scholarly journals High sensitivity piezoresistive cantilever sensor for biomolecular detection

2006 ◽  
Vol 34 ◽  
pp. 429-435 ◽  
Author(s):  
Johnny H HE ◽  
Yong Feng LI
Keyword(s):  
High Sensitivity ◽  
Biomolecular Detection ◽  
Cantilever Sensor

scholarly journals Biosynthesis of silver nanoparticles and exopolysaccharide using novel Thermophilic strain (Ts-1) of Bacillus amyloliquefaciens

2020 ◽  
Author(s):  
Sharath Chandra Thota ◽  
Bathini Sreelatha
Keyword(s):  
Silver Nanoparticles ◽  
Bacillus Amyloliquefaciens ◽  
High Sensitivity ◽  
Visual Observation ◽  
Purification And Characterization ◽  
Chemical Methods ◽  
Biomolecular Detection ◽  
Exopolysaccharide Biosynthesis ◽  
Uv Visible

AbstractIn the developing world, Nanotechnology became an efficient method in therapeutics, antimicrobials, diagnostics, catalysis, microelectronics, and high sensitivity biomolecular detection. As well as on the other hand, Exopolysaccharides are biopolymers which are also widely used in food formulation, bio- flocculants, bio-absorbents, drug delivery agents. As the chemical methods of synthesizing nanoparticles and polymers are environmentally risky, costly, and toxic. In the present study, we focused on production, purification, and characterization of silver nanoparticles (AgNPs) and exopolysaccharide (EPS) by eco-friendly, extracellular biosynthetic methods using novel thermophilic Bacillus amyloliquefaciens strain Ts-1. This strain was isolated from soil samples by employing pour and spread plate techniques. After obtaining pure culture, the bacterium was used for the synthesis of AgNPs and EPS. Nanoparticles were synthesized from AgNO3 by using reducing agents secreted by bacteria, and Exopolysaccharide biosynthesis is carried out in three steps by the organism in the presence of a carbon source. Synthesis of colloidal AgNPs and EPS was monitored by UV-Visible spectroscopy and Visual observation, respectively. SEM, Edax and FTIR were performed for the characterization of the AgNPs and EPS such as their size, morphology and composition and we also showed the catalytic activity of AgNps in degradation of methylene blue.

scholarly journals Label-Free Glucose Detection Using Cantilever Sensor Technology Based on Gravimetric Detection Principles

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Shuchen Hsieh ◽  
Shu-Ling Hsieh ◽  
Chiung-wen Hsieh ◽  
Po-Chiao Lin ◽  
Chun-Hsin Wu
Keyword(s):  
Specific Interaction ◽  
High Sensitivity ◽  
Sensor Technology ◽  
Glucose Detection ◽  
Label Free ◽  
Con A ◽  
Cantilever Sensor ◽  
Sensitivity And Selectivity ◽  
Free Glucose ◽  
Afm Cantilever

Efficient maintenance of glucose homeostasis is a major challenge in diabetes therapy, where accurate and reliable glucose level detection is required. Though several methods are currently used, these suffer from impaired response and often unpredictable drift, making them unsuitable for long-term therapeutic practice. In this study, we demonstrate a method that uses a functionalized atomic force microscope (AFM) cantilever as the sensor for reliable glucose detection with sufficient sensitivity and selectivity for clinical use. We first modified the AFM tip with aminopropylsilatrane (APS) and then adsorbed glucose-specific lectin concanavalin A (Con A) onto the surface. The Con A/APS-modified probes were then used to detect glucose by monitoring shifts in the cantilever resonance frequency. To confirm the molecule-specific interaction, AFM topographical images were acquired of identically treated silicon substrates which indicated a specific attachment for glucose-Con A and not for galactose-Con A. These results demonstrate that by monitoring the frequency shift of the AFM cantilever, this sensing system can detect the interaction between Con A and glucose, one of the biomolecule recognition processes, and may assist in the detection and mass quantification of glucose for clinical applications with very high sensitivity.

scholarly journals Liquid crystal-amplified optofluidic biosensor for ultra-highly sensitive and stable protein assay

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Ziyihui Wang ◽  
Yize Liu ◽  
Chaoyang Gong ◽  
Zhiyi Yuan ◽  
Liang Shen ◽  
...  
Keyword(s):  
Internal Surface ◽  
High Sensitivity ◽  
Optical Microscope ◽  
Wavelength Shift ◽  
Biomolecular Detection ◽  
Alignment Layer ◽  
Protein Assay ◽  
Sensing Platform ◽  
Protein Molecules ◽  
Protein Assays

AbstractProtein assays show great importance in medical research and disease diagnoses. Liquid crystals (LCs), as a branch of sensitive materials, offer promising applicability in the field of biosensing. Herein, we developed an ultrasensitive biosensor for the detection of low-concentration protein molecules, employing LC-amplified optofluidic resonators. In this design, the orientation of LCs was disturbed by immobilized protein molecules through the reduction of the vertical anchoring force from the alignment layer. A biosensing platform based on the whispering-gallery mode (WGM) from the LC-amplified optofluidic resonator was developed and explored, in which the spectral wavelength shift was monitored as the sensing parameter. The microbubble structure provided a stable and reliable WGM resonator with a high Q factor for LCs. It is demonstrated that the wall thickness of the microbubble played a key role in enhancing the sensitivity of the LC-amplified WGM microcavity. It is also found that protein molecules coated on the internal surface of microbubble led to their interactions with laser beams and the orientation transition of LCs. Both effects amplified the target information and triggered a sensitive wavelength shift in WGM spectra. A detection limit of 1 fM for bovine serum albumin (BSA) was achieved to demonstrate the high-sensitivity of our sensing platform in protein assays. Compared to the detection using a conventional polarized optical microscope (POM), the sensitivity was improved by seven orders of magnitude. Furthermore, multiple types of proteins and specific biosensing were also investigated to verify the potential of LC-amplified optofluidic resonators in the biomolecular detection. Our studies indicate that LC-amplified optofluidic resonators offer a new solution for the ultrasensitive real-time biosensing and the characterization of biomolecular interactions.

Model and Analysis of a High Sensitivity Resonant Optical Read-Out Approach Suitable for Cantilever Sensor Arrays

2012 ◽  
Vol 30 (12) ◽  
pp. 1863-1868 ◽  
Author(s):  
Gino Putrino ◽  
Adrian Keating ◽  
Mariusz Martyniuk ◽  
Lorenzo Faraone ◽  
John Dell
Keyword(s):  
Sensor Arrays ◽  
High Sensitivity ◽  
Cantilever Sensor

Theory and application of a novel co-resonant cantilever sensor

2018 ◽  
Vol 85 (6) ◽  
pp. 410-419 ◽  
Author(s):  
Julia Körner ◽  
Christopher F. Reiche ◽  
Bernd Büchner ◽  
Thomas Mühl
Keyword(s):  
Large Fraction ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Magnetic Field Sensors ◽  
Force Microscopy ◽  
Cantilever Sensor ◽  
Oscillatory State ◽  
Potential Applications ◽  
Oscillation Detection ◽  
Resonant Cantilever

Abstract Dynamic cantilever sensors have many applications, for example in material’s research, biology, as gas and magnetic field sensors. The sensing principle is based on the effect that a force gradient or mass change applied to the cantilever alter its oscillatory state which can be related to the parameter of interest. In order to detect very small interactions, the cantilever needs to have a low stiffness which is commonly achieved by a reduction of the beam’s dimensions, especially its thickness. However, this is limited by the commonly employed laser-based detection of the cantilever’s oscillatory state. In this paper, we describe a novel co-resonant cantilever sensor concept which is based on the coupling and eigenfrequency matching of a micro- and a nanocantilever. This approach allows to access a large fraction of the nanocantilever’s high sensitivity while ensuring a reliable oscillation detection with standard laser-based methods at the microcantilever. Experiments in cantilever magnetometry and magnetic force microscopy demonstrate the immense potential of the sensor concept. Furthermore, applications are not limited to material’s research, instead this concept creates a cantilever sensor platform with many potential applications, for example as gas, mass or pressure sensors.

LABEL-FREE BIOMOLECULAR DETECTION USING CARBON NANOTUBE FIELD EFFECT TRANSISTORS

NANO ◽  
2008 ◽  
Vol 03 (06) ◽  
pp. 415-431 ◽  
Author(s):  
HYE RYUNG BYON ◽  
SUPHIL KIM ◽  
HEE CHEUL CHOI
Keyword(s):  
Carbon Nanotube ◽  
Field Effect ◽  
Surface Passivation ◽  
Field Effect Transistors ◽  
High Sensitivity ◽  
Detection Methods ◽  
Label Free ◽  
Biomolecular Detection ◽  
Great Opportunity ◽  
High Level

Carbon nanotube field effect transistor (FET) type biosensors have been widely investigated as one of the promising platforms for highly sensitive personalized disease-monitoring electronic devices. Combined with high level cutting edge information technology (IT) infra systems, carbon nanotube transistor biosensors afford a great opportunity to contribute to human disease care by providing early diagnostic capability. Several key prerequisites that should be clarified for the real application include sensitivity, reliability, reproducibility, and expandability to multiplex detection systems. In this brief review, we introduce the types, fabrication, and detection methods of single-walled carbon nanotube FET (SWNT-FET) devices. As surface functionalization of the devices by which nonspecific bindings (NSBs) are efficiently prohibited is also another important issue regarding reliable biosensors, we discuss several key strategies about surface passivation along with examples of various biomolecules such as proteins, DNA, small molecules, aptamers, viruses, and cancer and neurodegenerative disease markers which have been successfully sensed by SWNT-FET devices. Finally, we discuss proposed detection mechanisms, according to which strategies for fabricating sensor devices having high sensitivity are determined. Two main mechanisms — charge transfer (or electrostatic gate effect) and Schottky barrier effect, depending on the place where biomolecules are adsorbed — will be covered.

scholarly journals Design of A NEMS Cantilever Sensor for Explosive Detection

2019 ◽  
Vol 8 (6S2) ◽  
pp. 912-916
Keyword(s):  
Real Time ◽  
High Sensitivity ◽  
Explosive Detection ◽  
Rectangular Shape ◽  
Cantilever Sensor ◽  
Psychological Warfare ◽  
Sensitivity And Selectivity ◽  
Resistive Material

The particular recognition of explosives in countering fear monger dangers and follow explosives has turned into an appallingly progressed and expensive exertion. This happens because of different impacts, similar to the extensive broad assortment of materials which will be used as explosives, the deficiency of basically perceivable marks, and the monstrous assortment of roads by these weapons might be sent and consequently there will be absence of shoddy sensors with high sensitivity and low vapor analyte property. High sensitivity and property joined with the power, to cut down the orchestrating cost of sensors. Misuse age is basic in winning the war an explosives based demonstration of psychological warfare. Nanosensors can possibly satisfy every one of the necessities of an effective stage for the follow identification explosives. Enhance the sensitivity and selectivity of NEMS cantilever for piezo resistive material in Humidity conditions and manufacture Rectangular Shape Omni directional NEMS cantilever cheap IC and Characteristic chip with Real time reenactment utilizing omnicant.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

1988 ◽  
Vol 46 ◽  
pp. 204-205
Author(s):  
Kazumichi Ogura ◽  
Michael M. Kersker
Keyword(s):  
High Resolution ◽  
Layer Structure ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Beam Current ◽  
Lattice Structures ◽  
Super Lattice ◽  
Different Types ◽  
Backscattered Electron ◽  
Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

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