scholarly journals A Sensitive Potentiometric Sensor for Isothermal Amplification-Coupled Detection of Nucleic Acids

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2277
Author(s):  
Kang-Ho Lee ◽  
Dongkyu Lee ◽  
Jongsu Yoon ◽  
Ohwon Kwon ◽  
Jaejong Lee
Keyword(s):  
Nucleic Acids ◽  
Real Time ◽  
Surface Potential ◽  
Pathogenic Bacteria ◽  
Field Effect Transistors ◽  
Potentiometric Sensor ◽  
Isothermal Amplification ◽  
Ring Oscillator ◽  
Oxide Semiconductor ◽  
High Signal

A disposable potentiometric sensor was newly developed for the amplification-coupled detection of nucleic acids. The hydrogen-ion is generally released during isothermal amplification of nucleic acids. The surface potential on the oxide-functionalized electrode of the extended gate was directly measured using full electrical circuits with the commercial metal-oxide semiconductor field-effect transistors (MOSFETs) and ring oscillator components, which resulted in cost-effective, portable and scalable real-time nucleic acid analysis. The current-starved ring oscillator changes surface potential to its frequency depending on the square of the variation in pH with a high signal-to-noise ratio during isothermal amplification. The device achieves a conversion rate of 20.5 kHz/mV and a detection resolution of 200 µV for the surface potential. It is demonstrated that the sensor successfully monitors in real-time isothermal amplification of the extracted nucleic acids from Salmonella pathogenic bacteria. The in situ variations in the frequency of the pH-sensitive sensor were compared with the results of both a conventional optical device and pH-meter during isothermal amplification.

scholarly journals Three-Way Junction-Induced Isothermal Amplification with High Signal-to-Background Ratio for Detection of Pathogenic Bacteria

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4132
Author(s):  
Jung Ho Kim ◽  
Seokjoon Kim ◽  
Sung Hyun Hwang ◽  
Tae Hwi Yoon ◽  
Jung Soo Park ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Pathogenic Bacteria ◽  
High Selectivity ◽  
Isothermal Amplification ◽  
Rna Aptamers ◽  
High Signal ◽  
Fluorescence Signal ◽  
Enhanced Fluorescence ◽  
Target Nucleic Acid

The consumption of water and food contaminated by pathogens is a major cause of numerous diseases and deaths globally. To control pathogen contamination and reduce the risk of illness, a system is required that can quickly detect and monitor target pathogens. We developed a simple and reproducible strategy, termed three-way junction (3WJ)-induced transcription amplification, to detect target nucleic acids by rationally combining 3WJ-induced isothermal amplification with a light-up RNA aptamer. In principle, the presence of the target nucleic acid generates a large number of light-up RNA aptamers (Spinach aptamers) through strand displacement and transcription amplification for 2 h at 37 °C. The resulting Spinach RNA aptamers specifically bind to fluorogens such as 3,5-difluoro-4-hydroxybenzylidene imidazolinone and emit a highly enhanced fluorescence signal, which is clearly distinguished from the signal emitted in the absence of the target nucleic acid. With the proposed strategy, concentrations of target nucleic acids selected from the genome of Salmonellaenterica serovar Typhi (S. Typhi) were quantitatively determined with high selectivity. In addition, the practical applicability of the method was demonstrated by performing spike-and-recovery experiments with S. Typhi in human serum.

Examining the Short Channel Characteristic and Performance of Triple Material Double Gate Silicon-on-Nothing Metal Oxide Semiconductor Field Effect Transistors with Grading Channel Concentration

2019 ◽  
Vol 14 (12) ◽  
pp. 1672-1679 ◽  
Author(s):  
Ningombam Ajit Kumar ◽  
Aheibam Dinamani Singh ◽  
Nameirakpam Basanta Singh
Keyword(s):  
Surface Potential ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Double Gate ◽  
Short Channel Effects ◽  
Parabolic Approximation ◽  
Short Channel ◽  
Channel Characteristic ◽  
Channel Effects ◽  
And Performance

A 2D surface potential analytical model of a channel with graded channel triple material double gate (GCTMDG) Silicon-on-Nothing (SON) MOSFET is proposed by intermixing the benefits of triple material in gate engineering and graded doping in the channel. The surface potential distribution function of the GCTMDG SON MOSFET is obtained by solving the Poisson's equation, applying suitable boundary conditions, and using a parabolic approximation method. It is seen in the proposed device that the Short Channel Effects (SCEs) are subdued due to the apprehensible step in the surface potential profile that screen the potential of the drain. The effects of the various device parameters are studied to check the merit of the device. For the validation of the proposed device, it is compared with the simulated results of ATLASTM, a device simulator from SILVACO.

scholarly journals Monolithic Wafer Scale Integration of Silicon Nanoribbon Sensors with CMOS for Lab-on-Chip Application

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 544 ◽  
Author(s):  
Ganesh Jayakumar ◽  
Per-Erik Hellström ◽  
Mikael Östling
Keyword(s):  
Real Time ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Efficient Production ◽  
Lab On Chip ◽  
Multiplexed Detection ◽  
Turn On ◽  
Strong Inversion ◽  
On Chip ◽  
P Type

Silicon ribbons (SiRi) have been well-established as highly sensitive transducers for biosensing applications thanks to their high surface to volume ratio. However, selective and multiplexed detection of biomarkers remains a challenge. Further, very few attempts have been made to integrate SiRi with complementary-metal-oxide-semiconductor (CMOS) circuits to form a complete lab-on-chip (LOC). Integration of SiRi with CMOS will facilitate real time detection of the output signal and provide a compact small sized LOC. Here, we propose a novel pixel based SiRi device monolithically integrated with CMOS field-effect-transistors (FET) for real-time selective multiplexed detection. The SiRi pixels are fabricated on a silicon-on-insulator wafer using a top-down method. Each pixel houses a control FET, fluid-gate (FG) and SiRi sensor. The pixel is controlled by simultaneously applying frontgate (VG) and backgate voltage (VBG). The liquid potential can be monitored using the FG. We report the transfer characteristics (ID-VG) of N- and P-type SiRi pixels. Further, the ID-VG characteristics of the SiRis are studied at different VBG. The application of VBG to turn ON the SiRi modulates the subthreshold slope (SS) and threshold voltage (VTH) of the control FET. Particularly, N-type pixels cannot be turned OFF due to the control NFET operating in the strong inversion regime. This is due to large VBG (≥25 V) application to turn ON the SiRi sensor. Conversely, the P-type SiRi sensors do not require large VBG to switch ON. Thus, P-type pixels exhibit excellent ION/IOFF ≥ 106, SS of 70–80 mV/dec and VTH of 0.5 V. These promising results will empower the large-scale cost-efficient production of SiRi based LOC sensors.

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