Zhengmao Ding

Robust hydrogel‐elastomer integration is crucial for soft electronics and robotics but hindered by interfacial fragility. Here, we present a spatially confined in situ photopolymerization strategy to grow hydrogel coatings directly from polydimethylsiloxane (PDMS). By confining the active radicals within the solvent‐swollen elastomeric boundary, this strategy achieves a bottom‐up growth. Crucially, both experimental characterizations and molecular dynamics (MD) simulations reveal a hydrogen‐bond‐mediated discrete nucleation process during the coating formation. This localized pre‐organization serves as physical evidence of the bottom‐up growth, which constructs a dual‐anchoring interface featuring simultaneous covalent grafting and topological entanglement. The dual‐anchoring (DA) hydrogel coatings achieve high interfacial toughness, long‐term stability, and applicability to other elastomers. We further extend this protocol for fabricating patterned conductive hydrogel coatings with high‐resolution reproduction of micron‐scale features. Furthermore, it enables rapid in situ fabrication of thin‐film actuators with enhanced actuation performance. This strategy presents a convenient protocol for integrating advanced hydrogel functionalities into soft matter systems.

The myocardial organ‐on‐a‐chip platform represents a transformative approach for replicating cardiac physiological functions in vitro, with significant potential for drug screening and disease modeling applications. Dynamic mechanical stimulation enhances both structural and functional maturation of cardiac tissues, leading to improved contractile performance, while real‐time contractility monitoring provides essential data for investigating cardiac disease mechanisms and evaluating pharmacological interventions. However, integrating mechanically stimulated mature myocardial tissue cultures with real‐time detection of weak contractile activity remains challenging. Here, an integrated platform that combines programmable mechanical stimulation with real‐time contractile force monitoring was developed. The system employs aligned fiber scaffolds to guide three‐dimensional (3D) cardiac tissue formation. Meanwhile, a wireless tunable magnetic actuation unit applying physiological relevant mechanical stimulation was employed demonstrating remarkable efficacy in enhancing sarcomeric structure (42.9% increase in sarcomere length, from 1.42 to 2.10 µm) and contractile function (47.5% increase in force amplitude, from 19.47 to 28.72 µN). An embedded flexible sensor based on liquid metal for real‐time monitoring of contraction force was introduced, achieved a minimum detectable force of 1.52 µN. The system addresses current limitations in cardiac tissue engineering where stimulation and sensing platforms are typically separate, integrating both dynamic maturation enhancement and continuous contractile performance monitoring.

Large amounts of binder system waste are produced upon the recovery of energetic components in scrapped hydroxyl-terminated polybutadiene (HTPB) propellant. This study investigated the biodegradability of the binder system waste using a microbial enrichment solution as the biodegradation medium. We measured the binder system weight loss and performed Fourier-transform infrared (FT-IR), thermogravimetric (TG), and scanning electron microscopy (SEM) analyses of the binder system after 60 days of biodegradation. The results show the binder system film weight decreased by approximately 43% and stabilized after 50 days. The FT-IR analysis shows a reduction in C=O and C-O bond signals, whereas N-H, C-N, and C=C bond signals remain nearly unchanged. The TG analysis shows that the difference between the DOA weight in the initial film and that of the thermal decomposition was almost equal to the weight loss of the binder system film after biodegradation. The SEM analysis shows irregular pits on the film. The binder system has a certain biodegradability, which is mainly caused by its plasticizer component, i.e., DOA. HTPB-based polyurethane, the other major component, is difficult to degrade by microorganisms. As such, the binder system was pretreated with sodium methoxide-methanol solution as a depolymerization reagent, and the pretreated product yielded higher biodegradability.

Developing high-efficiency catalysts for the hydrogen evolution reaction (HER) carries considerable significance for hydrogen production via water splitting. However, the intrinsic active sites of traditional molybdenum disulfide (MoS2) catalysts are scarce and the basal plane is inert, which severely restricts its overall catalytic efficiency. In this work, Ru doping and hydrogen peroxide temperate etching methods were used to jointly modify MoS2, effectively combining single atom protrusion defects and single atom vacancy defects to explore their synergistic effects. The results indicate that the Ru atom immersion concentration and liquid-phase etching time can accurately induce the phase transition of MoS2, resulting in changes in the Ru atom protrusions and S atom vacancy concentration of MoS2, further breaking through the unit point activity and the number of active sites, reducing the reaction barrier, and achieving significant optimization of hydrogen evolution kinetics. In particular, the SA-Ru-MoS2 electrocatalyst exhibits a low overpotential of 24 mV in alkaline medium at a current density of 10 mA·cm-2, corresponding to a Tafel slope of 24 mV dec-1, and almost no decay at a constant current of 10 mA·cm-2 within 72 h, which is superior to most electrocatalysts reported in the literature. This work offers new ideas for synergistically improving the performance of MoS2 electrocatalysts with single atom defects.

The emergence of Organ-on-a-Chip (OoC) has significantly advanced biomedical research mainly on aspects of disease modeling and drug research. The need for real-time and continuous monitoring of the OoCs has been driving the development of integrated sensors on-chip. To meet these needs across different scales, from microscopic to macroscopic, primary sensing strategies for in situ sensor integration typically include electrical, optical, and mechanical approaches. This review focuses on the detection methodologies driven by these requirements and analyzes the core sensing elements involved. It further explores current innovative pathways for achieving in situ sensing integration and discusses the future prospects brought about by the development of models in OoC and sensing technologies.

Two-dimensional (2D) materials open up exciting possibilities for the study of ion transport behavior for green energy. Here, a simple and effective strategy to fabricate high-conductivity nanofluidic channels based on exfoliated montmorillonite (MTM) nanosheets is proposed. The resource-rich and low-cost layered MTM was first exfoliated into monolayer nanosheets using Exolit OP 550. Subsequently, the MTM nanosheets with Exolit OP 550 were assembled into 2D nanofluidic devices by the layer-by-layer self-assembly method. The results show that Exolit OP 550 exfoliates different types of layered MTM into monolayer nanosheets with uniform contrast and integrity. The reconstructed Na-MTM nanofluidic device has the highest ionic conductance. The ionic conductivity of the Na-MTM 2D nanofluidic device was effectively improved after Li⁺ modification with a higher charge density. After further optimizing the content of Exolit OP 550, the ion conductivity of the MTM nanofluidic device reached 4.66 × 10⁻⁴ S cm⁻¹, which is 55.3% higher than the highest known value among the same nanofluidic devices. Interestingly, this nanofluidic device exhibited a very high sensitivity in detecting water evaporation, which can reach 10⁻¹² S s⁻¹ in resolution. This economically viable strategy may advance the study of low-dimensional ion transport properties in new energy coatings and the design of evaporation detectors.

A major challenge in myocardial tissue engineering is replicating the heart’s highly complex three-dimensional (3D) anisotropic structure. Heart-on-a-chip (HOC) is an emerging technology for constructing myocardial tissue in vitro in recent years, but most existing HOC systems face difficulties in constructing 3D myocardial tissue aligned with multiple cell layers. Electrospun nanofibers are commonly used as scaffolds for cell growth in myocardial tissue engineering, which can structurally simulate the extracellular matrix to induce the aligned growth of myocardial cells. Here, we developed an HOC that integrates multi-layered aligned polycaprolactone (PCL) nanofiber scaffolds inside microfluidic chips, and constructed 3D thick and aligned tissue with a layered seeding approach. By culturing human-induced pluripotent stem-cell-derived cardiomyocytes (hiPSC-CMs) on chip, the myocardial tissue on the two layered nanofibers reached a thickness of ~53 μm compared with ~19 μm for single-layered nanofibers. The obtained myocardial tissue presented well-aligned structures, with densely distributed α-actinin. By the third day post seeding, the hiPSC-CMs contract highly synchronously, with a contraction frequency of 18 times/min. The HOC with multi-layered biomimetic scaffolds provided a dynamic in vitro culture environment for hiPSC-CMs. Together with the layered cell-seeding process, the designed HOC promoted the formation of thick, well-aligned myocardial tissue.

Confronting the impending exhaustion of traditional energy, it is urgent to devise and deploy sustainable clean energy alternatives. Osmotic energy contained in the salinity gradient of the sea‐river interface is an innovative, abundant, clean, and renewable osmotic energy that has garnered considerable attention in recent years. Inspired by the impressively intelligent ion channels in nature, the developed angstrom‐scale 2D channels with simple fabrication process, outstanding design flexibility, and substantial charge density exhibit excellent energy conversion performance, opening up a new era for osmotic energy harvesting. However, this attractive research field remains fraught with numerous challenges, particularly due to the complexities associated with the regulation at angstrom scale. In this review, the latest advancements in the design of angstrom‐scale 2D channels are primarily outlined for harvesting osmotic energy. Drawing upon the analytical framework of osmotic power generation mechanisms and the insights gleaned from the biomimetic intelligent devices, the design strategies are highlighted for high‐performance angstrom channels in terms of structure, functionalization, and application, with a particular emphasis on ion selectivity and ion transport resistance. Finally, current challenges and future prospects are discussed to anticipate the emergence of more anomalous properties and disruptive technologies that can promote large‐scale power generation.