Microscopic Detection of DNA Hybridization using Miniaturized Diamond DNA-FETs

AbstractMiniaturized DNA sensitive field-effect transistors (DNA-FET) have been realized using single crystalline diamond grown by plasma-enhanced chemical vapor deposition (CVD). To bond DNA to diamond, amine linker-molecules are covalently attached by photochemical means to H-terminated diamond surfaces. Using hetero-bifunctional cross-linker and thiol-modified single-strand (ss) cancer marker DNA (CK20), the gate of diamond FETs is modified to sense hybridization of DNA, forming double-strand (ds) DNA molecules on the gate. The density of DNA bonded to diamond has been adjusted to about 1012 cm−2 and the experiments have been performed in phosphate buffer with different ionicity to control the Debye length of the Helmholtz layer. By hybridization, a gate-potential shift of 64 mV is detected in case of the 100 Å Debye lengths, while 46 mV is detected for 10 Å. This is discussed with respect to DNA related variations of charge and pH by hybridization. Time resolved experiments reveal exponential hybridization dynamics with a time constant of 600 s. The sensitivity limit of our experiment is about 1 nM.

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DNA-ISFETs from Single Crystalline Diamond

MRS Proceedings ◽

10.1557/proc-0956-j16-04 ◽

2006 ◽

Vol 956 ◽

Author(s):

Christoph E. Nebel ◽

Dongchan Shin ◽

Tomoko Yamamoto ◽

Takako Nakamura

Keyword(s):

Field Effect Transistors ◽

Chemical Vapor ◽

Buffer Solution ◽

Solution Ph ◽

Single Crystalline ◽

Diamond Surfaces ◽

Gate Potential ◽

Decreasing Ph ◽

Linker Molecules ◽

Dna Density

ABSTRACTDNA sensitive field-effect transistors (DNA-FET) have been realized using single crystalline diamond grown by plasma-enhanced chemical vapor deposition (CVD). To bond DNA to diamond, amine linker-molecules are covalently attached by photochemical means to H-terminated diamond surfaces. Using hetero-bifunctional cross-linker and thiol-modified single-strand (ss) marker DNA, the gate of diamond FETs is modified to sense hybridization of DNA, forming double-strand (ds) DNA molecules on the gate. The density of DNA bonded to diamond is varied between 1012 and 1013 cm−2 to explore sensitivity enhancements by reduction of the DNA molecule density. DNA-FET characterization in 1M NaCl buffer solution (pH 7.2) reveal gate-potential threshold shifts by hybridization in the range 30 mV to 100 mV with decreasing DNA density. The variation is discussed based on the transfer doping model which predicts with decreasing pH increasing hole-densities in the surface conductive layer of diamond.

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TEM evaluation of graded SixGe1-x heterolayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088786 ◽

1991 ◽

Vol 49 ◽

pp. 894-895

Author(s):

N. David Theodore ◽

Mamoru Tomozane ◽

Ming Liaw

Keyword(s):

Heterojunction Bipolar Transistors ◽

Gas Flow ◽

Field Effect Transistors ◽

Chemical Vapor ◽

Dark Field ◽

Bipolar Transistors ◽

Structural Quality ◽

Weak Beam ◽

Transmission Electron ◽

And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

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Label-Free Electrochemical Detection of DNA Hybridization Related to Anthrax Lethal Factor by using Carbon Nanotube Modified Sensors

Current Analytical Chemistry ◽

10.2174/1573411014666181004151547 ◽

2019 ◽

Vol 15 (4) ◽

pp. 502-510 ◽

Cited By ~ 1

Author(s):

Hakan Karadeniz ◽

Arzum Erdem

Keyword(s):

Detection Limit ◽

Dna Hybridization ◽

Lethal Factor ◽

Modified Electrodes ◽

Label Free ◽

Carbon Paste ◽

Chip Technology ◽

Anthrax Lethal Factor ◽

Hybridization Time ◽

Electrochemical Monitoring

Background: Anthrax Lethal Factor (ANT) is the dominant virulence factor produced by B. anthracis and is the major cause of death of infected animals. In this paper, pencil graphite electrodes GE were modified with single-walled and multi-walled carbon nanotubes (CNTs) for the detection of hybridization related to the ANT DNA for the first time in the literature. Methods: The electrochemical monitoring of label-free DNA hybridization related to ANT DNA was explored using both SCNT and MCNT modified PGEs with differential pulse voltammetry (DPV). The performance characteristics of ANT-DNA hybridization on disposable GEs were explored by measuring the guanine signal in terms of optimum analytical conditions; the concentration of SCNT and MCNT, the concentrations of probe and target, and also the hybridization time. Under the optimum conditions, the selectivity of probe modified electrodes was tested and the detection limit was calculated. Results: The selectivity of ANT probes immobilized onto MCNT-GEs was tested in the presence of hybridization of probe with NC no response was observed and with MM, smaller responses were observed in comparison to full-match DNA hybridization case. Even though there are unwanted substituents in the mixture samples containing both the target and NC in the ratio 1:1 and both the target and MM in the ratio 1:1, it has been found that ANT probe immobilized CNT modified graphite sensor can also select its target by resulting with 20.9% decreased response in comparison to the one measured in the case of full-match DNA hybridization case Therefore, it was concluded that the detection of direct DNA hybridization was performed by using MCNT-GEs with an acceptable selectivity. Conclusion: Disposable SCNT/MCNT modified GEs bring some important advantages to our assay including easy use, cost-effectiveness and giving a response in a shorter time compared to unmodified PGE, carbon paste electrode and glassy carbon electrode developed for electrochemical monitoring of DNA hybridization. Consequently, the detection of DNA hybridization related to the ANT DNA by MCNT modified sensors was performed by using lower CNT, probe and target concentrations, in a shorter hybridization time and resulting in a lower detection limit according to the SCNT modified sensors. In conclusion, MCNT modified sensors can yield the possibilities leading to the development of nucleic acid sensors platforms for the improvement of fast and cost-effective detection systems with respect to DNA chip technology.

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Influence of the Electrolyte Salt Concentration on DNA Detection with Graphene Transistors

Biosensors ◽

10.3390/bios11010024 ◽

2021 ◽

Vol 11 (1) ◽

pp. 24

Author(s):

Agnes Purwidyantri ◽

Telma Domingues ◽

Jérôme Borme ◽

Joana Rafaela Guerreiro ◽

Andrey Ipatov ◽

...

Keyword(s):

Phosphate Buffer ◽

Species Interactions ◽

Field Effect ◽

Field Effect Transistors ◽

Limit Of Detection ◽

Debye Length ◽

Intermolecular Forces ◽

Single Layer Graphene ◽

Dna Adsorption

Liquid-gated Graphene Field-Effect Transistors (GFET) are ultrasensitive bio-detection platforms carrying out the graphene’s exceptional intrinsic functionalities. Buffer and dilution factor are prevalent strategies towards the optimum performance of the GFETs. However, beyond the Debye length (λD), the role of the graphene-electrolytes’ ionic species interactions on the DNA behavior at the nanoscale interface is complicated. We studied the characteristics of the GFETs under different ionic strength, pH, and electrolyte type, e.g., phosphate buffer (PB), and phosphate buffer saline (PBS), in an automatic portable built-in system. The electrostatic gating and charge transfer phenomena were inferred from the field-effect measurements of the Dirac point position in single-layer graphene (SLG) transistors transfer curves. Results denote that λD is not the main factor governing the effective nanoscale screening environment. We observed that the longer λD was not the determining characteristic for sensitivity increment and limit of detection (LoD) as demonstrated by different types and ionic strengths of measuring buffers. In the DNA hybridization study, our findings show the role of the additional salts present in PBS, as compared to PB, in increasing graphene electron mobility, electrostatic shielding, intermolecular forces and DNA adsorption kinetics leading to an improved sensitivity.

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All-Organic, Low Voltage, Transparent and Compliant Organic Field-Effect Transistor Fabricated by Means of Large-Area, Cost-Effective Techniques

Applied Sciences ◽

10.3390/app10196656 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6656

Author(s):

Stefano Lai ◽

Giulia Casula ◽

Pier Carlo Ricci ◽

Piero Cosseddu ◽

Annalisa Bonfiglio

Keyword(s):

Field Effect ◽

Low Voltage ◽

Field Effect Transistors ◽

High Mobility ◽

Chemical Vapor ◽

Cost Effective ◽

Large Area ◽

Parylene C ◽

Biomedical Sensing ◽

Novel Applications

The development of electronic devices with enhanced properties of transparency and conformability is of high interest for the development of novel applications in the field of bioelectronics and biomedical sensing. Here, a fabrication process for all organic Organic Field-Effect Transistors (OFETs) by means of large-area, cost-effective techniques such as inkjet printing and chemical vapor deposition is reported. The fabricated device can operate at low voltages (as high as 4 V) with ideal electronic characteristics, including low threshold voltage, relatively high mobility and low subthreshold voltages. The employment of organic materials such as Parylene C, PEDOT:PSS and 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) helps to obtain highly transparent transistors, with a relative transmittance exceeding 80%. Interestingly enough, the proposed process can be reliably employed for OFET fabrication over different kind of substrates, ranging from transparent, flexible but relatively thick polyethylene terephthalate (PET) substrates to transparent, 700-nm-thick, compliant Parylene C films. OFETs fabricated on such sub-micrometrical substrates maintain their functionality after being transferred onto complex surfaces, such as human skin and wearable items. To this aim, the electrical and electromechanical stability of proposed devices will be discussed.

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