Thesis

Nanoparticle probes for the study of biomolecular interactions

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Awarding institution
  • University of Strathclyde
Date of award
  • 2010
Thesis identifier
  • T12647
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Abstract
  • There is a growing requirement to be able to detect interactions between biological molecules to develop our understanding of disease expression and progression and for improvement of patient diagnosis in medical applications. One of the most effective ways this can be achieved is to label biomolecules with optically active reporters. To date this has been performed using fluorescent dyes; however there has been recent interest in the use of noble metal nanoparticles due to their large extinction coefficients and near-field properties. This research details the preparation of oligonucleotide functionalised gold and silver nanoparticles for the detection of single and double stranded DNA sequences. The oligonucleotides are modified to incorporate locked nucleic acid (LNA) ribose sugars, affording highly advantageous affinity and selectivity properties. Hybridisation of the probes with the target sequence was monitored colorimetrically and by extinction spectroscopy. Double stranded DNA was targeted through formation of a triple-stranded DNA structure via Hoogsteen hydrogen bonding. The nanoparticle probes were further utilised for detection by surface enhanced resonance Raman scattering (SERRS). This method of detection enables multiple DNA sequences to be detected simultaneously due to the molecularly specific and narrow emission spectral profiles obtained. As such, the multiplexing capabilities of this detection method were investigated, indicating that as many as five dye-labelled oligonucleotides could be identified within one spectrum without application of chemometric techniques. A novel method for the incorporation of a SERRS label into oligonucleotide nanoparticle probes was developed which was found to be compatible with a number of commercially available dyes, increasing their potential in multiplexed analysis. Biomolecular SERRS detection was also extended towards cellular analysis using antibody functionalised gold nanoparticles for targeting cell surface receptors. Conjugation was achieved using a novel linker incorporating a chromophore excitable by near-infrared radiation. Using SERRS line mapping, numerous cells could be analysed and were shown to exhibit discrete areas of receptor expression which was quantified by inspection of SERRS intensity and the number of active pixels in the SERRS map.
Resource Type
DOI
Date Created
  • 2010
Former identifier
  • 818787

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