Nucleic acids water solubility

Lipids differ from the other classes of naturally occurring biomolecules (carbohy drates proteins and nucleic acids) in that they are more soluble m nonpolar to weakly polar solvents (diethyl ether hexane dichloromethane) than they are m water They include a variety of structural types a collection of which is introduced m this chapter... 

Neutral Water-Soluble Polymers Containing Nucleic Acid Bases. . . . 143... 

Neutral Water-Soluble Polymers Containing Nucleic Acid Bases... 

The N-3 position of uracil also can be modified with carbodiimide reagents. In particular, the water-soluble carbodiimide CMC [l-cyclohexyl-3-(2-morpholinoethyl) carbodiimide, as the metho p-toluene sulfonate salt] can react with the N-3 nitrogen at pH 8 to give an unstable, charged adduct. The derivative is reversible at pH 10.5, regenerating the original nucleic acid base (Figure 1.47). Cytosine is unreactive in this process. 

Delayed action cytotoxins that inhibit the synthesis of nucleic acids. They are obtained from various molds/fungi (Aspergillus flavus, Aspergillus parasiticus). They are colorless to pale-yellow crystalline materials melting above 450°F. The "B" toxins fluoresce blue in the presence of UV light while the "G" toxins fluoresce green. They are only slightly soluble in water, but are soluble in methanol, acetone, and chloroform. Aqueous solutions are "probably stable" and "probably tolerant" to chlorine at purification concentrations. 

Gel electrophoresis is widely used in the routine analysis and separation of many well-known biopolymers such as proteins or nucleic acids. Little has been reported concerning the use of this methodology for the analysis of synthetic polymers, undoubtedly since in many cases these polymers are not soluble in aqueous solution - a medium normally used for electrophoresis. Even for those water-soluble synthetic polymers, the broad molecular weight dispersities usually associated with traditional polymers generally preclude the use of electrophoretic methods. Dendrimers, however, especially those constructed using semi-controlled or controlled structure synthesis (Chapters 8 and 9), possess narrow molecular weight distribution and those that are sufficiently water solubile, usually are ideal analytes for electrophoretic methods. More specifically, poly(amidoamine) (PAMAM) and related dendrimers have been proven amendable to gel electrophoresis, as will be discussed in this chapter. 

Electrophoresis is normally run in aqueous media, hence the analytes must be soluble in water. Presently only three types of water-soluble dendrimers have been successfully analyzed using gel electrophoresis techniques. The list includes Starburst PAMAM dendrimers [21], nucleic acid dendrimers [21] and poly(lysine) dendrimers [23, 24] (see Figures 10.2, 10.4 and 10.6). However, in each case appropriate water solubilizing terminal groups are required (i.e. -NH2, -OH or C02H groups) for suitable electrophoretic analysis. 

In summary, dendrimers are a unique class of monodispersed synthetic molecules reminiscent of proteins or nucleic acids. If they can be functionalized to be soluble in water with appropriately charged terminal groups, they are generally ideal candidates for gel electrophoretic analyses. 

Gaylord BS, Heeger AJ, Bazan GC (2002) DNA detection using water-soluble conjugated polymers and peptide nucleic acid probes. Proc Natl Acad Sci USA 99 10954—10957... 

The reaction of the p-nitrophenyl esters with the polymer (4) was studied in dimethyl sulfoxide ( DMSO ) solution in the presence of triethylamine at 25°C. The poly-L-lysine derivatives obtained have different IR absorption spectra from those of the starting compounds, and have absorptions assigned to the nucleic acid bases. Poly( e,N-Ade-L-lysine )(5) was soluble in DMSO and ethylene glycol, and also in water below pH 3, where it was present as a protonated form. In dimethylformamide (... 

Through van der Waals and hydrophobic interactions, CNTs were functionalised and made water soluble by the strong adsorption of phospholipids (PLs) grafted onto amino-terminated polyethylene glycol (PEG). The group of Dai bound nucleic acids (DNA and RNA) and proteins to CNTs for specific detection of antibodies (Chen et al., 2003 Kam et al., 2005a, b Liu et al., 2007b). 

Concerning utilisation of CNTs for the delivery of nucleic acids, CNTs have already been shown to be versatile platforms for nucleic acid delivery in vitro and in vivo because of their high surface area, facile functionalisation of their surface and their ability to cross the cell membranes. To our knowledge, it is crucial to functionalise the surface of CNTs, in order to transform nonfunctionalised CNTs (insoluble in most solvents) into water-soluble and biocompatible CNTs. On the other hand, with a growing number of functionalisation routes, many important questions remain unanswered. Each functionalisation method is probably producing... 

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