scholarly journals A Low Spring Constant Piezoresistive Microcantilever for Biological Reagent Detection

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1001
Author(s):  
Yuan Tian ◽  
Rui Zhao ◽  
Yi Liu ◽  
Xiaomei Yu
Keyword(s):  
Bovine Serum Albumin ◽  
Output Voltage ◽  
Silicon Oxide ◽  
High Reliability ◽  
Wheatstone Bridge ◽  
Spring Constant ◽  
Voltage Fluctuation ◽  
Aptamer Probe ◽  
Mechanical Performances ◽  
Phosphate Buffered Saline

This paper introduces a piezoresistive microcantilever with a low spring constant. The microcantilever was fabricated with titanium (Ti) as the piezoresistor, a low spring constant polyimide (PI) layer, and a thin silicon oxide (SiO2) layer as the top and bottom passive layers, respectively. Excellent mechanical performances with the spring constant of 0.02128 N/m and the deflection sensitivity (∆V/V)/∆z of 1.03 × 10−7 nm−1 were obtained. The output voltage fluctuation of a Wheatstone bridge, which consists of four piezoresistive microcantilevers, is less than 3 μV@3 V in a phosphate buffered saline (PBS) environment. A microcantilever aptasensor was then developed through functionalizing the microcantilevers with a ricin aptamer probe, and detections on ricin with concentrations of 10, 20, 50 and 100 ng/mL were successfully realized. A good specificity was also confirmed by using bovine serum albumin (BSA) as a blank control. The experiment results show that the Ti and PI-based microcantilever has great prospects for ultrasensitive biochemical molecule detections with high reliability and specificity.

Immunocytochemical localization of p65 with one-nanometer gold particles following silver development

1989 ◽  
Vol 47 ◽  
pp. 1042-1043
Author(s):  
Richard W. Burry ◽  
Diane M. Hayes
Keyword(s):  
Plasma Membrane ◽  
Bovine Serum Albumin ◽  
Calf Serum ◽  
Specific Protein ◽  
Immunocytochemical Localization ◽  
Electron Microscopic ◽  
Gold Particles ◽  
Pass Through ◽  
Label Distribution ◽  
Phosphate Buffered Saline

Electron microscopic (EM) immunocytochemistry localization of the neuron specific protein p65 could show which organelles contain this antigen. Antibodies (Ab) labeled with horseradish peroxidase (HRP) followed by chromogen development show a broad diffuse label distribution within cells and restricting identification of organelles. Particulate label (e.g. 10 nm colloidal gold) is highly desirable but not practical because penetration into cells requires destroying the plasma membrane. We report pre-embedding immunocytochemistry with a particulate marker, 1 nm gold, that will pass through membranes treated with saponin, a mild detergent.Cell cultures of the rat cerebellum were fixed in buffered 4% paraformaldehyde and 0.1% glutaraldehyde (Glut.). The buffer for all incubations and rinses was phosphate buffered saline with: 1% calf serum, 0.2% saponin, 0.1% gelatin, 50 mM glycine 1 mg/ml bovine serum albumin, and (not in the HRP labeled cultures) 0.02% sodium azide. The monoclonal #48 to p65 was used with three label systems: HRP, 1 nm avidin gold with IntenSE M development, and 1 nm avidin gold with Danscher development.

scholarly journals A Flexible PI/Si/SiO2 Piezoresistive Microcantilever for Trace-Level Detection of Aflatoxin B1

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1118
Author(s):  
Yuan Tian ◽  
Yi Liu ◽  
Yang Wang ◽  
Jia Xu ◽  
Xiaomei Yu
Keyword(s):  
Single Crystal ◽  
Aflatoxin B1 ◽  
Single Crystal Silicon ◽  
Silicon Layer ◽  
Wheatstone Bridge ◽  
Silicon On Insulator ◽  
Passivation Layer ◽  
Spring Constant ◽  
Trace Level ◽  
Crystal Silicon

In this paper, a polyimide (PI)/Si/SiO2-based piezoresistive microcantilever biosensor was developed to achieve a trace level detection for aflatoxin B1. To take advantage of both the high piezoresistance coefficient of single-crystal silicon and the small spring constant of PI, the flexible piezoresistive microcantilever was designed using the buried oxide (BOX) layer of a silicon-on-insulator (SOI) wafer as a bottom passivation layer, the topmost single-crystal silicon layer as a piezoresistor layer, and a thin PI film as a top passivation layer. To obtain higher sensitivity and output voltage stability, four identical piezoresistors, two of which were located in the substrate and two integrated in the microcantilevers, were composed of a quarter-bridge configuration wheatstone bridge. The fabricated PI/Si/SiO2 microcantilever showed good mechanical properties with a spring constant of 21.31 nN/μm and a deflection sensitivity of 3.54 × 10−7 nm−1. The microcantilever biosensor also showed a stable voltage output in the Phosphate Buffered Saline (PBS) buffer with a fluctuation less than 1 μV @ 3 V. By functionalizing anti-aflatoxin B1 on the sensing piezoresistive microcantilever with a biotin avidin system (BAS), a linear aflatoxin B1 detection concentration resulting from 1 ng/mL to 100 ng/mL was obtained, and the toxic molecule detection also showed good specificity. The experimental results indicate that the PI/Si/SiO2 flexible piezoresistive microcantilever biosensor has excellent abilities in trace-level and specific detections of aflatoxin B1 and other biomolecules.

scholarly journals Ultracompact on-chip photothermal power monitor based on silicon hybrid plasmonic waveguides

Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 1121-1131 ◽  
Author(s):  
Hao Wu ◽  
Ke Ma ◽  
Yaocheng Shi ◽  
Lech Wosinski ◽  
Daoxin Dai
Keyword(s):  
Silicon Oxide ◽  
Dynamic Range ◽  
Optical Power ◽  
Wheatstone Bridge ◽  
Response Speed ◽  
Electrical Signal ◽  
Metal Strip ◽  
Plasmonic Waveguides ◽  
Insulator Layer ◽  
On Chip

AbstractWe propose and demonstrate an ultracompact on-chip photothermal power monitor based on a silicon hybrid plasmonic waveguide (HPWG), which consists of a metal strip, a silicon core, and a silicon oxide (SiO2) insulator layer between them. When light injected to an HPWG is absorbed by the metal strip, the temperature increases and the resistance of the metal strip changes accordingly due to the photothermal and thermal resistance effects of the metal. Therefore, the optical power variation can be monitored by measuring the resistance of the metal strip on the HPWG. To obtain the electrical signal for the resistance measurement conveniently, a Wheatstone bridge circuit is monolithically integrated with the HPWG on the same chip. As the HPWG has nanoscale light confinement, the present power monitor is as short as ~3 μm, which is the smallest photothermal power monitor reported until now. The compactness helps to improve the thermal efficiency and the response speed. For the present power monitor fabricated with simple fabrication processes, the measured responsivity is as high as about 17.7 mV/mW at a bias voltage of 2 V and the power dynamic range is as large as 35 dB.

A Simple Control Method of Output Voltage for Three-Phase Multilevel Inverter Considering the DC Voltage Fluctuation

2008 ◽  
Vol 128 (3) ◽  
pp. 244-250
Author(s):  
Kenji Amei ◽  
Kenji Teshima ◽  
Youhei Tanizaki ◽  
Takahisa Ohji ◽  
Masaaki Sakui
Keyword(s):  
Output Voltage ◽  
Control Method ◽  
Multilevel Inverter ◽  
Voltage Fluctuation ◽  
Dc Voltage ◽  
Three Phase

scholarly journals Output Voltage Control of MMC-Based Microgrid Based on Voltage Fluctuation Compensation Sliding Mode Control

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Sheng Xue ◽  
Xinggui Wang ◽  
Xiaoying Li
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Output Voltage ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Voltage Fluctuation ◽  
Hybrid Energy ◽  
Hybrid Energy Storage ◽  
System Output ◽  
Dc Component

As a novel topology of microgrid, the output voltage control of MMC half bridge series microgrid (MMC-MG) is rarely studied. In this paper, on the basis of fully analyzing the mechanism of output voltage fluctuation of MMC-MG under the condition of islanded mode, a control strategy of a hybrid energy storage system is proposed to reduce the generating module (GM) DC-link voltage fluctuation caused by the randomness of renewable energy microsource output power. Moreover, in order to further improve the stabilization of the MMC-MG output voltage and meet the requirements of fast voltage recovery and antijamming, a sliding mode controller is designed. Then, a voltage fluctuation compensation controller is designed to suppress the DC component and fundamental frequency deviation of system output voltage caused by GM DC-link voltage fluctuation. The proposed control approach is validated against simulations using MMC-MG models with 4-GM per arm. The results show that the proposed hybrid energy storage control strategy can suppress the GM DC-link voltage fluctuation, the sliding mode controller can stabilize the system output voltage when the load drastic changes, and the fluctuation compensation strategy can suppress the DC component and the fundamental frequency deviation of system output voltage.

A Dynamic Voltage Compensation Method for Improving Weighing Accuracy

2013 ◽  
Vol 333-335 ◽  
pp. 317-321
Author(s):  
Rong Sen Yin ◽  
Jia Qiang Yang
Keyword(s):  
Measurement Error ◽  
Digital Signal Processor ◽  
Digital Signal ◽  
Wheatstone Bridge ◽  
External Source ◽  
Compensation Method ◽  
Voltage Fluctuation ◽  
Voltage Compensation ◽  
Voltage Signal ◽  
Dynamic Voltage

In order to eliminate the measurement error caused by working voltage fluctuation of weighing sensor, a dynamic voltage compensation method for improving the weighing accuracy was proposed in the paper. The method takes strain gauge type pressure sensor as the weighing sensor and corrects Wheatstone bridge circuit. By synchronously detecting output voltage signal and working voltage of the weighing sensor, the method dynamically compensates the working voltage fluctuation of the weighing sensor, corrects the measurement error caused by the voltage fluctuation of external source and calculates the weight in real time. A weighing system based on the digital signal processor (DSP) was designed. Results of simulation experiment verify the feasibility of the proposed method.

A simple method for output voltage control of a three-phase multilevel inverter considering DC voltage fluctuation

2010 ◽  
Vol 170 (3) ◽  
pp. 40-47
Author(s):  
Kenji Amei ◽  
Kenji Teshima ◽  
Youhei Tanizaki ◽  
Takahisa Ohji ◽  
Masaaki Sakui
Keyword(s):  
Output Voltage ◽  
Voltage Control ◽  
Multilevel Inverter ◽  
Voltage Fluctuation ◽  
Simple Method ◽  
Dc Voltage ◽  
Three Phase

Research of Compensated AC Regulated Power Supply in Electric Power Systems Based on a High-Frequency Isolated Transformer

2013 ◽  
Vol 676 ◽  
pp. 227-230
Author(s):  
Qi Liang Zhang ◽  
Ping Wang ◽  
Liu Yang
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Power Supply ◽  
High Frequency ◽  
Output Voltage ◽  
Closed Loop ◽  
Electric Power Systems ◽  
Slow Response ◽  
Voltage Fluctuation ◽  
Simulation Results

In this paper, a new topology of compensated AC regulated power supply (ACRPS) in electric power systems based on a high-frequency isolated transformer (HFIT) is proposed. In order to overcome the slow response and low accuracy of the existing ACRPS, the phase shift regulating control (PSRC) based on instantaneous value of voltage single closed loop is applied as well as the software phase locked loop (SPLL). The proposed ACRPS has been simulated in the case of the voltage fluctuation, harmonics and frequency shift with Matlab. The simulation results show that output voltage precision is controlled within 0.5% and total harmonic distribution (THD) can be limited to less than 1%. In a word, the feasibility of the proposed ACRPS is effectively verified.

scholarly journals Alpha-Ketoglutarate: A Potential Inner Mitochondrial and Cytosolic Protector against Peroxynitrite and Peroxynitrite-Induced Nitration?

Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1501
Author(s):  
Joachim Greilberger ◽  
Michaela Greilberger ◽  
Reinhold Wintersteiger ◽  
Klaus Zangger ◽  
Ralf Herwig
Keyword(s):  
Bovine Serum Albumin ◽  
Final Concentration ◽  
Nmr Studies ◽  
Tyrosine Residues ◽  
Negative Linear Correlation ◽  
Elisa Technique ◽  
Cancer Inflammation ◽  
Phosphate Buffered Saline ◽  
Oxidative Species ◽  
Time Point

The generation of peroxynitrite (ONOO−) is associated with several diseases, including atherosclerosis, hypertension, neurodegeneration, cancer, inflammation, and sepsis. Alpha-ketoglutarate (αKG) is a known potential highly antioxidative agent for radical oxidative species such as peroxides. The question arises as to whether αKG is also a potential scavenger of ONOO− and a potential protector against ONOO−-mediated nitration of proteins. NMR studies of 1 mM αKG in 100 mM phosphate-buffered saline at pH 7.4 and pH 6.0 were carried out in the presence or absence of a final concentration of 2 mM ONOO−. An ONOO−–luminol-induced chemiluminescence reaction was used to measure the scavenging function of several concentrations of αKG; quantification of αKG was performed via spectrophotometric enzymatic assay of αKG in the absence or presence of 0, 1, or 2 mM ONOO−. The nitration of tyrosine residues on proteins was measured on ONOO−-treated bovine serum albumin (BSA) in the presence or absence of 0–24 mM αKG by an ELISA technique using a specific anti-IgG against nitro-tyrosine. The addition of ONOO− to αKG led to the formation of succinic acid and nitrite at pH 7.0, but not at pH 6.0, as αKG was stable against ONOO−. The absorbance of enzymatically estimated αKG at the time point of 30 min was significantly lower in favour of ONOO− (1 mM: 0.21 ± 0.03, 2 mM: 0.12 ± 0.05 vs. 0 mM: 0.32 ± 0.02; p < 0.001). The luminol technique showed an inverse logarithmic correlation of the ONOO− and αKG concentrations (y = −2 × 105 ln(x) + 1 × 106; r2 = 0.99). The usage of 4 mM αKG showed a significant reduction by nearly half in the chemiluminescence signal (284,456 ± 29,293 cps, p < 0.001) compared to the control (474,401 ± 18,259); for 20 and 200 mM αKG, there were further reductions to 163,546 ± 26,196 cps (p < 0.001) and 12,658 ± 1928 cps (p < 0.001). Nitrated tyrosine residues were estimated using the ELISA technique. A negative linear correlation was obtained by estimating nitrated tyrosine residues in the presence of αKG (r2 = 0.94): a reduction by half of nitrated tyrosine was estimated using 12 mM αKG compared to the control (326.1 ± 39.6 nmol vs. 844.5 ± 128.4 nmol; p < 0.001).

A Method of Obtaining a Suspension of Intact Parenchymal Cells from Adult Rat Liver

1971 ◽  
Vol 8 (1) ◽  
pp. 73-86
Author(s):  
JENNIFER J. GALLAI-HATCHARD ◽  
G. M. GRAY
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Culture Medium ◽  
High Yield ◽  
Alkaline Ph ◽  
High Osmolarity ◽  
Adult Rat ◽  
Parenchymal Cells ◽  
Phosphate Buffered Saline

The perfusion of liver with either citrate or tetraphenyl boron to remove Ca2+ or K+ or with a solution of high osmolarity and alkaline pH yields plenty of cells but they are all damaged. Perfusion of the liver with hyaluronidase and collagenase followed by incubation of liver slices in the same enzyme solution produced a high yield of cells (25%, w/w, of liver) of which only about 1% were undamaged. However, perfusion with 0.3% hyaluronidase, 0.3% collagenase and 0.1% trypsin in phosphate-buffered saline (excluding Mg2+ and Ca2+) followed by incubation at 25 °C of the chopped liver gave a small yield (2-4%, w/w) of undamaged cells which were not permeable to eosin for up to an hour when suspended in culture medium containing 2% bovine serum albumin.

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