Modified oligonucleotides for the functionalisation of nanoscale materials

The overall aim of this research was to develop a novel ligand for biomolecular functionalisation with a view to enhancing the stability of oligonucleotide-nanoparticle conjugates and assessing the suitability of a nanostructured surface for the detection of hybridisation events by surface enhanced resonance Raman scattering (SERRS). Thioctic acid was considered a suitable linker group with which to tether oligonucleotides to nanoparticle substrates. As such, routes to the modification of oligonucleotides by thioctic acid are reported herein. Although the phosphoramidite method was found to be unsuccessful, the H-phosphonate method has been shown to be effective for direct modification. In addition, a key intermediate - the N-hydroxysuccinimidyl ester of thioctic acid - has been isolated and employed in the modification of oligonucleotides. Pre- and post-synthetic modification of oligonucleotides by thioctic acid is shown. As a result of this research thioctic acid modified oligonucleotides are now commercially available as is the N-hydroxysuccinimidyl ester intermediate. Thioctic acid modified oligonucleotides have been conjugated to both gold and silver nanoparticles. The successful preparation of these materials was confirmed and the ability of both gold and silver nanoparticle conjugates to function as hybridisation sensors has been shown. This has extended the methodology of hybridisation induced aggregations from gold to silver nanoparticles. The stability of the thioctic acid oligonucleotide nanoparticle conjugates was investigated and found to be greatly enhanced with respect to monothiol linked analogues. A commercially available nanostructured surface was used to confirm the suitability of dye labelled thioctic acid modified oligonucleotides for SERRS detection. The ability to detect a hybridisation event was also investigated. The NHS-ester of thioctic acid was employed as a surface activation group. Dip pen nanolithography was used to immobilise thioctic acid modified oligonucleotides for the detection of an unmodified, biologically relevant, target sequence by SERRS.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2009

Author dc:creator

• Dougan, Jennifer Anne

DOI

10.48730/n9ge-4m57

Identifier

T12656

OAI identifier oai:identifier

oai:strathclyde:1r66j1131