CARBON nanotubes1 are expected to have a wide variety of interesting properties. Capillarity in open tubes has already been demonstrated2–5, while predictions regarding their electronic structure6–8 and mechanical strength9 remain to be tested. To examine the properties of these structures, one needs tubes with well defined morphologies, length, thickness and a number of concentric shells; but the normal carbon-arc synthesis10,11 yields a range of tube types. In particular, most calculations have been concerned with single-shell tubes, whereas the carbon-arc synthesis produces almost entirely multi-shell tubes. Here we report the synthesis of abundant single-shell tubes with diameters of about one nanometre. Whereas the multi-shell nanotubes are formed on the carbon cathode, these single-shell tubes grow in the gas phase. Electron diffraction from a single tube allows us to confirm the helical arrangement of carbon hexagons deduced previously for multi-shell tubes1.

Single-shell carbon nanotubes of 1-nm diameter

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.

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Carbon Nanotubes: Present and Future Commercial Applications

Nanoparticles — particles in the size range 1–100 nm — are emerging as a class of therapeutics for cancer. Early clinical results suggest that nanoparticle therapeutics can
show enhanced efficacy, while simultaneously reducing side effects, owing to properties such as more targeted localization in tumours and active cellular uptake. Here, we
highlight the features of nanoparticle therapeutics that distinguish them from previous anticancer therapies, and describe how these features provide the potential for
therapeutic effects that are not achievable with other modalities. While large numbers of preclinical studies have been published, the emphasis here is placed on preclinical and clinical studies that are likely to affect clinical investigations and their implications for advancing the treatment of patients with cancer.

Nanoparticle therapeutics: an emerging treatment modality for cancer

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Mechanical damage of carbon nanotubes by ultrasound

THE discovery1 and bulk synthesis2 of carbon nanotubes has stimulated great interest. It has been suggested that these structures may have useful electronic3–5 and mechanical6 properties, and these might be modified by introducing foreign materials into the nanotubes. But the tubes are invariably capped at the ends. Ajayan and lijima7 have succeeded in drawing molten material (lead or one of its compounds) into the tubes by heating them in the presence of lead and oxygen; less than 1% of the tubes in the sample studied could be filled in this way. Here we report that heating in carbon dioxide gas can result in the partial or complete destruction of the tube caps and stripping of the outer layers to produce thinner tubes. In some cases, we have thinned the extremity of tubes to a single layer. The opened tubes can be regarded as nanoscale test-tubes for adsorption of other molecules, and this controlled method of thinning may allow studies of the properties of single tubes.

Thinning and opening of carbon nanotubes by oxidation using carbon dioxide

A review of the main developments in the partial oxidation of methane to synthesis gas since the first paper in 1929 to the present day is given. The reaction is discussed from the view of the thermodynamics; the main catalysts studied for the reaction are summarised, and the reaction mechanism is discussed. The review is not comprehensive, but it is designed to provide a general background to the most important developments in the field.

Brief Overview of the Partial Oxidation of Methane to Synthesis Gas

Recent advances in the conversion of methane to synthesis gas

Metalloproteins and enzymes can be immobilized on SWNTs of different surface chemistry. The combination of high surface area, robust immobilization and inherent nanotube electrochemical properties is of promising application in bioelectrochemistry.

Malcolm L. H. Green

Papers

Mechanical damage of carbon nanotubes by ultrasound

Thinning and opening of carbon nanotubes by oxidation using carbon dioxide

Brief Overview of the Partial Oxidation of Methane to Synthesis Gas

Recent advances in the conversion of methane to synthesis gas

Bioelectrochemical single-walled carbon nanotubes.