Plasmonic nanostructures, like noble metal, have gained large attention due to their plasmonic properties so they can reach areas like electronics, photo-catalysis, biomedicine, and sensing. Plasmonic nanomaterials are known for their local surface plasmon resonance and enhanced electromagnetic field and wavelength dependence. The higher the electromagnetic field at the surface of the nanoparticles can interact with nearby molecules, the bigger the influence is on the intensity of the molecule signals. This phenomenon is called surface-enhanced Raman scattering (SERS) and plasmonic enhanced fluorescence (PEF), which enable the plasmonic nanomaterials as a signal amplifier. By using these plasmonic nanostructures as a signal amplifier, SERS and PEF have become ultrasensitive methods in biomedicine and biosensing. Plasmonic biosensing is fast and label-free detection of biologically relevant analytes in real time. The objective of my doctoral dissertation focusses on developing new plasmonic nanostructures for detecting biomarkers related to cancers and some other diseases based on hybrid platforms. In this work, a newly spiky nanostructure was developed, internal standard Raman molecules were embedded into the nanostructure for quantitative SERS detection of polycyclic aromatic hydrocarbons molecules. Then the morphology and dispersity of this nanostructure were optimized to get an approximately fusiform shape, which showed a stable, reproducible and high SERS signals. This nanostructure was furtherly functionalized by double strand DNA and aptamer, showing a good performance in drug delivery and detecting circulating tumor cells. Inspired by the mechanism of SERS, a SERS and PEF dual model sensor based on plasmonic nanostructures and newly synthesized probe molecules was developed. This dual model sensor combined the advantages of SERS and PEF and exhibited a lower limit of detection of γ-glutamyl transferase in living cells. This dissertation contains the fabrication of newly plasmonic nanostructures and utilizing them in bioanalysis.
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