which can continuously adsorb microplastics in a water environment. Particularly, the effective attraction distance of LCMs on microplastics exceeds 100 μm. After assembling the Fe3O4 nanoparticles, LMCMs can clean microplastics in groups from water environments under the control of a magnetic field. Utilizing precision manipulation and group control, LMCMs demonstrate a remarkable 98% cleaning efficiency in 93 s and can be recovered under the control of the directional magnetic field. This eco-friendly and energy-efficient microrobot is expected to provide a viable strategy to tackle the threat of microplastics or promote industrial microplastic removal.

Pioneering technologies over time to rehabilitate crude oil-contaminated ecosystems: a review

The unremitting pollution of our environment induced by crude oil spillage and drilling site accidents has jeopardized every living species in the biological ecosystem. Removing heavy crude oil constituents with the help of traditional and mainstream oil sorbents because of their ingrained raised viscosities is a strenuous venture. Lighter distillates of crude oil, like condensate, do not aggregate with tremulous shine on the aquatic surface nor settle at the bottom sediment of the water bodies like the heavier components do with time. Fabricating optimally designed materials capable of capturing, degrading, or removing toxic chemical constituents of this fossil fuel is critical in this modern era. This review comprehensively discusses the evolution of scientific technologies developed to separate these constituents from land and aquatic bodies. We provide an overview of the latest physical and chemical strategies and prevalent biological remediation schemes for removing these pollutants from soils and water for environmental protection. The article highlights the urgency of preventing oil spill accidents, whose anticipation is challenging to harness. A spectrum of advanced functional methodologies is also discussed to adequately treat discharged hydrocarbon contaminants, establish public safety, and pave the path to enhancing the circular economy metrics linked with oil industries.

Are micro/nanorobots an effective solution to eliminate micro/nanoplastics in water/wastewater treatment plants?

The extensive production and widespread use of plastic products have resulted in the gradual escalation of plastic pollution. Micro/nano/plastic pollution has become a global issue, and addressing how to "green" remove them is a crucial topic that needs to be tackled at this stage. Recently, micro/nanorobots have offered a promising solution for improving water monitoring and remediation as an environmentally friendly remediation strategy. Micro/nanorobots have been proven to efficiently remove micro/nanoplastics from water bodies. Micro/nanoplastics are captured by micro/nanorobots in water through electrostatic adsorption and electrophoretic interactions, and separation is achieved under the action of an external transverse rotating magnetic field. Their small size enables them to navigate easily in complex environments, while magnetic and optical drives help them move along established routes and reach different areas. With the assistance of these innovative robots, diffusion-limited reactions can be overcome, allowing for active contact with target pollutants. However, research on the removal of micro/nanoplastics by micro/nanorobots is still in its early stages. The dependence on chemical fuels and high costs severely limit the development and application of micro/nanorobots. Micro/nanoplastics are frequently captured by micro/nanorobots, but the degradation efficiency of micro/nanoplastics remains very low. Additionally, the secondary pollution caused by micro/nanorobots is also a key factor limiting their implementation. Although micro/nanorobots are a very promising technology for removing micro/nanoplastics, they still need to be explored in their applications. This paper discusses the opportunities and challenges faced by micro/nanorobots in removing micro/nanoplastics. Development and application of self-driven intelligent micro/nanorobots will help expedite the eco-friendly removal of micro/nanoplastics and other emerging pollutants.

The role of gut microbiota in MP/NP-induced toxicity

Microplastics (MPs) and nanoplastics (NPs) are globally recognized as emerging environmental pollutants in various environmental media, posing potential threats to ecosystems and human health. MPs/NPs are unavoidably ingested by humans, mainly through contaminated food and drinks, impairing the gastrointestinal ecology and seriously impacting the human body. The specific role of gut microbiota in the gastrointestinal tract upon MP/NP exposure remains unknown. Given the importance of gut microbiota in metabolism, immunity, and homeostasis, this review aims to enhance our current understanding of the role of gut microbiota in MP/NP-induced toxicity. First, it discusses human exposure to MPs/NPs through the diet and MP/NP-induced adverse effects on the respiratory, digestive, neural, urinary, reproductive, and immune systems. Second, it elucidates the complex interactions between the gut microbiota and MPs/NPs. MPs/NPs can disrupt gut microbiota homeostasis, while the gut microbiota can degrade MPs/NPs. Third, it reveals the role of the gut microbiota in MP/NP-mediated systematic toxicity. MPs/NPs cause direct intestinal toxicity and indirect toxicity in other organs via regulating the gut-brain, gut-liver, and gut-lung axes. Finally, novel approaches such as dietary interventions, prebiotics, probiotics, polyphenols, engineered bacteria, microalgae, and micro/nanorobots are recommended to reduce MP/NP toxicity in humans. Overall, this review provides a theoretical basis for targeting the gut microbiota to study MP/NP toxicity and develop novel strategies for its mitigation.

Wet oxidation technology can significantly reduce both microplastics and nanoplastics

For the resource recovery of biomass waste, it is a challenge to simultaneously remove micro-/nano-plastics pollution but preserve organic resources. Wet oxidation is a promising technology for valorization of organic wastes through thermal hydrolysis and oxidation. This might in turn result in the degradation of microplastics in the presence of oxygen and high temperatures. Based on this hypothesis, this study quantified both microplastics and nanoplastics in an industrial-scale wet oxidation reactor from a full-size coverage perspective. Wet oxidation significantly reduced the size and mass of individual microplastics, and decreased total mass concentration of microplastics and nanoplastics by 94.8 % to 98.6 %. This technology also reduced the micro- and nanoplastic shapes and polymer types, resulting in a complete removal of fibers, clusters, polypropylene (PP) and poly(methyl methacrylate) (PMMA). The present study confirms that wet oxidation technology is effective in removing microplastics and nanoplastics while recovering organic waste.

Cost-Effective and Wireless Portable Device for Rapid and Sensitive Quantification of Micro/Nanoplastics

The accumulation of micro/nanoplastics (MNPs) in ecosystems poses tremendous environmental risks for terrestrial and aquatic organisms. Designing rapid, field-deployable, and sensitive devices for assessing the potential risks of MNPs pollution is critical. However, current techniques for MNPs detection have limited effectiveness. Here, we design a wireless portable device that allows rapid, sensitive, and on-site detection of MNPs, followed by remote data processing via machine learning algorithms for quantitative fluorescence imaging. We utilized a supramolecular labeling strategy, employing luminescent metal-phenolic networks composed of zirconium ions, tannic acid, and rhodamine B, to efficiently label various sizes of MNPs (e.g., 50 nm-10 μm). Results showed that our device can quantify MNPs as low as 330 microplastics and 3.08 × 106 nanoplastics in less than 20 min. We demonstrated the applicability of the device to real-world samples through determination of MNPs released from plastic cups after hot water and flow induction and nanoplastics in tap water. Moreover, the device is user-friendly and operative by untrained personnel to conduct data processing on the APP remotely. The analytical platform integrating quantitative imaging, customized data processing, decision tree model, and low-cost analysis ($0.015 per assay) has great potential for high-throughput screening of MNPs in agrifood and environmental systems.

Advanced materials for micro/nanorobotics

Autonomous micro/nanorobots capable of performing programmed missions are at the forefront of next-generation micromachinery. These small robotic systems are predominantly constructed using functional components sourced from micro- and nanoscale materials; therefore, combining them with various advanced materials represents a pivotal direction toward achieving a higher level of intelligence and multifunctionality. This review provides a comprehensive overview of advanced materials for innovative micro/nanorobotics, focusing on the five families of materials that have witnessed the most rapid advancements over the last decade: two-dimensional materials, metal-organic frameworks, semiconductors, polymers, and biological cells. Their unique physicochemical, mechanical, optical, and biological properties have been integrated into micro/nanorobots to achieve greater maneuverability, programmability, intelligence, and multifunctionality in collective behaviors. The design and fabrication methods for hybrid robotic systems are discussed based on the material categories. In addition, their promising potential for powering motion and/or (multi-)functionality is described and the fundamental principles underlying them are explained. Finally, their extensive use in a variety of applications, including environmental remediation, (bio)sensing, therapeutics, etc., and remaining challenges and perspectives for future research are discussed.

Photophoretic MoS2-Fe2O3 Piranha Micromotors for Collective Dynamic Microplastics Removal

Microplastics are highly persistent emerging pollutants that are widely distributed in the environment. We report the use of MoS2@Fe2O3 core-shell micromotors prepared by a hydrothermal approach to explore the degradation of plastic microparticles. Polystyrene was chosen as the model plastic due to its wide distribution and resistance to degradation using current approaches. Micromotors show photophoretic-based motion at speeds of up to 6 mm s-1 and schooling behavior under full solar light spectra irradiation without the need for fuel or surfactants. During this impressive collective behavior, reactive oxygen species (ROS) are generated because of the semiconducting nature of the MoS2. Degradation of polystyrene beads is observed after 4 h irradiation because of the synergistic effect of ROS production and localized heat generation. The MoS2@Fe2O3 micromotors possess magnetic properties, which allow further cleaning and removal to be carried out after irradiation through magnetic pulling. The new micromotors hold considerable promise for full-scale treatment applications, only limited by our imagination.

Light-Driven Microrobots for Targeted Drug Delivery

As a new micromanipulation tool with the advantages of small size, flexible movement and easy manipulation, light-driven microrobots have a wide range of prospects in biomedical fields such as drug targeting and cell manipulation. Recently, microrobots have been controlled in various ways, and light field has become a research hotspot by its advantages of noncontact manipulation, precise localization, fast response, and biocompatibility. It utilizes the force or deformation generated by the light field to precisely control the microrobot, and combines with the drug release technology to realize the targeted drug application. Therefore, this paper provides an overview of light-driven microrobots with drug targeting to provide new ideas for the manipulation of microrobots. Here, this paper briefly categorizes the driving mechanisms and materials of light-driven microrobots, which mainly include photothermal, photochemical, and biological. Then, typical designs of light-driven microrobots with different driving mechanisms and control strategies for multiple physical fields are summarized. Finally, the applications of microrobots in the fields of drug targeting and bioimaging are presented as well as the future prospects of light-driven microrobots in the biomedical field are demonstrated.

Photoaging of polystyrene-based microplastics amplifies inflammatory response in macrophages

The continuous release of municipal and industrial products into the environment poses a growing concern for public health. Among environmental pollutants, polystyrene (PS) stands out as a primary constituent of environmental plastic waste, given its widespread use and high production rates owing to its durability and user-friendly properties. The detection of polystyrene microparticles (PS-MPs) in various living organisms has been well-documented, posing a serious threat due to their potential passage into the human ecosystem. In this manuscript, we aimed to study the toxicological effects of low concentrations of pristine and photoaged PS-MPs in a murine macrophage cell line. To this purpose, PS-MPs were photoaged by indoor exposure to visible light to simulate environmental weathering due to solar irradiation (PS-MPs3h). Physical characterization revealed that the irradiation treatment results in particle degradation and the possible release of nanoparticles. Monocultures of the RAW264.7 cell line were then exposed to PS-MPs and PS-MPs3h at concentrations comparable to experimental measurements from biological samples, to assess cytotoxicity, intracellular oxidative stress, primary genotoxicity, and inflammatory effects. Significant toxicity-related outcomes were observed in cells treated with both pristine PS-MPs and PS-MPs3h even at low concentrations (0,10 μg/ml and 1 μg/ml). PS-MPs3h exhibited greater adverse effects compared to PS-MPs, including reduced cell viability, increased ROS production, elevated DNA damage, and upregulation of IL-6 and NOS2 gene expression. Therefore, we can conclude that changes induced by environmental aging in the physicochemical composition of PS microplastics play a crucial role in the adverse health outcomes associated with microplastic exposure.

Innovative solutions for the removal of emerging microplastics from water by utilizing advanced techniques

Microplastic pollution is one of the most pressing global environmental problems due to its harmful effects on living organisms and ecosystems. To address this issue, researchers have explored several techniques to successfully eliminate microplastics from water sources. Chemical coagulation, electrocoagulation, magnetic extraction, adsorption, photocatalytic degradation, and biodegradation are some of the recognized techniques used for the removal of microplastics from water. In addition, membrane-based techniques encompass processes propelled by pressure or potential, along with sophisticated membrane technologies like the dynamic membrane and the membrane bioreactor. Recently, researchers have been developing advanced membranes composed of metal-organic frameworks, MXene, zeolites, carbon nanomaterials, metals, and metal oxides to remove microplastics. This paper aims to analyze the effectiveness, advantages, and drawbacks of each method to provide insights into their application for reducing microplastic pollution.

Metal-Organic Framework-Based Micro-/Nanomotors for Wastewater Remediation

Micro-/nanomotors (MNMs) in water remediation have garnered significant attention over the past two decades. More recently, metal-organic framework-based micro-/nanomotors (MOF-MNMs) have been applied for environmental remediation; however, a comprehensive summary of research in this research area is yet to be reported. Herein, a review is presented to cover the recent advances in MOF-MNMs and their various applications in wastewater remediation. The review presents a comprehensive introduction to MNMs, including different propulsion approaches, fabrication, and functionalization strategies, in addition to the unique features of MOF-MNMs. The conception and various synthetic routes of MOF-MNMs are extensively covered and the implementation of MOF-MNMs in water-related applications, including adsorption, degradation, sensing, and disinfection of different pollutants, is in depth discussed. Meanwhile, the propulsion and mechanism of action behind each MOF-MNM are systematically studied. Finally, the review provides insights into the challenges and perspectives to build more effective MOF-MNMs to cover versatile applications for wastewater treatment.

Programming hierarchical anisotropy in microactuators for multimodal actuation

Microactuators, capable of executing tasks typically repetitive, hazardous, or impossible for humans, hold great promise across fields such as precision medicine, environmental remediation, and swarm intelligence. However, intricate motions of microactuators normally require high complexity in design, making it increasingly challenging to realize at small scales using existing fabrication techniques. Taking inspiration from the hierarchical-anisotropy principle found in nature, we program liquid crystalline elastomer (LCE) microactuators with multimodal actuation tailored to their molecular, shape, and architectural anisotropies at (sub)nanometer, micrometer, and (sub)millimeter scales, respectively. Our strategy enables diverse deformations with individual LCE microstructures, including expanding, contracting, twisting, bending, and unwinding, as well as re-programmable shape transformations of assembled LCE architectures with negative Poisson's ratios, locally adjustable actuation, and changing from two-dimensional (2D) to three-dimensional (3D) structures. Furthermore, we design tetrahedral microactuators with well-controlled mobility and precise manipulation of both solids and liquids in various environments. This study provides a paradigm shift in the development of microactuators, unlocking a vast array of complexities achievable through manipulation at each hierarchical level of anisotropy.

Modulating nanostructures with polyvinylpyrrolidone: Design and development of a porous, biocompatible, and pH-Stable core-shell magnetic microrobot for demonstrating drug absorption from wastewater

Increased antineoplastic drug concentrations in wastewater stem from ineffective treatment plants and increased usage. Although microrobots are promising for pollutant removal, they face hurdles in developing a superstructure with superior adsorption capabilities, biocompatibility, porosity, and pH stability. This study focused on adjusting the PVP concentration from 0.05 to 0.375 mM during synthesis to create a favorable CMOC structure for drug absorption. Lower PVP concentrations (0.05 mM) yielded a three-dimensional nanoflower structure of CaMoO4 and CuS nanostructures, whereas five-fold concentrations (0.25 mM) produced a porous structure with a dense CuS core encased in a transparent CaMoO4 shell. The magnetically movable and pH-stable COF@CMOC microrobot, achieved by attaching CMOC to cobalt ferrite (CoF) NPs, captured doxorubicin efficiently, with up to 57 % efficiency at 200 ng/mL concentration for 30 min, facilitated by electrostatic interaction, hydrogen bonding, and pore filling of DOX. The results demonstrated that DOX removal through magnetic motion showed superior performance, with an estimated improvement of 57% compared to stirring conditions (17 %). A prototype PDMS microchannel system was developed to study drug absorption and microrobot recovery. The CaMoO4 shell of the microrobots exhibited remarkable robustness, ensuring long-lasting functionality in harsh wastewater environments and improving biocompatibility while safeguarding the CuS core from degradation. Therefore, microrobots are a promising eco-friendly solution for drug extraction. These microrobots show promise for the selective removal of doxorubicin from contaminated wastewater.

Arbitrary Construction of Versatile NIR-Driven Microrobots

Emerging light-driven micro/nanorobots (LMNRs) showcase profound potential for sophisticated manipulation and various applications. However, the realization of a versatile and straightforward fabrication technique remains a challenging pursuit. This study introduces an innovative bulk heterojunction organic semiconductor solar cell (OSC)-based spin-coating approach, aiming to facilitate the arbitrary construction of LMNRs. Leveraging the distinctive properties of a near-infrared (NIR)-responsive organic semiconductor heterojunction solution, this technique enables uniform coating across various dimensional structures (0D, 1D, 2D, 3D) to be LMNRs, denoted as "motorization." The film, with a slender profile measuring ≈140 nm in thickness, effectively preserves the original morphology of objects while imparting actuation capabilities exceeding hundreds of times their own weight. The propelled motion of these microrobots is realized through NIR-driven photoelectrochemical reaction-induced self-diffusiophoresis, showcasing a versatile array of controllable motion profiles. The strategic customization of arbitrary microrobot construction addresses specific applications, ranging from 0D microrobots inducing living crystal formation to intricate, multidimensional structures designed for tasks such as microplastic extraction, cargo delivery, and phototactic precise maneuvers. This study advances user-friendly and versatile LMNR technologies, unlocking new possibilities for various applications, signaling a transformative era in multifunctional micro/nanorobot technologies.

ZIF-8 functionalized S-tapered fiber-optic sensor for polystyrene nanoplastics detection by electrostatic adsorption

Microplastic (MP) residues in marine have become an increasingly serious environmental pollution issue, and in recent years the detection of MPs in marine started to attract worldwide research interests. Optical-fiber-based environmental sensors have been extensively employed for their several merits such as high sensitivity, pressure resistance, compactness and ease of constructing communication networks. However, fiber-optic refractive index sensors are not specifically developed for distinguishing MPs from other inorganic particles suspended in water. In this paper, an metal-organic framework (MOF) ZIF-8 functionalized S-tapered fiber (STF) sensor is proposed for specific detection of polystyrene nanoplastics (PSNPs) in aqueous environment. ZIF-8 coordination nanoporous polymers with different film thickness were immobilized over the surface of the fabricated STF structure based on self-growth technique and yielding a large surface area over the sensor surface. High sensitivity detection can be achieved by converting the concentration perturbation of PSNPs into evanescent waves over the ZIF-8 functionalized STF surface through the strong electrostatic adsorption effect and π-π stacking, while the fabricated sensor is insensitive to gravels with silica as the primary component in water. It is found that the proposed detector with 18 film layers achieves a sensitivity up to 114.1353nm/%(w/v) for the PSNPs concentration range of 0.01 %(w/v) to 0.08 %(w/v).

Bimetallic Photo-Activated and Steerable Janus Micromotors as Active Microcleaners for Wastewater

Photoactive colloidal motors whose motion can be controlled and even programed via external magnetic fields have significant potential in practical applications extending from biomedical fields to environmental remediation. Herein, we report a "three in one" strategy in a Co/Zn-TPM (3-trimethoxysilyl propyl methacrylate) bimetallic Janus colloidal micromotor (BMT-micromotor) which can be controlled by an optical field, chemical fuel, and magnetic field. The speed of the micromotors can be tuned by light intensity and with the concentration of the chemical fuel of H2O2, while it could be steered and programed through magnetic field due to the presence of Co in the bimetallic part. Finally, the BMT-micromotors were employed to effectively remove rubidium metal ions and organic dyes (methylene blue and rhodamine b). Benefited of excellent mobility, multiple active sites, and hierarchical morphology, the micromotors exhibit excellent adsorption capacity of 103 mg·g-1 to Rb metal ions and high photodegradation efficiency toward organic dyes in the presence of a lower concentration of H2O2. The experimental characterizations and DFT calculations confirmed the strong interaction of Rb metal ions on the surface of BMT-micromotors and the excellent decomposition of H2O2 which enhanced the photodegradation process. We expect the combination of light and fuel sensitivity with magnetic controllability to unlock an excess of opportunities for the application of BMT-micromotors in water treatments.

Biomass waste-assisted micro(nano)plastics capture, utilization, and storage for sustainable water remediation

Micro(nano)plastics (MNPs) have become a significant environmental concern due to their widespread presence in the biosphere and potential harm to ecosystems and human health. Here, we propose for the first time a MNPs capture, utilization, and storage (PCUS) concept to achieve MNPs remediation from water while meeting economically productive upcycling and environmentally sustainable plastic waste management. A highly efficient capturing material derived from surface-modified woody biomass waste (M-Basswood) is developed to remove a broad spectrum of multidimensional and compositional MNPs from water. The M-Basswood delivered a high and stable capture efficiency of >99.1% at different pH or salinity levels. This exceptional capture performance is driven by multiscale interactions between M-Basswood and MNPs, involving physical trapping, strong electrostatic attractions, and triggered MNPs cluster-like aggregation sedimentation. Additionally, the in vivo biodistribution of MNPs shows low ingestion and accumulation of MNPs in the mice organs. After MNPs remediation from water, the M-Basswood, together with captured MNPs, is further processed into a high-performance composite board product where MNPs serve as the glue for utilization and storage. Furthermore, the life cycle assessment (LCA) and techno-economic analysis (TEA) results demonstrate the environmental friendliness and economic viability of our proposed full-chain PCUS strategy, promising to drive positive change in plastic pollution and foster a circular economy.

Transforming pollution into solutions: A bibliometric analysis and sustainable strategies for reducing indoor microplastics while converting to value-added products

Microplastics (MPs), as emerging indoor contaminants, have garnered attention due to their ubiquity and unresolved implications for human health. These tiny particles have permeated indoor air and water, leading to inevitable human exposure. Preliminary evidence suggests MP exposure could be linked to respiratory, gastrointestinal, and potentially other health issues, yet the full scope of their effects remains unclear. To map the overall landscape of this research field, a bibliometric analysis based on research articles retrieved from the Web of Science database was conducted. The study synthesizes the current state of knowledge and spotlights the innovative mitigation strategies proposed to curb indoor MP pollution. These strategies involve minimizing the MP emission from source, advancements in filtration technology, aimed at reducing the MP exposure. Furthermore, this research sheds light on cutting-edge methods for converting MP waste into value-added products. These innovative approaches not only promise to alleviate environmental burdens but also contribute to a more sustainable and circular economy by transforming waste into resources such as biofuels, construction materials, and batteries. Despite these strides, this study acknowledges the ongoing challenges, including the need for more efficient removal technologies and a deeper understanding of MPs' health impacts. Looking forward, the study underscores the necessity for further research to fill these knowledge gaps, particularly in the areas of long-term health outcomes and the development of standardized, reliable methodologies for MP detection and quantification in indoor settings. This comprehensive approach paves the way for future exploration and the development of robust solutions to the complex issue of microplastic pollution.

Challenges and Recent Analytical Advances in Micro/Nanoplastic Detection

Despite growing ecological concerns, studies on microplastics and nanoplastics are still in their initial stages owing to technical hurdles in analytical techniques, especially for nanoplastics. We provide an overview of the general attributes of micro/nanoplastics in natural environments and analytical techniques commonly used for their analysis. After demonstrating the analytical challenges associated with the identification of nanoplastics due to their distinctive characteristics, we discuss recent technological advancements for detecting nanoplastics.

Degradation of microplastic in water by advanced oxidation processes

Plastic products have gained global popularity due to their lightweight, excellent ductility, high durability, and portability. However, out of the 8.3 billion tons of plastic waste generated by human activities, 80% of plastic waste is discarded due to improper disposal, and then transformed into microplastic pollution under the combined influence of environmental factors and microorganisms. In this comprehensive study, we present a thorough review of recent advancements in research on the source, distribution, and effect of microplastics. More importantly, we conducted deep research on the catalytic degradation technologies of microplastics in water, including advanced oxidation and photocatalytic technologies, and elaborated on the mechanisms of microplastics degradation in water. Besides, various strategies for mitigating microplastic pollution in aquatic ecosystems are discussed, ranging from policy interventions, the initiative for plastic recycling, the development of efficient catalytic materials, and the integration of multiple technological approaches. This review serves as a valuable resource for addressing the challenge of removing microplastic contaminants from water bodies, offering insights into effective and sustainable solutions.

Methamphetamine Removal from Aquatic Environments by Magnetic Microrobots with Cyclodextrin Chiral Recognition Elements

The growing consumption of drugs of abuse together with the inefficiency of the current wastewater treatment plants toward their presence has resulted in an emergent class of pollutants. Thus, the development of alternative approaches to remediate this environmental threat is urgently needed. Microrobots, combining autonomous motion with great tunability for the development of specific tasks, have turned into promising candidates to take on the challenge. Here, hybrid urchin-like hematite (α-Fe2O3) microparticles carrying magnetite (Fe3O4) nanoparticles and surface functionalization with organic β-cyclodextrin (CD) molecules are prepared with the aim of on-the-fly encapsulation of illicit drugs into the linked CD cavities of moving microrobots. The resulting mag-CD microrobots are tested against methamphetamine (MA), proving their ability for the removal of this psychoactive substance. A dramatically enhanced capture of MA from water with active magnetically powered microrobots when compared with static passive CD-modified particles is demonstrated. This work shows the advantages of enhanced mass transfer provided by the externally controlled magnetic navigation in microrobots that together with the versatility of their design is an efficient strategy to clean polluted waters.

Current Concerns about Microplastics and Nanoplastics: A Brief Overview

The widespread and increasing use of plastic-based goods in the present-day world has been raising many concerns about the formation of microplastics, their release, their impacts on the environment and, ultimately, on living organisms. These concerns are even greater regarding nanoplastics, i.e., nanosized microplastics, which may have even greater impacts. In this brief review, although without any claim or intention to exhaustively cover all the aspects of such a complex and many-sided issue, the very topical problem of the formation of microplastics, and the even more worrisome nanoplastics, from polymer-based products was considered. The approach is focused on a terse, straightforward, and easily accessible analysis oriented to the main technological engineering aspects regarding the sources of microplastics and nanoplastics released into the environment, their nature, some of the consequences arising from the release, the different polymers involved, their technological form (i.e., products or processes, with particular attention towards unintentional release), the formation mechanisms, and some possible mitigation pathways.

Magnetic Microrobot Swarms with Polymeric Hands Catching Bacteria and Microplastics in Water

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.

Nano revolution: pioneering the future of water reclamation with micro-/nano-robots

Earth's freshwater reserves are alarmingly limited, with less than 1% readily available. Factors such as industrialisation, population expansion, and climate change are compounding the scarcity of clean water. In this context, self-driven, programmable micro- and nano-scale synthetic robots offer a potential solution for enhancing water monitoring and remediation. With the aid of these innovative robots, diffusion-limited reactions can be overcome, allowing for active engagement with target pollutants, such as heavy metals, dyes, nano- and micro-plastics, oils, pathogenic microorganisms, and persistent organic pollutants. Herein, we introduced and reviewed recent influential and advanced studies on micro-/nano-robots (MNR) carried out over the past decade. Typical works are categorized by propulsion modes, analyzing their advantages and drawbacks in detail and looking at specific applications. Moreover, this review provides a concise overview of the contemporary advancements and applications of micro-/nano-robots in water-cleaning applications.

Removal of Nanoplastics from Copollutant Systems Using Seaweed Cellulose Nanofibers

Nanoplastic pollution poses a significant global concern for public health due to the potential toxicity it induces in the human body through food and water intake. Consequently, the urgent task of removing nanoplastics, especially from water resources, is paramount for enhancing food safety, and developing eco-friendly materials capable of efficiently removing nanoplastics is crucial. In this context, we propose the use of biodegradable anionic seaweed cellulose nanofibers (TEMPO-mediated seaweed cellulose nanofibers, TCNFs) and cationic seaweed cellulose nanofibers (quaternized seaweed cellulose nanofibers, QCNFs) for nanoplastic removal in both single- and copollutant systems. In our experiments under simulated practical conditions, we revealed that TCNFs and QCNFs achieved an average removal efficiency of 98.71% against nanoplastic particles. Moreover, TCNFs and QCNFs exhibited higher adsorption capacities compared to those of existing materials, potentially offering a cost-effective advantage. Toxicity assessments conducted with mammalian cells further confirmed the biosafety of TCNFs and QCNFs. This study contributes to the scientific and theoretical understanding of using edible seaweed as well as offers promising solutions for food safety control in an efficient, cost-effective, and eco-friendly manner.

Detection of nanoplastics released from consumer plastic food containers by electromagnetic heating pyrolysis mass spectrometry

Nanoplastics released from consumer plastic food containers are emerging environmental pollutants and directly ingested as part of the diet. However, quantification methods for nanoplastics are still lacking. Herein, a rapid identification and mass quantification approach was developed for nanoplastics analysis by combining electromagnetic heating with pyrolysis mass spectrometry (Eh-Py-MS). The pyrolysis products directly entered into the MS, which omits the gas phase separation process and shortens the detection time. A compact pyrolysis chamber was used and this increased the sample transfer efficiency and lowered power requirement. The operational parameters were systematically examined. The influence of nanoplastic size, additive, humic acid, and aging on detection was investigated, and it was concluded that environmental factors (humic acid, aging) and plastic properties (size, additives) did not influence the detection. The developed chamber showed that the limit of detection of polystyrene (PS) nanoplastics was 15.72 ng. Several typical food packages were demonstrated with satisfactory recovery rates (87.5-110%) and precision (RSD ≤11.36%). These results suggested that the consumer plastic food containers are a significant source of direct exposure to nanoplastics in humans from the environment.

Recent Advances in Light-Driven Semiconductor-Based Micro/Nanomotors: Optimization Strategies and Emerging Applications

Micro/nanomotors represent a burgeoning field of research featuring small devices capable of autonomous movement in liquid environments through catalytic reactions and/or external stimuli. This review delves into recent advancements in light-driven semiconductor-based micro/nanomotors (LDSM), focusing on optimized syntheses, enhanced motion mechanisms, and emerging applications in the environmental and biomedical domains. The survey commences with a theoretical introduction to micromotors and their propulsion mechanisms, followed by an exploration of commonly studied LDSM, emphasizing their advantages. Critical properties affecting propulsion, such as surface features, morphology, and size, are presented alongside discussions on external conditions related to light sources and intensity, which are crucial for optimizing the propulsion speed. Each property is accompanied by a theoretical background and conclusions drawn up to 2018. The review further investigates recent adaptations of LDSM, uncovering underlying mechanisms and associated benefits. A brief discussion is included on potential synergistic effects between different external conditions, aiming to enhance efficiency-a relatively underexplored topic. In conclusion, the review outlines emerging applications in biomedicine and environmental monitoring/remediation resulting from recent LDSM research, highlighting the growing significance of this field. The comprehensive exploration of LDSM advancements provides valuable insights for researchers and practitioners seeking to leverage these innovative micro/nanomotors in diverse applications.

Emerging isolation and degradation technology of microplastics and nanoplastics in the environment

Microplastics (MPs, less than 5 mm in size) are widely distributed in surroundings in various forms and ways, and threaten ecosystems security and human health. Its environmental behavior as pollutants carrier and the after-effects exposed to MPs has been extensively exploited; whereas, current knowledge on technologies for the separation and degradation of MPs is relatively limited. It is essential to isolate MPs from surroundings and/or degrade to safe levels. This in-depth review details the origin and distribution of MPs. Provides a comprehensive summary of currently available MPs separation and degradation technologies, and discusses the mechanisms, challenges, and application prospects of these technologies. Comparison of the contribution of various separation methods to the separation of NPs and MPs. Furthermore, the latest research trends and direction in bio-degradation technology are outlooked.

Innovations in chemical degradation technologies for the removal of micro/nano-plastics in water: A comprehensive review

Micro/nanoplastics (M/NPs) in water have raised global concern due to their potential environmental risks. To reestablish a M/NPs free world, enormous attempts have been made toward employing chemical technologies for their removal in water. This review comprehensively summarizes the advances in chemical degradation approaches for M/NPs elimination. It details and discusses promising techniques, including photo-based technologies, Fenton-based reaction, electrochemical oxidation, and novel micro/nanomotors approaches. Subsequently, critical influence factors, such as properties of M/NPs and operating factors, are analyzed in this review specifically. Finally, it concludes by addressing the current challenges and future perspectives in chemical degradation. This review will provide guidance for scientists to further explore novel strategies and develop feasible chemical methods for the improved control and remediation of M/NPs in the future.

Band Engineering versus Catalysis: Enhancing the Self-Propulsion of Light-Powered MXene-Derived Metal-TiO2 Micromotors To Degrade Polymer Chains

Light-powered micro- and nanomotors based on photocatalytic semiconductors convert light into mechanical energy, allowing self-propulsion and various functions. Despite recent progress, the ongoing quest to enhance their speed remains crucial, as it holds the potential for further accelerating mass transfer-limited chemical reactions and physical processes. This study focuses on multilayered MXene-derived metal-TiO2 micromotors with different metal materials to investigate the impact of electronic properties of the metal-semiconductor junction, such as energy band bending and built-in electric field, on self-propulsion. By asymmetrically depositing Au or Ag layers on thermally annealed Ti3C2Tx MXene microparticles using sputtering, Janus structures are formed with Schottky junctions at the metal-semiconductor interface. Under UV light irradiation, Au-TiO2 micromotors show higher self-propulsion velocities due to the stronger built-in electric field, enabling efficient photogenerated charge carrier separation within the semiconductor and higher hole accumulation beneath the Au layer. On the contrary, in 0.1 wt % H2O2, Ag-TiO2 micromotors reach higher velocities both in the presence and absence of UV light irradiation, owing to the superior catalytic properties of Ag in H2O2 decomposition. Due to the widespread use of plastics and polymers, and the consequent occurrence of nano/microplastics and polymeric waste in water, Au-TiO2 micromotors were applied in water remediation to break down polyethylene glycol (PEG) chains, which were used as a model for polymeric pollutants in water. These findings reveal the interplay between electronic properties and catalytic activity in metal-semiconductor junctions, offering insights into the future design of powerful light-driven micro- and nanomotors with promising implications for water treatment and photocatalysis applications.

Concentration analysis of metal-labeled nanoplastics in different water samples using electrochemistry

Despite the threats posed by nanoplastics to the environment and human health, little was known about the occurrence, formation, migration, and environmental impacts of nanoplastics due to the lack of quantitative and sensitive detection techniques. In this work, an electrochemical strategy for the detection of nanoplastics based on Ag labeling was proposed. Positively charged silver ions were attached to negatively charged polystyrene nanoplastics (PSNPs), and then the silver ions on the surface of PSNPs were reduced to Ag by sodium borohydride. Subsequently, the concentration of PSNPs was determined by identifying the signal of Ag by differential pulse voltammetry. The method showed different sensitivity for PSNPs of different sizes (100, 367, 500 nm). For tap water samples, the reason for the change in Ag electrochemical signal was discussed. The sensitivity of the method to PSNPs in tap water was investigated. The feasibility of the method for environmental water samples was verified using spiked lake water and spiked seawater, and satisfactory recoveries (93-112 %) were obtained for PSNPs of different sizes and concentrations. This study provided a sensitive, low-cost, and simple method without complex instrumentation, which was important for the determination of PSNPs in environmental water samples.

Advances in magnetic materials for microplastic separation and degradation

The widespread use of plastics in modern human society has led to severe environmental pollution with microplastics (MP/MPs). The rising consumption of plastics raises the omnipresence of microplastics in aquatic environments, which carry toxic organic matter, transport toxic chemicals, and spread through the food chain, seriously threatening marine life and human health. In this context, several advanced strategies for separating and degrading MPs from water have been developed recently, and magnetic materials and their nanostructures have emerged as promising materials for targeting, adsorbing, transporting, and degrading MPs. However, a comprehensive review of MP remediation using magnetic materials and their nanostructures is currently lacking. The present work provides a critical review of the recent advances in MP removal/degradation using magnetic materials. The focus is on the comparison and analysis of the MP's removal efficiencies of different magnetic materials, including iron/ferrite nanoparticles, magnetic nanocomposites, and micromotors, aiming to unravel the underlying roles of magnetic materials in different types of MP degradation and present the general strategies for designing them with optimal performance. Finally, the review outlines the forthcoming challenges and perspectives in the development of magnetic nanomaterials for MP remediation.