Artificial enzymes have become an increasingly interesting area of research due to their many advantages over natural protein enzymes which are expensive, difficult to isolate and unable to stand harsh environments. An important area of this research involves using metal nanoparticles as artificial enzymes, known as nanozymes, which exhibit peroxidase-like activity enabling them to catalyse the oxidation of substrates such as 3,3’,5,5’-tetramethylbenzidine (TMB) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and in the presence of hydrogen peroxide (H2O2). This yields a colorimetric response which can be characterised using ultraviolet-visible (UV-vis) spectroscopy, Resonance Raman scattering (RRS) and surface enhanced resonance Raman scattering (SERRS). Nanozymes have been applied to various different applications, some of which are explored in this thesis. The overall aim of this research was to investigate the synthesis of stable nanotags with a series of protective coatings to provide stability in harsh environments and catalytic activity. The catalytic activity of the nanotags were assessed using TMB and ABTS in the presence of H2O2 and the most promising were used for the detection of biomolecules with Raman spectroscopy which provided low limits of detection and were carried out on portable instruments making infield detection possible. The catalytic activity of silver nanoparticles were also used in a surface based silverlinked immunosorbent assay to detect human C-reactive protein (CRP), an inflammatory marker and to detect oxidative stress in cancerous cells by monitoring the oxidation of TMB and analysing with SERRS. Overall, nanozymes and Raman spectroscopy detection can be applied to a variety of applications leading to lower limits of detection of biomolecules in harsh environments and a cheaper alternative to enzymes.
|Date of Award||1 Apr 2017|
- University Of Strathclyde
|Sponsors||EPSRC (Engineering and Physical Sciences Research Council)|
|Supervisor||Karen Faulds (Supervisor) & Duncan Graham (Supervisor)|