Inspired by the reverse thrust generated by fuel injection, micromachines that are self-propelled by bubble ejection are developed, such as microrods, microtubes, and microspheres. However, controlling bubble ejection sites to build micromachines with programmable actuation and further enabling mechanical transmission remain challenging. Here, bubble-propelled mechanical microsystems are constructed by proposing a multimaterial femtosecond laser processing method, consisting of direct laser writing and selective laser metal reduction. The polymer frame of the microsystems is first printed, followed by the deposition of catalytic platinum into the desired local site of the microsystems by laser reduction. With this method, a variety of designable microrotors with selective bubble ejection sites are realized, which enable excellent mechanical transmission systems composed of single and multiple mechanical components, including a coupler, a crank slider, and a crank rocker system. We believe the presented bubble-propelled mechanical microsystems could be extended to applications in microrobotics, microfluidics, and microsensors.
Despite their notable unidirectional water transport capabilities, Janus membranes are commonly challenged by the fragility of their chemical coatings and the clogging of open microchannels. Here, an on-demand mode-switching strategy is presented to consider the Janus functionality and mechanical durability separately and implement them by simply stretching and releasing the membrane. The stretching Janus mode facilitates unidirectional liquid flow through the hydrophilic micropores-microgrooves channels (PG channels) fabricated by femtosecond laser. The releasing protection mode is designed for the in-situ closure of the PG channels upon encountering external abrasion and impact. The protection mode imparts the Janus membrane robustness to reserve water unidirectional penetration under harsh conditions, such as 2000 cycles mechanical abrasion, 10 days exposure in air and other rigorous tests (sandpaper abrasion, finger rubbing, sand impact and tape peeling). The underlying mechanism of gridded grooves in protecting and enhancing water flow is unveiled. The Janus membrane serves as a fog collector to demonstrate its unwavering mechanical durability in harsh real-world conditions. The presented design strategy could open up new possibilities of Janus membrane in a multitude of applications ranging from multiphase separation devices to fog harvesting and wearable health-monitoring patches.
The emerging two-photon polymerization (TPP) technique enables high-resolution printing of complex 3D structures, revolutionizing micro/nano additive manufacturing. Various fast scanning and parallel processing strategies have been proposed to promote its efficiency. However, obtaining large numbers of uniform focal spots for parallel high-speed scanning remains challenging, which hampers the realization of higher throughput. We report a TPP printing platform that combines galvanometric mirrors and liquid crystal on silicon spatial light modulator (LCoS-SLM). By setting the target light field at LCoS-SLM's diffraction center, sufficient energy is acquired to support simultaneous polymerization of over 400 foci. With fast scanning, the maximum printing speed achieves 1.49 × 108 voxels s-1, surpassing the existing scanning-based TPP methods while maintaining high printing resolution and flexibility. To demonstrate the processing capability, functional 3D microstructure arrays are rapidly fabricated and applied in micro-optics and micro-object manipulation. Our method may expand the prospects of TPP in large-scale micro/nanomanufacturing.
Magnetically-actuated microrobots (MARs) exhibit great potential in biomedicine owing to their precise navigation, wireless actuation and remote operation in confined space. However, most previously explored MARs unfold the drawback of hypodynamic magnetic torque due to low magnetic content, leading to their limited applications in controlled locomotion in fast-flowing fluid and massive cargo carrying to the target position. Here, we report a high-performance pure-nickel magnetically-actuated microrobot (Ni-MAR), prepared by a femtosecond laser polymerization followed by sintering method. Our Ni-MAR possesses a high magnetic content (â¼90 wt%), thus resulting in enhanced magnetic torque under low-strength rotating magnetic fields, which enables the microrobot to exhibit high-speed swimming and superior cargo carrying. The maximum velocity of our Ni-MAR, 12.5 body lengths per second, outperforms the velocity of traditional helical MARs. The high-speed Ni-MAR is capable of maintaining controlled locomotion in fast-flowing fluid. Moreover, the Ni-MAR with massive cargo carrying capability can push a 200-times heavier microcube with translation and rotation motion. A single cell and multiple cells can be transported facilely by a single Ni-MAR to the target position. This work provides a scheme for fabricating high-performance magnetic microrobots, which holds great promise for targeted therapy and drug delivery in vivo.
Fog harvesting is an effective way to relieve water shortages in arid regions; thus, improving the efficiency of fog harvesting is urgently needed for both academic research and practical applications. Here, we report an origami patterned Janus (O-P-Janus) membrane using laser-ablated copper foams inspired by origami handcraft and traditional Chinese architecture. Compared to the planar fully ablated Janus membrane, our O-P-Janus membrane, with selectively ablated rectangular areas, exhibits an exceptional water collection rate (WCR) of approximately 267%. The underlying physical mechanism of WCR enhancement is revealed and attributed to the enhanced fog adsorbing capacity on the upper superhydrophobic origami structures and the accelerated removal of accumulated droplets beneath the lower superhydrophilic V-shaped tips. This O-P-Janus membrane with excellent fog collection performance should open up a new avenue for both device designs and potential applications toward structuring-enhanced fog collection and microfluidic control platforms.
The versatile manipulation of cross-scale droplets is essential in many fields. Magnetic excitation is widely used for droplet manipulation due to its distinguishing merits. However, facile magnetic actuation strategies are still lacked to realize versatile multiscale droplet manipulation. Here, a type of magnetically actuated Janus origami robot is readily fabricated for versatile cross-scale droplet manipulation including three-dimensional transport, merging, splitting, dispensing and release of daughter droplets, stirring and remote heating. The robot allows untethered droplet manipulation from ~3.2 nL to ~51.14 µL. It enables splitting of droplet, precise dispensing (minimum of ~3.2 nL) and release (minimum of ~30.2 nL) of daughter droplets. The combination of magnetically controlled rotation and photothermal properties further endows the robot with the ability to stir and heat droplets remotely. Finally, the application of the robot in polymerase chain reaction (PCR) is explored. The extraction and purification of nucleic acids can be successfully achieved.
Although the biosynthesis of rifamycin has been studied for three decades, the biosynthetic formation of the naphthalenic ring remains unclear. In this study, by deletion of all post-PKS modification genes, we identified macrolactam precursors released from rif PKS. Isolated prorifamycins (M3 and M4) have a benzenic chromophore and exist in two sets of macrocyclic atropisomers. The transformation from prorifamycins to benzenoid (5) and naphthalenoid (6) was suggested to be a non-enzymatic process, which is an off-PKS assembly.
Benzene , Naphthalenes
Inspired by the flexible joints of humans, actuators containing soft joints have been developed for various applications, including soft grippers, artificial muscles, and wearable devices. However, integrating multiple microjoints into soft robots at the micrometer scale to achieve multi-deformation modalities remains challenging. Here, we propose a two-in-one femtosecond laser writing strategy to fabricate microjoints composed of hydrogel and metal nanoparticles, and develop multi-joint microactuators with multi-deformation modalities (>10), requiring short response time (30 ms) and low actuation power (<10 mW) to achieve deformation. Besides, independent joint deformation control and linkage of multi-joint deformation, including co-planar and spatial linkage, enables the microactuator to reconstruct a variety of complex human-like modalities. Finally, as a proof of concept, the collection of multiple microcargos at different locations is achieved by a double-joint micro robotic arm. Our microactuators with multiple modalities will bring many potential application opportunities in microcargo collection, microfluid operation, and cell manipulation.
Manipulation of droplets has increasingly garnered global attention, owing to its multifarious potential applications, including microfluidics and medical diagnostic tests. To control the droplet motion, geometry-gradient-based passive transport has emerged as a well-established strategy, which induces a Laplace pressure difference based on the droplet radius differences in confined state and transport droplets with no consumption of external energy, whereas this transportation method has inevitably shown some critical limitations: unidirectionality, uncontrollability, short moving distance, and low velocity. Herein, a magnetocontrollable lubricant-infused microwall array (MLIMA) is designed as a key solution to this issue. In the absence of a magnetic field, droplets can spontaneously travel from the tip toward the root of the structure as a result of the geometry-gradient-induced Laplace pressure difference. When the subject of an external magnetic field, the microwalls bend and overlap sequentially, ultimately resulting in the formation of a continuous slippery meniscus surface. The formed meniscus surface can exert sufficient propulsive force to surmount the Laplace pressure difference of the droplet, thereby effectuating active transport. Through the continuous movement of the microwalls, droplets can be actively transported against the Laplace pressure difference from the root to the tip side of the MLIMA or continue to actively move to the root after finishing the passive self-transport. This work demonstrates passive/active hybrid bidirectional droplet transport capabilities, validates its feasibility in the accurate control of droplet manipulation, and exhibits great potential in chemical microreactions, bioassays, and the medical field.
The functionality of tunable liquid droplet adhesion is crucial for many applications such as self-cleaning surfaces and water collectors. However, it is still a challenge to achieve real-time and fast reversible switching between isotropic and anisotropic liquid droplet rolling states. Inspired by the surface topography on lotus leaves and rice leaves, herein we report a biomimetic hybrid surface with gradient magnetism-responsive micropillar/microplate arrays (GMRMA), featuring dynamic fast switching toward different droplet rolling states. The exceptional dynamic switching characteristics of GMRMA are visualized and attributed to the fast asymmetric deformation between the two different biomimetic microstructures under a magnetic field; they endow the rolling droplets with anisotropic interfacial resistance. Based on the exceptional morphology switching surface, we demonstrate the function of classification and screening of liquid droplets, and thus propose a new strategy for liquid mixing and potential microchemical reactions. It is expected that this intelligent GMRMA will be conducive to many engineering applications, such as microfluidic devices and microchemical reactors.
Bottom-up self-assembly is regarded as an alternative way to manufacture series of microstructures in many fields, especially chiral microstructures, which attract tremendous attention because of their optical micromanipulations and chiroptical spectroscopies. However, most of the self-assembled microstructures cannot be tuned after processing, which largely hinders their broad applications. Here, we demonstrate a promising manufacturing strategy for switchable microstructures by combining the flexibility of femtosecond laser printing induced capillary force self-assembly and the temperature-responsive characteristics of smart hydrogels. Through designing asymmetric cross-link density, the printed microarchitectures can be deformed in the opposite direction and assembled into switchable ordered microstructures driven by capillary forces under different temperatures. Finally, the assembled chiral microstructures with switchable opposite handedness are realized, which shows tunable vortical dichroism. The proposed strategy holds potential applications in the fields of chiral photonics, chiral sensing, and so on.
The highly aligned extracellular matrix of metastatic breast cancer cells is considered to be the "highway" of cancer invasion, which strongly promotes the directional migration of cancer cells to break through the basement membrane. However, how the reorganized extracellular matrix regulates cancer cell migration remains unknown. Here, a single exposure of a femtosecond Airy beam followed by a capillary-assisted self-assembly process was used to fabricate a microclaw-array, which was used to mimic the highly oriented extracellular matrix of tumor cells and the pores in the matrix or basement membrane during cell invasion. Through the experiment, we found that metastatic breast cancer MDA-MB-231 cells and normal breast epithelial MCF-10A cells exhibit three major migration phenotypes on microclaw-array assembled with different lateral spacings: guidance, impasse, and penetration, whereas guided and penetrating migration are almost completely arrested in noninvasive MCF-7 cells. In addition, different mammary breast epithelial cells differ in their ability to spontaneously perceive and respond to the topology of the extracellular matrix at the subcellular and molecular levels, which ultimately affects the cell migratory phenotype and pathfinding. Altogether, we fabricated a microclaw-array as a flexible and high-throughput tool to mimic the extracellular matrix during invasion to study the migratory plasticity of cancer cells.
Breast Neoplasms , Epithelial Cells , Humans , Female , MCF-7 Cells , Epithelial Cells/metabolism , Phenotype , Carmustine/metabolism , Cell Movement/physiology , Breast Neoplasms/pathology , Cell Line, Tumor , Neoplasm Invasiveness
Structural color (SC) has enormous potential for improving the visualization and identification of functional micro/nano structures for information encryption and intelligent sensing. Nevertheless, achieving the direct writing of SCs at the micro/nano scale and the change of color in response to external stimuli simultaneously is rather challenging. To this end, we directly printed woodpile structures (WSs) utilizing femtosecond laser two-photon polymerization (fs-TPP), which demonstrated obvious SCs under an optical microscope. After that, we achieved the change of SCs by transferring WSs between different mediums. Furthermore, the influence of laser power, structural parameters, and mediums on the SCs was systematically investigated, and the mechanism of SCs using the finite-difference time-domain (FDTD) method was further explored. Finally, we realized the reversible encryption and decryption of certain information. This finding holds broad application prospects in smart sensing, anti-counterfeiting tags, and advanced photonic devices.
Here, the concept of "aerofluidics," in which a system uses microchannels to transport and manipulate trace gases at the microscopic scale to build a highly versatile integrated system based on gas-gas or gas-liquid microinteractions is proposed. A kind of underwater aerofluidic architecture is designed using superhydrophobic surface microgrooves written by a femtosecond laser. In the aqueous medium, a hollow microchannel is formed between the superhydrophobic microgrooves and the water environment, which allows gas to flow freely underwater for aerofluidic devices. Driven by Laplace pressure, gas can be self-transported along various complex patterned paths, curved surfaces, and even across different aerofluidic devices, with an ultralong transportation distance of more than 1 m. The width of the superhydrophobic microchannels of the designed aerofluidic devices is only ≈42.1 µm, enabling the aerofluidic system to achieve accurate gas transportation and control. With the advantages of flexible self-driving gas transportation and ultralong transportation distance, the underwater aerofluidic devices can realize a series of gas control functions, such as gas merging, gas aggregation, gas splitting, gas arrays, gas-gas microreactions, and gas-liquid microreactions. It is believed that underwater aerofluidic technology can have significant applications in gas-involved microanalysis, microdetection, biomedical engineering, sensors, and environmental protection.
Intelligent droplet manipulation plays a crucial role in both scientific research and industrial technology. Inspired by nature, meniscus driving is an ingenious way to spontaneously transport droplets. However, the shortages of short-range transport and droplet coalescence limit its application. Here, an active droplet manipulation strategy based on the slippery magnetic responsive micropillar array (SMRMA) is reported. With the aid of a magnetic field, the micropillar array bends and induces the infusing oil to form a moving meniscus, which can attract nearby droplets and transport them for a long range. Significantly, clustered droplets on SMRMA can be isolated by micropillars, avoiding droplet coalescence. Moreover, through adjusting the arrangement of the micropillars of SMRMA, multi-functional droplet manipulation such as unidirectional droplet transport, multi-droplet transport, droplet mixing, and droplet screening can be achieved. This work provides a promising approach for intelligent droplet manipulation and unfolds broad application prospects in microfluidics, microchemical reaction, biomedical engineering, and other fields.
Vortex beams, which intrinsically possess optical orbital angular momentum (OAM), are considered as one of the promising chiral light waves for classical optical communications and quantum information processing. For a long time, it has been an expectation to utilize artificial three-dimensional (3D) chiral metamaterials to manipulate the transmission of vortex beams for practical optical display applications. Here, we demonstrate the concept of selective transmission management of vortex beams with opposite OAM modes assisted by the designed 3D chiral metahelices. Utilizing the integrated array of the metahelices, a series of optical operations, including display, hiding, and even encryption, can be realized by the parallel processing of multiple vortex beams. The results open up an intriguing route for metamaterial-dominated optical OAM processing, which fosters the development of photonic angular momentum engineering and high-security optical encryption.
Biomaterials with natural hierarchical structures typically exhibit extraordinary properties because of their multilevel structural designs. They offer many templates and models as well as inspiration for material design, particularly for fabricating structure-regulated, performance-enhanced, and function-enriched materials. Biopolymer-based nanocomposites with ingenious nanostructures constructed through ecofriendly and sustainable approaches are highly desirable to meet the multifunctional requirements of developing bioinspired materials. Herein, an all-silk fibroin-based nanocomposite with a brush-like nanostructure was constructed for the first time using a nanotemplate-guided assembly approach in which dissolved silk assembled directly on a silk nanowhisker (SNW) backbone to form peculiar nanobrushes based on the classical micelle model. Three-dimensional spider-like or centipede-like silk nanobrushes (SNBs) were fabricated by varying the SNW backbone length from 0.16 to 6 µm. The branches with average lengths of 32-290 nm were also adjustable. SNBs were further designed to regulate and induce biomineralization of hydroxyapatite (HAP) to form interesting flower-like nanostructures, in which the HAP nanosphere (diameters â¼16 nm) "core" was covered by SNBs with branches extending to form a "shell" (â¼101 nm in length). Based on such protein nanotemplate-guided formation of nanoscale structures, practical hollow conduits with remarkable mechanical properties, biocompatibility, shape memory behavior, and bone engineering potential were fabricated. This study inspires the design of polymorphous biopolymer-based nanostructures with enhanced performance at multiple length scales where the weaknesses of individual building blocks are offset.
PURPOSE: Sepsis is characterized by an acute inflammatory response to infection, often with multiple organ failures, especially severe lung injury. This study was implemented to probe circular RNA (circRNA) protein tyrosine kinase 2 (circPTK2)-associated regulatory mechanisms in septic acute lung injury (ALI). METHODS: A cecal ligation and puncture-based mouse model and an lipopolysaccharides (LPS)-based alveolar type II cell (RLE-6TN) model were generated to mimic sepsis. In the two models, inflammation- and pyroptosis-related genes were measured. RESULTS: The degree of lung injury in mice was analyzed by hematoxylin and eosin (H&E) staining and the apoptosis was by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining. In addition, pyroptosis and toxicity were detected in cells. Finally, the binding relationship between circPTK2, miR-766, and eukaryotic initiation factor 5A (eIF5A) was detected. Data indicated that circPTK2 and eIF5A were up-regulated and miR-766 was down-regulated in LPS-treated RLE-6TN cells and lung tissue of septic mice. Lung injury in septic mice was ameliorated after inhibition of circPTK2. CONCLUSIONS: It was confirmed in the cell model that knockdown of circPTK2 effectively ameliorated LPS-induced ATP efflux, pyroptosis, and inflammation. Mechanistically, circPTK2 mediated eIF5A expression by competitively adsorbing miR-766. Taken together, circPTK2/miR-766/eIF5A axis ameliorates septic ALI, developing a novel therapeutic target for the disease.
Acute Lung Injury , MicroRNAs , Sepsis , Animals , Mice , Pyroptosis , RNA, Circular/genetics , RNA, Circular/pharmacology , Focal Adhesion Kinase 1/pharmacology , Lipopolysaccharides/adverse effects , Lung/metabolism , Apoptosis , Acute Lung Injury/metabolism , Sepsis/genetics , Peptide Initiation Factors/pharmacology , MicroRNAs/genetics , MicroRNAs/metabolism , Adenosine Triphosphate/pharmacology
Factors controlling the regioselectivity in alkene hydrocupration were computationally investigated using energy decomposition analysis. The results demonstrate that the Markovnikov-selective hydrocupration with electronically activated mono-substituted olefins is mostly affected by the destabilizing Pauli repulsion, which is due to the electron delocalization effect. The anti-Markovnikov-selective hydrocupration with 1,1-dialkyl-substituted terminal olefins is dominated by the repulsive electrostatic interactions, which is because of the unequal π electron distribution caused by the induction effect of alkyl substituents.
