Microsystems & Nanoengineering最新文献

High levels of sperm DNA fragmentation index (DFI) represent a critical factor in male infertility, with detrimental effects on embryonic development and offspring well-being. However, selecting sperm with low DFI remains a tremendous challenge. Here, we present an organ-level selection strategy capable of isolating spermatozoa with ultra-low DFI, achieving a remarkable reduction to 0.13% compared to 34.57% observed in raw semen. We design and fabricate a female reproductive tract (FRT)-on-a-chip (FRToC) device that mimics the entire physiological microenvironment for in vivo sperm selection, with clinical validation performed using samples from patients. The FRToC selects sperm with ultra-low DFI (mean: 0.71%) from patients with high DFI (mean: 41.93%), while also ensuring superior sperm motility and acrosome integrity. Additionally, trace sperm proteomic and single-cell copy number variants (CNV) analyses revealed that sperm sorted by FRToC exhibited an increased capacity to mitigate oxidative stress, thus resulting in more intact chromosomes. Our organ-scale selection method underscores the potential of the FRToC to select high-quality spermatozoa, offering a promising improvement for assisted reproductive technology (ART).

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.

Microneedle-based continuous glucose monitoring systems have advanced diabetes management in pain less manner, but challenges remain regarding detection sensitivity due to limited sensing area. Vertical graphene (VG) with large surface area offers high conductivity and excellent electrochemical properties for miniaturized, high-performance biomedical sensors. In this study, we developed a vertical graphene-coated core-shell microneedle glucose sensor (VCMGS) for continuous monitoring of glucose fluctuations. The VCMGS featured a hollow microneedle as the outer shell for effective skin penetration, coupled with a vertical graphene-modified sensing electrode core for glucose detection subcutaneously. The core-shell structure provides robust mechanical strength, minimizing damage to the sensing area and improving overall sensor stability. Meanwhile, the electrochemical performance and sensitivity of the microneedle electrode was enhanced by VG, enabling reliable, in situ, and real-time physiological signal acquisition from interstitial fluid. The VCMGS exhibited sensitive response to glucose variations, with a well-defined linear relationship, high selectivity, temporal stability, and dependable signal transmission in both in vitro and in vivo experiments, demonstrating high capability for precise, continuous tracking of glucose fluctuations in real time. This work offered potential applicability and benefits in aiding the diagnosis and treatment of diabetes.

The demand is increasing for compact, low-cost biosensors suitable for point-of-care diagnostics. In this study, we developed a novel chemiresistive biosensor based on a platinum (Pt) nanoparticle-polymer composite matrix functionalized with a creatinine enzyme cascade. The sensor detects creatinine through resistance changes triggered by redox reactions of enzymatically generated hydrogen peroxide at the Pt nanoparticle interface. Operating near the percolation threshold of metallic nanoparticles enhances sensor sensitivity, as it promotes the formation of efficient electron conduction paths through hopping and tunneling mechanisms. The simplified two-electrode structure of the device eliminates the need for a reference electrode, enabling miniaturization and facilitating fabrication. Both direct and alternating current measurements confirm that the electrical response arises from interfacial charge redistribution combined with bulk conduction network formation. The biosensor exhibits a wide detection range (1-300 mg/dL), fast response time (~35 s), and strong correlation between analyte concentration and electrical signal. This platform offers a promising approach for high sensitivity, high selectivity, real-time biosensing of creatinine and other biomarkers.

This study presents the development of a novel omnidirectional soft bending sensor tailored for humanoid dexterous hands to facilitate posture perception in delicate manipulation tasks. Drawing inspiration from the human hand's intricate design and proprioceptive capabilities, this study aims to enhance the dexterity of robotic hands, particularly in multi-degree-of-freedom (DoF) motion and posture perception. To this end, we designed a humanoid dexterous hand featuring 18 active DoFs, with five rigid-flexible structured fingers for improved joint mobility. Each finger is equipped with our innovative omnidirectional bending sensor, utilizing segmented polymethylmethacrylate (PMMA) optical fibers, a trichromatic LED, and a chromatic detector to detect the pitch and yaw angles of the metacarpophalangeal joints. The sensor demonstrated excellent measurement performance, stability, and repeatability in challenging tasks such as using scissors, operating a computer mouse, and playing the piano. This technology addresses the challenges associated with multi-DoF motion and omnidirectional posture perception in robotic hands, thereby enhancing their capabilities in delicate manipulation tasks and paving the way for further advancements in humanoid dexterous hand development.

Large-scale photovoltaic systems are a rapidly expanding contributor to sustainable energy production, and power management for these systems relies on measuring both solar angle and intensity simultaneously. However, current non-miniaturized sensors often offer a narrow field of view and measure only a single parameter, which does not meet the needs of advanced integrated photovoltaic power-management systems, motivating the need for a compact, multifunctional sensing solution. We propose a new, integrated, multifunctional sensor capable of capturing wide-view solar angle and intensity. This device integrates three detectors on a single chip, each with a differently inclined surface, to broaden the field of view. Tests under systematically varied angles and intensity levels showed that the three detectors respond most strongly at 117.5°, 87.5°, and 67.5°, with current-to-intensity coefficients of 2.85 × 10^-4, 2.31 × 10^-3, and 2.57 × 10^-4 μA/(W/m²). The device offers an unprecedented ±75° field of view for a single-chip solar sensor while maintaining a low mean error of 3.4° for the angle and a low relative mean error of 1.6% for intensity, respectively. This multifunctional micro-electro-mechanical system (MEMS) sensor, combining a wide field of view with high accuracy, marks an important step toward enabling distributed, in-situ power management in large-scale photovoltaic systems.

Mechanical frequency combs (MFCs), built upon wave mixing in mode-coupled micromechanical resonators, are often limited by their narrow and sparse spectra due to small energy exchange rates. However, the ability to model and enhance the energy exchange rate remains insufficiently explored. Here, we systematically propose coupling enhancement schemes for different architectures, and present a coupling-enhancement anchor design to achieve the giant energy exchange rate between the coupled modes of our device, enabling the broadening of comb spacing to overlap harmonic clusters of MFCs, leading to the generation of supercontinuum frequency combs. A theoretical model describing the physical relationship between the energy exchange rate and resonator parameters is developed, which is validated by the consistent correlation between the energy exchange rate and the induced mode amplitude under varying driving frequencies. Our finding builds a design-oriented approach to raise the energy exchange rate in mode-coupled resonators and to construct decade-wide dense spectral range of MFCs, paving the way for their potential applications in precision timekeeping and signal processing.

Achieving high-performance sodium-based solid-state electrolytes (SSEs) through environmentally friendly processes is crucial to establishing a solid foundation for safe and inexpensive energy storage devices. Here we demonstrate nonflammable sodium cation-transporting SSEs prepared from aqueous solutions of branched poly(ethylene imine) (bPEI), sodium hydroxide (NaOH), and sodium hexametaphosphate (SHMP). The bPEI:NaOH:SHMP (PNaS) SSEs exhibited an outstanding ion conductivity of ~1 mS/cm at SHMP = 20 mol%, which is 5 times higher than 0.18 mS/cm for the bPEI:NaOH (PNa) SSEs, due to the SHMP-induced morphology optimization for efficient Na⁺ transport. The optimum PNaS SSEs could deliver the output voltage of 4.4 V by galvanostatic charging at 0.5 mA/g, exhibiting long-term retention characteristics (>1000 s). The PNaS supercapacitors exhibited stable operation with 99.68% capacitance retained during 2000 charging/discharging cycles, while the PNaS films were considerably stable without burning upon the flammability test.

Microelectromechanical system fabrication represents a promising approach for silicon-based flexible electronics, leveraging its scalability and miniaturization merits. However, fabrication-induced geometric deviations stretchable microstructures can result in significant variations in mechanical performances. Current assessment methods lack sufficient accuracy for these precision-sensitive manufacturing processes. This work proposes a machine-learning (ML)-based assessment methodology for accurately and rapidly predicting the mechanical performances, including equivalent Young's modulus and the maximum elastic stretchability, of Parylene three-dimensional micro-Kirigami stretchable structures in a stretchable silicon array affected by the fabrication-induced geometric deviations. By applying the dimensionality reduction technique specifically designed for few-shot ML modeling, the framework achieves prediction accuracies exceeding 95% on the test set. SHapley Additive exPlanations (SHAP) analysis is further utilized to quantify the impact of various geometric features on mechanical performances. This ML-based assessment methodology successfully facilitates real-time feedback from process-induced geometric deviations to the qualification probability of mechanical performances. This proposed approach supports design-for-manufacturability (DFM) of silicon-based stretchable arrayed devices manufacturing and lays the foundation for high-consistency wafer-scale manufacturing of high-performance stretchable silicon electronics.

The precise measurement of pH variations is pivotal across scientific and industrial domains, with colorimetric pH sensors gaining prominence for their simplicity and advantages over electrochemical alternatives. However, their widespread adoption has been hindered by challenges such as dye leaching, limited long-term stability, and a narrow dynamic range (typically ~3 pH units). To address these constraints, we engineered nanopigments by covalently bonding sulfonephthalein dyes to raspberry-like silica nanoparticles (RSNs), which were subsequently embedded within an agarose/polyethylene oxide (PEO) matrix to create stable, non-leaching pH-sensing films. To further expand the detection range, we integrated two distinct sulfonephthalein nanopigments-Bromocresol Green and Phenol Red into the matrix, leveraging their complementary pH sensitivities. CIELAB color space analysis revealed a synergistic interplay within the RSN-agarose-PEO microenvironment, driving multiple protonation and deprotonation events that extend the sensor's operational range to pH 1-10 with a uniform linear response. The versatility of the nanopigments was demonstrated by coating them onto various substrates, where they maintained robust pH responsiveness. This innovative strategy yields a durable, colorimetric pH sensor that overcomes the limitations of conventional systems, offering a practical, wide-ranging tool for applications in research, industry, and beyond.