MEMS Based Differential Scanning Calorimeter for Biomolecular Study

2018 ◽  
Author(s):  
Shifeng Yu ◽  
Shuyu Wang ◽  
Ming Lu ◽  
Lei Zuo
Keyword(s):  
Differential Scanning Calorimeter ◽  
Protein Denaturation ◽  
Flexible Substrate ◽  
High Sensitivity ◽  
Step Response ◽  
Temperature Sensitive ◽  
Microfluidic Chamber ◽  
Sample Amount ◽  
Resolution Study ◽  
Thermistor Material

This paper presented a MEMS based differential scanning calorimeter (DSC) for biomolecular characterization. In this MEMS based DSC, PDMS (Polydimethylsiloxane) and Flexdyne thin film were used to construct the microfluidic chamber. Polyimide were used to fabricate the flexible substrate and temperature sensitive vanadium oxide was used as the thermistor material. A heating stage was used to heat the sample and reference up at a certain rate. The resolution study and step response characterization indicated the high sensitivity (6.1V/W) of the device. The test with Bovine Serum Albumin (BSA) samples showed clear phase transitions and the data was confirmed to be reasonable by comparing it with the results of commercial DSC’s test. This device used 0.63uL sample amount and could complete the scanning process in 3 minutes, significantly increasing the throughput of the biomolecular thermodynamics study like protein denaturation process compared to the traditional DSC (1 to 2 hours).

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 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 Fabrication and Characterization of Humidity Sensors Based on Graphene Oxide–PEDOT:PSS Composites on a Flexible Substrate

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 148 ◽  
Author(s):  
Francisco J. Romero ◽  
Almudena Rivadeneyra ◽  
Markus Becherer ◽  
Diego P. Morales ◽  
Noel Rodríguez
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Flexible Substrate ◽  
High Sensitivity ◽  
Cost Effective ◽  
Humidity Sensors ◽  
Good Thermal Stability ◽  
Cost Effective Method ◽  
And Performance ◽  
Stability Time

In this paper, we present a simple, fast, and cost-effective method for the large-scale fabrication of high-sensitivity humidity sensors on flexible substrates. These sensors consist of a micro screen-printed capacitive structure upon which a sensitive layer is deposited. We studied two different structures and three different sensing materials by modifying the concentration of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) in a graphene oxide (GO) solution. The results show that the aggregation of the PEDOT:PSS to the GO can modify its electrical properties, boosting the performance of the capacitive sensors in terms of both resistive losses and sensitivity to relative humidity (RH) changes. Thus, in an area less than 30 mm2, the GO/PEDOT:PSS-based sensors can achieve a sensitivity much higher (1.22 nF/%RH at 1 kHz) than other similar sensors presented in the literature which, together with their good thermal stability, time response, and performance over bending, demonstrates that the manufacturing approach described in this work paves the way for the mass production of flexible humidity sensors in an inexpensive way.

scholarly journals Sterilization Procedure for Temperature-Sensitive Hydrogels Loaded with Silver Nanoparticles for Clinical Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 380 ◽  
Author(s):  
Diana Rafael ◽  
Fernanda Andrade ◽  
Francesc Martinez-Trucharte ◽  
Jana Basas ◽  
Joaquín Seras-Franzoso ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Biomedical Applications ◽  
Gelation Time ◽  
Antimicrobial Properties ◽  
High Sensitivity ◽  
Cost Effective ◽  
Raw Material ◽  
Temperature Sensitive ◽  
Dry Heat

Hydrogels (HG) have recognized benefits as drug delivery platforms for biomedical applications. Their high sensitivity to sterilization processes is however one of the greatest challenges regarding their clinical translation. Concerning infection diseases, prevention of post-operatory related infections is crucial to ensure appropriate patient recovery and good clinical outcomes. Silver nanoparticles (AgNPs) have shown good antimicrobial properties but sustained release at the right place is required. Thus, we produced and characterized thermo-sensitive HG based on Pluronic® F127 loaded with AgNPs (HG-AgNPs) and their integrity and functionality after sterilization by dry-heat and autoclave methods were carefully assessed. The quality attributes of HG-AgNPs were seriously affected by dry-heat methods but not by autoclaving methods, which allowed to ensure the required sterility. Also, direct sterilization of the final HG-AgNPs product proved more effective than of the raw material, allowing simpler production procedures in non-sterile conditions. The mechanical properties were assessed in post mortem rat models and the HG-AgNPs were tested for its antimicrobial properties in vitro using extremely drug-resistant (XDR) clinical strains. The produced HG-AgNPs prove to be versatile, easy produced and cost-effective products, with activity against XDR strains and an adequate gelation time and spreadability features and optimal for in situ biomedical applications.

Flexible Pressure Sensor Based on Photo Paper-Molded Micro-Structural AgNWs/PDMS Electrode

2015 ◽  
Vol 748 ◽  
pp. 1-4 ◽  
Author(s):  
Li Xin Mo ◽  
Yu Qun Hou ◽  
Qing Bin Zhai ◽  
Wen Guan Zhang ◽  
Lu Hai Li
Keyword(s):  
Pressure Sensor ◽  
Silver Nanowires ◽  
Low Cost ◽  
Flexible Substrate ◽  
High Sensitivity ◽  
Low Energy ◽  
Capacitive Pressure Sensor ◽  
Micro Structure ◽  
Energy Consuming ◽  
Flexible Pressure Sensor

The novel flexible pressure sensor with skin-like stretchability and sensibility has attracted tremendous attention in academic and industrial world in recent years. And it also has demonstrated great potential in the applications of electronic skin and wearable devices. It is significant and challenging to develop a highly sensitive flexible pressure sensor with a simple, low energy consuming and low cost method. In this paper, the silver nanowires (AgNWs) as electrode material were synthesized by polyol process. The polydimethylsiloxane (PDMS) was chosen as a flexible substrate and polyimide (PI) film as dielectric layer. The AgNWs based electrode was prepared in two methods. One is coating the AgNWs on photographic paper followed by in situ PDMS curing. Another one is suction filtration of the AgNWs suspension followed by glass slide transfer and PDMS curing. Then the capacitive pressure sensor was packaged in a sandwich structure with two face to face electrodes and a PI film in the middle. The sensitivity of the sensor as well as the micro-structure of the electrodes was compared and studied. The results indicate that the roughness of the electrode based on AgNWs/PDMS micro-structure plays an important role in the sensitivity of sensor. The as-prepared flexible pressure sensor demonstrates high sensitivity of 0.65kPa-1. In addition, the fabrication method is simple, low energy consuming and low cost, which has great potential in the detection of pulse, heart rate, sound vibration and other tiny pressure.

scholarly journals A Flexible Temperature Sensor for Noncontact Human-Machine Interaction

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7112
Author(s):  
Shiqi Chen ◽  
Xiaolong Han ◽  
Peng Hong ◽  
Yue Zhang ◽  
Xiangyu Yin ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Flexible Substrate ◽  
High Sensitivity ◽  
Human Machine Interaction ◽  
Temperature Changes ◽  
Intelligent Robots ◽  
Sensing Material ◽  
Interaction Interface ◽  
Application Potential ◽  
Machine Interaction

Flexible sensors have attracted extensive attention because of their promising applications in the fields of health monitoring, intelligent robots, and electronic skin, etc. During the COVID-19 epidemic, noncontact control of public equipment such as elevators, game consoles, and doors has become particularly important, as it can effectively reduce the risk of cross-infection. In this work, a noncontact flexible temperature sensor is prepared via a simple dip-drying progress, in which poly(3,4-ethylenedioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) and printer paper served as the sensing material and the flexible substrate, respectively. We combined the highly sensitive temperature-responsive property of PEDOT:PSS with the good hygroscopicity of printer paper. The prepared sensor shows high sensitivity and good stability in noncontact sensing mode within the temperature range of 20–50 °C. To prove the practicability of the noncontact temperature sensor, a 3 × 2 sensing array is prepared as a noncontact human-machine interface to realize the interaction between player and “Pound-A-Mole game” and a Bluetooth car. These two demos show the sensor′s ability to perceive nearby temperature changes, verifying its application potential as a noncontact human-machine interaction interface.

scholarly journals Facile Fabrication of a Self-Healing Temperature-Sensitive Sensor Based on Ionogels and Its Application in Detection Human Breath

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 343 ◽  
Author(s):  
Fengxia Wang ◽  
Shaohui Zhang ◽  
Yunlin Zhang ◽  
Qihang Lin ◽  
Yun Chen ◽  
...  
Keyword(s):  
Electrical Property ◽  
Potential Application ◽  
High Sensitivity ◽  
Temperature Sensitive ◽  
Self Healing ◽  
Human Breath ◽  
Detection Range ◽  
Facile Fabrication ◽  
Sensitive Sensor ◽  
Healing Temperature

The biocompatible strechable ionogels were prepared by a facile solution-processed method. The ionogels showed outstanding stretchable and self-healing properties. The electrical property could revert to its original state after 4 s. The repaired ionogels could still bear stretching about 150%. Moreover, the ionogels exhibited high sensitivity and wide-detection range to temperature. The temperature-sensitive sensor could detect the human breath frequency and intensity, showing potential application in detecting disease.

A Temperature-Sensitive Hydrogel for Suppressing Oil Fire

2013 ◽  
Vol 785-786 ◽  
pp. 724-728
Author(s):  
Chun Lei Jia ◽  
Kai Tang
Keyword(s):  
Free Radical ◽  
Cooling Rate ◽  
Radical Polymerization ◽  
Differential Scanning Calorimeter ◽  
Digital Video ◽  
Free Radical Polymerization ◽  
Sodium Acrylate ◽  
Temperature Sensitive ◽  
Mass Fractions ◽  
Temperature Sensitive Hydrogel

A new attempt to suppress oil fire with a temperature-sensitive hydrogel was examed. The hydrogel were prepared by free radical polymerization methods with N-isopropy-lacrylamide (NIPAm) and Sodium acrylate (AA-Na). Different mass fractions of the aqueous hydrogen were measured by a differential scanning calorimeter (DSC) and viscosity tester. A series of gasoline fires were suppressed with hydrogel extinguishing agent B of Zhejiang University and the temperature-sensitive hydrogel respectively. The whole suppressing experiment was recorded by a digital video, four heat probes and eight thermocouples. It showed that the temperature-sensitive hydrogel has shorter extinguishment time and faster cooling rate than the hydrogel B, The extinguishing agent residual after the suppressing were observed by SEM, massive microporous structures were found in the temperature-sensitive hydrogel.

scholarly journals Direct Patterning of Carbon Nanotube via Stamp Contact Printing Process for Stretchable and Sensitive Sensing Devices

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Binghao Liang ◽  
Zian Zhang ◽  
Wenjun Chen ◽  
Dongwei Lu ◽  
Leilei Yang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Low Cost ◽  
Flexible Substrate ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Gauge Factor ◽  
Contact Printing ◽  
Target Pattern ◽  
Wearable Electronic Devices ◽  
Application Prospects

Abstract Flexible and wearable sensing devices have broad application prospects in bio-monitoring such as pulse measurement, motion detection and voice recognition. In recent years, many significant improvements had been made to enhance the sensor’s performance including sensitivity, flexibility and repeatability. However, it is still extremely complicated and difficult to prepare a patterned sensor directly on a flexible substrate. Herein, inspired by typography, a low-cost, environmentally friendly stamping method for the mass production of transparent conductive carbon nanotube (CNT) film is proposed. In this dry transfer strategy, a porous CNT block was used as both the seal and the ink; and Ecoflex film was served as an object substrate. Well-designed CNT patterns can be easily fabricated on the polymer substrate by engraving the target pattern on the CNT seal before the stamping process. Moreover, the CNT film can be directly used to fabricate ultrathin (300 μm) strain sensor. This strain sensor possesses high sensitivity with a gauge factor (GF) up to 9960 at 85% strain, high stretchability (> 200%) and repeatability (> 5000 cycles). It has been used to measure pulse signals and detect joint motion, suggesting promising application prospects in flexible and wearable electronic devices.

scholarly journals Elimination of the Slow Gating of Clc-0 Chloride Channel by a Point Mutation

1999 ◽  
Vol 114 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Yu-Wen Lin ◽  
Chia-Wei Lin ◽  
Tsung-Yu Chen
Keyword(s):  
Chloride Channel ◽  
Single Channel ◽  
High Sensitivity ◽  
Zinc Ion ◽  
Temperature Sensitive ◽  
Ion Permeation ◽  
Temperature Dependent ◽  
Dependent Inactivation ◽  
Fast Gating ◽  
Extracellular Side

The inactivation of the ClC-0 chloride channel is very temperature sensitive and is greatly facilitated by the binding of a zinc ion (Zn2+) from the extracellular side, leading to a Zn2+-induced current inhibition. To further explore the relation of Zn2+ inhibition and the ClC-0 inactivation, we mutated all 12 cysteine amino acids in the channel and assayed the effect of Zn2+ on these mutants. With this approach, we found that C212 appears to be important for the sensitivity of the Zn2+ inhibition. Upon mutating C212 to serine or alanine, the inactivation of the channel in macroscopic current recordings disappears and the channel does not show detectable inactivation events at the single-channel level. At the same time, the channel's sensitivity to Zn2+ inhibition is also greatly reduced. The other two cysteine mutants, C213G and C480S, as well as a previously identified mutant, S123T, also affect the inactivation of the channel to some degree, but the temperature-dependent inactivation process is still present, likewise the high sensitivity of the Zn2+ inhibition. These results further support the assertion that the inhibition of Zn2+ on ClC-0 is indeed due to an effect on the inactivation of the channel. The absence of inactivation in C212S mutants may provide a better defined system to study the fast gating and the ion permeation of ClC-0.

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