Advanced Sensor Research最新文献

Amyloids are protein aggregates implicated in both physiological functions and pathological conditions, including neurodegenerative diseases. Their polymorphic nature, dynamic aggregation behavior, and isoform complexity present significant challenges for detection and characterization. Traditional lock-and-key sensing methods often fall short in capturing this heterogeneity. Array-based sensing has emerged as a powerful alternative, leveraging cross-reactive sensors and multivariate data analysis to generate distinct response patterns or “fingerprints” for amyloids. This review highlights recent advances in arrays based on chemical sensors including colorimetric, fluorescent, and nanoparticle-based, capable of discriminating amyloid isoforms, aggregation states, and polymorphs with high sensitivity and accuracy. The integration of machine learning techniques and neural networks, which enhance pattern recognition and predictive accuracy, even in complex biological matrices, is discussed. Notably, multidimensional approaches expand the analytical power of single-sensor systems by exploiting excitation/emission spectral diversity. These innovations underscore the potential of array-based platforms for early diagnosis, mechanistic studies, and therapeutic monitoring of amyloid-related diseases. As the field evolves, combining sensor diversity with advanced computational tools promises to transform amyloid detection into a scalable and clinically relevant technology.

This work presents a highly sensitive, label-free, and redox probe-free electrochemical sensor for human serum albumin (SA) based on a molecularly imprinted polymer (MIP) of electropolymerized poly(azo-Bismarck Brown Y) on FTO electrodes. Successful imprinting creating specific recognition sites is confirmed spectroscopically and electrochemically. Comparative Electrochemical Impedance/Capacitance Spectroscopy (EIS/ECS) studies between the MIP and a non-imprinted polymer (NIP) demonstrated effective molecular recognition through distinct interfacial changes upon SA rebinding. Detailed EIS/ECS analysis using capacitance and kinetic parameters elucidated the specific binding mechanism versus non-specific effects at the electrochemical interface. Excellent analytical performance is achieved using real capacitance measurements at 0.1 Hz, yielding a linear response to log[SA] (0.25–3.0 ng mL⁻¹) and an ultralow limit of detection (LOD) of 0.02 ng mL⁻¹. Isotherm analysis indicated complex binding involving both specific recognition and non-specific adsorption. The sensor exhibits good selectivity against common interferents, although significant hemoglobin interference is observed at high concentrations. This study validates a robust, highly sensitive, probe-free MIP-capacitance sensor platform suitable for bioanalytical applications requiring trace biomarker quantification.

The next generation of wearable biomedical devices demands materials that behave like soft skin, stretchable, self-healing, and capable of continuous, high-fidelity sensing. Conductive hydrogels embody this vision, merging electronic function with biological compatibility. However, low cost, high elasticity with prompt self-healing capabilities and real-time sensing within single hydrogel systems remain challenging. Here, a soft highly stretchable, UV-curable hydrogel system engineered from polyvinyl alcohol (PVA), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylamide (AM), N,N′-methylenebisacrylamide (MBA), and photo-initiator, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959) is reported. The synthesized hydrogel exhibits exceptional mechanical and functional performance, including ultra-high stretchability up to 1000%, autonomous self-healing within 3 s, and mechanical stability over 1000 cycles at 20% strain. It also delivers a rapid electromechanical response, with a response time of 414 ms and recovery time of 460 ms, enabling real-time monitoring of joint and muscle motion. Furthermore, the sensor delivered reliable and repeatable signal outputs when integrated onto divers’ anatomical sites, including the finger and wrist, effectively capturing complex motion dynamics. Overall, this study presents a scalable, low-cost, and environmentally friendly fabrication route for hydrogel-based sensors, advancing the way for next-generation wearable healthcare technologies.

Wastewater-based epidemiology (WBE) has emerged as a significant tool for early infection detection during the COVID-19 pandemic, enabling timely diagnosis and effective control. However, conventional methods for sample transport and storage rely on cold chain logistics, which increase costs and limit accessibility. This study presented a portable and user-friendly strategy for room-temperature storage of RNA in wastewater using FTA Elute cards. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis demonstrated a 15.4% recovery of the original RNA with cards, compared to only 0.5% recovery without cards. Stability assessments under room temperature, -4 °C, and -20 °C confirmed that RNA retained detectability for over one month, with enhanced preservation at lower temperatures. Furthermore, FTA Elute cards exhibited good recovery for SARS-CoV-2, influenza A, and influenza B in spiked wastewater. This work provides a promising solution for RNA preservation and transport in environmental matrices without cold chain dependency.

Rapid and accurate detection of fentanyl in unknown products and aqueous samples can find the unexpected existence of the toxic chemical and assist law enforcement. In this paper, novel colorimetric biosensors for fentanyl and one of its metabolites, norfentanyl, are designed and fabricated by incorporating an enzyme-linked immunosorbent assay (ELISA) onto three dimensionally macroporous framework melamine foam (MF). The MF-based ELISA sensors (f-ELISA) have performance features of ultrahigh sensitivity, selectivity, and on-site detection without using any laboratory instruments. The lowest visually distinguishable concentration of fentanyl in wastewater is 0.005 mg L⁻¹ by naked eye and can be further improved to 0.001 mg L⁻¹ with the aid of a smartphone. Furthermore, by increasing sample volume, the sensitivity of the f-ELISA sensor can reach naked-eye detection of fentanyl at concentrations as low as 0.0005 mg L⁻¹, a volume-responsive signal enhancement, and a special structural advantage provided by the macroporous structure of the foam. The norfentanyl f-ELISA sensor can reveal a lowest visually distinguishable concentration of 0.001 mg L⁻¹ in PBS buffer for both naked-eye and smartphone analysis. The new biosensors can overcome limitations of current techniques in detecting fentanyl and its derivatives in fluids and are suitable for on-site use.

Microelectromechanical system (MEMS) sensors based on piezoresistive elements are widely used in various applications due to their high sensitivity and compact size. Traditionally, silicon-based MEMS devices have been fabricated using lithography-based processes, with piezoresistive layers formed through thermal diffusion or ion implantation. However, these processes involve complex fabrication workflows. In response, laser fabrication techniques, such as laser micromachining and laser annealing-based impurity diffusion, have attracted attention. In this study, a laser-based approach for fabricating a silicon piezoresistive cantilever using nanosecond-pulse laser annealing is proposed. The proposed process integrates two steps: localized laser annealing for impurity doping and the formation of a partially 3D cantilever structure through laser cutting and etching. All the fabrication steps are performed using a single-laser processing system, enabling direct-write patterning and automatic alignment of the piezoresistive layer with the sensor structure without lithography. In this paper, the effectiveness of the proposed method is evaluated through electrical and mechanical characterizations of the fabricated sensor. The fabricated piezoresistive layer exhibits a gauge factor exceeding 15, indicating that the sensor is sufficiently effective for practical use.

Molecularly imprinted polymers (MIPs) are synthetic alternatives to biological recognition elements like antibodies and are commonly used in developing electrochemical biosensors. However, comprehensive mechanistic studies of electrochemical detection methods on identical platforms remain scarce. This study fills this gap by creating an electropolymerized MIP (e-MIP) on a single electrode (e-MIP/SE) and systematically comparing differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) for protein sensing. Cystatin-C (Cys-C) is used as a model protein for both molecular imprinting and sensing. Polybithiophene-based recognition layers are directly formed on gold electrodes using a carboxylic acid-derivatized bithiophene crosslinker and a bithiophene monomer under potentiostatic conditions. Morphological and spectroscopic analyses confirm the uniformity of the functional cavity-enriched e-MIP films, which are ≈2.5 µm thick. The electrochemical comparison shows that DPV outperforms EIS, with detection and quantification limits of 0.19 µg mL⁻¹ (≈15 nM) and 0.64 µg mL⁻¹ (≈49 nM), respectively, and excellent linearity (R² = 0.99). The superior performance of DPV results from an enhanced signal-to-noise ratio due to suppression of capacitive current. Overall, this work provides a mechanistic understanding of electrochemical protein detection strategies using e-MIP/SEs, employing a methodology adaptable for detecting various protein targets.

A novel inorganic–organic nanocomposite material composed of multi-walled carbon nanotubes (MWCNTs), polyoxometalates (POMs), and aptamers is presented for the electrochemical detection of target molecules in aqueous environments. The responsive POM–aptamer units are synthesized via a strain-promoted azide–alkyne cycloaddition (SPAAC) reaction, covalently linking a single-stranded DNA (ssDNA) aptamer to the Lindqvist-type hexavanadate [V₆O₁₃((OCH₂)₃CCH₂N₃)₂]²⁻ (V₆-N₃) through a triazole bridge. These conjugates are immobilized onto amine-functionalized MWCNTs and drop-casted onto a platinum microelectrode surface to form a “Pt//MWCNT/POM–aptamer” heterostructure. The sensor is evaluated using diclofenac, a pharmaceutical pollutant, as a model analyte. By combining the molecular recognition capabilities of aptamers with the redox properties of POMs and the excellent electrical conductivity of MWCNTs, the hybrid sensor demonstrates significantly enhanced electrochemical sensitivity. This sensing platform shows great potential for application in decentralized medical devices for rapid ex-vivo diagnostics of complex biological matrices such as blood.

Human-Machine Interface

In article 2500012, Gursel Alici, and co-workers introduce a textile-based micro-structured pressure sensor with excellent sensitivity, resolution, linearity, and accuracy. Integrated into a 4-channel capacitive-based force myography (cFMG) armband, this wearable system enables accurate muscle activity monitoring and hand gesture recognition for advanced assistive devices and interactive human-machine interface (HMI) applications.