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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.

Gating systems have been extensively researched in energy harvesting, lab-on-chip applications, and so forth. However, the controlled drug delivery system with artificial hydrogel-based porous gating systems (HPGSs) is rarely reported. Herein, a biomimetic HPGS with a pH-responsive hydrogel as the valve and polydimethylsiloxane as the frame is fabricated by in situ femtosecond laser microdrilling and subsequent ultraviolet exposure. The proposed HPGS loaded with doxorubicin hydrochloride (DOX) is stable under physiological conditions, has a low drug leakage rate, and can achieve sustained drug release in a low pH environment. The experimental results show that the drug release is mainly controlled by non-Fickian diffusion, which renders the dynamic speed control of molecular transport possible. Moreover, the HPGS can also be prepared into an antitumor microcapsule. The results of in vitro cell experiments demonstrate that DOX@HPGS can release drugs and achieve terrific therapeutic efficacy in the elimination of HeLa cells in the acidic environments around tumor cells. This functional HPGS is envisioned to be an ideal pH-response carrier for sustained drug release treatment of digestive diseases such as inflammatory bowel disease and gastrointestinal cancer.

Graphical Abstract

Backgroud: The interactions between Chinese herbs and drugs pose a great challenge to the combined clinical application of Chinese herbs and drugs. Chinese medicinal products contain complex pharmacologically active components that may influence the in vivo processes of drugs in a variety of ways. In China, drugs based onPanax ginsengtotal saponins (PNS) are often combined with warfarin for the treatment of cardiovascular diseases. Objectives: To assess the effects of Panaxnotoginsengsaponins (PNS) on the pharmacokinetics of warfarin and its mechanism. Method: Blood was collected for the determination of the prothrombin time (PT) and international normalized ratio (INR) from rats treated with warfarin alone or with warfarin + PNS. The plasma concentration of warfarin was determined by high-performance liquid chromatography. Western blot was used to detect the expression of cytochrome P450 (CYP) enzymes. Results: When warfarin and PNS were co-administered, the PT and INR increased compared to when warfarin was given alone. 72 hours after administration, compared to the warfarin alone group, the warfarin + low-dose PNS, warfarin + medium-dose PNS, and warfarin + high-dose PNS groups showed 110%, 122%, and 126% increases in PT, respectively (allP< 0.05), as well as 111%, 124%, and 128% increases in INR (allP< 0.05). Compared with the warfarin alone group, the clearance rate (CL/F) of warfarin in the warfarin + low-dose PNS, warfarin + medium-dose PNS, and warfarin + high-dose PNS groups was 10% (P > 0.05), 23% (P < 0.05), and 33% (P  < 0.05) lower, respectively, while the systemic exposure (area under the concentration-time curve, AUC0–t) increased by 106% (P > 0.05), 119% (P < 0.05), and 134% (P < 0.05), respectively, and the blood concentration of warfarin incresed by 112%, 113%, and 114%, respectively (allP> 0.05). After combined treatment of HepG2 cells with warfarin + PNS, CYP1A2 expression was upregulated (P < 0.05) and CYP3A4 was downregulated (P < 0.05) but there was no effect on CYP2C9. In animal experiments, PNS had different effect on the expression of CYP1A2 in different doses. While a low dose of PNS resulted in downregulated CYP1A2 expression (P < 0.05), a medium dose resulted in upregulation (P < 0.05), and CYP1A2 expression was not significantly affected by a high dose of PNS (P > 0.05). Meanwhile, PNS at all doses downregulated the expression of CYP3A4 (P < 0.05) but had no effect on the expression of CYP2C9 (P>  0.05). Conclusion: PNS can increase the blood concentration of warfarin, as well as the exposure time, and it can enhance the anticoagulant effect of warfarin by inhibiting the expression of the liver enzyme CYP3A4.

Droplet manipulation is crucial for diverse applications ranging from bioassay to medical diagnosis. Current magnetic-field-driven manipulation strategies are mainly based on fixed or partially tunable structures, which limits their flexibility and versatility. Here, a reconfigurable magnetic liquid metal robot (MLMR) is proposed to address these challenges. Diverse droplet manipulation behaviors including steady transport, oscillatory transport, and release can be achieved by the MLMR, and their underlying physical mechanisms are revealed. Moreover, benefiting from the magnetic-field-induced active deformability and temperature-induced phase transition characteristics, its droplet-loading capacity and shape-locking/unlocking switching can be flexibly adjusted. Because of the fluidity-based adaptive deformability, MLMR can manipulate droplets in challenging confined environments. Significantly, MLMR can accomplish cooperative manipulation of multiple droplets efficiently through on-demand self-splitting and merging. The high-performance droplet manipulation using the reconfigurable and multifunctional MLMR unfolds new potential in microfluidics, biochemistry, and other interdisciplinary fields.

Frontispiece 2: The cover image is based on the Review Article Magnetically responsive manipulation of droplets and bubblesby Jiang et al. Based on the merits of remote control, exceptional biocompatibility, and no need for complex circuits, magnetically responsive manipulation of droplets/bubbles has a wide range of application potential in biomedical, microchemistry, analytical detection, and so on. This review provides a comprehensive and systematic overview of the current state of the art of the magnetically responsive manipulation of droplets and bubbles. (DOI: 10.1002/dro2.117)

Droplets and bubbles have a wide range of applications in industry, agriculture, and daily life, and their controllable manipulation is of significant scientific and technological importance. Versatile magnetically responsive manipulation strategies have been developed to achieve precise control over droplets and bubbles. To manipulate nonmagnetic droplets or bubbles with magnetic fields, the presence of magnetic medium is indispensable. Magnetic additives can be added to the surface or interior of droplets and bubbles, allowing for on‐demand manipulation by direct magnetic actuation. Alternatively, magnetically responsive elastomer substrates can be used to actuate droplets and bubbles by controlling the deformation of microstructures on the substrates through magnetic stimulation. Another strategy is based on untethered magnetic devices, which enables free mobility, facilitating versatile manipulation of droplets and bubbles in a flexible manner. This paper reviews the advances in magnetically responsive manipulation strategies from the perspective of droplets and bubbles. An overview of the different classes of magnetic medium, along with their respective corresponding droplet/bubble manipulation methods and principles, is first introduced. Then, the applications of droplet/bubble manipulation in biomedicine, microchemistry, and other fields are presented. Finally, the remaining challenges and future opportunities related to regulating droplet/bubble behavior using magnetic fields are discussed. Versatile magnetic manipulation strategies enable precise control of droplets and bubbles. Magnetic additives, magnetically responsive surfaces, and untethered magnetic devices are used as magnetic media for on‐demand droplet/bubble manipulation. This paper reviews advances in magnetically responsive manipulation of droplets and bubbles, including different magnetic media, along with their respective corresponding droplet/bubble manipulation methods and principles. Applications, challenges, and future opportunities in regulating droplet/bubble behavior using magnetic fields are discussed.

Small-scale electromagnetic soft actuators are characterized by a fast response and simple control, holding prospects in the field of soft and miniaturized robotics. The use of liquid metal (LM) to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness. Despite research efforts, challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance. To address these challenges, we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method. Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber (1.03 kPa), our actuator exhibits an excellent deformation angle (265.25°) and actuation bending angular velocity (284.66 rad·s−1). Furthermore, multiple actuators have been combined to build an artificial gripper with a wide range of functionalities. Our actuator presents new possibilities for designing small-scale artificial machines and supports advancements in ultrafast soft and miniaturized robotics.

Soft pressure sensors based on liquid metals (LMs) may find broad applications, but it is challenging to fabricate such sensors that can achieve high stress resolution without additional parts. Herein, a method named laser-induced selective adhesion transfer (LISAT) is proposed. LISAT can pattern LM by selectively changing high adhesion of the poly(dimethylsiloxane) (PDMS) surface to LM into low adhesion with the aid of rough micro/nanostructures induced by a femtosecond laser. Based on this principle, LM microchannels with controllable shapes can be obtained by LM transfer and subsequent encapsulation. Since the smallest microchannel thickness is only ∼25 μm, sensor stress resolution can reach 0.0168 kPa without any additional parts to amplify the effect of pressure. As proof-of-concept demonstrations, the sensor is used for sensing the dynamic movement of a small sphere (∼0.16 g) and even an ant (∼0.025 g). LISAT provides a versatile platform for fabricating high-stress-resolution LM pressure sensors with controllable patterns and device structures to adapt to different application scenarios.

Bioinspired surface material with re-entrant texture has been proven effective in exhibiting good pressure resistance to droplets with low surface tension under static conditions. In this work, we combined femtosecond laser cutting with shape memory polymer (SMP) and tape to fabricate re-entrant micropillar arrays by proposing a top-restricted self-growth (TRSG) strategy. Our proposed TRSG strategy simplifies the fabrication process and improves the processing efficiency of the re-entrant structure-based surface material. The structural parameters of the re-entrant micropillar array (microdisk diameter D, center-to-center distance P, and height H) can be adjusted through our TRSG processing method. To better characterize the anti-infiltration ability of various re-entrant micropillars, we studied the dynamic process of ethylene glycol droplet deformation by applying external vertical vibration to the surface material. Three parameters (vibration mode, amplitude, and frequency) of the external excitation and structural parameters of the re-entrant micropillar array were systemically investigated. We found that the surface material had better dynamic pressure resistance when Pand Dof the re-entrant texture were 650 and 500 μm, respectively, after heating for 6 min. This work provides new insights into the preparation and characterization of the surface material, which may find potential applications in microdroplet manipulation, drug testing, and biological sensors.

Nature-inspired magnetically responsive intelligent topography surfaces have attracted considerable attention owing to their controllable droplet manipulation abilities. However, it is still challenging for magnetically responsive surfaces to realize three-dimensional (3D) droplet/multidroplet transport in both horizontal and vertical directions. Additionally, the droplet horizontal propulsion speed needs to be improved. In this work, a 3D droplet/multidroplet transport strategy based on magnetically responsive microplates array (MMA) actuated by a spatially varying and periodic magnetic field is proposed. The modified superhydrophobic surface can transport droplets rapidly both in horizontal and vertical directions, and it can even realize against-gravity upslope propulsion. The rapid horizontal droplet propulsion (∼58.6 mm/s) is ascribed to the abrupt inversion of the modified surface induced by the specific magnetic field. Furthermore, the nonmagnetically responsive microplates (NMMs)/MMA composite surface is constructed to realize 3D multidroplet manipulation. The implementations of MMA in manipulation of continuous fluids and liquid metal are further demonstrated, providing a valuable platform for microfluidic applications.

Natural evolution has endowed diverse species with distinct geometric micro/nanostructures exhibiting admirable functions. Examples include anisotropic microgrooves/microstripes on the rice leaf surface for passive liquid directional rolling, and motile microcilia widely existed in mammals’ body for active matter transportation through in situ oscillation. Till now, bionic studies have been extensively performed by imitating a single specific biologic functional system. However, bionic fabrication of devices integrating multispecies architectures is rarely reported, which may sparkle more fascinating functionalities beyond natural findings. Here, a cross-species design strategy is adopted by combining the anisotropic wettability of the rice leaf surface and the directional transportation characteristics of motile cilia. High-aspect-ratio magnetically responsive microcolumn array (HAR-MRMA) is prepared for active droplet transportation. It is found that just like the motile microcilia, the unidirectional waves are formed by the real-time reconstruction of the microcolumn array under the moving magnetic field, enabling droplet (1–6 μL) to transport along the predetermined anisotropic orbit. Meanwhile, on-demand droplet horizontal transportation on the inclined plane can be realized by the rice leaf-like anisotropic surface, showcasing active nongravity-driven droplet transportation capability of the HAR-MRMA. The directional lossless transportation of droplet holds great potential in the fields of microfluidics, chemical microreaction, and intelligent droplet control system.

FeS nanoparticles have been reported to exhibit efficiency in Cr(VI) removal, while it might fail in practical water treatment engineering. A novel monolithic composite (PSA-nFeS) by embedding nFeS into Poly Sodium Acrylate (PSA) through ion-exchanging and homogeneous precipitation was therefore synthesized in this study. PSA-nFeS showed high efficiency in Cr(VI) removal in pH 2–10, corresponding to an enhancement of efficiency from 16.40 % (41.30 mg Cr(VI) per g nFeS) to 90.51 % (282.43 mg Cr(VI) per g nFeS) relative to that achieved by nFeS. The removal mechanism of PSA-nFeS was further elucidated via SEM, EDS, FTIR, XRD and XPS. The results showed that reduction and adsorption accounted for 81 % and 19 % of Cr(VI) removal respectively, and Fe(II) played a key role in Cr(VI) reduction with the contribution of three times as much as S(-II), which was confirmed by density functional theory (DFT) calculation. Furthermore, PSA cryogel also facilitated the electron transfer process of interfacial Cr(VI) reduction demonstrated by EIS and LSV. This work suggested a novel multifunctional material for high-effective treatment of aqueous Cr(VI) in practical engineering application.

Diabetic nephropathy (DN) has become the leading cause of end stage failure, but no renoprotective treatment has been very available for use in DN. Astragalussaponin I (AS I), a component extracted from Astragalus membranaceusBUNGE, was studied in experimental DN induced by administration of streptozotocin in male rats. The early DN rats were treated with 3 doses of AS I for 8 weeks to analyze its efficacy with different parameters. By comparison with vehicle-treated DN rats, the renal hypertrophy, the oxidative stress intensity, and the blood glucose level of DN rats were ameliorated by AS I. Also, the microalbuminuria level, advanced glycated end-products either in serum or in kidney cortex, and the aldose reductase activity were significantly reduced. Furthermore, the expression of transforming growth factor β1 mRNA in kidney cortex by RT-PCR analysis was markedly declined. Both the relative grade of mesangium hyperplasia by microscopical observation and the thickness of glomerular base membrane by electron microscope measurement were decreased significantly. Therefore, the results suggest that AS I has therapeutic effects on several pharmacological targets in the progress of DN and is a potential drug for prevention of early stage DN.

Several natural organism can change shape under external stimuli. These natural phenomena have inspired a vast amount of research on exploration and implementation of reconfigurable shape transformation. The Janus structure is a promising approach to achieve shape transformation based on its heterogeneous chemical or physical properties on opposite sides. However, the heterogeneity is generally realized by multi-step processing, different materials, and/or different processing parameters. Here, we present a simple and flexible method of producing pH-sensitive Janus microactuators from a single material, using the same laser printing parameters. These microactuators exhibit reversible structural deformations with large bending angles of ∼31° and fast response (∼0.2 s) by changing the pH value of the aqueous environment. Benefited from the high flexibility of the laser printing technique and the spatial arrangements, pillar heights, and bending directions of microactuators are readily controlled, enabling a variety of switchable ordered patterns and complex petal-like structures on flat surfaces and inside microchannels. Finally, we explore the potential applications of this method in information encryption/decryption and microtarget capturing.

Abstract: It has been reported that artificial restoration of barrier function by a water vapor-impermeable membrane after tape stripping induces barrier abrogation in hairless mice, impeding rather than enhancing barrier recovery. To address this issue, we examined the morphologic changes in the epidermis after tape stripping and occlusion with a water vapor-impermeable membrane in murine skin. Male hairless mice were used for all studies of barrier perturbation and occlusion. Barrier disruption was achieved by repeated application of cellophane tape. Immediately after tape stripping the animals were wrapped in a tightly fitting water vapor-impermeable membrane. Transepidermal water loss (TEWL) was measured 20 min after tape stripping and 14, 24, 36, 48 and 60 h after occlusion. For electron microscopy the samples were treated with osmium tetroxide (OsO 4 ) or ruthenium tetroxide (RuO 4 ). When tape-stripped animals were wrapped in a water vapor-impermeable membrane, thereby preventing water flux, barrier function did not recover normally. These results demonstrate that an artificial block to TEWL with an impermeable membrane did not enhance barrier recovery. By electron microscopy many transitional cells and lacunae of various sizes were seen within the intercellular spaces of the stratum corneum after occlusion following tape stripping. Occlusion also caused alterations in both lipid lamellar membrane structures in the stratum corneum interstices and the lamellar bodies in the cytosol of granulocytes and transitional cells. Secreted lamellar body contents also appeared to be abnormal in the stratum corneum-stratum granulosum junction.

When comparing enzymatic degumming, chemical degumming and microorganism degumming, it was found that mixed method of degumming is better suited to apocynum. Apart from better degumming result, it also improves the quality of degummed ramie. [ABSTRACT FROM AUTHOR]