Intercalation, chromonics

The Effect of Additives on Chromonic Systems Miscibility and Intercalation... 

Intercalating species By analogy with the general mutual solubility of lipids and conventional alkyl chain amphiphiles or with the co-miscibility of smectic phases of the same type, it might be expected that the co-miscibility of chromonic species would be widespread. Complete miscibility has been found in only a few cases, but the intercalation of sol-... 

Figure 13. The chromonic nature of DNA (a) A stylized sketch of the B form of DNA showing the central stack of base pairs and the two helical sugar-phosphate chains, (b) A chromonic column of unpolymerized molecules, to be compared with the central stack of bases in DNA. (c) The intercalation of a guest molecule in DNA. Note the untwisting of the sugar-phosphate chain to accommodate the host molecule, (d) The intercalation of a guest molecule in an unpolymerized chromonic column.

The ease of intercalation of other chro-monic and potentially chromonic materials. A number of biochemical reagents, such as acridines and ethidium bromide, intercalate readily between the stacked bases in DNA and RNA. Anticancer drugs, such as the square planar platinum complexes, intercalate avidly (Fig. 14) and naturally occurring antibiotics, such as actinomycin, similarly act by intercalation into the stack of bases [67]. They act as tailor-made spanners in the works and prevent the reading and replication of DNA. 

Many compounds of commercial interest, e.g., dyes, drugs, antibiotics, and anticancer agents, are either chromonic or have sufficiently chromonic character to be able to intercalate into chromonic systems. However, there is a distinction between commercially useful compounds, which incidentally happen to form liquid-crystalline phases, and compounds that have technological value specifically because of their mesogenic properties. 

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