Reversible immobilisation of DNA and metal nanoparticles on engineered surfaces using the fluorous effect

Onilude, Hammed Ayantola (2024) Reversible immobilisation of DNA and metal nanoparticles on engineered surfaces using the fluorous effect. PhD thesis, University of Glasgow.

Abstract

This thesis investigates the reversible attachment of nanomaterials to modified surfaces via the fluorous effect, a hydrophobic and non-covalent interaction involving perfluorinated molecules or molecules with a high fluorine content. The study introduces a novel approach to utilising the fluorous effect for the reversible attachment of fluorous-tagged nanomaterials, such as DNA and nanoparticles, on fluorous-modified patterned glass surfaces.

In the first method, the stability of perfluorinated DNA when immobilised on solid support was evaluated based on factors including size, the number of fluorine atoms attached, branching systems, and the incorporation of a spacer/linker. The results revealed that the attachment strength of the DNA to the solid support increases with the length of the DNA chain, the number of branches, and a higher number of incorporated fluorine atoms. Consequently, the methanol concentration necessary to detach these strands from the solid support correlates with the number of attached fluorines. Additionally, the study compared the selective removal of different fluorous-tagged DNA structures (single and branched) based on their attachment strength to the fluorous-modified solid support. The results revealed that as the number of branch systems increases from one to four, the strength of attachment increases with the highest strength from the tetra-branch (four branches) without a linker, and the perfluorinated chains can be selectively removed from the solid support. This method is suitable for multiplex systems to identify and selectively remove target probes.

The second method extends this approach to the reversible attachment of thiolmodified metal nanoparticles (gold and silver) in aqueous environments. Here, citrate-coated gold nanoparticles of varying sizes (15 nm, 20 nm, and 45 nm) and chloride-coated silver nanoparticles (52 nm) were functionalised and reversibly attached to an 800 µm-sized fluorous-modified micropatterned surface. This method enables the repeatable and switchable attachment of gold and silver nanoparticles on the same reusable surface multiple times without damaging the fluorous-modified layer.

Finally, the fluorous effect facilitated the self-assembly of 55 nm gold nanoparticles on a fluorous-modified nanopatterned surface (sub-500 nm). This method demonstrated repeatability at 500 nm without unwanted aggregation and promising outcomes in the sub-100 nm region, enabling single-particle attachment.

Overall, this research highlights the potential of the fluorous effect in the selfassembly of nanomaterials, offering a practical method for microarray development and the reversible attachment of nanomaterials on solid supports.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QH Natural history > QH426 Genetics; T Technology > TA Engineering (General). Civil engineering (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Supervisor's Name: Clark, Professor Alasdair
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84888
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Feb 2025 15:02
• Last Modified: 12 Feb 2025 08:31
• Thesis DOI: 10.5525/gla.thesis.84888
• URI: https://theses.gla.ac.uk/id/eprint/84888

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