Efficient guest inclusion by ß-cyclodextrin attached to the ends of DNA oligomers upon hybridization to various DNA conjugates.

Two types of 5'-ß-CyD-DNA conjugates were synthesized using two different strategies and were hybridized with cDNA conjugates bearing various possible guest compounds at the 3' ends. One of the ß-CyD conjugates was synthesized on the basis of solid-phase postmodification of DNA with a monoamino-ß-CyD derivative on a synthesis column for automated DNA synthesis. The other ß-CyD conjugate was synthesized by the solution-phase coupling of DNA with a monomercapto-ß-CyD derivative using a heterobifunctional cross-coupling reagent. When these 5'-ß-CyD-DNA conjugates were hybridized with cDNA conjugates bearing 1-adamantaneacetic acid at the 3' ends, significant stabilization of the duplexes was observed as compared with the control duplex without ß-CyD. Duplexes of 5'-ß-CyD-DNA conjugates and complementary 3'-dansyl-glycine-DNA conjugates were also moderately stabilized. Thermodynamic measurements revealed that the host-guest inclusion interactions between ß-CyD and 1-adamantaneacetic acid or dansyl-glycine are roughly as strong as those found in bulk solution even if they are tethered to the ends of the DNA.

Electrochemical signal modulation in homogeneous solutions using the formation of an inclusion complex between ferrocene and ß-cyclodextrin on a DNA scaffold.

Two DNA conjugates modified with ferrocene and ß-cyclodextrin were prepared as a pair of probes that work cooperatively for DNA sensing, in which the electrochemical signal of ferrocene on one probe was significantly "quenched" by the formation of an inclusion complex with ß-cyclodextrin of the other probe on the DNA templates.