Synthesis of oligonucleotide analogues for use in DNA nanostructures

Thanks to its ability to form duplexes through selective base-pair recognition, DNA is a<br/>unique material for orderly self-assembled construction at the nanoscale. To develop a<br/>nanotechnology platform on a grid of addressable molecular building blocks using DNA<br/>node structures, DNA complexes need to be fixed onto surfaces. To fulfil this<br/>requirement on lipid membranes, phosphoramidites monomers modified with a<br/>cholesterol moiety and a spacer unit were synthesised. The hydrophobic spacer provides<br/>separation between the hydrophobic cholesterol moiety and the phosphate backbone of<br/>the DNA strand. For better anchorage of the network to a lipid surface, a hydrophilic<br/>spacer was also used to link the cholesterol to the nucleoside. Solution studies demonstrated that the melting temperature (Tm) of the duplex with<br/>adjacent cholesterols on each strand is much higher than that of the unmodified duplex.<br/><br/>The reliable and highly selective copper(I)-catalysed azide-alkyne 1,3-dipolar<br/>cycloadition (CuAAC), the best known example of click chemistry, has proven to be of<br/>remarkably broad utility in synthetic chemistry and in nucleic acid chemistry in<br/>particular. CuAAC was exploited for the synthesis of a very stable double stranded<br/>catenane duplex. The catenane was formed from a single stranded cyclic template and<br/>its linear complement, using a third short oligonucleotide (ODN) as a helper for the<br/>circularisation of the second ODN. The copper(I)-catalysed cyclisation of<br/>oligonucleotides occurred by reaction between their terminal azide and their opposite<br/>terminal alkyne, to produce a 1,2,3-triazole linkage between the two reactants. The<br/>catenane was characterised by denaturing polyacrylamide gel electrophoresis, UV<br/>melting studies and enzyme digestion.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2010

Author dc:creator

• Durand, Adeline

Advisor dc:contributor.advisor

• Brown, T.