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Environmental microvibrations, often originating from unidentified sources, pose a significant challenge for predicting and controlling their complex wave fields, potentially leading to measurement errors of sensitive instruments in high-precision laboratories and impacting the accuracy of experimental outcomes. Therefore, investigating effective control measures for environmental microvibrations under passive conditions is key to addressing such engineering issues. This paper presents a finite element analysis method tailored to address environmental microvibrations in the absence of apparent sources. This method involves obtaining the vibration time history at specific ground surface points through field measurements and combining the Rayleigh wave velocity attenuation character with depth at the center frequencies of one-third octave bands within the 1–100 Hz frequency range; the vibration time history at any depth in the soil is calculated. These calculated vibrations are then applied as input loads to the corresponding nodes on one boundary of the foundation–soil model, serving as the source of environmental microvibrations. The predicted results are compared with measured data and the empirical point source input method, indicating that this approach is more precise and efficient, providing valuable reference for the prediction and analysis of environmental microvibrations. In addition, utilizing this method, the study examines the effects of pile foundation parameters such as the pile length, burial depth, and concrete baseplate thickness on the vibration isolation performance of environmental microvibrations, providing guidance for designing pile foundation isolation. [ABSTRACT FROM AUTHOR]

Drug-induced cardiotoxicity is a significant contributor to drug recalls, primarily attributed to limitations in existing drug screening platforms. Traditional heart-on-a-chip platforms often employ metallic electrodes to record cardiomyocyte electrical signals. However, this approach hinders direct cardiomyocyte morphology observation and typically yields limited functionality. Consequently, this limitation may lead to an incomplete understanding of cardiomyocyte characteristics. To address these challenges, we introduce a multifunctional cardiac microphysiological system featuring transparent indium tin oxide electrodes. This innovative design aims to overcome the limitations of conventional heart-on-a-chip systems where metal electrodes interfere with the observation of cells and increase the difficulty of subsequent image processing of cell images. In addition to facilitating optical measurement combined with image processing capabilities, this system integrates a range of electrodes with diverse functionalities. These electrodes can realize cellular electrical stimulation, field potential monitoring, and impedance change tracking, enabling a comprehensive investigation of various cardiomyocyte traits. To demonstrate its versatility, we investigate the effects of four cardiac drugs with distinct pharmacological profiles on cardiomyocytes using this system. This platform provides a means for quantitatively and predictively assessing cardiac toxicity, which could be applied to conduct a comprehensive evaluation during the drug discovery process. [ABSTRACT FROM AUTHOR]

Targeted microrobotic delivery within the circulatory system holds significant potential for medical theranostic applications. Existing delivery strategies of microrobots encounter challenges such as slow speed, limited navigation control, and dispersal under dynamic flow conditions. Furthermore, within the realm of microrobots, in vitro testing platforms often lack essential biological microenvironments, while in vivo studies conducted on animal models are constrained by limited detection resolution. In this study, we propose a multi-level magnetic delivery strategy that integrates a tethered microrobotic guidewire and untethered swimming microrobots. The amalgamation compensates for their inherent constraints, ensuring a robust and highly efficient delivery of microrobots under complex physiological conditions over extensive distances. Concurrently, a hierarchical vascular network encompassing engineered arteries/veins and capillary networks was constructed by integrating vasculogenesis and endothelial cell (EC) lining strategies, thereby providing an in vivo-like testing platform for microrobots. Experimental evidence demonstrates that the flexible microrobotic guidewire can be precisely directed to any entrance of the second-tier branches, with its inner lumen providing an "express lane" for rapid passage of microrobots through complex fluidic environments without direct contact. After release, dynamically assembled swarms could effectively locomote on the micro-topography of the EC-lined channel surface without becoming trapped and congregate within specified regions inside capillary lumens when guided collectively by a biologically safe magnetic field. Additionally, the superparamagnetic capabilities of microrobotic swarms ensure their dissolution into monodispersed entities upon withdrawal of the magnetic field, mitigating the risk of intravascular thrombosis. The hierarchical vascularized organ-on-a-chip platform establishes a comprehensive testing platform that integrates imaging, control, and a functional 3D microvascular environment, thereby enhancing its suitability for microrobotic applications encompassing targeted drug delivery, thrombus ablation, sensing and diagnosis, etc. [ABSTRACT FROM AUTHOR]

In vitro organoid models, typically defined as 3D multicellular aggregates, have been extensively used as a promising tool in drug screening, disease progression research, and precision medicine. Combined with advanced microfluidics technique, organoid-on-a-chip can flexibly replicate in vivo organs within the biomimetic physiological microenvironment by accurately regulating different parameters, such as fluid conditions and concentration gradients of biochemical factors. Since engineered organ reconstruction has opened a new paradigm in biomedicine, innovative approaches are increasingly required in micro-nano fabrication, tissue construction, and development of pharmaceutical products. In this Perspective review, the advantages and characteristics of organoid-on-a-chip are first introduced. Challenges in current organoid culture, extracellular matrix building, and device manufacturing techniques are subsequently demonstrated, followed by potential alternative approaches, respectively. The future directions and emerging application scenarios of organoid-on-a-chip are finally prospected to further satisfy the clinical demands. [ABSTRACT FROM AUTHOR]

Amino‐terminated naphthalimide (NDI) with ultraviolet (UV) absorptivity was synthesized to sizing on poly(p‐phenylene benzobisoxazole) (PBO) fiber surface, and UV aging resistance PBO fiber and interfacial adhesion of their composites was investigated. Compared with pristine PBO fiber, the surface chemical activity and roughness of NDI‐PBO fiber were increased. In comparison with pristine PBO fiber, tensile strength, intrinsic viscosity ([η]), and diameter of NDI‐PBO fiber showed a better retention, and the enhanced UV‐aging resistance was verified by hardly visible macroscopic defects on NDI‐PBO fiber. Meanwhile, transverse fiber bundle test strength of NDI‐PBO fiber composites was promoted by stronger mechanical interlocking and chemical interaction. The synergistic improvement in UV aging resistance and interfacial adhesion of PBO fiber was attributed to undamaged crystal and molecular structure from UV protection effects of NDI layer and strong chemical bonding between reactive groups of NDI and epoxy matrix. [ABSTRACT FROM AUTHOR]

Thermally reduced graphene oxide–polyamide (TrGO‐PA) hybrids were fabricated by self‐assembly between TrGO nanosheets and PA microparticles, and the dispersibility, interphase extension, and thermal conduction mechanism of TrGO‐PA/epoxy (EP) composites were investigated. Most of the oxygen‐containing functional groups of TrGO were removed, and a conjugated structure of graphene was recovered. TrGO was distributed evenly on the PA surface via electrostatic adsorption between TrGO and PA, which resulted in the inhibition of TrGO aggregation in the epoxy matrix. Compared with that of TrGO/EP and PA/EP composites, the thermal interface resistance (RTIM) of TrGO‐PA/EP composites was greatly decreased to 38.3 mm2 kW−1 and the thermal conductivity was improved to 0.268 W/(m K), which was attributed to the enhanced dispersibility of TrGO‐PA and the enlarged interphase in TrGO‐PA/EP composites. A schematic model of thermal conduction mechanisms was proposed based on the formation of contiguous thermal transfer pathways by bridged TrGO adsorbed on well‐dispersed PA microparticles in TrGO‐PA/EP composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47826. [ABSTRACT FROM AUTHOR]

In recent years, advances in microfabrication technology and tissue engineering have propelled the development of a novel drug screening and disease modelling platform known as organoid-on-a-chip. This platform integrates organoids and organ-on-a-chip technologies, emerging as a promising approach for in vitro modelling of human organ physiology. Organoid-on-a-chip devices leverage microfluidic systems to simulate the physiological microenvironment of specific organs, offering a more dynamic and flexible setting that can mimic a more comprehensive human biological context. However, the lack of functional vasculature has remained a significant challenge in this technology. Vascularisation is crucial for the long-term culture and in vitro modelling of organoids, holding important implications for drug development and personalised medical approaches. This review provides an overview of research progress in developing vascularised organoid-on-a-chip models, addressing methods for in vitro vascularisation and advancements in vascularised organoids. The aim is to serve as a reference for future endeavors in constructing fully functional vascularised organoid-on-a-chip platforms., Competing Interests: Conflicts of interest statement: The authors have no conflicts to disclose.