Microsystems & Nanoengineering最新文献

Continuous monitoring of cardiovascular risk factors in daily life is crucial for disease prevention and management. Current wearable systems, such as photoplethysmography (PPG), ultrasound, and pressure sensors, can capture some of these parameters but require precise sensor alignment over arteries. This alignment dependency complicates daily use and makes the signals highly susceptible to motion artifacts. In this work, we present a textile-based alignment-free electrophysiological sensing sleeve (TAESS) that can be comfortably worn on the upper arm. The TAESS integrates impedance plethysmography (IPG) and electrocardiography (ECG) to enable synchronized cardiovascular haemodynamic monitoring, including blood pressure (BP), cardiac output (CO), systemic vascular resistance (SVR), heart rate (HR), and other metrics. The sleeve is fabricated using silver-based conductive yarns, forming flexible, breathable, and stretchable electrodes that are produced via an automated, low-cost knitting process. Compared to commercial electrodes, TAESS demonstrates superior permeability (37.5 mg·cm^-2·h^-1), stretchability (exceeding 45% in wale direction), and thermal regulation (remaining within 0.4 °C after exercise). Most importantly, it maintains high signal fidelity and is minimally affected by radial movements, outperforming commercial PPG sensors in blood volume detection. The TAESS achieved systolic and diastolic BP prediction root-mean-squared errors of 7.05 mmHg and 5.93 mmHg, respectively, even under respiratory interference and after re-wearing. This scalable, low-cost sensing sleeve offers a robust and alignment-free solution for continuous cardiovascular monitoring, paving the way for personalized healthcare in daily life.

Skin converts multisensory stimuli into bioelectrical signals through cutaneous receptors and then transmits them to the central nervous system (CNS), implementing an analog-digital response to perceive the environment. However, target engagement components that access multisensory stimuli face significant challenges in multimodal interaction, especially the intrinsic decoupling in stretchable heterogeneous integrating systems and the dimensional broadening in traditional human five sensations. In this work, we propose a passive wireless multimodal self-decoupling methodology paradigm to optimize the signal scheduling of systems and broaden the cognitive dimensions of humans, which engages the strategic configuration of symmetrical inductor-capacitor (LC) resonant circuit combined with LC tank to unlock the single-port output self-decoupling sensing, thereby decoding five sensible stimuli to augment situational awareness of human. Systematic theoretical model is established to verify the self-decoupling methodology and the multimodal sensing scheme based on RLC-modulated mechanism. Multiple prototypes of single-port liquid metal (LM)-based wireless multimodal electronic skin implement targeted responses of skin-like receptors. That incorporating pressure (0 kPa~40 kPa), temperature (25 °C ~ 45 °C), humidity (5%RH ~ 90%RH), ultraviolet (0 lm~20 lm) and inclination (30°, 45°, 60°, 90°) through accessing corresponding sensing components. This technique proposal is designed to render a self-decoupling methodology for stretchable wireless multimodal unperturbed platforms and bridge the spatial sensory dimensions in traditional multisensory mechanisms for human-machine interaction.

Surface acoustic wave (SAW) sensors demonstrate significant potential in environmental monitoring due to their high sensitivity and fast response capabilities. However, conventional single-component gas-sensitive materials struggle to achieve both wide detection ranges and rapid response simultaneously. This study developed a high-performance composite film through heterostructure engineering to enhance carbon dioxide (CO₂) sensing performance. A bilayer composite gas-sensing functional layer was fabricated by sequentially depositing tin oxide (SnO₂) and copper oxide (CuO) films on a lithium niobate (LiNbO₃) substrate via magnetron sputtering. Experimental results demonstrated that the SnO₂-CuO composite sensor exhibited a CO₂ sensitivity of 11.35 mV/%, representing 4.3-fold and 10.3-fold improvements over pure CuO (2.65 mV/%) and SnO₂ (1.10 mV/%), respectively. The detection range was extended to 0.1-4vol%, with response and recovery times reduced to 9.3 s and 28.9 s at room temperature (25 °C). In addition, the SAW sensor demonstrated excellent repeatability, humidity interference resistance, high selectivity and long-term stability (5.7% signal attenuation over 30 days). Density functional theory (DFT) calculations revealed that the enhanced performance was attributed to heterointerface charge modulation, which increased the adsorption capacity for CO₂ molecules.

Extending the depth of field (DOF) is essential for large-volume imaging in biological research, particularly in thick tissue environments. Bessel beams and their variants are widely used due to their simplicity and have been successfully applied to in vivo imaging. A recent advancement demonstrated the application of droplet Bessel beams (DBBs) for multi-photon microscopy, enabling functional imaging in live mouse brains. However, DBB generation inevitably requires active phase switching devices such as spatial light modulators, which reduce imaging speed and increase system complexity. This study introduces a droplet Bessel beam metalens (DBBM) that passively generates DBBs without phase switching by employing rectangular meta-atoms for orthogonal polarization modulation and X-shaped meta-atoms for amplitude control. Optical simulations identify optimal DBBM parameters that maximize the point spread function (PSF) aspect ratio while minimizing energy leakage into side lobes. Furthermore, the fabricated DBBM produces PSFs consistent with simulations. Imaging simulations based on three-dimensional confocal images of expansion microscopy-treated organoids demonstrated that the DBBM maintains superior performance even in the presence of aberrations. These findings establish the DBBM as a compact and passive solution for extended DOF imaging without the need for beam-shaping devices. Metalens technology is anticipated to have broad applications in real-time volumetric bioimaging and enable simplified optical system designs.

Flexible humidity sensors, as pivotal sensing components in the Internet of Things and intelligent era, have achieved significant progress in material innovation, fabrication engineering, and application diversification in recent years. This review systematically presents the current research status of flexible humidity sensors, focusing on the influence of novel humidity-sensitive materials(including polymers, metal oxides, carbon-based materials, and two-dimensional materials) on key performance metrics such as sensitivity, response time, and stability. The optimization effects of fabrication technologies such as screen printing, spraying, and deposition on device performance are also analyzed. Furthermore, the innovative applications of flexible humidity sensors in fields including healthcare, smart agriculture, smart homes, and human-machine interaction are elaborated in detail. These applications highlight the sensors' adaptability to diverse environmental requirements and their potential to enable intelligent monitoring and interactive systems. Finally, future technological directions for flexible humidity sensors are proposed from the perspectives of material system innovation, improvement of multi-parameter collaborative sensing performance, and optimization of adaptability to complex environments. The proposed development directions are targeted at achieving higher precision, multifunctionality, and self-powered operation, providing insights and guidance for the research and development of next-generation flexible intelligent sensing devices. By bridging material science, manufacturing engineering, and application engineering, this comprehensive review provides a forward-looking perspective on advancing flexible humidity sensing technologies for emerging intelligent systems.

Superconducting optomechanical circuits enable frequency mixing of optical and mechanical modes, facilitating the generation of microwave frequency combs. However, such optomechanical combs suffer from frequency fluctuations, requiring their stabilization for applications in precision sensing and signal processing. Here, we investigate the sideband injection locking of microwave frequency combs in a niobium-based superconducting optomechanical circuit. By strongly driving the device with a blue-detuned pump to induce parametric instability and introducing an additional tone near individual comb peaks, we study how the locking range varies with the power, the frequency position, and the sweep direction of the injection tone. The locking responses show interesting features such as injection hysteresis, which cannot be explained by existing models. Numerical simulations of the classical optomechanical equations implementing a cubic mechanical nonlinearity show that the nonlinearity contributes to broadening the locking range. We also characterize the Allan deviations and phase noise of the injection-locked combs for different injection frequencies, demonstrating enhanced stability performance. Our results lay the foundation for the utilization of optomechanical combs for applications in nanomechanical sensing and cryogenic microwave pulse generation.

Acne vulgaris, a prevalent inflammatory skin disorder, poses significant clinical challenges due to its multifactorial pathogenesis involving Propionibacterium acnes (P. acnes) proliferation and chronic inflammation. Conventional therapies, including topical applications, oral medication, and laser treatments, face limitations in drug penetration, patient compliance, and therapy efficacy. Currently, the combined use of hydrophilic drugs and hydrophobic drugs is a commonly recommended clinical approach. However, conventional formulations severely struggle to effectively deliver and release both therapeutic agents at the affected site. To address these issues, we developed the dissolved bubble microneedle patches (DBMNPs) for the co-delivery of hydrophilic (dipotassium glycyrrhizinate, DPG), hydrophobic (PIONIN) drugs, and alongside salicylic acid (SA) at the same time. The DBMNPs, which were fabricated basing on hyaluronic acid (HA), featured hollow bubble structures to encapsulate lipophilic agents, enabling spatially segregated and temporally controlled drug release. The patches exhibited good mechanical strength, excellent biocompatibility, and potent antimicrobial activity against P. acnes. In vivo studies confirmed their efficacy in treating acne vulgaris, offering a minimally invasive and clinically translatable approach to enhance therapeutic effect while minimizing systemic side effects. This study reports a microneedle platform that successfully addresses the key challenge of co-loading and co-delivering both hydrophilic and hydrophobic drugs, and is expected to be applied in the treatment of other skin diseases.

In nuclear magnetic resonance (NMR) co-magnetometers, the non-uniform transverse energy distribution of the pumping Gaussian beam can result in substantial optical pumping inhomogeneity and decoherence of atomic spins, which hinder the improvement of the precision and sensitivity of the sensor. One of the most significant recent technological advances for laser beam homogenization is the utilization of the microlens array system. However, the homogenized characteristics of the microlens array system vary with the propagation distance of the pumping light and are not suitable for chip integration, which will affect the sensitivity and compactness of the NMR system. To solve this issue, a metasurface homogenizer is demonstrated for encoding intensity information into the polarization profile of an incident Gaussian beam by combining the geometric phase and Malus' law with the transverse intensity distribution independent of the propagation distance. Compared to Gaussian beam pumping at identical input power, the metasurface homogenizer enhances the measured optical magnetic sensitivity by 23%. The proposed metasurface homogenizer not only realizes the higher precision and sensitivity in NMR co-magnetometers, but also highlights how metasurface-based technologies can contribute to the integrated quantum sensing regime.

Haematococcus pluvialis (H. pluvialis) is a critical natural source of astaxanthin, recognized for its potent antioxidant capacity, anti-inflammatory properties, and ability to suppress the proliferation of breast and skin cancer cells. The size difference between microalgae such as Chlorella vulgaris (C. vulgaris) and Haematococcus pluvialis (H. pluvialis), coupled with their high research value, makes size-based separation of microalgae essential for efficient extraction of valuable species and advancing directed algal evolution. In this study, we introduce an innovative method utilizing microfluidic devices that integrate spiral channels with contraction-expansion channels. We systematically examine how variables such as flow rate, cell concentration, cell size, and three distinct coupling configurations impact cell sorting. Our results highlight that each coupling configuration of the spiral and contraction-expansion channels exerts unique control over sorting performance, offering promising new approaches for optimizing microchannel design.

High overtone bulk acoustic resonators (HBAR) are advantageous for on-chip quantum acoustodynamics (QAD) system as it gives access to stream of phonon modes with high lifetime in the microwave frequency range while retaining low power consumption and microscale footprint. In this paper we present a HBAR based on barium strontium titanate (BST) thin-film mounted on sapphire with modes exhibiting frequency quality factor product (fQ) of 1.72 × 10¹⁵Hz which is the highest reported for a bulk acoustic wave resonator utilizing polycrystalline ferroelectric material as a means for acoustic wave excitation. Unlike other piezoelectric based HBARs, the DC field-induced piezoelectricity utilized in this work offers multiple on-chip tuneability of resonator's dynamic parameters such as phonon lifetime, frequency modulation and coupling. The higher overtone feature can enable qubit(s) in a hybrid quantum circuit to interact with one or more acoustic modes to form a quantum transducer. Here, the multi-mode resonator exhibits a unique DC bias dependency, and this feature of the ferroelectric thin film adds control variables that efficiently tune static and dynamic material, mechanical and electrical properties of the device. The resonator records a loaded quality factor of 180,000 in X band and 140,000 in the L band when measured at 10 K. A controllable robust resonator with simple fabrication technique offering high fQ can be a strong platform to be used in QAD circuits for applications in metrology, quantum memory and quantum information processing.