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In nature, microorganisms could sense the intensity of the incident visible light and exhibit bidirectional (positive or negative) phototaxis. However, it is still challenging to achieve the similar biomimetic phototaxis for the artificial micro/nanomotor (MNM) counterparts with the size from a few nanometers to a few micrometers. In this work, we report a fuel-free carbon nitride (C₃N₄)/polypyrrole nanoparticle (PPyNP)-based smart MNM operating in water, whose behavior resembles that of the phototactic microorganism. The MNM moves toward the visible light source under low illumination and away from it under high irradiation, which relies on the competitive interplay between the light-induced self-diffusiophoresis and self-thermophoresis mechanisms concurrently integrated into the MNM. Interestingly, the competition between these two mechanisms leads to a collective bidirectional phototaxis of an ensemble of MNMs under uniform illuminations and a spinning schooling behavior under a nonuniform light, both of which can be finely controllable by visible light energy. Our results provide important insights into the design of the artificial counterpart of the phototactic microorganism with sophisticated motion behaviors for diverse applications.

Rotary Electromagnetic Micromotors (REM) are miniature motors that operate based on the principles of electromagnetic interactions. They hold great potential for various applications in microelectromechanical systems (MEMS), offering precise rotary motion at a microscale level. REM micromotors are still in the introductory stages of development, and extensive research and development efforts are ongoing to enhance their performance and address various technical challenges. The technical literature in this area is relatively limited, indicating that REM technology is still an emerging field with considerable scope for exploration and innovation. In this article, we present REM MEMS as quoted in academic articles and explore their presence in the REM market. Given that most articles on REM MEMS do not provide parameter values, we proceeded to assess the performance parameters of 84 market DC micromotors. These evaluations covered a range of 19 weight scales (from 0.35 g to 16.1 g) and diameter scales (from 4 mm to 26 mm). The specific micromotors chosen for the analysis were from Maxon and Faulhaber, two well-known and reputable manufacturers in the field of micromotors. Consequently, we conducted a comparison of the operating parameters of the micromotors, specifically focusing on the ratios of mass to output power and torque, as well as the ratios of energy efficiency to output power and torque. Power and torque are fundamental measurements used to evaluate the performance of REM motors in the market. These curves and correlation coefficients can serve as a valuable reference for engineers and designers when making informed decisions regarding motor selection for specific applications.

Herein, we studied localized electroporation and gene transfection of mammalian cells using a metallodielectric hybrid micromotor that is magnetically and electrically powered. Much like nanochannel-based, local electroporation of single cells, the presented micromotor was expected to increase reversible electroporation yield, relative to standard electroporation, as only a small portion of the cell’s membrane (in contact with the micromotor) is affected. In contrast to methods in which the entire membrane of all cells within the sample are electroporated, the presented micromotor can perform, via magnetic steering, localized, spatially precise electroporation of the target cells that it traps and transports. In order to minimize nonselective electrical lysis of all cells within the chamber, resulting from extended exposure to an electrical field, magnetic propulsion was used to approach the immediate vicinity of the targeted cell, after which short-duration, electric-driven propulsion was activated to enable contact with the cell, followed by electroporation. In addition to local injection of fluorescent dye molecules, we demonstrated that the micromotor can enhance the introduction of plasmids into the suspension cells because of the dielectrophoretic accumulation of the plasmids in between the Janus particle and the attached cell prior to the electroporation step. Here, we chose a different strategy involving the simultaneous operation of many micromotors that are self-propelling, without external steering, and pair with cells in an autonomic manner. The locally electroporated suspension cells that are considered to be very difficult to transfect were shown to express the transfected gene, which is of significant importance for molecular biology research.

Tetracycline (TC), a widely used antibiotic, poses environmental persistence and contributes substantially to the formation of drug-resistant bacteria, warranting urgent actions for effective detection and degradation. Recent progress in micro/nanomotor technology has opened a compelling avenue, enabling active maneuverability in aqueous environments while improving interaction efficacy and functionality. In this study, a succulent-like ZnO/metal-organic framework (MOF)/Fe 3 O 4 hybrid micromotor designed for dynamic fluorescence detection and efficient photocatalytic degradation of TC is proposed. By leveraging micro- and nano-fabrication approaches and the seeded growth method, the fabrication of ZnO micromotors with succulent-like structures is realized. Notably, chemical modifications are employed to manipulate the surface potential and precisely control the motion direction of the micromotor. Further incorporation of fluorescent MOF nanoparticles renders the micromotors capable of dynamic TC detection. Furthermore, under ultraviolet irradiation, the micromotors exhibit dynamic TC degradation and can be conveniently recovered and reused by magnetic separation. The rational design of functional micromotors may offer promising platforms for various applications such as dynamic detection and environmental remediation.

The self-propulsion of biohybrid and synthetic micromotors extends their localized retention on the intestinal wall and leads to high bioavailability.Micromotors released from oral formulations maintain their functionality upon reaching the target treatment site.Synthetic micromotors utilize body fluids as a fuel source for their powerful bubble-thrust propulsion, while biohybrid motors rely on long-lasting fuel-free self-propulsion.Drugs can be loaded onto the surfaces of micromotors or embedded along with micromotor stirrers within the pill matrix.Enhanced macromolecule delivery is accomplished by embedding microinjectors and microneedles within oral pills. Oral medication is preferred for its convenience; however, efficient drug delivery remains challenging due to issues such as poor solubility, and absorption caused by mucosal barriers, which result in low bioavailability. In this review, we discuss new strategies integrating robotic capabilities into oral formulations to enhance drug delivery. Such robotic pill systems leverage the efficient propulsion of biological and synthetic micromotors to accelerate pill disintegration and overcome mucosal barriers, increasing bioavailability with lower doses and fewer side effects. In addition, advanced bioinspired robotic capsules, including microneedles, microinjectors, and microjet systems, offer enhanced macromolecule bioavailability comparable with that achieved with subcutaneous injections. The future of precision medicine lies in encapsulating diverse micromotors (with unique capabilities) within pharmaceutical carriers, offering groundbreaking opportunities for enhanced therapeutic interventions. Oral medication is preferred for its convenience; however, efficient drug delivery remains challenging due to issues such as poor solubility, and absorption caused by mucosal barriers, which result in low bioavailability. In this review, we discuss new strategies integrating robotic capabilities into oral formulations to enhance drug delivery. Such robotic pill systems leverage the efficient propulsion of biological and synthetic micromotors to accelerate pill disintegration and overcome mucosal barriers, increasing bioavailability with lower doses and fewer side effects. In addition, advanced bioinspired robotic capsules, including microneedles, microinjectors, and microjet systems, offer enhanced macromolecule bioavailability comparable with that achieved with subcutaneous injections. The future of precision medicine lies in encapsulating diverse micromotors (with unique capabilities) within pharmaceutical carriers, offering groundbreaking opportunities for enhanced therapeutic interventions.

This in vivo animal study aimed to evaluate the effects of two different implant placement micromotor systems on implant stability and removal torque. In a within-animal crossover design, twenty titanium implants (AnyOne fixture; internal type; diameter, 3.5 mm; length, 7.0 mm; Megagen, Daegu, Republic of Korea) were placed in the tibiae of five rabbits using a conventional micromotor system (NSK group: SurgicPro+; NSK, Kanuma, Japan) and a diode laser-integrated micromotor system (SAESHIN group: BLP 10; Saeshin, Daegu, Republic of Korea). Resonance frequency analysis provided the implant stability quotient (ISQ) immediately after placement and at four weeks. Micro-computed tomography quantified the bone–implant interface gap (BIG). Removal torque was measured at sacrifice. Linear mixed-effects models with a random intercept for rabbit generated adjusted means with 95% confidence intervals (CIs) (α = 0.05). Equivalence for the four-week ISQ used two one-sided tests with a margin of ±5 ISQ. The SAESHIN group achieved a higher immediate ISQ than the NSK group (difference =+6.9 ISQ; 95% CI +1.3–+12.5; p = 0.018). At four weeks, the ISQ did not differ (difference = −1.2 ISQ; 95% CI −4.3–+1.9; p = 0.42), and equivalence was supported (TOST p_lower = 0.024; p_upper = 0.019). Removal torque was comparable (difference = +4.3 N·cm; 95% CI −5.2–+13.8; p = 0.36). BIG metrics showed no between-system differences across regions. ICC indicated clustering for ISQ and torque (0.36 and 0.31). The diode laser-integrated micromotor system yielded a higher immediate ISQ under a standardized 35 N·cm seating torque, whereas the ISQ, removal torque, and BIG at four weeks were comparable to those of the conventional system. The immediate ISQ should be interpreted as stiffness under fixed torque rather than superior device-dependent interlocking. These findings support the clinical interchangeability of the two systems for early osseointegration endpoints in preclinical settings.

Advances in bioinspired design principles and nanomaterials have led to tremendous progress in autonomously moving synthetic nano/micromotors with diverse functionalities in different environments. However, a significant gap remains in moving nano/micromotors from test tubes to living organisms for treating diseases with high efficacy. Here we present the first, to our knowledge, in vivo therapeutic micromotors application for active drug delivery to treat gastric bacterial infection in a mouse model using clarithromycin as a model antibiotic and Helicobacter pylori infection as a model disease. The propulsion of drug-loaded magnesium micromotors in gastric media enables effective antibiotic delivery, leading to significant bacteria burden reduction in the mouse stomach compared with passive drug carriers, with no apparent toxicity. Moreover, while the drug-loaded micromotors reach similar therapeutic efficacy as the positive control of free drug plus proton pump inhibitor, the micromotors can function without proton pump inhibitors because of their built-in proton depletion function associated with their locomotion. Nano- and micromotors have been demonstrated in vitro for a range of applications. Here the authors demonstrate the in-vivo therapeutic use of micromotors to treat H. pylori infection.

Bio-hybrid micromotors, active structures composed of both biological and synthetic components, are promising for use in several biomedical applications including targeted drug delivery, tissue engineering, and biosensing. Among biological candidates, erythrocytes are well suited for use as the biological component of bio-hybrid micromotors due to their biocompatibility, mechanical deformability, and long circulation time. However, their symmetric shape and small size make controlled actuation of these devices particularly challenging. Here, we present a novel strategy to overcome these limitations by fabricating achiral erythrocyte micromotors with enhanced propulsion efficiency. Inspired by recent work on synthetic achiral microswimmers, we report two and three-cell micromotors fabricated through biotin-streptavidin binding. These self-assembled red blood cell (RBC) structures are then interfaced with magnetic beads enabling them to swim and roll under the propulsion of a single homogenous rotating magnetic field at a much greater velocity compared to single cell micromotors in both Newtonian and viscoelastic fluids. Further, to demonstrate biomedical application of these self-assembled micromotors, the chemotherapeutic agent doxorubicin is loaded into RBC achiral micromotors, which are magnetically directed to cancer cells within a microfluidic chamber, successfully delivering their anticancer payload. The fabrication and propulsion method reported here will aid in the development of future erythrocyte-based micromotors for drug delivery and cancer therapy.

A new detection platform based on CaCO 3 -based magnetic micromotor (CaCO 3 @Fe 3 O 4 ) integrated with graphene field effect transistor (GFET) was construct and used for on-site SARS-CoV-2 coronavirus pathogen detection. The CaCO 3 @Fe 3 O 4 micromotor, which was modified with anti-SARS-CoV-2 (labelled antibody, AntiE1), can self-moved in the solution containing hydrochloric acid (HCl) and effective to capture the SARS-CoV-2 coronavirus pathogens. After magnetic field separation, the capture micromotor was detected by GFET, exhibiting a good linear relationship within the range of 1 ag/mL to 100 ng/mL and low detection limit (0.39 ag/mL). Furthermore, the detection platform was also successfully applied to detection of SARS-CoV-2 coronavirus pathogens in soil solution, indicating the potential use in on-site application. Graphical Abstract

A colloidal particle connected to suspensions of motile bacteria forms a model system for studying microscale engines in contact with active baths. The engine outperforms its passive counterparts due to the presence of non-Gaussian fluctuations. Artificial microscale heat engines are prototypical models to explore the mechanisms of energy transduction in a fluctuation-dominated regime 1 , 2 . The heat engines realized so far on this scale have operated between thermal reservoirs, such that stochastic thermodynamics provides a precise framework for quantifying their performance 3 , 4 , 5 , 6 . It remains to be seen whether these concepts readily carry over to situations where the reservoirs are out of equilibrium 7 , a scenario of particular importance to the functioning of synthetic 8 , 9 and biological 10 microscale engines and motors. Here, we experimentally realize a micrometre-sized active Stirling engine by periodically cycling a colloidal particle in a time-varying optical potential across bacterial baths characterized by different degrees of activity. We find that the displacement statistics of the trapped particle becomes increasingly non-Gaussian with activity and contributes substantially to the overall power output and the efficiency. Remarkably, even for engines with the same energy input, differences in non-Gaussianity of reservoir noise results in distinct performances. At high activities, the efficiency of our engines surpasses the equilibrium saturation limit of Stirling efficiency, the maximum efficiency of a Stirling engine where the ratio of cold to hot reservoir temperatures is vanishingly small. Our experiments provide fundamental insights into the functioning of micromotors and engines operating out of equilibrium.