Carbon Nanotubes by Cycloaddition

The covalent methods previously discussed for fullerene modification using cycloaddition reactions also can be applied to carbon nanotubes. This strategy results in chemically linking molecules to the graphene rings on the outer surface of the cylinder, resulting in stable 

Felekis and Tagmatarchis (2005) used this cycloaddition process to prepare SWNT derivatives possessing photoactive components, such as the addition of ferrocene groups. They used a short PEG-type spacer on the glycine to impart water solubility at the same time. 

The demonstration that the 1,3-dipolar cycloaddition process with azomethine ylides works with nanotubes implies that similar reactions developed for use with fullerenes also may be successful with carbon nanotubes. In particular, the cyclopropanation reactions discussed previously for the modification of Cg0, likely will work for derivatization of SWNTs and MWNTs (Zakharian et al., 2005). 

Mass spectrometry has become one of the most important tools for analyzing proteins in complex biological samples. The ability to separate proteins and peptides in high resolution has made possible the simultaneous identification of hundreds of proteins within samples (for reviews, see Gingras et al., 2005 Hamdan and Righetti, 2005 Siuzdak, 2006). Proteins can be analyzed for their presence or compared between samples for their relative expression level. One cell population treated with a drug candidate, for instance, can be compared by mass spec to another sample as control to assess the affect of the drug on expression levels of certain proteins. 

The following sections describe some of the major mass tag types and discuss the general protocols for their use. 

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