Ultrasensitive Flexible Temperature Sensors Based on Thermal-Mediated Ions Migration Dynamics in Asymmetrical Polymer Bilayers.

Accurately acquiring crucial data on the ambient surroundings and physiological processes delivered via subtle temperature fluctuation is vital for advancing artificial intelligence and personal healthcare techniques but is still challenging. Here, we introduce an electrically induced cation injection mechanism based on thermal-mediated ion migration dynamics in an asymmetrical polymer bilayer (APB) composed of nonionic polymer and polyelectrolyte layers, enabling the development of ultrasensitive flexible temperature sensors. The resulting optimized sensor achieves ultrahigh sensitivity, with a thermal index surpassing 10,000 K-1, which allows identifying temperature differences as small as 10 mK with a sensitivity that exceeds 1.5 mK. The mechanism also enables APB sensors to possess good insensitivity to various mechanical deformations─features essential for practical applications. As a proof of concept, we demonstrate the potential impact of APB sensors in various conceptual applications, such as mental tension evaluation, biomimetic thermal tactile, and thermal radiation detection.

A CRISPR/Cas12a-assisted bacteria quantification platform combined with magnetic covalent organic frameworks and hybridization chain reaction.

The total bacterial count is an important indicator of food contamination in food safety supervision and management. Recently, the CRISPR/Cas12a system integrated with nucleic acid amplification has increasingly shown tremendous potential in microorganism detection. However, a general quantification strategy for total bacteria count based on the CRISPR/Cas12a system has not yet been developed. Herein, we established a sensitive bacterial quantification strategy based on the CRISPR/Cas12a system combined with magnetic covalent organic frameworks (MCOFs) and hybridization chain reaction (HCR). MCOFs acted as a carrier, adsorbing the ssDNA as HCR trigger sequence through π-π stacking. Then, the HCR circuit produces DNA duplexes containing the PAM sequences that activate the trans-cleavage activity of Cas12a for further signal amplification. Under the optimal conditions, the proposed method can quantify total bacteria in 50 min with a minimum detection concentration of 10 CFU/mL. The successful applications in food samples confirmed the feasibility and broad application prospects.

Wearable Temperature Sensor with High Resolution for Skin Temperature Monitoring.

Flexible temperature sensors with high resolution and good reliability under deformation are a major research focus for wearable electronic devices for skin temperature monitoring. In this study, a fiber-like temperature sensor is fabricated by in situ growing poly(3,4-ethylenedioxythiophene) (PEDOT) on the surface of thermoplastic polyurethane (TPU) fiber. The temperature sensor achieves a high sensitivity of 0.95%·°C-1 with a high linearity between 20 and 40 °C. Most importantly, the sensor achieves a high temperature resolution of 0.2 °C. Due to its structure, the temperature-sensitive fiber is easily embedded into textiles. By sewing the fiber into normal textiles in an S-shape, the interference of strain can be nearly avoided, even when the textile is stretched to 140%. Also, the obtained sensors can monitor skin temperature during exercise, which demonstrates the potential of the sensor's application in healthcare and disease diagnosis.

All-Nanofibrous Ionic Capacitive Pressure Sensor for Wearable Applications.

Currently, with the development of electronic skins (e-skins), wearable pressure sensors with low energy consumption and excellent wearability for long-term physiological signal monitoring are urgently desired but remain a challenge. Capacitive-type devices are desirable candidates for wearable applications, but traditional capacitive pressure sensors are limited by low capacitance and sensitivity. In this study, an all-nanofibrous ionic pressure sensor (IPS) is developed, and the formation of an electrical double layer at the electrode/electrolyte contact interface significantly enhances the capacitance and sensing properties. The IPS is fabricated by sandwiching a nanofibrous ionic gel sensing layer between two thermoplastic polyurethane nanofibrous membranes with graphene electrodes. The IPS has a high sensitivity of 217.5 kPa-1 in the pressure range of 0-5 kPa, which is much higher than that of conventional capacitive pressure sensors. Combined with the rapid response and recovery speed (30 and 60 ms), the IPS is suitable for real-time monitoring of multiple physiological signals. Moreover, the nanofiber network endows the IPS with excellent air permeability and heat dissipation, which guarantees comfort during long-term wearing. This work provides a viable strategy to improve the wearability of wearable sensors, which can promote healthcare and human-machine interaction applications.

Biocompatible Multifunctional E-Skins with Excellent Self-Healing Ability Enabled by Clean and Scalable Fabrication.

Electronic skins (e-skins) with an excellent sensing performance have been widely developed over the last few decades. However, wearability, biocompatibility, environmental friendliness and scalability have become new limitations. Self-healing ability can improve the long-term robustness and reliability of e-skins. However, self-healing ability and integration are hardly balanced in classical structures of self-healable devices. Here, cellulose nanofiber/poly(vinyl alcohol) (CNF/PVA), a biocompatible moisture-inspired self-healable composite, was applied both as the binder in functional layers and the substrate. Various functional layers comprising particular carbon materials and CNF/PVA were patterned on the substrate. A planar structure was beneficial for integration, and the active self-healing ability of the functional layers endowed self-healed e-skins with a higher toughness. Water served as both the only solvent throughout the fabrication process and the trigger of the self-healing process, which avoids the pollution and bioincompatibility caused by the application of noxious additives. Our e-skins could achieve real-time monitoring of whole-body physiological signals and environmental temperature and humidity. Cross-interference between different external stimuli was suppressed through reasonable material selection and structural design. Combined with conventional electronics, data could be transmitted to a nearby smartphone for post-processing. This work provides a previously unexplored strategy for multifunctional e-skins with an excellent practicality.

Proton-Conductive Gas Sensor: a New Way to Realize Highly Selective Ammonia Detection for Analysis of Exhaled Human Breath.

The analysis of exhaled human breath has great significance for early noninvasive diagnosis. Poor selectivity and strong humidity are two bottlenecks for the application of gas sensors to exhaled breath analysis. In this work, we utilized the adsorption, dissolution, ionization, and migration processes of ammonia in wet nonconjugated hydrophilic polymers to realize effective ammonia detection. The indispensable high-humidity atmosphere of exhaled breath was turned into a favorable condition for ammonia sensing. Nonconjugated polymer sensors can distinguish ammonia from most other gases because of its extremely high solubility and good ionization ability. A sensor based on poly(vinyl pyrrolidone) (PVP) could detect 0.5 ppm ammonia with an extremely high selectivity. The ammonia-sensing mechanism was thoroughly investigated by complex impedance plots (CIPs) and a quartz crystal microbalance (QCM) measurement. Finally, the potential of the PVP sensor for ammonia detection in exhaled breath was evaluated in simulated environments.

Ultrafast Response Polyelectrolyte Humidity Sensor for Respiration Monitoring.

Respiration monitoring is important for evaluating human health. Humidity sensing is a promising way to establish a relationship between human respiration and electrical signal. This work describes polymer humidity sensors with ultrafast response for respiration monitoring. The humidity-sensitive polyelectrolyte is in situ cross-linked on the substrate printed with interdigitated electrodes by a thiol-ene click reaction. The polyelectrolyte humidity sensor shows rapid water adsorption/desorption ability, excellent stability, and repeatability. The sensor with ultrafast response and recovery (0.29/0.47 s) when changing humidity between 33 and 95% shows good application prospects in breath monitoring and touchless sensing. Different respiration patterns can be distinguished, and the breath rate/depth of detection subjects can also be determined by the sensor. In addition, the obtained sensor can sense the skin evaporation in a noncontact way.

Preparation of Highly Dispersed Reduced Graphene Oxide Modified with Carboxymethyl Chitosan for Highly Sensitive Detection of Trace Cu(II) in Water.

In this article, reduced graphene oxide (RGO)/carboxymethyl chitosan (CMC) composites (RGO/CMC) were synthesized by a hydrothermal method through in-situ reduction and modification of graphene oxide (GO) in the presence of CMC. An electrochemical sensor for the determination of Cu(II) by differential pulse anodic stripping voltammetry (DPASV) was constructed by an electrode modified with RGO/CMC. The fabricated electrochemical sensor shows a linear range of 0.02⁻1.2 µmol·L-1, a detection limit of 3.25 nmol·L-1 (S/N = 3) and a sensitivity of 130.75 µA·µmol·L-1·cm-2, indicating the sensor has an excellent detection performance for Cu(II).

High Sensitive Sensor Fabricated by Reduced Graphene Oxide/Polyvinyl Butyral Nanofibers for Detecting Cu (II) in Water.

Graphene oxide (GO)/polyvinyl butyral (PVB) nanofibers were prepared by a simple electrospinning technique with PVB as matrix and GO as a functional nanomaterial. GO/PVB nanofibers on glassy carbon electrode (GCE) were reduced through electrochemical method to form reduced graphene oxide (RGO)/PVB nanofibers. The morphology and structure of GO/PVB nanofiber were studied by scanning election microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR). RGO/PVB modified GCE was used for fabricating an electrochemical sensor for detecting Cu (II) in water. The analysis results showed that RGO/PVB modified GCE had good analytical results with the linear range of 0.06-2.2 µM, detection limit of 4.10 nM (S/N = 3), and the sensitivity of 103.51 µA·µM(-1)·cm(-2).

Influences of h on the adsorption of a single ag atom on si(111)-7 × 7 surface.

The adsorption of a single Ag atom on both clear Si(111)-7 × 7 and 19 hydrogen terminated Si(111)-7 × 7 (hereafter referred as 19H-Si(111)-7 × 7) surfaces has been investigated using first-principles calculations. The results indicated that the pre-adsorbed H on Si surface altered the surface electronic properties of Si and influenced the adsorption properties of Ag atom on the H terminated Si surface (e.g., adsorption site and bonding properties). Difference charge density data indicated that covalent bond is formed between adsorbed Ag and H atoms on 19H-Si(111)-7 × 7 surface, which increases the adsorption energy of Ag atom on Si surface.

[Current trends in emergency triage in Taiwan: the five-level triage system].

An ideal triage system should accurately and quickly sort patients according to seriousness of diseases, and ensure that patients in emergency departments (EDs) get adequate management in an appropriate medical environment. Recently, EDs throughout the world have been confronting overcrowding, and are developing a five-level triage system to solve the problems that this presents. Taiwan EDs have used the Taiwan triage system (TTS) since 1999 until recently. In order to follow the trend of the times, EDs in Taiwan adjusted the four-level TTS to a five-level system, and built a computer system which is reliable and effective. This article reviews the literature about emergency triage systems, and describes the differences between the four-level and five-level systems, exploring the reliability, effectiveness, and outcomes of triage systems. Taiwan nurses might treat this article as a basis for reflection on the importance of the five-level triage system.