Advanced Sensor Research最新文献

3D-Printable Sensors

This study investigates the development of 3D printable thermoplastic polyurethane filaments incorporating multi-walled carbon nanotubes (MWCNT) for enhanced strain-sensing capabilities. Piezoresistive structures are fabricated and tested to demonstrate the potential applicability of the custom filaments. More details can be found in article number 2300198 by Behrad Koohbor and co-workers.

Lipid Droplet Imaging

In article 2300178, Yuning Hong and co-workers present a newly developed imaging agent for cellular lipid droplets. This high-performance fluorescent dye is capable to quantify lipid droplet dynamics in live cells and reveals larger but fewer lipid droplets in fibroblasts from ME/CFS patients compared to the healthy controls, suggesting their potential application in disease study and diagnosis.

In recent years, the field of sensing technology has experienced notable advancements, where sensing devices have emerged as pivotal tools in enhancing operational efficiency, cutting costs, and bolstering security across diverse sectors. In this context, the preparation of nanoscale materials and structures, including colloidal particle synthesis and lithographic structure fabrication will be discussed. The significance of managing the interface environment in sensor designs, with nanofabrication advancements enabling the development of innovative sensing devices, is highlighted. Control over the interface environment is argued not only dictates the capability of sensor designs but also opens avenues for next-generation sensor fabrication and integration. By focusing on the interface-mediated mechanism, this approach offers a comprehensive roadmap of this research area, its challenges and potential solutions, and prospective opportunities.

Liquid levels must be monitored in almost any process involving liquids. Most level sensors are mounted inside the vessel containing the liquid. Herein, a fully screen-printed level sensor is demonstrated for external use. It consists of a vertical array of 16 pixels, each comprising a voltage divider of a positive temperature coefficient (PTC) element and a shunt resistor. The self-regulating PTC elements are heated with constant voltage. Heat flow out of the PTCs dictate their resistances and enables inference about their thermal surrounding. Water in a polypropylene container changes voltage levels by (33 ± 2) % compared to air. Applications with a glass container and household oil instead of water are also successfully tested. Both liquids yield a distinctive difference in signal and the sensor determines the height of the oil/water interface as well as the surfaces of the liquid. To further demonstrate the capabilities of the sensor, segregation of a water-oil mixture, slowed by a mixing agent, is observed in real time. This work offers an adaptable and simple alternative for external level sensing.

Corroles, a family of contracted porphyrinoids, exhibit broad chemical interactions, undergo straightforward synthetic preparation and functionalization, and enable versatile thin film deposition. These attributes render them promising candidates for use in chemical sensors. Nevertheless, the inherently limited conductivity of corrole solid films constrains their application in mass and optical sensors. Despite this impediment, there is a great interest in matching the sensitive properties of the corrole with the features of facile miniaturization and integration into low-cost electronic circuits. This work explores the possibility of directly and simply depositing conductometric polymeric films of [5,10,15-(4-aminophenyl)corrolato] copper onto interdigitated electrodes. Remarkably, the electropolymerization protocol allows the selection of the semiconductive nature (p- or n-type) of these films, yielding two distinct sensor types: the former exhibiting high sensitivity and selectivity toward nitrogen monoxide (NO) with a slight influence of relative humidity and the other manifesting a broad spectrum of sensitivities. This breakthrough lays the foundation for developing miniaturized conductometric gas detectors, nonlinear conductometric sensing elements, and electronic nose platforms based on polycorroles.

In diagnostic tools, rapid in vitro tests such as COVID-19 antigen or pregnancy tests are gaining significance for identifying various pathologies or health conditions. This shift contributes to a change in the way diagnostic efforts are carried out, emphasizing decentralized approaches that offer valuable services within communities, yielding long-term advantages for the healthcare system. Considering the substantial quantity of these tests manufactured and used annually, a straightforward manufacturing process is proposed for highly sensitive carbon electrodes designed for antibody-type biomarker sensors. This process, utilizing pad printing – an additive, low-temperature, and cost-effective method, coupled with plasma activation – has proven the electrodes capability to measure interferon gamma protein, a tuberculosis biomarker. Using electrochemical impedance spectroscopy, the electrodes display high sensitivity and are capable of measuring concentrations from 10 to 1000 pg mL⁻¹ in undiluted serum within an hour. The sensor, utilizing solely a monolayer of antibodies, achieves a performance equivalent to that of a commercial standard sandwich ELISA tested in this study.

Foreign body response is the main reason for the limited lifetime of implantable glucose biosensors. A new measurement strategy exerting minimal disturbance from the equilibrium glucose concentration in the sensor compartment has been proposed to mitigate its adverse effects on the sensor signal. Here, a new measurement strategy using automatically fabricated and robust pencil-lead-based glucose biosensors is implemented. The sensor response depends on critical parameters such as redox-polymer film thickness, film uniformity, rigidity, polymer composition, and the ratio between the enzyme and the polymer. These parameters are controlled by introducing a short-chain redox polymer, a low crosslinker amount, a short-chain electrografting agent and linker, pulse electrografting, and an automated fabrication procedure.

Using the flexibility and diversity of material and structure designs possible with 3D printing fiber technology, an all-solid photonic crystal fiber (PCF) is fabricated using borate (B₂O₃) doping. The geometry, material, and optical properties of this 3D printed PCF are characterized and analyzed using optical microscopy, scanning electron microscopy (SEM), fiber index profilometry, and Fourier transform infrared (FTIR) microscopy. Analysis demonstrates that B₂O₃ doped in fabricated PCF has experienced evaporation leading to mass loss during drawing. In addition, there is no observable difference between the structure of substrate silica (SiO₂) and the SiO₂ nanoparticles. However, microdomain differences may explain enhanced reflectance. Furthermore, a Mach–Zehnder interferometer (MZI) sensor is constructed with this 3D printed solid PCF and applied to temperature, refractive index, tensile force, and bending sensing. The specially designed 3D printed PCF has maximum temperature sensitivity up to Δλ/ΔT ≈0.075 nm °C⁻¹. When immersed in 76.34 wt.% glycerol-water solution, the sensitivity can be further improved. These results demonstrate that 3D printing fiber technology enables the custom fabrication of highly sensitive optical fiber sensors, increasing opportunities for the development of diverse and flexible sensors and devices for future internet-of-things (IoT) applications.

The development and application of Electrochemical Quartz Crystal Microbalance (EQCM) sensing to study metal electroplating, especially for energy storage purposes, are reviewed. The roles of EQCM in describing electrode/electrolyte interface dynamics, such as the electric double-layer build-up, ionic/molecular adsorption, metal nucleation, and growth, are addressed. Modeling of the QCM sensor is introduced and its importance is emphasized. Challenges of metal electrode use, including side reactions and dendrite formation, along with their mitigation strategies are reviewed. Numerous factors affecting the electroplating processes, such as electrolyte composition, additives, temperature, and current density, and their influence on the electroplated metals’ mass, structural, and mechanical characteristics are discussed. Looking forward, the need for deeper fundamental understanding and advancing simulations of the QCM signal response as a result of electroplating metal nanostructures is stressed. Further development and integration of innovative EQCM-strategies will provide unique future means to fundamentally understand and optimize metal electroplating for energy storage and application alike.

Smart hydrogel sensors, functioning as implantable devices, play a vital role in health monitoring and early warning, overcoming the limitations of conventional clinical methods to achieve direct, continuous, and precise monitoring. Widely employed across various biomedical fields, these sensors offer unique advantages for early health monitoring, ensuring direct, continuous, and highly accurate monitoring. In addition to detecting biomolecules, smart hydrogel sensors, with their flexibility and biocompatibility, monitor disease-specific markers, offer insights into disease progression, and contribute to the early identification of diseases. This article provides a comprehensive review of the types of hydrogel sensors employed in human health monitoring. The study discusses recent advancements in smart hydrogel sensor research, aiming to offer promising methods for human health monitoring. Finally, the paper outlines prospective research directions for hydrogel sensors in the field of human health monitoring. While further research and clinical validation are essential, hydrogel sensors are poised to play a pivotal role in clinical applications, furnishing people with accurate and continuous health monitoring.