scholarly journals Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications

2016 ◽  
Vol 2 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Ulrike Schmidt ◽  
Margarita Guenther ◽  
Gerald Gerlach
Keyword(s):  
Pressure Sensors ◽  
Glucose Monitoring ◽  
Biological Species ◽  
Detection Sensitivity ◽  
Tetraethylene Glycol ◽  
Piezoresistive Sensors ◽  
Piezoresistive Pressure Sensor ◽  
Set Up ◽  
Reversible Gel ◽  
Piezoresistive Pressure Sensors

AbstractMany conventional analysis techniques to detect chemical or biological species are able to achieve a high detection sensitivity, however, they are equipment- or time-expensive due to a multi-step procedure. In this work we describe sensor concepts using piezoresistive pressure sensor chips with integrated analyte-sensitive hydrogels, that enable inexpensive and robust biochemical sensors which are miniaturizable and in-line capable. Biocompatible hydrogels were developed and tested for pH- and glucose-monitoring during the chemical and biochemical processes. For that, monomer mixtures based on hydroxypropyl methacrylate HPMA, 2-(dimethylamino)ethyl methacrylate DMAEMA, tetraethylene glycol dimethacrylate TEGDMA and ethylene glycol EG were photo-polymerized. By means of carbodiimide chemistry, glucose oxidase was bound to the pH-sensitive HPMA/DMAEMA/TEGDMA/EG hydrogel squares causing the glucose-sensitivity. The crosslinked hydrogels were integrated in piezoresistive pressure sensors of different designs. pH- and glucose-depending reversible gel swelling processes were observed by means of the output voltage of dip sensors and of a novel implantable flexible sensor set-up. Due to its biocompatible components, the latter could be used inside the human body monitoring physiological blood values, for example glucose.

scholarly journals Biochemical piezoresistive sensors based on hydrogels for biotechnology and medical applications

2016 ◽  
Vol 5 (2) ◽  
pp. 409-417 ◽  
Author(s):  
Ulrike Schmidt ◽  
Carola Jorsch ◽  
Margarita Guenther ◽  
Gerald Gerlach
Keyword(s):  
Aqueous Media ◽  
Glucose Monitoring ◽  
Ammonium Persulfate ◽  
Swelling Behavior ◽  
Detection Sensitivity ◽  
Tetraethylene Glycol ◽  
Molar Ratios ◽  
Piezoresistive Sensors ◽  
Piezoresistive Pressure Sensor ◽  
Implantable Sensor

Abstract. Many conventional analysis techniques achieve a high-detection sensitivity; however, they are equipment or time expensive due to a multi-step procedure. Sensor concepts, introduced in this work, using piezoresistive pressure sensor chips with integrated analyte-sensitive hydrogels enable inexpensive and robust biochemical sensors, which are miniaturized and in-line capable. For these sensor setups, it is important to optimize current established analyte-sensitive, reversible and biocompatible hydrogels for pH and glucose monitoring of chemical and biochemical processes. Therefore, low-viscous monomer mixtures based on hydroxypropyl methacrylate (HPMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), tetraethylene glycol dimethacrylate (TEGDMA) and ethylene glycol (EG) were prepared in molar ratios of 70∕30∕01∕20, 60∕40∕01∕20 and 60∕40∕02∕20, respectively. Redox-polymerization of these pre-gel solutions were realized with N,N,N′,N′-tetramethylethylenediamine and ammonium persulfate. The reversible pH-sensitive swelling behavior of hydrogels with compositions were compared. By using the photoinitiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, the free radical photopolymerization could be implemented leading to an increase of the swelling degree (SG). Glucose-sensitive hydrogels were prepared via immobilization of glucose oxidase in HPMA–DMAEMA–TEGDMA–EG hydrogel discs. These showed increasing swelling degrees with higher glucose concentrations in aqueous media and a reversible swelling behavior. The synthesized hydrogels were integrated in different piezoresistive sensors of different designs. The pH-depending course of the output voltage of a dip sensor with photopolymerized 60∕40∕02∕20 hydrogel was studied in detail. Besides the usage of a dip sensor, two implantable, parylene C-coated setups are presented. The implantable sensor with long isolated gold bond wires was proved to be functional even after storage in aqueous media for several days.

Modeling and Simulation of the Thermal Drift Characteristics of the Piezoresistive Pressure Sensor

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000373-000378
Author(s):  
R. Otmani ◽  
N. Benmoussa ◽  
K. Ghaffour
Keyword(s):  
Thermal Behavior ◽  
Modeling And Simulation ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Thermal Drift ◽  
Piezoresistive Pressure Sensor ◽  
Output Characteristics ◽  
Piezoresistive Pressure Sensors

Piezoresistive pressure sensors based on Silicon have a large thermal drift because of their high sensitivity to temperature (ten times more sensitive to temperature than metals). So the study of the thermal behavior of these sensors is essential to define the parameters that cause the drift of the output characteristics. In this study, we adopted the behavior of 2nd degree gauges depending on the temperature. Then we model the thermal behavior of the sensor and its characteristics.

Design and Optimization of a Highly Sensitive and Linearity Piezoresistive Pressure Sensor Based on a Combination of Cross Beam-Peninsula-Membrane Structure

2017 ◽  
Author(s):  
Tran Anh Vang ◽  
Xianmin Zhang ◽  
Benliang Zhu
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Single Crystal Silicon ◽  
High Sensitivity ◽  
Crystal Silicon ◽  
Nonlinearity Error ◽  
Trade Off ◽  
Design And Optimization ◽  
Piezoresistive Pressure Sensor ◽  
Piezoresistive Pressure Sensors

The sensitivity and linearity trade-off problem has become the hotly important issues in designing the piezoresistive pressure sensors. To solve these trade-off problems, this paper presents the design, optimization, fabrication, and experiment of a novel piezoresistive pressure sensor for micro pressure measurement based on a combined cross beam - membrane and peninsula (CBMP) structure diaphragm. Through using finite element method (FEM), the proposed sensor performances as well as comparisons with other sensor structures are simulated and analyzed. Compared with the cross beam-membrane (CBM) structure, the sensitivity of CBMP structure sensor is increased about 38.7 % and nonlinearity error is reduced nearly 8%. In comparison with the peninsula structure, the maximum non-linearity error of CBMP sensor is decreased about 40% and the maximum deflection is extremely reduced 73%. Besides, the proposed sensor fabrication is performed on the n-type single crystal silicon wafer. The experimental results of the fabricated sensor with CBMP membrane has a high sensitivity of 23.4 mV/kPa and a low non-linearity of −0.53% FSS in the pressure range 0–10 kPa at the room temperature. According to the excellent performance, the sensor can be applied to measure micro-pressure lower than 10 kPa.

FEM Simulation of a Twin-Island Structure Chip in Piezoresistive Pressure Sensor

2011 ◽  
Vol 464 ◽  
pp. 208-212
Author(s):  
Hai Bin Pan ◽  
Jian Ning Ding ◽  
Guang Gui Cheng ◽  
Hui Juan Fan
Keyword(s):  
Finite Element ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Fem Simulation ◽  
Sensor Chip ◽  
Stress Distributions ◽  
Island Structure ◽  
Piezoresistive Pressure Sensor ◽  
Mems Technology ◽  
Piezoresistive Pressure Sensors

In this paper a twin-island structure in piezoresistive pressure sensor based on MEMS technology has been presented, and a finite element mechanical model has been developed to simulate the static mechanical behavior of this twin-island structure sensor chip, especially the stress distributions in diaphragm of the sensor chip, which has a vital significance on piezoresistive pressure sensors’ sensitivity. The possible impacts of twin-island’s location and twin-island’s width on the stress distributions, as well as the maximum value of compressive stress and tensile stress, have been investigated based on numerical simulation with Finite Element Method (FEM). The simulation results show that twin-island’s location has great effect on the stress distributions in sensor chips’ diaphragms and the sensitivity of piezoresistive pressure sensors, compared with the twin-island’s width.

SIMULATION METHODS OF PIEZORESISTIVE PRESSURE SENSORS IN ORDER TO IMPROVE CONSISTENCY

2012 ◽  
Vol 27 (02) ◽  
pp. 1350011 ◽  
Author(s):  
ZHAOHUA ZHANG ◽  
TIANLING REN ◽  
RUIRUI HAN ◽  
LI YUAN ◽  
BO PANG
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Simulation Method ◽  
Test Results ◽  
Silicon Membrane ◽  
Element Analysis ◽  
Piezoresistive Pressure Sensor ◽  
Consistency Results ◽  
Good Consistency ◽  
Piezoresistive Pressure Sensors

It is important to realize good consistency among different device units on a big wafer. The bad product consistency results from the processing deviation which is hard to control. A novel simulation method to control and reduce the influence of processing deviation on the sensitivity of a piezoresistive pressure sensor is provided in this paper. Based on finite element analysis (FEA) and mathematical integration, the performance of the pressure sensors is simulated. The pressure sensors are designed and fabricated according to the simulation results. The test results confirm that this simulation method can help to design the pressure sensor very precisely. From the simulation and test results, we find that properly enlarging the size of the square silicon membrane can improve the devices consistency.

TCR of the Ni-Cr Thin Film Resistors Used in Piezoresistive Pressure Sensor

2011 ◽  
Vol 483 ◽  
pp. 735-739 ◽  
Author(s):  
Li Xiao ◽  
Li Dong Du ◽  
Zhan Zhao ◽  
Zhen Fang ◽  
Jing Xu
Keyword(s):  
Thin Film ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Temperature Characteristic ◽  
Piezoresistive Pressure Sensor ◽  
Mems Technology ◽  
Thin Film Resistors ◽  
Metal Materials ◽  
Piezoresistive Pressure Sensors ◽  
Effect Of The Composition

In this paper, temperature characteristic of Ni-Cr thin film resistors is studied which have a low temperature drifting coefficient and used in a kind of metal piezoresistive pressure sensors based on MEMS technology. Normally, Ni-Cr alloys have a small temperature coefficient of resistance (TCR) compared with some other metal materials. But it depends on the composition of Ni and Cr in the alloy and on the annealing process under different temperature. Through the research of the effect of the composition of the alloy and annealing cycles, it is found that 50:50wt% Ni-Cr thin film has negative TCR and 80:20wt% NiCr thin film has positive TCR. Both of them have a small TCR and can improve the precision of piezoresistive pressure sensor.

scholarly journals A Micromachined Piezoresistive Pressure Sensor with a Shield Layer

2016 ◽  
Author(s):  
Gang Cao ◽  
Xiaoping Wang ◽  
Yong Xu ◽  
Sheng Liu
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Temperature Drift ◽  
Electrical Field ◽  
Piezoresistive Pressure Sensor ◽  
Improved Stability ◽  
Developed Pressure ◽  
Piezoresistive Pressure Sensors ◽  
P Type ◽  
The Impact

This paper presents a piezoresistive pressure sensor with a shield layer for improved stability. Compared with the conventional piezoresistive pressure sensors, p-type piezoresistors are covered by an n-type shield layer, which is formed by ion implantation. The proposed pressure sensors have been successfully fabricated by bulk micromachining techniques. The impact of electrical field on piezoresistors is studied by simulation. The temperature drift of the pressure sensor has been investigated by both simulation and experimental measurement. Characteristics of developed pressure sensors are tested from -40 C to 125 C. A sensitivity of 0.022 mV/V/KPa and a maximum non-linearity of 0.085% FS are measured for the fabricated sensor in a pressure range of 1 MPa. The temperature coefficients of resistance of shielded piezoresistors are found to be smaller than those of un-shielded ones. It is demonstrated that the shield layer is able to reduce the drift caused by electrical field and ambient temperature variation.

scholarly journals Study and Analysis of the Effective Geometries for the Piezoresistive Pressure Sensors

2021 ◽  
Vol 12 (6) ◽  
pp. 281-288
Author(s):  
S.Suganthi Et.al
Keyword(s):  
Microelectromechanical Systems ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Wheatstone Bridge ◽  
Diaphragm Thickness ◽  
Piezoresistive Effect ◽  
Induced Stress ◽  
Piezoresistive Pressure Sensor ◽  
The One ◽  
Piezoresistive Pressure Sensors

THE REPORTED WORK IS ON THE DESIGN AND SIMULATION OF MICROELECTROMECHANICAL SYSTEMS (MEMS) BASED SILICON PIEZORESISTIVE PRESSURE SENSOR DEPLOYED TOSENSE PRESSURE IN THE RANGE OF 0 TO 1.1 BAR. THE PRESSURE IS APPLIED ON THE DIAPHRAGM CONSISTING OF FOUR PIEZORESISTORS CONNECTED IN THE WHEATSTONE BRIDGE CONFIGURATION. THE INDUCED STRESS AS A RESULT OF THE PRESSURE CAUSES CHANGE IN RESISTANCE OF PIEZORESISTORS DUE TO PIEZORESISTIVE EFFECT. THE DESIGN AND SIMULATION OF THE SENSORS PRIOR TO FABRICATION HELPS US TO OPTIMIZE THE DIAPHRAGM THICKNESS AND SIZE. MEANDER SHAPED PIEZORESISTORS WITH DIFFERENT NUMBER OF TURNS ARE STUDIED IN ORDER TO FIND OUT THE BEST CONFIGURATION FOR HIGH SENSITIVITY AND LINEARITY. THE DESIGN AND SIMULATION IS CARRIED OUT USING FEM (FINITE ELEMENT METHOD) BASED COMSOLMULTIPHYSICS. BASED ON THE SIMULATION RESULTS, THE TWO-TURN CONFIGURATION IS FOUND TO HAVE THE BEST SENSITIVITY OF 4.181 MV/V/BAR AND THE ONE TURN CONFIGURATION GIVES THE LEAST NON-LINEARITY OF 0.5051 %

Sign in / Sign up

Export Citation Format

Share Document