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The surface-enhanced Raman scattering (SERS) bioprobe's strategy for identifying tumor cells always depended on the intensity difference of the Raman signal compared with that of normal cells. Hence, exploring novel SERS nanostructure with excellent spectra stability, a high enhancement factor (EF), and good biocompatibility is a primary premise for boosting SERS signal reliability and accuracy of tumor cells. Here, high SERS EF (5.52 × 106) is acquired by developing novel amorphous nitrogen-doped carbon (NDC) nanocages (NCs), whose EF value was in a leading position among carbon-based SERS substrates. In addition, a uniform SERS signal was obtained on NDC NCs due to homogeneous morphology and size. The delocalized carbon-conjugated systems of graphitic-N, pyrrole-N, and pyridine-N with lone pair electrons increase the electronic density of states and reduce the electron localization function of NDC NCs, thereby promoting the charge transfer process. The electron-donor platform of the NDC NCs facilitates the thermodynamic process of charge transfer, resulting in multimode vibrational coupling in the surface complexes, which greatly amplifies the molecular polarizability. Importantly, the good biocompatibility and signal stability endow these NDC NC SERS bioprobes unique superiority in distinguishing tumor cells, and quantitative recognition of two triple-negative breast cancer cells based on SERS detection mode has been successfully realized. This work was supported by the funding from National Natural Science Foundation of China (52002380, 32025021, 31971292, 52022006, 12274018, 21875008 and 32111540257), Ningbo 3315 Innovative Teams Program (2019A-14-C), the Science and Technology Bureau of Ningbo City (2020Z094), Zhejiang Province Key Research Project (2019C03058, 2020C03110), Youth Innovation Promotion Association Foundation of CAS, and Zhejiang Provincial Natural Science Foundation of China (LQ20E020003).

We report enzyme-powered upconversion-nanoparticle-functionalized Janus micromotors, which are prepared by immobilizing uricase asymmetrically onto the surface of silicon particles, to actively and rapidly detect uric acid. The asymmetric distribution of uricase on silicon particles allows the Janus micromotors to display efficient motion in urine under the propulsion of biocatalytic decomposition of uric acid and simultaneously detect uric acid based on the luminescence quenching effect of the UCNPs modified on the other side of SiO

We report a direct experimental observation of the torque-driven active reorientation of glucose-fueled flasklike colloidal motors to a glucose gradient exhibiting a positive chemotaxis. These streamlined flasklike colloidal motors are prepared by combining a hydrothermal synthesis and a vacuum infusion and can be propelled by an enzymatic cascade reaction in the glucose fuel. Their flasklike architecture can be used to recognize their moving posture, and thus the dynamic glucose-gradient-induced alignment and orientation-dependent motility during positive chemotaxis can be examined experimentally. The chemotactic mechanism is that the enzymatic reactions inside lead to the glucose acid gradient and the glucose gradient which generate two phoretic torques at the bottom and the opening respectively, and thus continuously steer it to the glucose gradient. Such glucose-fueled flasklike colloidal motors resembling the chemotactic capability of living organisms hold considerable potential for engineering active delivery vehicles in response to specific chemical signals.

We report a carbonaceous nanomotor with a characteristic flask-like hollow structure that can autonomously move under the propulsion of oxygen bubbles. The carbonaceous nanoflask (CNF) motor was fabricated by encapsulating platinum nanoparticles (Pt NPs) into the hollow cavity of the CNF. The internally encapsulated Pt NPs act as catalysts to decompose hydrogen peroxide (H2O2) fuel into oxygen bubbles. The generated oxygen bubbles recoil the motion of the CNF motors. Besides, the velocity of CNF motors can be controlled by adjusting the concentration of the H2O2 solution. The motion velocity increases with the increase of H2O2 concentration, up to 109.25 μm s-1 at 10% H2O2. This study provides important implications for understanding the motion behaviors of nanomotors with an internal cavity, and the self-propelled CNF motors as smart carrier systems have potential applications in the future.

Chemically driven colloidal motors capable of implementing different movements under a common environment are of great importance for various complex tasks. However, the key parameters underlying different motion behaviors are incompletely understood. Here, we demonstrate that carbonaceous nanoflask (CNF) motors move spontaneously in glucose powered by the cascade reaction of glucose oxidase and catalase, and their directional propulsion can be premeditated by controlling the surface wettability of nanomotors. The hydrophilic CNF motors move from the round-bottom to the opening neck (backward), whereas the hydrophobic CNF motors swim from the opening neck to the round-bottom (forward). We demonstrate that the backward motion of the hydrophilic CNF motors is driven by the local glucose gradient due to self-diffusiophoresis, and the forward movement of the hydrophobic CNF motors is caused by the locally produced glucose acid gradient. The fluid simulation reveals that the hydrophilic and hydrophobic CNF motors correspond to the puller and pusher models, respectively. Our study offers a minimal strategy to manipulate the direction of motion of motors for specific applications and to change the hydrodynamic behaviors of glucose-powered motors.

Photodynamic therapy (PDT) is a promising cancer therapeutic strategy, which typically kills cancer cells through converting nontoxic oxygen into reactive oxygen species using photosensitizers (PSs). However, the existing PDTs are still limited by the tumor hypoxia and poor targeted accumulation of PSs. To address these challenges, we here report an acoustically powered and magnetically navigated red blood cell-mimicking (RBCM) micromotor capable of actively transporting oxygen and PS for enhanced PDT. The RBCM micromotors consist of biconcave RBC-shaped magnetic hemoglobin cores encapsulating PSs and natural RBC membrane shells. Upon exposure to an acoustic field, they are able to move in biological media at a speed of up to 56.5 μm s-1 (28.2 body lengths s-1). The direction of these RBCM micromotors can be navigated using an external magnetic field. Moreover, RBCM micromotors can not only avoid the serum fouling during the movement toward the targeted cancer cells but also possess considerable oxygen- and PS-carrying capacity. Such fuel-free RBCM micromotors provide a new approach for efficient and rapid active delivery of oxygen and PSs in a biofriendly manner for future PDT.

We report a bubble-propelled Janus gallium/zinc (Ga/Zn) micromotor with good biocompatibility and biodegradability for active target treatment of bacteria. The Janus Ga/Zn micromotors are fabricated by asymmetrically coating liquid metal Ga on Zn microparticles and display self-propulsion in simulated gastroenteric acid (pH 0.5) at a speed of up to 383 μm s-1 , propelled by hydrogen bubbles generated by the zinc-acid reaction. This motion of Ga/Zn micromotors is enhanced by the Ga-Zn galvanic effect. The GaIII cations produced from the degradation of Ga/Zn micromotors serve as a built-in antibiotic agent. The movement improves the diffusion of GaIII and results in a significant increase of the antibacterial efficiency against H. pylori, compared with passive Ga microparticles. Such Ga/Zn micromotors combine the self-propulsion, good biocompatibility and biodegradability, and Ga-based antibacterial properties, providing a proof of concept for the active treatment of bacterial infections.

We report the reconfigurable assembly of rod-shaped eutectic gallium-indium alloy (EGaIn) liquid metal colloidal motors by mimicking the growth behavior of a dandelion. EGaIn nanorods with a diameter of 210 nm and a length of 850 nm were synthesized via an ultrasound-assisted physical dispersion method. The nanorods possess a core-shell structure with a 30 nm GaOOH shell and zero-valent liquid core. The EGaIn motors move autonomously at a speed of 41.2 μm s-1 under an acoustic field. By modulating the frequency of the applied acoustic field, the EGaIn colloidal motors self-organize into various striped and circular patterns, followed by a flower-like cluster. The dandelion-like EGaIn colloidal motor clusters move collectively and redisperse when the applied acoustic frequency is changed. Numerical simulations reveal that the flower-like clusters are created by the acoustic propulsion in combination with steric repulsion and hydrodynamics.

We report a hollow dumbbell-shaped manganese dioxide (MnO2) colloidal kayaker capable of converting a pair of breathing oxygen bubbles into self-propelled movement. The bubble pair generated by catalytic decomposition of hydrogen peroxide fuel grew either synchronously or asynchronously, driving the colloidal kayaker to move along a fluctuating circle. The synchronous or asynchronous breathing mode of bubble pair is governed by the asymmetric catalytic sites of the colloidal kayakers. This imbalanced distribution of bubble propulsion force generates the driving force and the centripetal force on the colloidal kayaker. The dynamics of colloidal kayakers is well-described by the overdamped Langevin equation and fluid field simulation. Such bubble-pair propelled colloidal kayakers could advance applications of catalytic nanomotors, offering effective implementation for diverse tasks for a wide range of practical applications.

We report a near-infrared (NIR) light-powered Janus mesoporous silica nanomotor (JMSNM) with macrophage cell membrane (MPCM) cloaking that can actively seek cancer cells and thermomechanically percolate cell membrane. Upon exposure to NIR light, a heat gradient across the Janus boundary of the JMSNMs is generated by the photothermal effect of the Au half-shells, resulting in a self-thermophoretic force that propels the JMSNMs. In biological medium, the MPCM camouflaging can not only prevent dissociative biological blocks from adhering to JMSNMs but also improve the seeking sensitivity of the nanomotors by specifically recognizing cancer cells. The biofriendly propulsion and recognition capability enable JMSNMs to achieve the active seeking and bind to the membrane of cancer cells. Subsequent illumination with NIR then triggers the photothermal effect of MPCM@JMSNMs to thermomechanically perforate the cytomembranes for guest molecular injection. This approach integrates the functions of active seeking, cytomembranes perforating, and thermomechanical therapy in nanomotors, which may pave the way to apply self-propelled motors in biomedical fields.

Collectively dynamic self-assembly arising from the living mobility is the fundamental process of lives. Inspired by collective behaviors of living systems, collective motion and self-assembly of synthetic colloid motors have been brought into focus due to high performance and emerging phenomena beyond the power of single colloid motor. Here, we summarize the recent progress on the collectively dynamic self-assembly systems of synthetic colloid motors sorted by various triggers of self-propulsion and external fields (such as chemicals, light, electric fields, and acoustic fields), ranging from the propulsion to stimuli of collective self-assembly. The typical physical phenomena are presented, including phase separation, clustering, and giant number fluctuations. The collectively dynamic self-assembly of colloid motors are expected to provide unlimited opportunities to various applications with continuous innovation both in the design of synthetic colloid motors and the modulation of collectively dynamic self-assembly.

We report a magnetically actuated peanut-shaped hematite colloid motor that can not only move in a rolling or wobbling mode in fluids but also perform single cell manipulation and patterning in a noncontact way. The peanut motor in a rolling mode can reach a maximal velocity of 10.6 μm s–1 under a rotating magnetic field of 130 Hz and 6.3 mT and achieve a more precisely controllable motion in predefined tracks. While in a wobbling mode, the motor reaches a maximal velocity of 14.5 μm s–1 under a conical rotating magnetic field of 80 Hz and 6.3 mT and can climb over steep slopes to adapt the motor for more complex environments. The fluid flow simulation results reveal that the difference between two movement modes mostly comes from the distribution discrepancy of the flow fields near the motors. Through the integration of the rolling and wobbling movement, these peanut motors can autonomously transport and release cells to a predefined site and thus form complex cell patterns without a physical contact. Su...

Carbon fiber reinforced plastic (CFRP) has been widely used in many fields such as in the aerospace and automotive industries. Drilling of CFRP is a key process in the manufacture of CFRP components. The existing quality control and tool change decision methods are mainly based on delamination damage. However, estimating delamination damage in situ is still a challenge in the process of continuous drilling. To solve this problem, a comprehensive delamination prediction method based on multi-sensor data is proposed in this paper. In process of the drilling, the force, torque, temperature, vibration and hole exit images were collected, and the delamination was quantified by a proposed statistical delamination factor F s . Singular spectrum analysis (SSA) is used to smooth the F s sequence to reduce randomness. Then, a XGBoost-ARIMA model is constructed for rolling prediction of F s . Finally, drilling experiments were carried out to verify the effectiveness of the proposed method. The experimental results showed that compared with traditional delamination evaluation factors, F s reduced the mean square error (MSE) of prediction by more than 50%. Compared with that of traditional machine learning models such as an SVM and ANN, the MSE of the model’s regression part is decreased by more than 39%. The proposed method can provide a solution for real-time and in situ prediction of delamination damage in the continuous drilling process of CFRP components.

We report a dynamic self-organization of self-propelled peanut-shaped hematite motors from non-equilibrium driving forces where the propulsion can be triggered by blue light. They result in one-dimensional, active colloid ribbons with a positive phototactic characteristic. The motion of colloid motors is ascribed to the diffusion-osmotic flow in a chemical gradient by the photocatalytic decomposition of hydrogen peroxide fuel. We show that self-propelled peanut-shaped colloids readily form one-dimensional, slithering ribbon structures under the out-of-equilibrium collisions. This self-organization intrinsically results from the competition among the osmotically driven motion, the phoretic attraction and the inherent magnetic moments. The giant size number fluctuation in colloid ribbons is observed above a critical point 4.1 % of the surface density of colloid motors. Such phototactic colloid ribbons may provide a model system to understand the emergence of function in biological systems and have potential to construct bioinspired active materials based on different active building blocks.

Self-propelled micro- and nanomotors (MNMs) have shown great potential for applications in the biomedical field, such as active targeted delivery, detoxification, minimally invasive diagnostics, and nanosurgery, owing to their tiny size, autonomous motion, and navigation capacities. To enter the clinic, biomedical MNMs request the biodegradability of their manufacturing materials, the biocompatibility of chemical fuels or externally physical fields, the capability of overcoming various biological barriers (e.g., biofouling, blood flow, blood-brain barrier, cell membrane), and the in vivo visual positioning for autonomous navigation. Herein, the recent advances of synthetic MNMs in overcoming biological barriers and in vivo motion-tracking imaging techniques are highlighted. The challenges and future research priorities are also addressed. With continued attention and innovation, it is believed that, in the future, biomedical MNMs will pave the way to improve the targeted drug delivery efficiency.

We report a leukocyte membrane-coated gallium nanoswimmer (LMGNS) capable of ultrasound-propelled motion, antibiofouling, and cancer cell recognition and targeting. The LMGNS consists of a needle-shaped gallium core encapsulating an anticancer drug and a natural leukocyte membrane shell. Under the propulsion of an ultrasound field, LMGNSs could autonomously move in biological media with a speed up to 108.7 μ m s −1 . The velocity and motion direction of the LMGNSs can be modulated by regulating the frequency and voltage of the applied ultrasound field. Owing to the leukocyte membrane coating, LMGNSs can not only avoid biofouling during the motion in blood but also possess cancer cell recognition capability. These LMGNSs could actively seek, penetrate, and internalize into the cancer cells and achieve enhanced anticancer efficiency by combined photothermal and chemical therapy. Such biofunctionalized liquid metal nanoswimmer presents a new type of multifunctional platform for biomedical applications.

An active TNT (2,4,6-trinitrotoluene) catalytic sensor based on Janus upconverting nanoparticle (UCNP)-functionalized micromotor capsules, displaying “on–off” luminescence with a low limit of detection has been developed. The Janus capsule motors were fabricated by layer-by-layer assembly of UCNP-functionalized polyelectrolyte microcapsules, followed by sputtering of a platinum layer onto one half of the capsule. By catalytic decomposition of hydrogen peroxide to oxygen bubbles, the Janus UCNP capsule motors are rapidly propelled with a speed of up to 110 μm s−1. Moreover, the Janus motors display efficient on–off luminescent detection of TNT. Owing to the unique motion of the Janus motor with bubble generation, the likelihood of collision with TNT molecules and the reaction rate between them are increased, resulting in a limit of detection as low as 2.4 ng mL−1 TNT within 1 minute. Such bubble-propelled Janus UCNP capsule motors have great potential for contaminated water analysis.

We report a needlelike liquid metal gallium nanoswimmer (LMGNS) with a controllable motion under the exposure of a near-infrared (NIR) laser. The needlelike LMGNS is constructed by a nanoporous template-assisted plastic molding technique. Under the irradiation of a continuous NIR laser, LMGNSs can autonomously move in a direction of tip forward, and their speed could reach up to 31.22 μm s−1 at a laser intensity of 5 W cm−2. The speed of motion and on/off behavior of LMGNSs can be conveniently modulated by controlling the intensity of a NIR laser. Computer simulations reveal that the propulsion of LMGNS is attributed to the self-thermophoresis caused by the temperature gradient along its longitudinal axis, which is induced by the difference of diameters of the two ends. The speed of LMGNS is higher on the substrate with lower surface potential because the thermoosmosis effect, as a resistance, is weaker. Such needlelike liquid metal nanoswimmers have a potential for biomedical applications and active soft matter materials.

The T-1000 liquid metal terminator, which can transform and self-repair, represents a dream for decades that robots can fundamentally change our daily life. Until now, some large-scale liquid metal machines have been developed. However, there is no report on nanoscaled liquid metal machines and their biomedical applications. We describe here a shape-transformable and fusible rodlike swimming liquid metal nanomachine, based on the biocompatible and transformable liquid metal gallium. These nanomachines were prepared by a pressure-filter-template technology, and the diameter and length could be controlled by adjusting the nanoporous templates, filter time, and pressure. The as-prepared liquid gallium nanomotors display a core-shell nanorod structure composed of a liquid gallium core and solid gallium oxide shell. Upon exposure to an ultrasound field, the generated acoustic radiation force in the levitation plane can propel them to move autonomously. The liquid metal nanomachine can actively seek cancer cells and transform from a rod to a droplet after drilling into cells owing to the removal of gallium oxide layers in the acidic endosomes. These transformed nanomachines could fuse together inside cells and photothermally kill cancer cells under illumination of near-infrared light. Such acoustically propelled shape-transformable rodlike liquid metal nanomachines have great potential for biomedical applications.

We report a carbonaceous nanobottle (CNB) motor for near infrared (NIR) light-driven jet propulsion. The bottle structure of the CNB motor is fabricated by soft-template-based polymerization. Upon illumination with NIR light, the photothermal effect of the CNB motor carbon shell causes a rapid increase in the temperature of the water inside the nanobottle and thus the ejection of the heated fluid from the open neck, which propels the CNB motor. The occurrence of an explosion, the on/off motion, and the swing behavior of the CNB motor can be modulated by adjusting the NIR light source. Moreover, we simulated the physical field distribution (temperature, fluid velocity, and pressure) of the CNB motor to demonstrate the mechanism of NIR light-driven jet propulsion. This NIR light-powered CNB motor exhibits fuel-free propulsion and control of the swimming velocity by external light and has great potential for future biomedical applications.

The upconversion nanoparticle (UCNP)-based photodynamic therapy (PDT) agents are promising for deep-tissue cancer treatment because they may overcome current limitations due to the shallow penetration depth of visible light. However, limited blood circulation time and poor tumor-targeting capability challenge the therapeutic efficacy of UCNP-based PDT in vivo. Here, we demonstrate intravenous injectable stem-cell-membrane-camouflaged upconversion nanoarchitectures as a biomimetic tumor PDT platform. The biomimetic PDT system is constructed by fusing mesoporous-silica-encapsulated β-NaYF4:Yb3+,Er3+ UCNPs with stem-cell membranes. Translocation of the stem-cell membranes to the UCNPs led to the translation of multiple membrane components, bringing the membranes’ long circulation and tumor-targeting capability to the resulting platform. Multiphotosensitizers were encapsulated and simultaneously activated by a 980 nm single laser because of the multicolor emission capability of the UCNP cores. In vitro and in...

Stem cell membrane-coated nanogels can effectively evade clearance of the immune system, enhance the tumor targeting properties and antitumor chemotherapy efficacy of gelatin nanogels loaded doxorubicin in mice.

Environmental chamber is widely used for testing the performance of the equipment with all kinds of natural ambient parameters. In this study, water droplet generated from ultrasonic humidifier is ascertained by laser diffraction measurement technology. The accurate droplet size and distribution is offered to CFD simulation as the initial condition. Humidity distribution with different initial conditions is studied by both experiment and CFD simulation. Comparisons show that the proposed CFD method can provide reliable results in simulation on the humidity distribution. The numerical and experimental results indicate that as the increase of inlet temperature, fluctuation of relative humidity (RH) at each point decrease with the time. Under the inlet condition with low-humidity, the deviation of average RH is decrease with inlet temperature. On the other hand, under the high-humidity condition, the difference of average RH is getting larger with the increase of inlet temperature. Compared with the mean value, the fluctuation of the humidity is big but the RH at measuring points is close to the inlet RH value under the inlet condition with low humidity.

We report a biomimetic delivery of microsized capsule-cushioned leukocyte membrane vesicles (CLMVs) through the conversion of freshly reassembled leukocyte membrane vesicles (LMVs), including membrane lipids and membrane-bound proteins onto the surface of layer-by-layer assembled polymeric multilayer microcapsules. The leukocyte membrane coating was verified by using electron microscopy, a quartz crystal microbalance, dynamic light scattering, and confocal laser scanning microscopy. The resulting CLMVs have the ability to effectively evade clearance by the immune system and thus prolong the circulation time in mice. Moreover, we also show that the right-side-out leukocyte membrane coating can distinctly improve the accumulation of capsules in tumor sites through the molecular recognition of membrane-bound proteins of CLMVs with those of tumor cells in vitro and in vivo. The natural cell membrane camouflaged polymeric multilayer capsules with the immunosuppressive and tumor-recognition functionalities of natural leukocytes provide a new biomimetic delivery platform for disease therapy.