Sensing with Nafion Coated Carbon Nanotube Field‐Effect Transistors

Star, Alexander; Han, Tzong‐Ru; Joshi, V. K.; Stetter, Joseph R.

doi:10.1002/elan.200302925

Cited by 65 publications

(33 citation statements)

References 24 publications

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“…SWNT-polypyrrole (PPY) nanocomposites formed by in-situ chemical polymerization of pyrrole in an SWNT mixture demonstrated enhanced sensitivity to NO 2 gas [9]. Nanotube field effect transistors (NTFETs), created by noncovalently coating SWNTs with Nafion membranes, have been evaluated as a very sensitive humidity sensor [10]. Also, sensors fabricated via the noncovalent functionalization of SWNTs with PEI and starch polymers showed a highly sensitive response to low concentrations of CO 2 [11].…”

Section: Introductionmentioning

confidence: 99%

Electrochemically Functionalized Single‐Walled Carbon Nanotube Gas Sensor

et al. 2006

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We demonstrate a facile fabrication method to make chemical gas sensors using single-walled carbon nanotubes (SWNT) electrochemically functionalized with polyaniline (PANI). The potential advantage of this method is to enable targeted functionalization with different materials to allow for creation of high-density individually addressable nanosensor arrays. PANI-SWNT network based sensors were tested for on-line monitoring of ammonia gas. The results show a superior sensitivity of 2.44% DR/R per ppm v NH 3 (which is more than 60 times higher than intrinsic SWNT based sensors), a detection limit as low as 50 ppb v , and good reproducibility upon repeated exposure to 10 ppm v NH 3 . The typical response time of the sensors at room temperature is on the order of minutes and the recovery time is a few hours. Higher sensitivities were observed at lower temperatures. These results indicate that electrochemical functionalization of SWNTs provides a promising new method of creating highly advanced nanosensors with improved sensitivity, detection limit, and reproducibility.

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Section: Introductionmentioning

confidence: 99%

Electrochemically Functionalized Single‐Walled Carbon Nanotube Gas Sensor

et al. 2006

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“…It is tempting to attribute the difference in the slope value, which is almost factor of two, i.e., Ϫ0.11 for DNA (Na ϩ ) versus Ϫ0.06 for both devices titrated with DNA (Mg 2ϩ ), to differences between single charge for monovalent sodium cation and double charge for divalent magnesium cation in DNA hybrid. These results are somewhat related to changes in NTN-FET device characteristics when the devices were coated with Nafion electrolyte containing either monovalent (Na ϩ , K ϩ ) or divalent (Ca 2ϩ ) ions (26).…”

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confidence: 99%

Label-free detection of DNA hybridization using carbon nanotube network field-effect transistors

Star

Niemann

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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We report carbon nanotube network field-effect transistors (NTNFETs) that function as selective detectors of DNA immobilization and hybridization. NTNFETs with immobilized synthetic oligonucleotides have been shown to specifically recognize target DNA sequences, including H63D single-nucleotide polymorphism (SNP) discrimination in the HFE gene, responsible for hereditary hemochromatosis. The electronic responses of NTNFETs upon single-stranded DNA immobilization and subsequent DNA hybridization events were confirmed by using fluorescence-labeled oligonucleotides and then were further explored for label-free DNA detection at picomolar to micromolar concentrations. We have also observed a strong effect of DNA counterions on the electronic response, thus suggesting a charge-based mechanism of DNA detection using NTNFET devices. Implementation of label-free electronic detection assays using NTNFETs constitutes an important step toward low-cost, low-complexity, highly sensitive and accurate molecular diagnostics.hemochromatosis ͉ SNP ͉ biosensor T he development of nucleic acids diagnostics has become the subject of intense research, especially in the postgenome era. Current methods have mainly focused on optical detection using fluorescence-labeled oligonucleotides with dyes (1), quantum dots (2), or enhanced absorption of light by oligonucleotidemodified gold nanoparticles (3). On the other hand, label-free electronic methods promise to offer sensitivity, selectivity, and low cost for the detection of DNA hybridization (4). For example, microfabricated silicon field-effect sensors can monitor directly the increase in surface charge when DNA was hybridized on the sensor surface (5). Nanomaterials possess unique properties that are amenable to biosensor applications; they are one-dimensional structures that are extremely sensitive to electronic perturbations, readily functionalized with biorecognition layers, and compatible with many semiconducting manufacturing processes. Thus, one-dimensional silicon nanowires (6-8) and indium oxide nanowires (9) have shown promising performance, because their electronic conductance is more sensitive to DNA-associated charges as a result of their high surface-tovolume ratio. Using smaller nanowires with virtually all atoms on their surface, such as single-walled carbon nanotubes (SWNTs), will provide additional advantages in DNA detection. To date, there are several reports on electrochemical detection of DNA hybridization using multi-walled carbon nanotube electrodes (ref. 10 and references therein, and ref. 11). Whereas electrochemical methods rely on electrochemical behavior of the labels, measurement of direct electron transfer between SWNTs and DNA molecules paves the way for label-free DNA detection. SWNT-based field-effect transistors (12) have excellent operating characteristics (13), and they have already been explored for highly sensitive electronic detection of gases (14, 15) and biomolecules such as antibodies (16,17).Single-stranded DNA (ssDNA) has been recently demons...

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“…Then the modified GC electrode was introduced from one side of the cell. Also from the opposite, side a white light LED, as well as a digital camera (model: AGPtek, magnifying ratio: X 800) were positioned with angle between [10][11][12][13][14][15][16][17][18][19][20] o versus the GC carbon electrode. Also to remove the hysteresis of the GC electrode from any adsorption and diffusion of humidity, an IR light source was positioned next to the GC electrode to eliminate the memory effect.…”

Section: Synthesis Of Salen and Salen-based Polymermentioning

confidence: 99%

“…surface acoustic waves (SAWs) [7], inter-digitated circuit [8], electronic devices such as field effect transistors (FETs) [9][10][11], quartz crystal microbalance [12][13][14][15] and optical detection system [16], have been investigated for humidity detection and determination. However between these ranges of sensing methods, optical sensing has been selected in this study, because of its significant advantages such as improved detection system, fast response time, high sensitivity and its wide linear response [16].…”

mentioning

confidence: 99%