Thesis

Rational design of SERS active silica coated silver nanoparticles as a versatile platform for semi-quantitative bio-imaging

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Awarding institution
  • University of Strathclyde
Date of award
  • 2012
Thesis identifier
  • T13510
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Abstract
  • In recent years there has been an increased demand for real-time detection of specific biological species and interactions within a meaningful environment. Surface enhanced Raman scattering (SERS) from metallic nanoparticles represents an approach under development with added advantages over fluorescence. One such benefit is the narrower vibrational bands in SERS compared to fluorescence which increases potential for simultaneous detection of more than one species. The use of metallic nanoparticles in Raman enhancement is hindered by non-specific adsorption of contaminating species and uncontrolled aggregation in vivo. Silica encapsulation of the nanoparticles results in a biocompatible and robust substrate with consistent surface chemistry. While gold nanoparticles have been shelled in silica by many different methods, transfer of encapsulation methods to silver has not been possible due to the reduced chemical stability of silver. New surface chemistries are therefore required to achieve reproducible, silica encapsulated silver nanoparticles. Tri-functional molecules were synthesised which stabilise the silver nanoparticle core, act as (resonance) Raman reporters and provide suitable precursors for subsequent silica encapsulation. Subsequent bio-functionalisation of these nanoparticles, by covalent attachment of proteins, generates SERS active bioimaging nanoparticles. Raman mapping of biological samples has been used for ex vivo detection and imaging of the inflammatory marker tumour necrosis factor. Semi-quantitative discrimination, of cerebral tissue sections, was achieved between mice infected with experimental cerebral malaria and uninfected controls. These results were produced using both 632.8 nm and 514.5 nm excitation wavelengths. In this work, a sensitive SERS based approach to biomolecule imaging has been developed. Successful targeting of TNF using silver nanoparticles, and excitation wavelengths in the visible region, may provide advantages over the use of gold in a wide range of SERS based applications.
Resource Type
DOI
Date Created
  • 2012
Former identifier
  • 996268

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