Advanced Sensor Research最新文献

The synergy resulting from the high conductivity of graphene and catalytic properties of metal nanoparticle has been a resource to improve the activity and functionality of electrochemical sensors. This work focuses on the simultaneous synthesis of copper nanoparticles (CuNPs) and laser-induced graphene (LIG) derived from paper, through a one-step laser processing approach. A chromatography paper substrate with drop-casted copper sulfate is used for the fabrication of this hybrid material, characterized in terms of its morphological, chemical, and conductive properties. Appealing conductive properties are achieved, with sheet resistance of 170 Ω sq⁻¹ being reached, while chemical characterization confirms the simultaneous synthesis of the conductive carbon electrode material and metallic copper nanostructures. Using optimized laser synthesis and patterning conditions, LIG/CuNPs-based working electrodes are fabricated within a three-electrode planar cell, and their electrochemical performance is assessed against pristine LIG electrodes, demonstrating good electron transfer kinetics appropriate for electrochemical sensing. The sensor's ability to detect glucose through a non-enzymatic route is optimized, to assure good sensing performance in standard samples and in artificial sweat complex matrix.

Research on implantable glucose biosensors is driven by the need for innovative medical devices for continuous glucose monitoring in patients with diabetes mellitus. However, biosensor sterilization is a step that is widely omitted during the process of innovation. To compare the effects of gamma irradiation and chemical treatment with ethylene oxide (carbon microarray electrodes are fabricated, functionalized with glucose oxidizing enzymes (cellobiose dehydrogenase CDH or glucose oxidase GOx), and coated with a specifically designed zwitterionic polymer prior to the sterilization step. Cyclic voltammetry in the presence of 100 mm glucose of the biosensors before and after sterilization shows that gamma irradiation with a low radiation rate (25 kGy, 260 Gy h⁻¹) does not induce a sensor performance loss, unlike the EtO treatment. In addition, no cytotoxic by-products are released after gamma sterilization. Based on these results obtained with both glucose oxidizing enzymes (CDH and GOx), gamma irradiation of the glucose biosensors with a low dose rate is preferable to exposure to EtO for biosensor terminal sterilization.

 Recently, significant progress has been made regarding conductive hydrogels-based flexible sensors in health detection, electronic skin, soft robots, etc. However, the requirement of bonding with the substrate through the adhesive tape, brokenness sensitivity, and degradation of performance under low-temperature environments, strongly limit the wide applications of conductive hydrogels in flexible sensors. To solve these problems, this study introduces lithium chloride (LiCl) into poly(vinyl alcohol)/tannic acid/polyacrylamide (PVA/TA/PAM) hydrogels to endow the hydrogels with excellent conductivity and antifreeze properties. In addition, the addition of tannic acid (TA) and zwitterionic 3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate (SBMA) enables the hydrogel to have good self-healing performance (after 72 h of healing at 20 °C, the healing efficiency of fracture stress is 24%, and the healing efficiency of fracture strain is 52%) and adhesion (the adhesion strength to paper at 20 °C is 14.12 KPa). The sensors based on PVA/TA/PAM composite hydrogels exhibit good sensibility, stability, and durability, and can respond quickly to human joint activities (finger bending, wrist bending, arm bending, and leg bending). Therefore, the multifunctional PVA/TA/PAM composite hydrogel demonstrates significant potential for applications in flexible strain sensors under extreme environments.

This mini-review explores the evolution of image sensors, essential electronic components increasingly integrated into daily life. Traditional manufacturing methods for image sensors and photodetectors, employing high carbon footprint techniques like thermal evaporation and chemical vapor deposition, are being replaced by environmentally conscious solution processing. Organic and Colloidal Quantum Dot-based image sensors emerge as promising candidates, aligning with the shift toward solution-based device integration. This review provides insights into the working principles of photodetectors and image sensors, summarizing relevant materials and fabrication approaches. Additionally, it delves into the detailed exploration of pixelated patterning techniques and their potential applications in the realm of solution-processed image sensor fabrication.

Smart Monitoring Hydrogel Sensors

In article 2400003, Hong Zhang, Yang Luo, and co-workers report advancements in smart hydrogel sensors for health monitoring and early warning. Leveraging the biocompatible properties of hydrogels, these sensors facilitate continuous, precise monitoring of various physiological parameters. The review highlights the mechanisms of these sensors, their benefits for medical diagnostics, and directions for future research. It also explores their potential in various medical scenarios, such as disease monitoring and management, underscoring the need for further clinical validation.

In this study, nonlinear damping is introduced as the fourth dimension in the operation of a fiber tip optomechanical anemometer. The flow sensing element, featuring a 3D rotor measuring 110 µm in diameter and fabricated through a two-photon nanomachining process, is monolithically integrated onto the cleaved face of the optical fiber, which serves as an integrated waveguide. As the rotor encounters airflow, it spins, and mirrors on its blades reflect light across the fiber core at each pass. This setup permits precise measurement of gaseous fluid flow with minimal sensor footprint at the point of detection and accommodates a variety of optical sources and measurement apparatuses without the need for specific wavelength or broad-spectrum capabilities. To stabilize the rotation of the rotor and facilitate consistent frequency-domain analysis, a polydimethylsiloxane hydrocarbon stabilizing agent is infused into the gap between the rotor and stator of the sensing element via dual-function microfluidic channels. This enhancement allows for the measurement of gaseous nitrogen flow rates from 10 to 20 liters per minute (LPM), with a consistent periodic response. Comprehensive characterizations of the fiber tip anemometer are presented with and without the stabilizing medium, demonstrating its crucial role in regulating the dynamics between the rotor and the stator.

This study introduces a novel fluorescent light-up electrospun membrane, integrating PbBr₂, which serves as an exceptionally selective probe for the detection of cesium ions (Cs⁺). Leveraging the superior optical properties of CsPbBr₃ perovskite nanocrystals (PNCs), the researchers employ electrospinning technology to fabricate a test strip, namely PbBr₂@polyacrylonitrile (PbBr₂@PAN) nanofiber membranes, capable of swiftly detecting Cs⁺ in water merely by observing changes in the nanocrystals' luminescence with the naked eye. By the introduction of NH₄⁺-modified montmorillonite (NH₄⁺-MMT), PbBr₂-MT@PAN nanofiber membranes is obtained. The selectivity and sensitivity to Cs⁺ can be further improved because NH₄⁺-MMT endows PbBr₂-MT@PAN nanofiber membranes with the hydrophilic property and selective adsorption toward Cs⁺ ions. The membrane's fabrication is simple, scalable, and cost-effective, with high cesium selectivity and sensitivity down to 44 ppb. This innovation enables efficient, on-site cesium monitoring critical for environmental safety and nuclear waste management.

In medical diagnosis, detecting disease biomarkers at ultra-low concentrations is vital. Point-of-care (POC) diagnostics require rapid detection, live monitoring, high sensitivity, low detection threshold, and cost-effectiveness. Carbon-based nanomaterials (CBNs) are promising due to their large surface-to-volume ratio, conductivity, biocompatibility, and stability, making them ideal for biosensors. Recent advancements in CBN applications, including biosensing, drug delivery, and cancer therapy, highlight their potential in enhancing detection sensitivity and specificity. Electrochemical sensors and biosensor platforms using carbon nanocomposites are pivotal in diagnostics. This review explores the current state and future challenges of CBN integration in POC settings, envisioning a transformative impact on healthcare diagnostics and therapeutics.

A novel approach is demonstrated to identify glucose concentration in aqueous solutions based on the combined effect of its frequency-dependent interaction with microwaves propagating in graphene channels and the modification of graphene radio frequency (RF) conductivity caused by physisorbed molecules. This approach combines broadband microwave sensing and chemical field effect transistor sensing in a single device, leading to information-rich, multidimensional datasets in the form of scattering parameters. A sensitivity of 7.30 dB(mg/L)⁻¹ is achieved, significantly higher than metallic state-of-the-art RF sensors. Different machine learning methods are applied to the raw, multidimensional datasets to infer concentrations of the analyte, without the need for parasitic effect removals via de-embedding or circuit modeling, and a classification accuracy of 100% is achieved for aqueous glucose solutions with a concentration variation of 0.09 mgL⁻¹.