Phosphate-dependent DNA Immobilization on Hafnium Oxide for Bio-Sensing Applications

2009 ◽  
Vol 1191 ◽  
Author(s):  
Nicholas M Fahrenkopf ◽  
Serge Oktyabrsky ◽  
Eric Eisenbraun ◽  
Magnus Bergkvist ◽  
Hua Shi ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Hafnium Oxide ◽  
Dielectric Material ◽  
Field Effect Transistors ◽  
Leading Edge ◽  
High Sensitivity ◽  
Cmos Technology ◽  
Label Free ◽  
Sensing Applications ◽  
Label Free Detection

AbstractHafnium(IV) oxide (HfO2) has replaced silicon oxide as a gate dielectric material in leading edge CMOS technology, providing significant improvement in gate performance for field effect transistors (FETs). We are currently exploring this high-k dielectric for its use in nucleic acid-based FET biosensors. Due to its intrinsic negative charge, label-free detection of DNA can be achieved in the gate region of high-sensitivity FET devices. Previous work has shown that phosphates and phosphonates coordinate specifically onto metal oxide substrates including aluminum and titanium oxides. This property can therefore be exploited for direct immobilization of biomolecules such as nucleic acids. Our work demonstrates that 5’ phosphate-terminated single stranded DNA (ssDNA) can be directly immobilized onto HfO2 surfaces, without the need for additional chemical modification or crosslinking. Non-phosphorylated ssDNA does not form stable surface interactions with HfO2, indicating that immobilization is dependent upon the 5’ terminal phosphate. Further work has shown that surface immobilized ssDNA can be hybridized to complementary target DNA and that sequence-based hybridization specificity is preserved. These results suggest that the direct DNA-HfO2 immobilization strategy can enable nucleic acid-based biosensing assays on HfO2 terminated surfaces. This work will further enable high sensitivity electrical detection of biological targets utilizing transistor-based technologies.

Design of Photonic Crystals Waveguide Using Microfluidic Infiltration

2014 ◽  
Vol 492 ◽  
pp. 301-305 ◽  
Author(s):  
Faida Bougriou ◽  
Touraya Boumaza ◽  
Mohamed Bouchemat
Keyword(s):  
Photonic Crystals ◽  
Fdtd Method ◽  
High Sensitivity ◽  
Slab Waveguide ◽  
Label Free ◽  
Single Chip ◽  
Photonic Crystal Slab ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Label Free Detection

The use of photonic crystals (PCS) in biosensor applications has lead to the development of highly sensitive and selective microfluidic sensor elements. Two main advantages of these devices for sensing applications are their high sensitivity and their reduced size, which makes it possible, in one hand, to detect very small analytes without the need of markers (label-free detection), and to integrate many of these devices on a single chip to perform a multi-parameter detection on the other hand. In the present paper, we analyze the design of a highly sensitive microfluidic sensors based on 2D photonic crystal slab waveguide formed by increasing the radii of air holes localized at each side of the line defect and filling with homogenous de-ionized water (nc =1.33). The transmission spectrum of the sensor has been obtained with the use of Finite Difference Time Domain (FDTD) method and it has been observed that a 306 nm wavelength position of the lower band edge shift was observed corresponding to a sensitivity of more than 927 nm per refractive index unit (RIU). Development of microfluidic sensor designs that enhance sensitivity is especially important because it allows detection of lower concentrations of analytes.

scholarly journals Chemical-free and scalable process for the fabrication of a uniform array of liquid-gated CNTFET, evaluated by KCl electrolyte

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pankaj B. Agarwal ◽  
Navneet Kumar Thakur ◽  
Rishi Sharma ◽  
Parul Singh ◽  
Joshy Joseph ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Reference Electrode ◽  
High Sensitivity ◽  
Label Free ◽  
Practical Applications ◽  
Lithography Process ◽  
Free Process ◽  
Label Free Detection ◽  
Sensitivity And Selectivity ◽  
Uniform Array

AbstractBiosensors based on liquid-gated carbon nanotubes field-effect transistors (LG-CNTFETs) have attracted considerable attention, as they offer high sensitivity and selectivity; quick response and label-free detection. However, their practical applications are limited due to the numerous fabrication challenges including resist-based lithography, in which after the lithography process, the resist leaves trace level contaminations over the CNTs that affect the performance of the fabricated biosensors. Here, we report the realization of LG-CNTFET devices using silicon shadow mask-based chemical-free lithography process on a 3-in. silicon wafer, yielding 21 sensor chips. Each sensor chip consists of 3 × 3 array of LG-CNTFET devices. Field emission scanning electron microscope (FESEM) and Raman mapping confirm the isolation of devices within the array chip having 9 individual devices. A reference electrode (Ag/AgCl) is used to demonstrate the uniformity of sensing performances among the fabricated LG-CNTFET devices in an array using different KCl molar solutions. The average threshold voltage (Vth) for all 9 devices varies from 0.46 to 0.19 V for 0.1 mM to 1 M KCl concentration range. This developed chemical-free process of LG-CNTFET array fabrication is simple, inexpensive, rapid having a commercial scope and thus opens a new realm of scalable realization of various biosensors.

scholarly journals Affinity Sensors for the Diagnosis of COVID-19

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 390
Author(s):  
Maryia Drobysh ◽  
Almira Ramanaviciene ◽  
Roman Viter ◽  
Arunas Ramanavicius
Keyword(s):  
Field Effect Transistors ◽  
Resonance Field ◽  
Analytical Signal ◽  
Nucleic Acid Hybridization ◽  
Detection Methods ◽  
Label Free ◽  
Infected People ◽  
Label Free Detection ◽  
Main Instrument ◽  
Antigen Antibody

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proclaimed a global pandemic in March 2020. Reducing the dissemination rate, in particular by tracking the infected people and their contacts, is the main instrument against infection spreading. Therefore, the creation and implementation of fast, reliable and responsive methods suitable for the diagnosis of COVID-19 are required. These needs can be fulfilled using affinity sensors, which differ in applied detection methods and markers that are generating analytical signals. Recently, nucleic acid hybridization, antigen-antibody interaction, and change of reactive oxygen species (ROS) level are mostly used for the generation of analytical signals, which can be accurately measured by electrochemical, optical, surface plasmon resonance, field-effect transistors, and some other methods and transducers. Electrochemical biosensors are the most consistent with the general trend towards, acceleration, and simplification of the bioanalytical process. These biosensors mostly are based on the determination of antigen-antibody interaction and are robust, sensitive, accurate, and sometimes enable label-free detection of an analyte. Along with the specification of biosensors, we also provide a brief overview of generally used testing techniques, and the description of the structure, life cycle and immune host response to SARS-CoV-2, and some deeper details of analytical signal detection principles.

scholarly journals Biologically sensitive field-effect transistors: from ISFETs to NanoFETs

2016 ◽  
Vol 60 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Vivek Pachauri ◽  
Sven Ingebrandt
Keyword(s):  
Field Effect ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Field Effect Transistors ◽  
Silicon Nanowire ◽  
Label Free ◽  
Biomolecular Detection ◽  
New Device ◽  
Label Free Detection ◽  
History Of

Biologically sensitive field-effect transistors (BioFETs) are one of the most abundant classes of electronic sensors for biomolecular detection. Most of the time these sensors are realized as classical ion-sensitive field-effect transistors (ISFETs) having non-metallized gate dielectrics facing an electrolyte solution. In ISFETs, a semiconductor material is used as the active transducer element covered by a gate dielectric layer which is electronically sensitive to the (bio-)chemical changes that occur on its surface. This review will provide a brief overview of the history of ISFET biosensors with general operation concepts and sensing mechanisms. We also discuss silicon nanowire-based ISFETs (SiNW FETs) as the modern nanoscale version of classical ISFETs, as well as strategies to functionalize them with biologically sensitive layers. We include in our discussion other ISFET types based on nanomaterials such as carbon nanotubes, metal oxides and so on. The latest examples of highly sensitive label-free detection of deoxyribonucleic acid (DNA) molecules using SiNW FETs and single-cell recordings for drug screening and other applications of ISFETs will be highlighted. Finally, we suggest new device platforms and newly developed, miniaturized read-out tools with multichannel potentiometric and impedimetric measurement capabilities for future biomedical applications.

Photonic crystals: A platform for label-free and enhanced fluorescence biomolecular and cellular assays

2008 ◽  
Vol 1133 ◽  
Author(s):  
Brian T. Cunningham ◽  
Leo Chan ◽  
Patrick C. Mathias ◽  
Nikhil Ganesh ◽  
Sherine George ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
High Throughput Screening ◽  
High Sensitivity ◽  
Excitation Wavelength ◽  
Label Free ◽  
Crystal Surfaces ◽  
Enhanced Fluorescence ◽  
Preferred Direction ◽  
Label Free Detection

Abstract Photonic crystal surfaces represent a class of resonant optical structures that are capable of supporting high intensity electromagnetic standing waves with near-field and far-field properties that can be exploited for high sensitivity detection of biomolecules and cells. While modulation of the resonant wavelength of a photonic crystal by the dielectric permittivity of adsorbed biomaterials enables label-free detection, the resonance can also be tuned to coincide with the excitation wavelength of common fluorescent tags - including organic molecules and semiconductor quantum dots. Photonic crystals are also capable of efficiently channeling fluorescent emission into a preferred direction for enhanced extraction efficiency. Photonic crystals can be designed to support multiple resonant modes that can perform label free detection, enhanced fluorescence excitation, and enhanced fluorescence extraction simultaneously on the same device. Because photonic crystal surfaces may be inexpensively produced over large surface areas by nanoreplica molding processes, they can be incorporated into disposable labware for applications such as pharmaceutical high throughput screening. In this talk, the optical properties of surface photonic crystals will be reviewed and several applications will be described, including results from screening a 200,000-member chemical compound library for inhibitors of protein-DNA interactions, gene expression microarrays, and high sensitivity of protein biomarkers.

Label-free detection of nucleic acid and protein microarrays by scanning Kelvin nanoprobe

2005 ◽  
Vol 20 (8) ◽  
pp. 1471-1481 ◽  
Author(s):  
Michael Thompson ◽  
Larisa-Emilia Cheran ◽  
Mingquan Zhang ◽  
Melissa Chacko ◽  
Hong Huo ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Protein Microarrays ◽  
Label Free ◽  
Label Free Detection

scholarly journals Rapid label-free SERS detection of foodborne pathogenic bacteria based on hafnium ditelluride-Au nanocomposites

2020 ◽  
Vol 13 (05) ◽  
pp. 2041004 ◽  
Author(s):  
Yang Li ◽  
Yanxian Guo ◽  
Binggang Ye ◽  
Zhengfei Zhuang ◽  
Peilin Lan ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Limit Of Detection ◽  
Principal Component ◽  
High Sensitivity ◽  
Chemical Mechanism ◽  
Sers Substrate ◽  
Label Free ◽  
Label Free Detection ◽  
Surface Enhanced Raman ◽  
Foodborne Pathogenic Bacteria

Two-dimensional (2D) nanomaterials have captured an increasing attention in biophotonics owing to their excellent optical features. Herein, 2D hafnium ditelluride (HfTe[Formula: see text], a new member of transition metal tellurides, is exploited to support gold nanoparticles fabricating HfTe2-Au nanocomposites. The nanohybrids can serve as novel 2D surface-enhanced Raman scattering (SERS) substrate for the label-free detection of analyte with high sensitivity and reproducibility. Chemical mechanism originated from HfTe2 nanosheets and the electromagnetic enhancement induced by the hot spots on the nanohybrids may largely contribute to the superior SERS effect of HfTe2-Au nanocomposites. Finally, HfTe2-Au nanocomposites are utilized for the label-free SERS analysis of foodborne pathogenic bacteria, which realize the rapid and ultrasensitive Raman test of Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella with the limit of detection of 10 CFU/mL and the maximum Raman enhancement factor up to [Formula: see text]. Combined with principal component analysis, HfTe2-Au-based SERS analysis also completes the bacterial classification without extra treatment.

scholarly journals Single-Molecule Detection of DNA in a Nanochannel by High-Field Strength-Assisted Electrical Impedance Spectroscopy

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 189 ◽  
Author(s):  
Porpin Pungetmongkol ◽  
Takatoki Yamamoto
Keyword(s):  
Single Molecule ◽  
High Intensity ◽  
High Sensitivity ◽  
Electrical Impedance Spectroscopy ◽  
Random Coil ◽  
Label Free ◽  
Electrode Gap ◽  
Label Free Detection ◽  
Intensity Field ◽  
Nanogap Electrodes

Many researchers have fabricated micro and nanofluidic devices incorporating optical, chemical, and electrical detection systems with the aim of achieving on-chip analysis of macromolecules. The present study demonstrates a label-free detection of DNA using a nanofluidic device based on impedance measurements that is both sensitive and simple to operate. Using this device, the electrophoresis and dielectrophoresis effect on DNA conformation and the length dependence were examined. A low alternating voltage was applied to the nanogap electrodes to generate a high intensity field (>0.5 MV/m) under non-faradaic conditions. In addition, a 100 nm thick gold electrode was completely embedded in the substrate to allow direct measurements of a solution containing the sample passing through the gap, without any surface modification required. The high intensity field in this device produced a dielectrophoretic force that stretched the DNA molecule across the electrode gap at a specific frequency, based on back and forth movements between the electrodes with the DNA in a random coil conformation. The characteristics of 100 bp, 500 bp, 1 kbp, 5 kbp, 10 kbp, and 48 kbp λ DNA associated with various conformations were quantitatively analyzed with high resolution (on the femtomolar level). The sensitivity of this system was found to be more than about 10 orders of magnitude higher than that obtained from conventional linear alternating current (AC) impedance for the analysis of bio-polymers. This new high-sensitivity process is expected to be advantageous with regard to the study of complex macromolecules and nanoparticles.

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