Advanced Sensor Research最新文献

Triboelectric Based Face Mask

In article 2400114, Mustafa Ordu and co-workers report a smart triboelectric face mask for real-time monitoring of human breathing rate and breathing conditions. A triboelectric fiber is integrated with the smart mask. The superior sensitivity of the face mask is achieved by the enhancement of triboelectric properties of thermally drawn polyvinylidene fluoride (PVDF) with the addition of molybdenum disulfide which modulates the electroactive phase behaviors of PVDF.

Electrochemical Biosensors

Accessible diagnostics are essential to maintain public health and prevent the spread of infectious disease. High-quality disposable gold electrodes are reported that enable cost-effective biosensing. These electrodes are readily modified with DNA, and they support the sensitive monitoring of protein activity. More details can be found in article 2400058 by Ariel L. Furst and co-workers.

Smart hydrogels hold great promise as sensing elements that can be tailored to respond to a wide array of biomarkers and can be integrated with different readout modalities. However, a major challenge with these sensors is response time, which depends on the hydrogel swelling behavior and is limited by diffusion. While geometrical miniaturization can accelerate response time, it often requires complex readout systems to detect volume changes, which is detrimental for use in point-of-need (PoN) applications. This study introduces a novel approach for hydrogel-based platforms that realizes important PoN requirements such as sensitivity, cost-effectiveness, instrument-free, and fast response time. The proposed sensing mechanism involves constraining a hydrogel strand at both ends and utilizing a visually observable buckling behavior instead of directly measuring a volume change. The sensing principle is validated by measuring glucose, an important biological analyte, and examines measurement repeatability, response time, sensitivity, and dynamic range. The performance is also demonstrated in blood and serum. The effects of design parameters such as strand length and diameter on sensor performance are also investigated. This new sensor offers a straightforward visual readout without requiring complex instrumentation, paving the way for more accessible and affordable PoN devices.

Real-time monitoring of public safety, individual health, and environmental conditions relies on accurate continuous data collected by gas sensors, which provide users with cost-effective insights to support informed decision-making. This study presents an innovative approach that simplifies the manufacturing process of nanowire (NW)-based gas sensors by enabling direct electrodeposition of NW crystals on various substrates, such as silicon wafers and polyethylene terephthalate (PET). Copper 7,7,8,8-Tetracyanoquinodimethane (CuTCNQ), a charge-transfer complex, is electrodeposited directly onto photolithographically patterned interdigitated triangle-tip electrodes and functions as a chemiresistive gas sensor that responds to ammonia gas through charge interactions. The sensor's performance can be precisely controlled using electrochemical techniques, allowing for tailored sensitivity across different concentration ranges. To enhance the practical application of this technology, a flexible, near-field communication-based passive tag is developed by integrating the CuTCNQ gas sensor with a flexible printed circuit board. This device enables on-demand ammonia concentration analysis and operates battery-free and wireless through mobile phone scanning. This capability is crucial for wearable or industrial devices and aligns with the increasing demand for robust environmental monitoring solutions. This approach represents a significant step forward in improving both human health and environmental protection through accessible and efficient gas sensing technology.

Printable and wearable plant sensors offer an approach for collecting critical environmental data at high spatial resolution to understand plant conditions and aid land management practices. Here, screen printed capacitive devices that can measure relative humidity (RH) directly at the plant-environment interface, are demonstrated in an ultra-thin (<6 µm) form factor. Using screen printing and a temporary tattoo transfer process, a simple technique is established to: 1) enclose printed electronic features between two layers of ethyl cellulose (EtC), 2) mount printed microparticle carbon-based electronics onto a variety of plant structures, and 3) dramatically increase the capacitance and sensitivity for humidity sensors when compared to unencapsulated devices. This sandwich tattoo capacitor (STC) platform exhibits an RH sensitivity up to 1000 pF/%RH and stability while mounted to living plant leaves over several days. Electrochemical impedance spectroscopy (EIS) validates the formation of electric double layers within the EtC films that encapsulate the printed electrodes providing tunable capacitance values based on the ionic concentration of the device transfer fluid.

Biorecognition elements immobilized into nanopores have transformed point-of-care (POC) diagnostics by converting molecular interactions into electrical and fluorescent signals.This study introduces Bio-Sensei, a high-throughput screening (HTS) microfluidic platform based on nanopore biosensing. Integrating a robotic sampler, electrochemical, and fluorescence setup, Bio-Sensei operates as an Internet of Things (IoT) platform with integrated data analysis. The platform's utility is demonstrated on functionalized with an amino terminal Cu(II)- and Ni(II)-binding (ATCUN) peptide ion track-etched membrane. Automated testing achieves a significantly higher F-stat value than the critical threshold, while unsupervised clustering reveals optimal nanopores pore size. The biosensor demonstrates remarkable stability, selectivity, and sensitivity with detection limits of 10⁻⁶ using fluorescence and 10⁻¹⁵ M using cyclic voltammetry measurements. Combining these methods enhances machine learning models for Cu²⁺ concentration prediction, achieving receiver operating characteristic area under the curve values exceeding 95%.

Isomer discrimination is of paramount importance across various sectors, including pharmaceuticals, agriculture, and the food industry, owing to their unique physicochemical characteristics. Because of their extremely similar characteristics, traditional analytical methods fail or encounter severe limitations in isomer discrimination. To overcome this grand challenge, a novel sensing strategy is proposed based on surface-enhanced Raman scattering (SERS) substrates (i.e., plasmonic platforms) combined with machine learning algorithms. These plasmonic platforms exhibit exceptional signal uniformity across wide regions and sensitivity, enabling the discrimination of structural isomers (hydroquinone, resorcinol, pyrocatechol), geometric isomers ((Z/E)-stilbene, (Z/E)-resveratrol), and optical isomers (R/S-ibuprofen). Notably, for the analysis of optical isomers, 1-naphthalenethiol is employed as a probe to facilitate specific isomer orientation on the surface of the plasmonic platform through, for the first time, π–π interactions. The integration of machine learning methodologies, such as Partial Least Squares Regression and Artificial Neural Networks, significantly enhances both quantitative analysis and classification accuracy, achieving detection limits as low as 2 × 10⁻⁸ m. Validation with commercially available ibuprofen samples shows excellent agreement with traditional circular dichroism results, highlighting the method's robustness and precision. The strategy provides a versatile, ultrasensitive, and reliable solution for isomer discrimination, with broad applications in pharmaceuticals, environmental monitoring, and clinical diagnostics.

Biomolecular sensing is routinely implemented in healthcare industries for disease diagnostics. Copper nanoparticles efficiently mimic peroxidase, which is needed for efficient glucose and glutathione sensing. However, bare copper nanoparticles are toxic to humans, therefore, anchoring materials are needed to prevent health hazards. Among the carbon-based anchoring materials, graphene and its derivatives have already been implemented. However, due to poor C–Cu interaction, copper incorporation is inefficient in those systems, which necessitates the exploration of new suitable anchoring platforms. Nitrogen-rich carbon nitride C₃N₆ with edge nitrogen atoms and plenty of in-built vacancy sites in its lattice, apart from its facile synthesis, low cost, scalable production, and non-toxic nature; offers excellent candidature for this purpose. Cu-loaded mC₃N₆ (Cu-mC₃N₆) nanozyme is synthesized employing hard silica template SBA-15 and aminoguanidine hydrochloride and hydrated copper nitrate. First, peroxidase-like activity is investigated for Cu-mC₃N₆ nanozyme with chromogenic 3,3′,5,5′- tetramethylbenzidine (TMB) dye, followed by calorimetric detection of glutathione and glucose. Edge nitrogen active sites in the mC₃N₆ accommodate higher copper loading, resulting in enhanced peroxidase-like activity and glutathione biosensing performance with a low detection limit of 0.42 ppm. It is believed that the present research will inspire the development of future-generation nanozymes.