1. Manipulation of individual carbon nanotubes by reconstructing the intracellular transport of a living cell.
Cerasela Zoica Dinu, Shyam Sundhar Bale , Douglas B. Chrisey, Jonathan S. Dordick. (2009, February 2). Advanced Materials, Volume 21 Issue 10-11, Pages 1182 – 1186
Abstract: We used kinesin motor protein and its microtubule track to transport multi-walled carbon nanotubes (MWNTs) on engineered surfaces. Using a flow chamber, surface-adsorbed kinesins are shown to transport red-labeled microtubules loaded with green cargos of MWNTs. Our results establish a platform for assembling individually addressable MWNT nanostructures using microtubule templates.
2. Comparison of the electrochemical reactivity of electrodes modified with carbon nanotubes from different sources.
Nathan S. Lawrence, Randhir P. Deo, Joseph Wang. (2004, October 20). Electroanalysis, Volume 17 Issue 1, Pages 65 – 72.
Abstract: The electrochemical activity of five different commercial carbon nanotubes (CNT), prepared by the ARC discharge and chemical vapor deposition (CVD) methods, has been assessed and compared. The various multi-walled CNT were immobilized onto a glassy carbon electrode using three different dispersing agents (Nafion, concentrated nitric acid and dimethylformamide (DMF)) and their voltammetric response to ferricyanide, NADH and hydrogen peroxide examined. SEM was used to characterize the surface morphology. The corresponding cyclic voltammetry and amperometric data showed that the electrocatalytic activity, the background current and the electroanalytical performance are strongly depended on the preparation of the CNT and on the dispersing agent used. The most favorable amperometric detection of NADH and hydrogen peroxide is observed at the NanoLab CVD-produced CNT in connection to a DMF-surface dispersion. ARC-produced CNT display a smaller capacitance, particularly in connection to the DMF dispersion. Such differences in the electrochemical reactivity are attributed to the different surface chemistries (primarily defect densities) of the corresponding CNT layers, associated with the different production and dispersion protocols.
3. Low-potential stable NADH detection at carbon-nanotube-modified glassy carbon electrodes.
Mustafa Musameh, Joseph Wang, Arben Merkoci and Yuehe Lin. (2002 October). Electrochemistry communications, Volume 4, Issue 10, Pages 743-746
Abstract: Carbon-nanotube (CNT)-modified glassy carbon electrodes exhibiting strong and stable electrocatalytic response toward NADH are described. A substantial (490 mV) decrease in the overvoltage of the NADH oxidation reaction (compared to ordinary carbon electrodes) is observed using single-wall and multi-wall carbon-nanotube coatings, with oxidation starting at ca. −0.05 V (vs. Ag/AgCl; pH 7.4). Furthermore, the NADH amperometric response of the coated electrodes is extremely stable, with 96% and 90% of the initial activity remaining after 60 min stirring of 2×10−4 and 5×10−3 M NADH solutions, respectively (compared to 20% and 14% at the bare surface). The CNT-coated electrodes thus allow highly sensitive, low-potential, stable amperometric sensing. Such ability of carbon nanotubes to promote the NADH electron-transfer reaction suggests great promise for dehydrogenase-based amperometric biosensors.
4. Carbon nanotube array-based biosensor.
Sofia Sotiropoulou • Nikolas A. Chaniotakis. (2002 October 31). Anal bioanal chem., (2003) 375 :103–105
Abstract: Aligned multi-wall carbon nanotubes (MWNT) grown on platinum substrate are used for the development of an amperometric biosensor. The opening and functionalization by oxidation of the nanotube array allows for the efficient immobilization of the model enzyme, glucose oxidase. The carboxylated open-ends of nanotubes are used for the immobilization of the enzymes, while the platinum substrate provides the direct transduction platform for signal monitoring. It is also shown that carbon nanotubes can play a dual role, both as immobilization
matrices and as mediators, allowing for the development of a third generation of biosensor systems, with good overall analytical characteristics.
5. Electrochemical detection of trace insulin at carbon-nanotube-modified electrodes.
Joseph Wang and Mustafa Musameh. (2004, May 24). Analytica chimica acta, Volume 511, Issue 1, Pages 33-36
Abstract: Carbon-nanotube (CNT)-modified glassy-carbon electrodes dramatically accelerate the electrooxidation of insulin to offer an attractive amperometric detection of this important hormone. Hydrodynamic voltammograms indicate a substantial lowering of the detection potential, with oxidation starting above +0.5 V (versus Ag/AgCl) and leveling off of the response above +0.7 V. The flow-injection amperometric response (at pH 7.4) is highly linear (to at least 1000 nM), reproducible (RSD=4.8%;n=30), and fast (peak width of 45 s). The high sensitivity (48 nA/μM) and moderate detection potential (+0.8 V) lead to a low detection limit of 14 nM. Such performance characteristics compare favorably with those of previously reported metal-oxide-modified electrodes for insulin, and indicate great promise for in vivo measurements of insulin release and for monitoring this hormone in chromatographic effluents.
6. Electrochemical detection of carbohydrates at carbon-nanotube modified glassy-carbon electrodes.
Randhir P. Deo and Joseph Wang. (2004, March). Electrochemistry communications, Volume 6, Issue 3, Pages 284-287
Abstract: This communication reports on the catalytic oxidation of carbohydrates and the sensitive and stable fixed-potential (+0.45 V) amperometric carbohydrate response at glassy-carbon electrodes modified with single-wall carbon-nanotube (CNT) coatings. Variables affecting the electrocatalytic oxidation are assessed and optimized. The oxidation process starts around +0.25 V using a 0.1 M NaOH electrolyte solution. The amperometric response is extremely stable, with no loss in sensitivity over a continuous 2 h operation. The flow-injection response is characterized with a detection limit of 10 μM galactose and a relative standard deviation of 3.45% (n=20). Such attractive performance characteristics indicate great promise for monitoring sugars in chromatographic effluents.
7. Carbon nanotube screen-printed electrochemical sensors.
Joseph Wang and Mustafa Musameh. (2004). Analyst, 129, 1 - 2, DOI: 10.1039/b313431h
Abstract: The fabrication, and evaluation of carbon-nanotube (CNT)-derived screen-printed (SP) electrochemical sensors based on a CNT ink are reported. The fabricated CNT strips combine the attractive advantages of CNT materials and disposable screen-printed electrodes. Such thick-film CNT sensors have a well-defined appearance, are mechanically stable, and exhibit high electrochemical reactivity.
8. Carbon-nanotube-modified glassy carbon electrodes for amplified label-free electrochemical detection of DNA hybridization.
Joseph Wang, Abdel-Nasser Kawde and Mustafa Musameh. (2003). Analyst, 128, 912 - 916
Abstract: The preparation and attractive performance of carbon-nanotube modified glassy-carbon (CNT/GC) electrodes for improved detection of purines, nucleic acids, and DNA hybridization are described. The surface-confined multiwall carbon-nanotube (MWCNT) facilitates the adsorptive accumulation of the guanine nucleobase and greatly enhances its oxidation signal. The advantages of CNT/GC electrodes are illustrated from comparison to the common unmodified glassy carbon, carbon paste and graphite pencil electrodes. The dramatic amplification of the guanine signal has been combined with a label-free electrical detection of DNA hybridization. Factors influencing the enhancement of the guanine signal are assessed and optimized. The performance characteristics of the amplified label-free electrochemical detection of DNA hybridization are reported in connection to measurements of nucleic-acid segments related to the breast-cancer BRCA1 gene.
9. The dissolution of carbon nanotubes in aniline, revisited.
Dmitrii F. Perepichka, Fred Wudl, Stephen R. Wilson, Yi Sun and David I. Schuster. (2004). J. Mater. Chem., 14, 2749 - 2752,
Abstract: Thorough examination of a previous report on the high solubility of carbon nanotubes in refluxing aniline reveals that the reported optical properties of the nanotube solution are due to aniline decomposition products, rather than functionalized nanotubes. No appreciable dissolution of single-wall carbon nanotubes can be achieved by this method, although some solubilization of multiwall nanotubes has been confirmed by SEM and TEM analyses.
10. Fabrication and biocompatibility of carbon nanotube-based 3D networks as scaffolds for cell seeding and growth.
Miguel A. Correa-Duarte, Nicholas Wagner, Jose´ Rojas-Chapana, Christian Morsczeck, Michael Thie, and Michael Giersig. (2004). Nano Letters, Vol. 4, No. 11 2233-2236
Abstract: Thin film networks of multiwalled carbon nanotubes (MWCNTs) were prepared by exerting chemically induced capillary forces upon the nanotubes. During this process MWCNTs undergo a transformation from being a vertically aligned structure to an interlocking resistive network of interconnected nanotubes, whose main feature is a regular three-dimensional (3D) sieve architecture. Due to their structural characteristics at
the nanoscale level, 3D-MWCNT-based networks are in principle ideal candidates for scaffolds/matrices in tissue engineering. Their potential application in this field was confirmed by extensive growth, spreading, and adhesion of the common mouse fibroblast cell line L929.
11. Nano-architecture on carbon nanotube surface by biomimetic coating.
Tsukasa Akasaka and Fumio Watari, Hokkaido University. (2005). Chemistry letters, Vol. 34, No. 6 p.826
Abstract: Calcium phosphate (Ca-P) coating on carbon nanotubes (CNTs) was done with a biomimetic coating method. The multi-walled CNTs (MWNTs) were immersed for 2 weeks in the simulated body fluid. Observation by scanning electron microscopy showed that needle shape of Ca-P crystallites at nano-scale levels were massively grown on MWNTs. Thus the nano-architecture of crystalline Ca-P on MWNT surface could be produced by simple method and the MWNT may be acting as core for initial crystallization.
12-1. Carbon nanotubes paste electrode.
María D. Rubianes and Gustavo A. Rivas. (2003, August). Electrochemistry communications, Volume 5, Issue 8, Pages 689-694
Abstract: The performance of carbon nanotubes paste electrodes (CNTPE) prepared by dispersion of multi-wall carbon nanotubes (MWNT) within mineral oil is described. The resulting electrode shows an excellent electrocatalytic activity toward ascorbic acid, uric acid, dopamine, 3,4-dihydroxyphenylacetic acid (dopac) and hydrogen peroxide. These properties permit an important decrease in the overvoltage for the oxidation of ascorbic acid (230 mV), uric acid (160 mV) and hydrogen peroxide (300 mV) as well as a dramatic improvement in the reversibility of the redox behavior of dopamine and dopac, in comparison with the classical carbon (graphite) paste electrodes (CPE). The substantial decrease in the overvoltage of the hydrogen peroxide reduction (400 mV) associated with a successful incorporation of glucose oxidase (GOx) into the composite material, allow the development of a highly selective and sensitive glucose biosensor without using any metal, redox mediator or anti-interference membrane. No interference was observed at −0.100 V even for large excess of ascorbic acid, uric acid and acetaminophen. A linear response up to 30 mM (5.40 g l−1) glucose with a detection limit of 0.6 mM (0.11 g l−1) were obtained with the CNTPE modified with 10% w/w GOx. Such an excellent performance of CNTPE toward hydrogen peroxide, represents a very good alternative for developing other enzymatic biosensors.
12-2. Carbon nanotubes paste electrodes as new detectors for capillary electrophoresis.
M. Chicharro, A. Sanchez, E. Bermejo, A. Zapardiel, M. D. Rubianes and G. A. Rivas Analytica Chimica Acta, CNT paste electrodes as new detectors for capillary electrophoresis
Abstract:Carbon nanotubes paste electrodes (CNTPE) prepared with short (1–5mlength) and long carbon nanotubes (5–20mlength) of 20–50 nm
diameter have demonstrated to be highly useful as detectors in flow injection analysis and capillary electrophoresis. Compared to the classical
graphite paste electrode, CNTPE improved the detection limits of dopac, ascorbic acid, dopamine, norepinephrine and epinephrine. The content
of agglutinant has shown to be an important variable in the preparation of these carbon nanotubes composites. Even when no substantial
differences were observed between the electrodes, those prepared with long carbon nanotubes (55.0%, w/w) and mineral oil (45.0%, w/w)
have allowed us to obtain less noisy and more reproducible signals. In this article we also report the successful use of a new electrochemical
cell for the detection in capillary electrophoresis that allows an easier handling and more reproducible responses. Therefore, the combination
of the carbon nanotubes electrocatalytic activity with the known advantages of composite materials, the efficiency of the new electrochemical
cell and the excellent separative properties of capillary electrophoresis represents a very important alternative for new electroanalytical
© 2005 Elsevier B.V. All rights reserved.
13. Adsorption and electrooxidation of nucleic acids at carbon nanotubes paste electrodes.
María L. Pedano and Gustavo A. Rivas. (2004, January). Electrochemistry communications, Volume 6, Issue 1, Pages 10-16
Abstract: Carbon nanotubes paste electrodes (CNTPE) are shown to be suitable for adsorptive stripping potentiometric measurements of trace levels of nucleic acids. The influence of surface pretreatments, paste composition, nature of the nucleic acid, and accumulation conditions on the adsorption and further electrooxidation of different oligonucleotides and polynucleotides at CNTPE is described. The electroactivity inherent to carbon nanotubes has allowed us to obtain a large enhancement of the guanine oxidation signal compared to that obtained at its analogue carbon (graphite) paste electrode (CPE). Trace (μg/l) levels of the oligonucleotides and polynucleotides can be readily detected following short accumulation periods with detection limits of 2.0 μg/l for a 21 bases oligonucleotide and 170 μg/l for calf thymus dsDNA. The interaction between nucleic acids and CNTPE demonstrated to be mainly hydrophobic. The confined DNA layers demonstrated to be stable in air, in 0.200 M acetate buffer pH 5.00 and in 0.020 M phosphate buffer pH 7.40 + 0.50 M NaCl.
14. Detection of homocysteine at carbon nanotube paste electrodes.
Nathan S.Lawrence, Randhir P. Deo and Joseph Wang. (2004, May 28). Talanta, Volume 63, Issue 2, Pages 443-449
Abstract: The use of a carbon-nanotube paste (CNTP) electrode provides an effective means for the determination of homocysteine. A decrease of ca. 120 mV in the overpotential for the oxidation of homocysteine compared to a traditional carbon paste electrode, is reported along with greatly enhanced signal-to-noise characteristics. The analytical parameters have been assessed with a linear range from 5 to 200 μM and a detection limit of 4.6 μM. Furthermore, the generic nature of this increased reactivity of the CNTP surface towards thiol moieties has been demonstrated with cysteine, glutathione and n-acetylcysteine, providing a greatly enhanced electrochemical response compared to the carbon paste electrode.
15. Enzyme-dispersed carbon-nanotube electrodes: a needle microsensor for monitoring glucose.
Joseph Wang and Mustafa Musameh. (2003). Analyst, 2003, 128, 1382 - 1385, DOI: 10.1039/b309928h
Abstract: The preparation of an enzyme-dispersed carbon-nanotube (CNT) electrode, based on mixing glucose oxidase (GOx) within CNT, is described. The new binderless biocomposite was packed within a 21-gauge needle and used for amperometric monitoring of glucose. The resulting microsensor offers a low-potential highly selective and sensitive detection of glucose. The high sensitivity and selectivity are coupled to a wide linear range, prolonged lifetime and oxygen independence. About 80% of the GOx activity is retained during a 24 h thermal stress at 90 °C, reflecting the enzyme-stabilization action of CNT. The marked electrocatalytic action towards hydrogen peroxide allows highly selective detection of the glucose substrate at –0.1 V (vs. Ag/AgCl) with no interferences from coexisting ascorbic acid, acetaminophen or uric acid. Linearity prevails up to 40 mM glucose (with analytically useful signals observed up to 0.1 M). Factors affecting the performance of the CNT-based glucose biosensor were assessed and optimized. The attractive performance of the new needle electrode offers great promise for continuous monitoring of glucose in connection to the management of diabetes, and for the biosensing of other metabolites.
16. Abrasive immobilization of carbon nanotubes on a basal plane pyrolytic graphite electrode: application to the detection of epinephrine.
Abdollah Salimi, Craig E. Banks and Richard G. Compton. (2004). Analyst, 2004, 129, 225 - 228, DOI: 10.1039/b315877b
Abstract: The performance of a basal plane pyrolytic graphite (bppg) electrode modified with carbon nanotubes is described. Abrasive immobilization of multiwall carbon nanotubes on a bppg electrode was achieved by gently rubbing the electrode surface on a filter paper supporting carbon nanotubes. The resulting electrode showed excellent mediation of epinephrine oxidation: a decrease in the overvoltage of the epinephrine electro-oxidation (200–500 mV) was observed as well as a dramatic increase in the peak current (4 times) compared to that seen at a bare bppg electrode. The oxidation peaks of epinephrine and ascorbic acid which overlap on bare bppg electrode were separated successfully (by ca. 220 mV) at the surface of the modified bppg electrode. The modified electrode showed good stability in comparison to most modified carbon nanotubes electrodes prepared by alternative methods.
17. Investigation of modified basal plane pyrolytic graphite electrodes: definitive evidence for the electrocatalytic properties of the ends of carbon nanotubes.
Craig E. Banks, Ryan R. Moore, Trevor J. Davies and Richard G. Compton. (2004). Chem. Commun., 2004, 1804 - 1805, DOI: 10.1039/b406174h
Abstract: The basis of the electrocatalytic nature of multi-wall carbon nanotubes is suggested to reside in electron transfer from the ends of nanotubes, which structurally resemble the behaviour of edge plane (as opposed to basal plane) graphite, and is demonstrated via the comparison of the electrochemical oxidation of epinephrine and the electrochemical reduction of ferricyanide at nanotube-modified electrodes using different types of graphite electrodes and with C60-modified electrodes.
18. Electrochemical reduction of oxygen on multiwalled carbon nanotube modified glassy carbon electrodes in acid media.
Nadezda Alexeyeva, Kaido Tammeveski. (2007). Electrochem. solid-state iett., Volume 10, Issue 5, pp. F18-F21
Abstract: The electrocatalytic reduction of oxygen has been studied on multiwalled carbon nanotube (MWCNT) modified glassy carbon (GC) electrodes in 0.5 M H2SO4 solution using the rotating disk electrode technique. The oxygen reduction behavior of oxidatively pretreated and untreated MWCNT modified GC electrodes was compared. The results obtained indicate that the electrocatalytic properties of untreated MWCNTs toward O2 reduction in acid media are noticeably better than that of pretreated MWCNTs. This effect is caused by catalyst impurities which remain in the nanotubes prepared by chemical vapor deposition and can be largely removed by treatment in acids.
19. Carbon nanotube-mediated delivery of nucleic acids does not result in non-specific activation of B lymphocytes.
Dong Cai, Cheryl A Doughty, Terra B Potocky, Fay J Dufort,Zhongping Huang, Derek Blair, Krzysztof Kempa, Z F Ren and Thomas C Chiles. (2007). Nanotechnology18 (2007) 365101 (10pp)., Volume 10, Issue 5, pp. F18-F21
See CNT mediated delivery
Abstract:The efficient delivery of genes and proteins into primary mammalian cells and tissues has represented a formidable challenge. Recent advances in the
research of carbon nanotubes (CNTs) offer much promise for their use as delivery platforms into mammalian cells. Ideally, CNT-mediated applications should not result in cellular toxicity nor perturb cellular homeostasis (e.g.,
result in non-specific activation of primary cells). It is therefore critical to evaluate the impact of CNT exposure on the cellular metabolism, proliferation and survival of primary mammalian cells. We investigated the compatibility of a recently developed CNT-mediated delivery method, termed nanospearing, with primary ex vivo cultures of B lymphocytes. Several parameters were evaluated to assess the impact of CNTs on naive B lymphocytes, including cell survival, activation, proliferation and intracellular signal transduction. Our results indicate that nanospearing does not result in the activation of naive primary B lymphocytes nor alter survival in ex vivo cultures. Herein, B cells exposed to CNTs were capable of responding to extrinsic pro-survival signals such as interleukin-4 and signaling by the B-cell antigen receptor in a manner similar to that of B cells cultured in the absence of CNTs. Our study demonstrates the bioocompatibility of the CNT-mediated nanospearing procedure with respect to primary B lymphocytes.
20.Highly efficient molecular delivery into mammalian cells using carbon nanotube spearing
Dong Cai,Jennifer M Mataraza,Zheng-Hong Qin,Zhongping Huang,Jianyu Huang,Thomas C Chiles,David Carnahan, Krzysztof Kempa & Z F Ren. (2005). Nature Methods June(2005)., Volume 2,No.6, pp.449-454
Abstract:Introduction of exogenous DNA into mammalian ceLLs represents a powerful approach for manipuLating signal transduction. The avaiLable techniques, however, are limited by Low transduction efficiency and Low cell viability after transduction. Here we report a highly efficient molecular delivery technique, named nanotube spearing, based on the penetration of nickel-embedded nanotubes into cell membranes by magnetic field driving. DNA pLasmids containing the enhanced green fluorescent protein (EGFP) sequence were immobilized onto the nanotubes,and subsequently speared into targeted cells. We have achieved an unprecedented high transduction efficiency in Ba117 B-lyinphoma, ex vivo B cells and primary neurons with high viability after transduction. This technique may provide a powerful tool for highly efficient gene transfer into a variety of cells,especially the hard-to-transfect cells.
21.Carbon Nanotube Nanoelectrode Array for Ultrasensitive DNA Detection
Jun Li,Hou Tee Ng, Alan Cassell,Wendy Fan,Hua Chen,Qi Ye,Jessica Koehne, Jie Han, and M. Meyyappan. NANO
LETTERS June(2003)., Volume 3,No.5, pp.597-602
Abstract:A nanoelectrode array based on vertically aligned multiwalled carbon nanotubes (MWNTs) embedded in SiO2 is used for ultrasensitive DNA
detection. Characteristic electrochemical behaviors are observed for measuring bulk and surface-immobilized redox species. Sensitivity is dramatically improved by lowering the nanotube density. Oligonucleotide probes are selectively functionalized to the open ends of nanotubes.
The hybridization of subattomole DNA targets can be detected by combining such electrodes with Ru(bpy)32+ mediated guanine oxidation.
22.Interaction between carbon nanotubes and mammalian cells: characterization by flow cytometry and application
Dong Cai,Derek Blair, Fay J Dufort, Maria R Gumina,
Zhongping Huang, George Hong, DeanWagner, D Canahan,
KKempa, Z F Ren and Thomas C Chiles
Nanotechnology 19 (2008) 345102 (10pp)
Abstract:We show herein that CNT–cell complexes are formed in the presence of a magnetic field. The
complexes were analyzed by flow cytometry as a quantitative method for monitoring the
physical interactions between CNTs and cells. We observed an increase in side scattering
signals, where the amplitude was proportional to the amount of CNTs that are associated with
cells. Even after the formation of CNT–cell complexes, cell viability was not significantly
decreased. The association between CNTs and cells was strong enough to be used for
manipulating the complexes and thereby conducting cell separation with magnetic force. In
addition, the CNT–cell complexes were also utilized to facilitate electroporation. We observed a
time constant from CNT–cell complexes but not from cells alone, indicating a high level of pore
formation in cell membranes. Experimentally, we achieved the expression of enhanced green
fluorescence protein by using a low electroporation voltage after the formation of CNT–cell
complexes. These results suggest that higher transfection efficiency, lower electroporation
voltage, and miniaturized setup dimension of electroporation may be accomplished through the CNT strategy outlined herein.