scholarly journals Soft and ion-conducting hydrogel artificial tongue for astringency perception

2020 ◽  
Vol 6 (23) ◽  
pp. eaba5785 ◽  
Author(s):  
Jeonghee Yeom ◽  
Ayoung Choe ◽  
Seongdong Lim ◽  
Youngsu Lee ◽  
Sangyun Na ◽  
...  
Keyword(s):  
Flexible Substrate ◽  
High Sensitivity ◽  
Humanoid Robots ◽  
Fast Response ◽  
Nanoporous Structure ◽  
Proof Of Concept ◽  
Human Tongue ◽  
Wide Range ◽  
Ion Conducting ◽  
Monitoring Devices

Artificial tongues have been receiving increasing attention for the perception of five basic tastes. However, it is still challenging to fully mimic human tongue–like performance for tastes such as astringency. Mimicking the mechanism of astringency perception on the human tongue, we use a saliva-like chemiresistive ionic hydrogel anchored to a flexible substrate as a soft artificial tongue. When exposed to astringent compounds, hydrophobic aggregates form inside the microporous network and transform it into a micro/nanoporous structure with enhanced ionic conductivity. This unique human tongue–like performance enables tannic acid to be detected over a wide range (0.0005 to 1 wt %) with high sensitivity (0.292 wt %−1) and fast response time (~10 s). As a proof of concept, our sensor can detect the degree of astringency in beverages and fruits using a simple wipe-and-detection method, making a powerful platform for future applications involving humanoid robots and taste monitoring devices.

scholarly journals Locally Controlled Sensing Properties of Stretchable Pressure Sensors Enabled by Micro-Patterned Piezoresistive Device Architecture

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6588
Author(s):  
Jun Ho Lee ◽  
Jae Sang Heo ◽  
Keon Woo Lee ◽  
Jae Cheol Shin ◽  
Jeong-Wan Jo ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Silver Nanowires ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Fast Response ◽  
Large Area ◽  
Site Specific ◽  
Sensing Properties ◽  
Sensing Range ◽  
Wide Range

For wearable health monitoring systems and soft robotics, stretchable/flexible pressure sensors have continuously drawn attention owing to a wide range of potential applications such as the detection of human physiological and activity signals, and electronic skin (e-skin). Here, we demonstrated a highly stretchable pressure sensor using silver nanowires (AgNWs) and photo-patternable polyurethane acrylate (PUA). In particular, the characteristics of the pressure sensors could be moderately controlled through a micro-patterned hole structure in the PUA spacer and size-designs of the patterned hole area. With the structural-tuning strategies, adequate control of the site-specific sensitivity in the range of 47~83 kPa−1 and in the sensing range from 0.1 to 20 kPa was achieved. Moreover, stacked AgNW/PUA/AgNW (APA) structural designed pressure sensors with mixed hole sizes of 10/200 µm and spacer thickness of 800 µm exhibited high sensitivity (~171.5 kPa−1) in the pressure sensing range of 0~20 kPa, fast response (100~110 ms), and high stretchability (40%). From the results, we envision that the effective structural-tuning strategy capable of controlling the sensing properties of the APA pressure sensor would be employed in a large-area stretchable pressure sensor system, which needs site-specific sensing properties, providing monolithic implementation by simply arranging appropriate micro-patterned hole architectures.

Gas Sensing Properties of TiO2 and SnO2 Nanopowders Obtained through Gel Combustion

2006 ◽  
Vol 45 ◽  
pp. 1828-1833
Author(s):  
Fabio A. Deorsola ◽  
P. Mossino ◽  
Ignazio Amato ◽  
Bruno DeBenedetti ◽  
A. Bonavita ◽  
...  
Keyword(s):  
Response Time ◽  
Metal Oxides ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Fast Response ◽  
High Specific Surface Area ◽  
Research Field ◽  
Wide Range ◽  
Gel Combustion

Nanostructured semiconductor metal oxides have played a central role in the gas sensing research field, because of their high sensitivity, selectivity and low response time. Among all the processes, developed for the synthesis of nanostructured metal oxides, gel combustion seems to be the most promising route due to low-cost precursors and simplicity of the process. It combines chemical gelation and combustion, involving the formation of a gel from an acqueous solution and an exothermic redox reaction, yielding to very porous and softly agglomerated nanopowders. In this work, nanostructured tin oxide, SnO2, and titanium oxide, TiO2, have been synthesized through gel combustion. Powders showed nanometric particle size and high specific surface area. The so-obtained TiO2 and SnO2 nanopowders have been used as sensitive element of resistive λ sensor and ethanol sensor respectively, realized depositing films of nanopowders dispersed in water onto alumina substrates provided with Pt contacts and heater. TiO2-based sensors showed at high temperature good response, fast response time, linearity in a wide range of O2 concentration and long-term stability. SnO2-based sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature.

scholarly journals Wearable System for Biosignal Acquisition and Monitoring Based on Reconfigurable Technologies

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1590 ◽  
Author(s):  
Víctor Toral ◽  
Antonio García ◽  
Francisco Romero ◽  
Diego Morales ◽  
Encarnación Castillo ◽  
...  
Keyword(s):  
Law Enforcement ◽  
Ad Hoc ◽  
Proof Of Concept ◽  
Non Invasive ◽  
Qrs Complex Detection ◽  
Wide Range ◽  
Complex Detection ◽  
Sports And Physical Activity ◽  
Reconfigurable Device ◽  
Monitoring Devices

Wearable monitoring devices are now a usual commodity in the market, especially for the monitoring of sports and physical activity. However, specialized wearable devices remain an open field for high-risk professionals, such as military personnel, fire and rescue, law enforcement, etc. In this work, a prototype wearable instrument, based on reconfigurable technologies and capable of monitoring electrocardiogram, oxygen saturation, and motion, is presented. This reconfigurable device allows a wide range of applications in conjunction with mobile devices. As a proof-of-concept, the reconfigurable instrument was been integrated into ad hoc glasses, in order to illustrate the non-invasive monitoring of the user. The performance of the presented prototype was validated against a commercial pulse oximeter, while several alternatives for QRS-complex detection were tested. For this type of scenario, clustering-based classification was found to be a very robust option.

scholarly journals Graphene and its Derivatives-Based Optical Sensors

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiao-Guang Gao ◽  
Ling-Xiao Cheng ◽  
Wen-Shuai Jiang ◽  
Xiao-Kuan Li ◽  
Fei Xing
Keyword(s):  
Optical Sensors ◽  
Low Cost ◽  
High Sensitivity ◽  
Fast Response ◽  
Cell Detection ◽  
Single Cell Detection ◽  
Sensing Applications ◽  
Wide Range ◽  
Surface Enhanced Raman ◽  
Recent Developments

Being the first successfully prepared two-dimensional material, graphene has attracted extensive attention from researchers due to its excellent properties and extremely wide range of applications. In particular, graphene and its derivatives have displayed several ideal properties, including broadband light absorption, ability to quench fluorescence, excellent biocompatibility, and strong polarization-dependent effects, thus emerging as one of the most popular platforms for optical sensors. Graphene and its derivatives-based optical sensors have numerous advantages, such as high sensitivity, low-cost, fast response time, and small dimensions. In this review, recent developments in graphene and its derivatives-based optical sensors are summarized, covering aspects related to fluorescence, graphene-based substrates for surface-enhanced Raman scattering (SERS), optical fiber biological sensors, and other kinds of graphene-based optical sensors. Various sensing applications, such as single-cell detection, cancer diagnosis, protein, and DNA sensing, are introduced and discussed systematically. Finally, a summary and roadmap of current and future trends are presented in order to provide a prospect for the development of graphene and its derivatives-based optical sensors.

scholarly journals Drop-casted Graphene Oxide Love wave sensor for detection of humidity and VOCs

2016 ◽  
Vol 11 (1) ◽  
pp. 49-56
Author(s):  
I. Nikolaou ◽  
H. Hallil ◽  
B. Plano ◽  
G. Deligeorgis ◽  
V. Conedera ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Detection Limit ◽  
Love Wave ◽  
Public Awareness ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Fast Response ◽  
Detection Methods ◽  
Wide Range ◽  
Highly Sensitive Detection

The rising demand for sensitive analytical techniques have led to a great deal of research interest in the recent years, which has also generated much public awareness of health risks caused by environmental humidity and air pollution. This study reports advancements in highly-sensitive detection methods using Love wave devices fabricated from Graphene Oxide (GO). Under this, solutions of GO were prepared and used to achieve improved efficiency of the oxidation process and enhance the sensitivity of Relative Humidity (RH) and Volatile Organic Compounds (VOCs) detections. This work demonstrates that the detection limit of RH could be set very low due to the certain sensitivity levels. Similarly, GO prepared by us exhibited low detection limit for VOCs, proving the multi-functionality of GO rather than alternative sensing materials. The experiments conducted at room temperature and realized fast response and recovery times. This Love wave sensor provides high accuracy under full scale exposure of target analytes. Eventually, these ultrasensitive GO based devices can pave the way for a wide range of high-sensitivity detection applications.

scholarly journals Potentiometric Biosensing Applications of Graphene Electrode with Stabilized Polymer Lipid Membranes

2018 ◽  
Author(s):  
Georgia-Pareaskevi Nikoleli ◽  
Dimitrios P. Nikolelis ◽  
Christina G. Siontorou ◽  
Marianna-Thalia Nikolelis ◽  
Stephanos Karapetis
Keyword(s):  
Lipid Membranes ◽  
Rapid Detection ◽  
Toxic Substance ◽  
Environmental Pollutants ◽  
High Sensitivity ◽  
Fast Response ◽  
Toxic Compounds ◽  
Wide Range ◽  
Sensitivity And Selectivity ◽  
Clinical Interest

This review provides informations and details for the fabrication of biosensors that are composed from lipid membranes and have been utilized and applied to rapidly detect food toxic compounds, environmental pollutants and analytes of clinical interest. Biosensors based on polymeric lipid membranes have been used to rapidly detect a wide range of these analytes and offer several advantages such as fast response, high sensitivity and selectivity, can be portable for in the field applications, and small size. A description of the construction of these devices and their applications for the rapid detection of food toxic substance, environmental pollutants and analytes of clinical interest is provided in this review.

scholarly journals A Sprayed Graphene Pattern-Based Flexible Strain Sensor with High Sensitivity and Fast Response

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1077 ◽  
Author(s):  
Wei Xu ◽  
Tingting Yang ◽  
Feng Qin ◽  
Dongdong Gong ◽  
Yijia Du ◽  
...  
Keyword(s):  
Strain Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Strain Sensors ◽  
Biomedical Science ◽  
Gauge Factor ◽  
Experimental Conditions ◽  
Simple Method ◽  
Wide Range ◽  
Flexible Strain Sensor

Flexible strain sensors have a wide range of applications in biomedical science, aerospace industry, portable devices, precise manufacturing, etc. However, the manufacturing processes of most flexible strain sensors previously reported have usually required high manufacturing costs and harsh experimental conditions. Besides, research interests are often focused on improving a single attribute parameter while ignoring others. This work aims to propose a simple method of manufacturing flexible graphene-based strain sensors with high sensitivity and fast response. Firstly, oxygen plasma treats the substrate to improve the interfacial interaction between graphene and the substrate, thereby improving device performance. The graphene solution is then sprayed using a soft PET mask to define a pattern for making the sensitive layer. This flexible strain sensor exhibits high sensitivity (gauge factor ~100 at 1% strain), fast response (response time: 400–700 μs), good stability (1000 cycles), and low overshoot (<5%) as well. Those processes used are compatible with a variety of complexly curved substrates and is expected to broaden the application of flexible strain sensors.

Nanomaterial LaNiTiO3-Fe3O4-based peroxidase biomimetic sensor with high sensitivity

2020 ◽  
Vol 16 ◽  
Author(s):  
Yanhong Xu ◽  
Ying Sun ◽  
Qiao Feng
Keyword(s):  
Detection Limit ◽  
Low Cost ◽  
Supporting Electrolyte ◽  
High Sensitivity ◽  
Fast Response ◽  
H2o2 Concentration ◽  
Current Time ◽  
Real Samples ◽  
Wide Range ◽  
Biomimetic Sensor

Background: Hydrogen peroxide (H2O2) is widely present in various fields. And H2O2 plays quintessential role in variety of biomolecular processes. H2O2 concentration level is an essential biological parameter in monitoring and maintaining the physiological balance of a living cell, and its variation will cause some related diseases. Therefore, it is extremely significant to fabricate biosensor with low cost which can quickly, accurately and sensitively detect H2O2 in a wide range. The aims of this paper are to explore a novel electrochemical sensor with high intrinsic peroxidase-like activity, high sensitivity and stability to detect effectively H2O2 concentration in real samples. Methods: The chemical modified electrode LaNiTiO3-Fe3O4/GCE is fabricated based on nanomaterial LaNiTiO3-Fe3O4 by simply process, and its electrochemical properties are investigated in the supporting electrolyte of 0.1 M NaOH by the techniques of cyclic voltammetry and current-time curves on an electrochemical workstation with a conventional threeelectrode system. Results: LaNiTiO3-Fe3O4 nanoparticles show good peroxidase-like activity for H2O2 at a low applied potential of +0.50 V. Under the optimum conditions, the peroxidase biomimetic sensor LaNiTiO3-Fe3O4/GCE exhibits a wide linear response for H2O2 oxidation in the range of 0.05 μM - 3.0 mM (R = 0.9994) with a high sensitivity of 3946.2 μA∙mM1 ∙cm-2 and fast response time of 2 s, and the detection limit of H2O2 is found to be ca. 5.15 nM (S/N = 3). Moreover, the biosensor presents a good repeatability, stability and anti-interference. Satisfactory results were obtained when the sensor LaNiTiO3-Fe3O4/GCE is applied to determine H2O2 in real samples. All of these results provide support to practical application. Conclusion: A highly sensitive peroxidase biomimetic sensor based on LaNiTiO3-Fe3O4 with nano-scaled material is successfully explored, and shows good activity for H2O2. The proposed biosensor with simple and low cost has exhibited excellent advantages of quick response, wide linear range, low detection limit, high sensitivity, long-term stability and good anti-interference ability, which provides promising applications.

A temperature sensor based on flexible substrate with ultra-high sensitivity for low temperature measurement

2020 ◽  
Vol 315 ◽  
pp. 112341
Author(s):  
Zhaojun Liu ◽  
Bian Tian ◽  
Xu Fan ◽  
Jiangjiang Liu ◽  
Zhongkai Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Measurement ◽  
Temperature Sensor ◽  
Flexible Substrate ◽  
High Sensitivity

scholarly journals Tin Disulfide-Coated Microfiber for Humidity Sensing with Fast Response and High Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 648
Author(s):  
Aijie Liang ◽  
Jingyuan Ming ◽  
Wenguo Zhu ◽  
Heyuan Guan ◽  
Xinyang Han ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Small Diameter ◽  
High Sensitivity ◽  
Large Change ◽  
Small Variation ◽  
Response Speed ◽  
Fast Response ◽  
Tin Disulfide ◽  
Recovery Times ◽  
Response And Recovery

Breath monitoring is significant in assessing human body conditions, such as cardiac and pulmonary symptoms. Optical fiber-based sensors have attracted much attention since they are immune to electromagnetic radiation, thus are safe for patients. Here, a microfiber (MF) humidity sensor is fabricated by coating tin disulfide (SnS2) nanosheets onto the surface of MF. The small diameter (~8 μm) and the long length (~5 mm) of the MF promise strong interaction between guiding light and SnS2. Thus, a small variation in the relative humidity (RH) will lead to a large change in optical transmitted power. A high RH sensitivity of 0.57 dB/%RH is therefore achieved. The response and recovery times are estimated to be 0.08 and 0.28 s, respectively. The high sensitivity and fast response speed enable our SnS2-MF sensor to monitor human breath in real time.

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