Thesis

2D and 3D optical imaging of SERS nanotags intracellularly

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Awarding institution
  • University of Strathclyde
Date of award
  • 2014
Thesis identifier
  • T13920
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Adoption of a multi-marker nanotag approach will led to better disease characterisation whilst simultaneously enabling targeting of multiple disease markers or organelles. The employed nanotag method controllably aggregated nanoparticles with 1,6-hexamethylene diamine (1,6-HMD), before polymer coating with polyvinylpyrrolidone (PVP) and labelling with small molecule reporters; 4-mercaptopyridine (MPY), 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), 4-nitrobenzenethiol (NBT) and 2-naphthalenethiol (2-NPT). Within a multiple component suspension reporters were identified by their unique peak and when present within single cells or populations they were additionally identified using component direct classical least squares (DCLS). Within a single cell three of the four components (MPY, DTNB and NBT) were positively identified. 2D SERS imaging can monitor nanotag uptake but it provides no conclusive evidence of cellular inclusion. The simultaneous determination of cellular uptake and nanotag identification was however achieved using combined 3D Raman and SERS imaging. Three of the four components were detected within a single cell and by combining 2D sections from the 3D images it was possible to determine their intracellular location. Determination of intracellular localisation was achieved using principal component analysis (PCA) since it resulted in the resolution of a subcellular compartment. However, the ultimate success of the system will only be realised when active targeting is demonstrated. Nanotags were functionalised with peptide sequences specific for the endoplasmic reticulum (ER) and trans-Golgi network (TGN). Both nanotag systems were found to locate within lipid rich regions of the cell but they could not be positively confirmed as the ER or TGN. To identify these structures and confirm localisation, further chemometric methods must be investigated including hierarchical cluster analysis (HCA). In conclusion, the SERS nanotags were suitable imaging agents for 2 and 3D cell interrogation. 3D imaging simultaneously permitted organelle resolution and the intracellular localisation of the SERS nanotags. Targeting systems were developed and in future work their localisation within organelles will be confirmed by the application of advanced chemometric methods.
Resource Type
DOI
Date Created
  • 2014
Former identifier
  • 1042638

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