Advanced Sensor Research最新文献

This work aimed to create a capacitive force sensing system based on flexible materials and structures, miniaturizing the hardware by 87% and the interface, and improving the stability of the signal processing module (from force to capacitance) for robot applications in a wearable shape. The system includes a force sensor, signal acquisition integrated circuit (IC), microcontroller unit, Bluetooth IC, and lithium-polymer battery. The sensor was composed of polymeric materials and elastomers, which were connected to the wristwatch-shaped transmission port before the signal was wirelessly analyze in real-time. Field tests indicated that the responses exhibited reasonable tolerance (less than 2%), reliable short- and long-term stability (variation less than 5%), and remarkable repeatability (linear coefficient of determination of 0.9975). The wristwatch-shaped transmission port thus demonstrated its superiority in practical application and exhibited novelty from the viewpoint of modularization, with balanced characteristics among similar solutions, which provided add-on functions to existing robots.

The present study focusses on the innovative design of a multimaterial pressure sensor with a soft sensing core and soft electrodes. In the first part of the work, nanocomposites based on low-stiffness poly(dimethylsiloxane) (PDMS) and different fractions of single-walled carbon nanotubes (CNTs, from 0.15 to 0.5 wt.%) are tested electromechanically to assess piezoresistivity and stiffness. In the second, the design of the sensor is described. It features an innovative architecture with liquid-metal electrodes placed on the sides of the sensing nanomaterial. This alignment enhances sensitivity and induces monotonicity by coupling constructively the geometric and resistivity components of the piezoresistive response. Fabrication by stepwise molding is demonstrated trying two outer shells of different stiffness, and then various pressure sensors are produced with the best-performing sensing nanomaterials, before being characterized and compared. We highlight the innovative characteristics of the proposed sensors in terms of electrode material architecture and positioning, simple design and fabrication, integral softness and low stiffness (< 1 MPa), appreciable linearity up to 0.0105 (Ω/Ω)/kPa, mid-high working stresses in the 0–210 kPa range, and recoverable compressive strains up to 43%. The reduced bandwidth of the sensor suggests applicability in the detection of pressure changes rather than the measurement of pressure values.

Endotoxins, predominantly lipopolysaccharides (LPS) derived from the cell walls of Gram-negative bacteria, represent a critical challenge in biopharmaceuticals, medical device manufacturing, and food safety. Current gold-standard endotoxin detection relies on Limulus Amebocyte Lysate (LAL) reagents, yet this approach suffers from two limitations: unsustainable exploitation of Limulus (horseshoe crab) resources and vulnerability to non-specific interference due to its turbidity-based readout. Here, we developed a fiber-optic Surface-enhanced Raman scattering (SERS) probe that enables highly sensitive endotoxin detection with drastically reduced LAL consumption. The probe was fabricated by immobilizing silver-coated gold nanostars onto the surface of a tapered-cylinder optical fiber, which was then integrated into a microfluidic capillary. Its sensing mechanism is based on a competitive assay that captures the characteristic Raman “fingerprint” of LAL-endotoxin interactions: endotoxins competitively inhibit the adsorption of LAL reagents onto the fiber surface, resulting in a quantifiable SERS signal. Experimental results demonstrate that the fiber-optic SERS sensor detects ultra-low endotoxin concentrations (100 µEU mL⁻¹) using only 5 µL of LAL reagent, marking a substantial reduction compared to conventional LAL assays. Tests with serum samples demonstrated that the sensor can differentiate between healthy individuals and septic patients, further confirming its translational potential. This technology offers a cost-effective, rapid, and efficient solution for biosafety monitoring, clinical diagnostics, and quality control in food and pharmaceutical industries, advancing sustainable and reliable endotoxin detection beyond the limitations of traditional LAL-based methods.

Wearable human-machine interfaces (HMIs) are vital for seamless interactions between humans and machines in wearable assistive and rehabilitative technologies, digital, and mixed environments. Here, an innovative non-invasive, lightweight, comfortable, and wearable HMI is introduced for gesture recognition. The proposed HMI combines reliable soft optical waveguide sensing mechanism and comfortable-on-human-skin textile structures to create flat and thin textile-based optical force myography (oFMG) sensors that can detect pressure signals generated from muscle activities. Constructed mostly from textiles, the presented oFMG sensors offer excellent wearability together with highly sensitive, stable, and durable sensing performance. Leveraging the high-quality signals of the textile oFMG sensors and machine learning algorithms, a forearm-worn textile oFMG armband developed can achieve the highest offline gesture recognition accuracy of 99.80%. The capabilities of the textile oFMG sensors in this study are demonstrated as wearable HMIs for control of a computer game and a robotic prosthetic hand, highlighting the promising potential of the textile oFMG HMI for a wide range of applications, from control interfaces in digital or mixed environment to gesture recognition systems for biomedical assistive and rehabilitative technologies.

Femtosecond Laser-Enabled Monolithic Sensors

Depicting single-step femtosecond laser fabrication of flexible capacitive pressure sensors with embedded silver electrodes and microhole structuring, highlighting the research on streamlined, high-sensitivity devices for next-generation wearable and biomedical applications. More details can be found in the Research Article by SeungYeon Kang and co-workers (DOI: 10.1002/adsr.202500068).

Flexible pressure sensors are foundational to soft robotics, wearable electronics, and human-machine interfaces, yet their performance is critically dictated by the fabrication paradigm. While conventional fabrication offers high resolution and proven reliability, it is constrained by limited design freedom and complex processes; conversely, additive manufacturing (AM) provides unparalleled design flexibility but faces challenges in resolution and material maturity. A direct comparative analysis linking fabrication strategies to key sensing performance—sensitivity, response time, and pressure range—has been largely absent, creating a knowledge gap for researchers. To address this gap, this review provides a systematic, performance-driven comparison between these two manufacturing paradigms for piezoresistive and capacitive pressure sensors. First, we identify specific structural and material requirements imposed by sensing mechanisms to establish manufacturing criteria. We then analyze how design strategies, like engineering hierarchical structures, are enabled or limited by each approach. By establishing a quantitative mapping between manufacturing capabilities (e.g., resolution vs. volumetric control) and sensor figures-of-merit, we provide a methodical comparative process-selection framework for optimizing sensitivity and dynamic range. This framework equips researchers with strategic insights to navigate trade-offs between conventional and AM techniques, accelerating the development of high-performance flexible pressure sensors.

Modern technological advances are reshaping the ways we live, travel, and communicate. However, these advances simultaneously introduce new forms of risk, ranging from energy storage hazards to information security threats that demand proactive and multidisciplinary solutions. Nanophotonics, which enables precise control of light–matter interactions at the nanoscale, has emerged as a versatile platform for developing functional systems that can improve safety, resilience, and reliability across diverse real–world scenarios. In this review, we explore the growing role of functional nanophotonic materials and structures in managing contemporary safety concerns. We highlight how nanophotonic strategies enable responses to various types of threats, offering advanced functionalities such as real–time sensing, secure authentication, and adaptive vision control. We further discuss emerging trends and future directions for nanophotonic technologies in safety–critical applications, emphasizing their potential to translate into practical implementations for sustainable and resilient societies.

Achieving accurate reconstruction of spatial pressure distributions remains a challenge for flexible robotic sensor arrays due to issues such as signal crosstalk and spatial ambiguity. This study presents a flexible sensor array based on eutectic gallium-indium (EGaIn) liquid metal microchannels, which enables high-fidelity shape reconstruction through a combined theoretical and algorithmic framework. We establish a resistance-sum model integrated with a bipartite graph mapping to theoretically analyze and guarantee uniqueness in pressure localization. Experimental and simulation results demonstrate that single-point and continuous multi-point pressures can be uniquely localized, whereas discrete distributions may exhibit ambiguity when pressure points lack row or column continuity, such as in cross-row or cross-column patterns, due to multiple equivalent edge sets in the bipartite graph. Furthermore, we develop a threshold-based reconstruction method that significantly enhances the restoration of complex morphologies, including squares, square rings, and circles. This work provides a robust foundation for high-fidelity shape reconstruction in flexible tactile sensing practices.

The rapid evolution of neuroscience and bioelectronics has intensified the demand for highly sensitive, selective, and miniaturized biosensors capable of monitoring neurochemical activity with high spatial and temporal resolution. Among these, microfabricated thin-film biosensors have emerged as a powerful platform for the detection of neurotransmitters and small molecules, owing to their ultrathin form factor, mechanical flexibility, and compatibility with implantable systems. Design strategies, material innovations, and functional surface chemistries are now central to enabling real-time, in vivo monitoring with minimal tissue disruption and long-term stability. This review covers the recent progress in microfabricated biosensors, focusing on electrochemical, optical, acoustic, and magnetic modalities for the detection of key neurotransmitters, such as dopamine, serotonin, glutamate, and acetylcholine, as well as biologically relevant small molecules, including glucose, lactate, hydrogen peroxide, and nitric oxide. The integration of thin-film sensors for inflammatory and neurodegenerative disease biomarkers, such as cytokines (e.g., IL-6, TNF-α), amyloid-β, and tau proteins, is also discussed. Key challenges such as drift, biofouling, and signal specificity are critically examined alongside emerging solutions. Finally, current and future applications ranging from fundamental neuroscience and brain-machine interfaces to personalized medicine emphasize the potential of thin-film biosensing technologies in real-world biomedical scenarios.