Self-propelled carbohydrate-sensitive microtransporters with built-in boronic acid recognition for isolating sugars and cells

Modified Au:Fe-Ni magnetic micromotors improve drug delivery and diagnosis in MCF-7 cells and spheroids

Nano/micromotors hold immense potential for revolutionizing drug delivery and detection systems, especially in the realm of cancer diagnosis and treatment, owing to their distinctive features, including precise propulsion, maneuverability, and meticulously designed surface modifications. In this study, we explore the capabilities of modified and magnetically driven micromotors as active drug delivery systems within 2D and 3D cell culture environments and cancer diagnosis. We synthesized gold (Au) and iron-nickel (Fe-Ni) metallic-based magnetic micromotors (Au:Fe-Ni MMs) through electrochemical methods, equipping them with functionalities for controlled doxorubicin (DOX) release and cancer cell recognition. In 2D and spheroids of MCF-7 adenocarcinoma cells, the Au segment of these micromotors was utilized to help DOX loading through poly(sodium-4-styrenesulfonate) (PSS) functionalization, and the attachment of antiHER2 antibodies for specific recognition. This innovative approach enabled controlled drug release within the cancerous microenvironment, coupled with magnetic (Fe-Ni) propulsion for biocompatible drug delivery to MCF-7 cells. Furthermore, antiHER2 immobilized Au:Fe-Ni MMs effectively interacted with receptors, capitalizing on the overexpression of HER2 antigens on MCF-7 cells. Encouraging outcomes were observed, particularly in spheroid models, underscoring the remarkable potential of these multifunctional micromotors for advancing intelligent drug delivery methodologies and diagnostic purposes.

Focus on the performance enhancement of micro/nanomotor-based biosensors

Micro/nanomotors (MNMs) emerge as a vital candidate for biosensing due to its nano-size structure, high surface-to-area ratio, directional mobility, biocompatibility, and ease of functionalization, therefore being able to detect objects with high efficiency, precision, and selectivity. The driving mode, nanostructure, materials property, preparation technique, and biosensing applications have been thoroughly discussed in publications. To promote the MNMs-based biosensors from in vitro to in vivo, it is necessary to give a comprehensive discussion from the perspective of sensing performances enhancement. However, until now, there is few reviews dedicated to the systematic discussion on the multiple performance enhancement schemes and the current challenges of MNMs-based biosensors. Bearing it in mind and based on our research experience in this field, we summarized the enhancement methods for biosensing properties such as sensitivity, selectivity, detection time, biocompatibility, simplify system operation, and environmental availability. We hope that this review provides the readers with fundamental understanding on performance enhancement schemes for MNMs-based biosensors.

Untethered Micro/Nanorobots for Remote Sensing: Toward Intelligent Platform

Untethered micro/nanorobots that can wirelessly control their motion and deformation state have gained enormous interest in remote sensing applications due to their unique motion characteristics in various media and diverse functionalities. Researchers are developing micro/nanorobots as innovative tools to improve sensing performance and miniaturize sensing systems, enabling in situ detection of substances that traditional sensing methods struggle to achieve. Over the past decade of development, significant research progress has been made in designing sensing strategies based on micro/nanorobots, employing various coordinated control and sensing approaches. This review summarizes the latest developments on micro/nanorobots for remote sensing applications by utilizing the self-generated signals of the robots, robot behavior, microrobotic manipulation, and robot-environment interactions. Providing recent studies and relevant applications in remote sensing, we also discuss the challenges and future perspectives facing micro/nanorobots-based intelligent sensing platforms to achieve sensing in complex environments, translating lab research achievements into widespread real applications.

Biocatalytic Buoyancy-Driven Nanobots for Autonomous Cell Recognition and Enrichment

Autonomously self-propelled nanoswimmers represent the next-generation nano-devices for bio- and environmental technology. However, current nanoswimmers generate limited energy output and can only move in short distances and duration, thus are struggling to be applied in practical challenges, such as living cell transportation. Here, we describe the construction of biodegradable metal-organic framework based nanobots with chemically driven buoyancy to achieve highly efficient, long-distance, directional vertical motion to "find-and-fetch" target cells. Nanobots surface-functionalized with antibodies against the cell surface marker carcinoembryonic antigen are exploited to impart the nanobots with specific cell targeting capacity to recognize and separate cancer cells. We demonstrate that the self-propelled motility of the nanobots can sufficiently transport the recognized cells autonomously, and the separated cells can be easily collected with a customized glass column, and finally regain their full metabolic potential after the separation. The utilization of nanobots with easy synthetic pathway shows considerable promise in cell recognition, separation, and enrichment.

Small-Scale Robotics with Tailored Wettability

Small-scale robots (SSRs) have emerged as promising and versatile tools in various biomedical, sensing, decontamination, and manipulation applications, as they are uniquely capable of performing tasks at small length scales. With the miniaturization of robots from the macroscale to millimeter-, micrometer-, and nanometer-scales, the viscous and surface forces, namely adhesive forces and surface tension have become dominant. These forces significantly impact motion efficiency. Surface engineering of robots with both hydrophilic and hydrophobic functionalization presents a brand-new pathway to overcome motion resistance and enhance the ability to target and regulate robots for various tasks. This review focuses on the current progress and future perspectives of SSRs with hydrophilic and hydrophobic modifications (including both tethered and untethered robots). The study emphasizes the distinct advantages of SSRs, such as improved maneuverability and reduced drag forces, and outlines their potential applications. With continued innovation, rational surface engineering is expected to endow SSRs with exceptional mobility and functionality, which can broaden their applications, enhance their penetration depth, reduce surface fouling, and inhibit bacterial adhesion.

Plasmonic/magnetic nanoarchitectures: From controllable design to biosensing and bioelectronic interfaces

Controllable design of the nanocrystal-assembled plasmonic/magnetic nanoarchitectures (P/MNAs) inspires abundant methodologies to enhance light-matter interactions and control magnetic-induced effects by means of fine-tuning the morphology and ordered packing of noble metallic or magnetic building blocks. The burgeoning development of multifunctional nanoarchitectures has opened up broad range of interdisciplinary applications including biosensing, in vitro diagnostic devices, point-of-care (POC) platforms, and soft bioelectronics. By taking advantage of their customizability and efficient conjugation with capping biomolecules, various nanoarchitectures have been integrated into high-performance biosensors with remarkable sensitivity and versatility, enabling key features that combined multiplexed detection, ease-of-use and miniaturization. In this review, we provide an overview of the representative developments of nanoarchitectures that being built by plasmonic and magnetic nanoparticles over recent decades. The design principles and key mechanisms for signal amplification and quantitative sensitivity have been explored. We highlight the structure-function programmability and prospects of addressing the main limitations for conventional biosensing strategies in terms of accurate selectivity, sensitivity, throughput, and optoelectronic integration. State-of-the-art strategies to achieve affordable and field-deployable POC devices for early multiplexed detection of infectious diseases such as COVID-19 has been covered in this review. Finally, we discuss the urgent yet challenging issues in nanoarchitectures design and related biosensing application, such as large-scale fabrication and integration with portable devices, and provide perspectives and suggestions on developing smart biosensors that connecting the materials science and biomedical engineering for personal health monitoring.

Micro/nanomotor technology: the new era for food safety control

Food poisoning caused by eating contaminated food remains a threat to global public health. Making the situation even worse is the aggravated global environmental pollution, which poses a major threat to the safety of agricultural resources. Food adulteration has been rampant owing to negligent national food safety regulations. The speed at which contaminated food is detected and disposed of determines the extent to which consumers' lives are safeguarded and agricultural economic losses are prevented. Micro/nanomotors offer a high-speed mobile loading platform that substantially increases the chemical reaction rates and, accordingly, exhibit great potential as alternatives to conventional detection and degradation techniques. This review summarizes the propulsion modes applicable to micro/nanomotors in food systems and the advantages of using micro/nanomotors, highlighting examples of their potential use in recent years for the detection and removal of food contaminants. Micro/nanomotors are an emerging technology for food applications that is moving toward mass production, simple preparation, and important functions.

A Critical Review on Nanowire-Motors: Design, Mechanism and Applications

Nanowire-motors (NW-Ms) are promoting the rapid development of emerging biomedicine and environmental governance, and are an important branch of micro-nano motors in the development of nanotechnology. In recent years, huge research breakthroughs have been made in these fields in terms of the fascinating microstructure, conversion efficiency and practical applications of NW-Ms. This review article introduces the latest milestones in NW-Ms research, from production methods, driving mechanisms, control methods to targeted drug delivery, sewage detection, sensors and cell capture. The dynamics and physics of micro-nano devices are reviewed, and finally the current challenges and future research directions in this field are discussed. This review further aims to provide certain guidance for the driving of NW-Ms to meet the urgent needs of emerging applications.

Toward a Multifunctional Light-Driven Biomimetic Mudskipper-Like Robot for Various Application Scenarios

The systematicness, flexibility, and complexity of natural biological organisms are a constant stream of inspiration for researchers. Therefore, mimicking the natural intelligence system to develop microrobotics has attracted broad interests. However, developing a multifunctional device for various application scenarios has great challenges. Herein, we present a bionic multifunctional actuation device─a light-driven mudskipper-like actuator that is composed of a porous silicone elastomer and graphene oxide. The actuator exhibits a reversible and well-integrated response to near-infrared (NIR) light due to the photothermal-induced contractile stress in the actuation film, which promotes generation of cyclical and rapid locomotion upon NIR light being switched on and off, such as bending in air and crawling in liquid. Furthermore, through rational device design and modulation of light, the mechanically versatile device can float and swim controllably following a predesigned route at the liquid/air interface. More interestingly, the actuator can jump from liquid medium to air with an extremely short response time (400 ms), a maximum speed of 2 m s^-1, and a height of 14.3 cm under the stimulation of near-infrared light. The present work possesses great potential in the applications of bioinspired actuators in various fields, such as microrobots, sensors, and locomotion.

Facile engineering of ECM-mimetic injectable dual crosslinking hydrogels with excellent mechanical resilience, tissue adhesion, and biocompatibility

Injectable hydrogels have aroused ever-increasing interest for their cell/biomaterial delivery ability through minimally invasive procedures. Nevertheless, it is still a challenge to simply fabricate natural biopolymer-based injectable hydrogels possessing satisfactory mechanical properties, bioadhesion, and cell delivery ability. Herein, we describe a facile dual crosslinking (DC) strategy for preparing extracellular matrix (ECM) mimetic hydrogels with desirable comprehensive performance. The chondroitin sulfate (CS)- and gelatin (Gel)-based single crosslinked (SC) hydrogels were first developed via reversible borate ester bonds, and further strengthened through the Michael-addition crosslinking reaction or visible-light initiated photopolymerization with thiol-containing polyethylene glycol (PEG) crosslinkers. The dynamic SC hydrogels showed good injectability, pH-sensitive gel-sol transformation, and self-adhesion ability to various biological tissues such as skin, liver, and intervertebral disc. The mechanically tough DC hydrogels displayed tunable stiffness, and resilience to compression load (up to 90% strain) owing to the effective energy dissipation mechanism. The formed DC hydrogels after subcutaneous injection well integrated with surrounding tissues and exhibited fast self-recovery properties. Moreover, the photoencapsulation of human mesenchymal stem cells (hMSCs) within the developed DC hydrogels was achieved and has been proved to be biocompatible, highlighting the great potential of the photopolymerized DC hydrogels in cell delivery and three-dimensional (3D) cell culture. This biomimetic, mechanically resilient, adhesive, and cytocompatible injectable DC hydrogel could serve as a promising candidate for tissue engineering.

Chitosan functionalized gold-nickel bimetallic magnetic nanomachines for motion-based deoxyribonucleic acid recognition

In this present study, the preparation of chitosan functionalized gold‑nickel wire nanomachines (nanomotors) (CS@Au-Ni NMs) for motion-based double-stranded deoxyribonucleic acid (dsDNA) recognition and detection was described. Synthesis of the nanomachines was accomplished by Ni layer formation using direct current (DC) magnetron sputtering over electrochemically deposited Au wires. Subsequently, biopolymer chitosan was dispersed onto this bimetallic layer by drop casting which could provide a novel and functional surface for leading bio-applications. CS@Au-Ni NMs were characterized via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and zeta potential analysis methods for the elucidation of structural morphology, elemental composition and electrophoretic mobility. On account of presenting the application of these magnetic nanomachines, they were interacted with different concentrations of dsDNA and the changes in their velocities were investigated. The speed CS@Au-Ni NMs were measured as 19 μm/s under 22 mT magnetic field. These magnetically guided nanomachines demonstrated a practical and good sensing ability by recognizing dsDNA between 0.01 mg/L and 10 mg/L. Electrochemical characterization was also performed to identify the surface characteristics. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments presented the interaction of the NMs with dsDNA by indicating the convenient recognition.

Self-Propelled Nanojets for Fenton Catalysts Based on Halloysite with Embedded Pt and Outside-Grafted Fe3O4

Taking inspirations from nature, we endeavor to develop catalytically self-propelled nanojets from a type of tubular clay minerals, halloysite nanotubes (HNTs), and utilize them as catalysts targeted for catalysis where the traditional means of mechanical agitation cannot be implemented. Nanojets of Fe₃O₄@HNTs/Pt were prepared by impregnating platinum nanoparticles (Pt NPs) in lumens of HNTs and selective grafting of magnetite (Fe₃O₄) particles on the external surface. The HNT-based nanojets were validated to be highly suitable both in free bulk solution and in microfluidic flow. An example of Fenton degradation catalyzed by these jets was demonstrated. The powerful movement of Fe₃O₄@HNTs/Pt (368 ± 50 μm·s^-1) fueled by 5.0% wt. H₂O₂ was found to follow a bubble propulsion mechanism, and the motion exhibits collective behavior as swarms. The clay tubes were for the first time observed to self-assemble into fish-like aggregates during swimming, reflecting natural occurrence of motion-evolution philosophy. Guided motion was realized by employing magnetic manipulation which makes jets feasible for reactors with complex microchannels/reactors.

ATRP of MIDA Boronate-Containing Monomers as a Tool for Synthesizing Linear Phenolic and Functionalized Polymers

Despite numerous novel polymeric materials that have been produced by incorporating boronic acid or ester groups into polymers, it remains a challenge to prepare well-defined boronate-containing polymers due to their inherent instability. Herein, we used N-methyliminodiacetic acid (MIDA) to stabilize the reactive organoboron structure. MIDA boronate-containing polymers were synthesized in a good control by initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP). Oxidation and Suzuki-Miyaura coupling were conducted to prepare linear phenol-containing polymers and aromatic functionalized polymers. Upon comparison of similar polymers prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization, of which the chain transfer agent (CTA) end groups cause multiple undesired side reactions, the halogen end groups of polymers prepared by ATRP are nontoxic to metal catalysts and stable during the postmodifications, thus providing a more facile tool for synthesizing various functionalized polymers with great potentials in advanced materials.

Polymeric Micro/Nanomotors and Their Biomedical Applications

Since their naissance in the 2000s, various micro or nanomotors with powerful functions have been proposed. Among them, polymer-based micro or nanomotors stand out for the easy processing and facile functionalization, holding immense potential for bioapplications. In this review, fabrication of polymer-based micro or nanomotors and their applications in biomedical areas are covered. Classic manufacturing approaches as well as cutting-edge techniques are discussed with representative works highlighted. Current challenges and future prospects are presented in the hope of pointing new research directions to facilitate practical translations of micro/nanomotors.

Recent progress of biomimetic motions-from microscopic micro/nanomotors to macroscopic actuators and soft robotics

Motion is a basic behavioral attribute of organisms, and it is a behavioral response of organisms to the external environment and internal state changes. Materials with switchable mechanical properties are widespread in living organisms and play crucial roles in the motion of organisms. Therefore, significant efforts have been made toward mimicking such architectures and motion behaviors by making full use of the properties of stimulus-responsive materials to design smart materials/machines with specific functions. In recent years, the biomimetic motions based on micro/nanomotors, actuators and soft robots constructed from smart response materials have been developed gradually. However, a comprehensive discussion on various categories of biomimetic motions in this field is still missing. This review aims to provide such a panoramic overview. From nano-to macroscales, we summarize various biomimetic motions based on micro/nanomotors, actuators and soft robotics. For each biomimetic motion, we discuss the driving modes and the key functions. The challenges and opportunities of biomimetic motions are also discussed. With rapidly increasing innovation, advanced, intelligent and multifunctional biomimetic motions based on micro/nanomotors, actuators and soft robotics will certainly bring profound impacts and changes for human life in the near future.

Biomimetic motions are derived from the many different functional materials and/or intricate and highly organized structure of the biological material from the molecular to the nanoscale, microscale and macroscale.

Research progress of using micro/nanomotors in the detection and therapy of diseases related to the blood environment

Micro/nanomotors bring new possibilities for the detection and therapy of diseases related to the blood environment with their unique motion effect. This work reviews the research progress of using micro/nanomotors in the detection and therapy of diseases related to the blood environment. First, we outline the advantages of using micro/nanomotors in blood-related disease detection. To be specific, the motion capability of micro/nanomotors can increase plasma or blood fluid convection and accelerate the interaction between the sample and the capture probe. This allows the effective reduction of the amount of reagents and treatment steps. Therefore, the application of micro/nanomotors significantly improves the analytical performance. Second, we discuss the key challenges and future prospects of micro/nanomotors in the treatment of blood-environment related diseases. It is very important to design a unique treatment plan according to the etiology and specific microenvironment of the disease. The next generation of micro/nanomotors is expected to bring exciting progress to the detection and therapy of blood-environment related diseases.

3D printing of functional microrobots

3D printing (also called "additive manufacturing" or "rapid prototyping") is able to translate computer-aided and designed virtual 3D models into 3D tangible constructs/objects through a layer-by-layer deposition approach. Since its introduction, 3D printing has aroused enormous interest among researchers and engineers to understand the fabrication process and composition-structure-property correlation of printed 3D objects and unleash its great potential for application in a variety of industrial sectors. Because of its unique technological advantages, 3D printing can definitely benefit the field of microrobotics and advance the design and development of functional microrobots in a customized manner. This review aims to present a generic overview of 3D printing for functional microrobots. The most applicable 3D printing techniques, with a focus on laser-based printing, are introduced for the 3D microfabrication of microrobots. 3D-printable materials for fabricating microrobots are reviewed in detail, including photopolymers, photo-crosslinkable hydrogels, and cell-laden hydrogels. The representative applications of 3D-printed microrobots with rational designs heretofore give evidence of how these printed microrobots are being exploited in the medical, environmental, and other relevant fields. A future outlook on the 3D printing of microrobots is also provided.

A light-activated nanotherapeutic with broad-spectrum bacterial recognition to eliminate drug-resistant pathogens

Obstinate infections caused by drug-resistant bacteria severely threaten human health. And the emergence of multidrug-resistant bacteria increases the morbidity and mortality of patients, thus necessitating the development of innovative or alternative therapeutics. Here, a light-activated nanotherapeutic with broad-spectrum bacterial recognition is established as an antibiotic-free therapeutic agent against pathogens. The nanotherapeutic with external phenylboronic acid-based glycopolymers increases the stability and biocompatibility and shows the ability of bacterial recognition. Once irradiated with near-infrared light, this nanotherapeutic with high photothermal conversion efficiency disrupts the cytoplasmic membrane, thus killing bacterial cells. Importantly, it also eliminates the biofilms formed by both drug-resistant Gram-negative bacteria (Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus) effectively. Thus, this antibiotic-free nanotherapeutic with hypotoxicity offers a promising approach to fight increasingly serious antimicrobial resistance.

Trends in Micro-/Nanorobotics: Materials Development, Actuation, Localization, and System Integration for Biomedical Applications

Micro-/nanorobots (m-bots) have attracted significant interest due to their suitability for applications in biomedical engineering and environmental remediation. Particularly, their applications in in vivo diagnosis and intervention have been the focus of extensive research in recent years with various clinical imaging techniques being applied for localization and tracking. The successful integration of well-designed m-bots with surface functionalization, remote actuation systems, and imaging techniques becomes the crucial step toward biomedical applications, especially for the in vivo uses. This review thus addresses four different aspects of biomedical m-bots: design/fabrication, functionalization, actuation, and localization. The biomedical applications of the m-bots in diagnosis, sensing, microsurgery, targeted drug/cell delivery, thrombus ablation, and wound healing are reviewed from these viewpoints. The developed biomedical m-bot systems are comprehensively compared and evaluated based on their characteristics. The current challenges and the directions of future research in this field are summarized.

Medical Micro/Nanorobots in Precision Medicine

Advances in medical robots promise to improve modern medicine and the quality of life. Miniaturization of these robotic platforms has led to numerous applications that leverages precision medicine. In this review, the current trends of medical micro and nanorobotics for therapy, surgery, diagnosis, and medical imaging are discussed. The use of micro and nanorobots in precision medicine still faces technical, regulatory, and market challenges for their widespread use in clinical settings. Nevertheless, recent translations from proof of concept to in vivo studies demonstrate their potential toward precision medicine.

Current status of micro/nanomotors in drug delivery

Synthetic micro/nanomotors (MNMs) are novel, self-propelled nano or microscale devices that are widely used in drug transport, cell stimulation and isolation, bio-imaging, diagnostic and monitoring, sensing, photocatalysis and environmental remediation. Various preparation methods and propulsion mechanisms make MNMs "tailormade" nanosystems for the intended purpose or use. As the one of the newest members of nano carriers, MNMs open a new perspective especially for rapid drug transport and gene delivery. Although there exists limited number of in-vivo studies for drug delivery purposes, existence of in-vitro supportive data strongly encourages researchers to move on in this field and benefit from the manoeuvre capability of these novel systems. In this article, we reviewed the preparation and propulsion mechanisms of nanomotors in various fields with special attention to drug delivery systems.

Near-Infrared Light-Steered Graphene Aerogel Micromotor with High Speed and Precise Navigation for Active Transport and Microassembly

Fuel-free light-driven micromotors have attracted increasing attention since the advantages of reversible, noninvasive, and remote maneuver are on demand with excellent spatial and temporal resolution. However, they suffer from a challenging bottleneck of the rather modest motion speed, which hinders their applications, needing to overcome the water flow movement in environmental water. Herein, we demonstrate a near-infrared (NIR) light-steered, precise navigation-controlled micromotor based on a reduced graphene oxide aerogel microsphere (RGOAM), which possesses an isotropic structure and is easily prepared by a one-step electrospray approach other than conventional light-propelled micromotors with the Janus structure. Benefiting from the ultralight weight of the aerogel and lesser fluid resistance on the water surface, the RGOAM motors show a higher motion speed (up to 17.60 mm/s) than that in the published literature, letting it overcome counterflow. Taking advantage of the photothermal conversion capacity of the RGOAM under an asymmetric light field, it is capable of moving both on the water driven by the Marangoni effect and under the water via light-manipulated density change. The motion direction and speed on water as well as the "start/stop" state can be precisely steered by NIR light even in a complicated maze. Due to its strong adsorption and loading capacity, the RGOAM can be applied for active loading-transport-release of dyes on demand as well as micropart assembling and shaping. Our work provides a strategy to achieve high speed, precise navigation control, and functional extensibility simultaneously for micromotors, which may offer considerable promise for the broad biomedical and environmental applications.

Chemical modification of enveloped viruses for biomedical applications

The unique characteristics of enveloped viruses including nanometer size, consistent morphology, narrow size distribution, versatile functionality and biocompatibility have attracted attention from scientists to develop enveloped viruses for biomedical applications. The biomedical applications of the viral-based nanoparticles include vaccine development, imaging and targeted drug delivery. The modification of the structural elements of enveloped viruses is necessary for the desired functions. Here, we review the chemical approaches that have been utilized to develop bionanomaterials based on enveloped viruses for biomedical applications. We first provide an overview of the structures of enveloped viruses which are composed of nucleic acids, structural and functional proteins, glycan residues and lipid envelope. The methods for modification, including direct conjugation, metabolic incorporation of functional groups and peptide tag insertion, are described based on the biomolecular types of viral components. Layer-by-layer technology is also included in this review to illustrate the non-covalent modification of enveloped viruses. Then, we further elaborate the applications of chemically-modified enveloped viruses, virus-like particles and viral subcomponents in biomedical research.

Visible-Light-Driven Single-Component BiVO4 Micromotors with the Autonomous Ability for Capturing Microorganisms

Light-driven micro/nanomotors represent the next generation of automotive devices that can be easily actuated and controlled by using an external light source. As the field evolves, there is a need for developing more sophisticated micromachines that can fulfill diverse tasks in complex environments. Herein, we introduce single-component BiVO₄ micromotors with well-defined micro/nanostructures that can swim both individually and as collectively assembled entities under visible-light irradiation. These devices can perform cargo loading and transport of passive particles as well as living microorganisms without any surface functionalization. Interestingly, after photoactivation, the BiVO₄ micromotors exhibited an ability to seek and adhere to yeast cell walls, with the possibility to control their attachment/release by switching the light on/off, respectively. Taking advantage of the selective motor/fungal cells attachment, the fungicidal activity of BiVO₄ micromotors under visible illumination was also demonstrated. The presented star-shaped BiVO₄ micromotors, obtained by a hydrothermal synthesis, contribute to the potential large-scale fabrication of light-powered micromotors. Moreover, these multifunctional single-component micromachines with controlled self-propulsion, collective behavior, cargo transportation, and photocatalytic activity capabilities hold promising applications in sensing, biohybrids assembly, cargo delivery, and microbiological water pollution remediation.

Three-Dimensional Microtubular Devices for Lab-on-a-Chip Sensing Applications

The rapid advance of micro-/nanofabrication technologies opens up new opportunities for miniaturized sensing devices based on novel three-dimensional (3D) architectures. Notably, microtubular geometry exhibits natural advantages for sensing applications due to its unique properties including the hollow sensing channel, high surface-volume ratio, well-controlled shape parameters and compatibility to on-chip integration. Here the state-of-the-art sensing techniques based on microtubular devices are reviewed. The developed microtubular sensors cover microcapillaries, rolled-up nanomembranes, chemically synthesized tubular arrays, and photoresist-based tubular structures via 3D printing. Various types of microtubular sensors working in optical, electrical, and magnetic principles exhibit an extremely broad scope of sensing targets including liquids, biomolecules, micrometer-sized/nanosized objects, and gases. Moreover, they have also been applied for the detection of mechanical, acoustic, and magnetic fields as well as fluorescence signals in labeling-based analyses. At last, a comprehensive outlook of future research on microtubular sensors is discussed on pushing the detection limit, extending the functionality, and taking a step forward to a compact and integrable core module in a lab-on-a-chip analytical system for understanding fundamental biological events or performing accurate point-of-care diagnostics.

Design and Fabrication of Tubular Micro/Nanomotors via 3D Laser Lithography

Catalytic tubular micro/nanomachines convert chemical energy from a surrounding aqueous fuel solution into mechanical energy to generate autonomous movements, propelled by the oxygen bubbles decomposed by hydrogen peroxide and expelled from the microtubular cavity. With the development of nanotechnology, micro/nanomotors have attracted more and more interest due to their numerous potential for in vivo and in vitro applications. Here, highly efficient chemical catalytic microtubular motors were fabricated via 3D laser lithography and their motion behavior under the action of driving force in fluids was demonstrated. The frequency of catalytically-generated bubbles ejection was influenced by the geometrical shape of the micro/nanomotor and surrounding chemical fuel environment, resulting in the variation in motion speed. The micro/nanomotors generated with a rocket-like shape displayed a more active motion compared with that of a single tubular micro/nanomotor, providing a wider range of practical micro-/nanoscale applications in the future.

An array consisting of glycosylated quantum dots conjugated to MoS2 nanosheets for fluorometric identification and quantitation of lectins and bacteria

A fluorescent array based on the use of saccharide-functionalized multicolored quantum dots (s-QDs) and of 4-mercaptophenylboronic acid-functionalized MoS₂ nanosheets (PBA-MoS₂) was constructed for multiple identification and quantitation of lectins and bacteria. In this array, the fluorescence of the s-QDs is quenched by the PBA-MoS₂ nanosheets. In the presence of multiple lectins, s-QDs differentially detach from the surface of PBA-MoS₂ nanosheets, producing distinct fluorescence response patterns due to both quenching and enhancement of fluorescence. By analyzing the fluorescence responses with linear discriminant analysis, multiple lectins and bacteria were accurately identified with 100% accuracy. The limits of detection of Concanavalin A, Pisum sativum agglutinin, Peanut agglutinin, and Ricius communis I agglutinin are as low as 3.7, 8.3, 4.2 and 3.9 nM, respectively. The array has further been evidenced to be potent for distinguishing and quantifying different bacterial species by recognizing their surface lectins. The detection limits of Escherichia coli and Enterococcus faecium are 87 and 66 cfu mL^-1, respectively. Graphical abstract Schematic of a fluorometric array based on the use of saccharides-functionalized quantum dots (s-QDs) and 4-mercaptophenylboronic acid-functionalized MoS₂ (PBA- MoS₂) nanosheets. This array was successfully applied to simultaneously analysis of lectins, bacteria in real samples with high sensitivity and accuracy.

Glycosylated cellulose derivatives with regioselective distributions of pendant glucose moieties

Inspired by the presence of diverse carbohydrates on the surface of biological systems, we present herein a method for the synthesis of sugar-bearing polymers derived from renewable cellulose. In this paper, novel glycosylated cellulose derivatives were successfully synthesized containing a series of subsequent reactions: (1) synthesis of cellulose derivatives with pendant hydroxyl groups via nucleophilic substitution; (2) further sequential reactions containing a novel TEMPO/[bis(acetoxy)iodo]benzene (BAIB)-mediated oxidation of pendant hydroxyl groups, Schiff base formation and reduction in one-pot reaction; and (3) thiol-ene click reaction as an efficient tool to generate cellulose derivatives with pendant glucosyl groups. Furthermore, the glucosyl groups were only linked with the C6 position of anhydroglucose units (AGUs) of cellulose. Moreover, the glycosylated cellulose derivatives could be reversibly cross-linked by 1,4-phenylenediboronic acid at pH 10 and dissociated into single polymer chains by using glucose, which allow such glycolated cellulose derivatives to be interesting responsive materials.

Nanoscale Biosensors Based on Self-Propelled Objects

This review provides a comprehensive overview of the latest developments (2016⁻2018 period) in the nano and micromotors field for biosensing applications. Nano and micromotor designs, functionalization, propulsion modes and transduction mechanism are described. A second important part of the review is devoted to novel in vitro and in vivo biosensing schemes. The potential and future prospect of such moving nanoscale biosensors are given in the conclusions.

Progress toward Catalytic Micro- and Nanomotors for Biomedical and Environmental Applications

Synthetic micro- and nanomotors (MNMs) are tiny objects that can autonomously move under the influence of an appropriate source of energy, such as a chemical fuel, magnetic field, ultrasound, or light. Chemically driven MNMs are composed of or contain certain reactive material(s) that convert chemical energy of a fuel into kinetic energy (motion) of the particles. Several different materials have been explored over the last decade for the preparation of a wide variety of MNMs. Here, the discovery of materials and approaches to enhance the efficiency of chemically driven MNMs are reviewed. Several prominent applications of the MNMs, especially in the fields of biomedicine and environmental science, are also discussed, as well as the limitations of existing materials and future research directions.

Nanomotors for Nucleic Acid, Proteins, Pollutants and Cells Detection

The development of nanomachines able to operate at the nanoscale, performing complex tasks such as drug delivery, precision surgery, or cell detection, constitutes one of the most important challenges in nanotechnology. The principles that rule the nanoscale are completely different from the ones which govern the macroscopic world and, therefore, the collaboration of scientists with expertise in different fields is required for the effective fabrication of these tiny machines. In this review, the most recent advances carried out in the synthesis and application of nanomachines for diagnosis applications will be presented in order to provide a picture of their potential in the detection of important biomolecules or pathogens in a selective and controlled manner.

Polymer platforms for micro- and nanomotor fabrication

Artificial, self-propelled micro- and nanomotors are small devices capable of autonomous movement, which are a powerful scientific innovation for solving various medical and environmental issues. Their design is frequently inspired by complex biological structures which are composed of biopolymers and their composites. The choice of materials for nano- and micromachines is crucial for their shape, mechanism and efficiency of propulsion. In this review, we discuss the utilization and fabrication of polymers as soft components of micro- and nanomotors.

Micro/nanomotors towards in vivo application: cell, tissue and biofluid

Inspired by highly efficient natural motors, synthetic micro/nanomotors are self-propelled machines capable of converting the supplied fuel into mechanical motion. A significant advance has been made in the construction of diverse motors over the last decade. These synthetic motor systems, with rapid transporting and efficient cargo towing abilities, are expected to open up new horizons for various applications. Utilizing emergent motor platforms for in vivo applications is one important aspect receiving growing interest as conventional therapeutic methodology still remains limited for cancer, heart, or vasculature diseases. In this review we will highlight the recent efforts towards realistic in vivo application of various motor systems. With ever booming research enthusiasm in this field and increasing multidisciplinary cooperation, micro/nanomotors with integrated multifunctionality and selectivity are on their way to revolutionize clinical practice.

Isolation of HL-60 cancer cells from the human serum sample using MnO2-PEI/Ni/Au/aptamer as a novel nanomotor and electrochemical determination of thereof by aptamer/gold nanoparticles-poly(3,4-ethylene dioxythiophene) modified GC electrode

Herein, aptamer-modified self-propelled nanomotors were used for transportation of human promyelocytic leukemia cells (HL-60) from a human serum sample. For this purpose, the fabricated manganese oxide nanosheets-polyethyleneimine decorated with nickel/gold nanoparticles (MnO₂-PEI/Ni/Au) as nanomotors were added to a vial containing thiolated aptamer KH1C12 solution as a capture aptamer to attach to the gold nanoparticles on the surface of nanomotors covalently. The aptamer-modified self-propelled nanomotors (aptamer_KH1C12/nanomotors) were then separated by placing the vial in a magnetic stand. The aptamer-modified self-propelled nanomotors were rinsed three times with water to remove the non-attached aptamers. Then, the resulting aptamer_KH1C12/nanomotors were applied for the on-the-fly" transporting of HL-60 cancer cell from a human serum sample. To release of the captured HL-60 cancer cells, the complementary nucleotide sequences of KH1C12 aptamer solution (releasing aptamer) that has a with capture aptamer was added to phosphate buffer solution (1 M, pH 7.4) containing HL-60/aptamer_KH1C12/nanomotors. Because of the high affinity of capture aptamer to complementary nucleotide sequences of aptamer_KH1C12, the HL-60 cancer cells released on the surface of aptamer_KH1C12/nanomotors into the solution. The second goal of the present work was determining the concentration of HL-60 cancer cell in the human serum samples. The electrochemical impedance spectroscopy technique (EIS) was used for the determination of HL-60 cancer cell. The concentration of separated cancer cell was determined by aptamer/gold nanoparticles-poly(3,4-ethylene dioxythiophene) modified GC electrode (GC/PEDOT-Au_nano/aptamer _KH1C12). The proposed aptasensor exhibited a good response to the concentration of HL-60 cancer cells in the range of 2.5 × 10¹ to 5 × 10⁵ cells mL^-1 with a low limit of detection of 250 cells mL^-1.