Now showing 1 - 7 of 7
  • Publication
    Surface-enhanced Raman scattering spectra of radial breathing modes and G+/- bands in functionalised nanotubes
    In this paper we perform surface enhanced Raman scattering studies of two functionalised nanotubes, an oxidised SWCNT and a SWCNT with a fluorescein side group covalently attached to the nanotube was compared with pristine SWCNTs. Our studies showed that in the G- band a significant shift was seen, while relatively little change occurred in the G+ and RBM spectral regions. These results indicate that SERS is broadly in line with Raman studies of chemically altered SWCNTs.
      420Scopus© Citations 4
  • Publication
    Nanoscale infrared absorption imaging permits non-destructive intracellular photosensitizer localization for subcellular uptake analysis
    The most immediate biological and medical advantages of therapeutic agent localization on the nanoscale arise from the increased understanding of targeted delivery, selectivity and intracellular distribution that are gained by imaging at the resolution scale of individual nanovectors and therapeutic agents themselves. This paper reports on the use of a nanoscale resolution chemical imaging method, infrared (IR) nanospectral absorption imaging, used to map the subcellular localization of a photoactive therapeutic agent - toluidine blue-conjugated gold nanoparticles (TBO) within nanoscale subsections of single colon adenocarcinoma cells. By comparison of photosensitizer distribution with diffraction limited optical imaging, the benefits of IR nanospectral localization are highlighted and the spatial and spectral accuracy of the non-destructive IR imaging method is confirmed. IR spectral ratio imaging is presented as a means to map intracellular nanoparticle density at sub 50 nm lateral resolution with IR nanospectroscopy enabling distinction of nanoparticle seeded cells from a control group with 95% confidence. In this way we illustrate that IR absorption nanoimaging combined with IR point source data does not only yield intracellular drug detection on the order of nanometres, but also permits extension of the AFM-IR technique from subcellular analysis up to studies of cell numbers that are statistically significant.
      533Scopus© Citations 30
  • Publication
    Nanoscale spectroscopy and imaging of hemoglobin
    Sub diffraction limited infrared absorption imaging of hemoglobin was performed by coupling IR optics with an atomic force microscope. Comparisons between the AFM topography and IR absorption images of micron sized hemoglobin features are presented, along with nanoscale IR spectroscopic analysis of the metalloprotein.
      517Scopus© Citations 9
  • Publication
    Quantifying nanoscale biochemical heterogeneity in human epithelial cancer cells using combined AFM and PTIR absorption nanoimaging
    Subcellular chemical heterogeneity plays a key role in cell organization and function. However the biomechanics underlying the structure-function relationship is governed by cell substructures which are poorly resolved using conventional chemical imaging methods. To date, advances in sub-diffraction limited infrared (IR) nanoscopy have permitted intracellular chemical mapping. In this work we report how image analysis applied to a combination of IR absorption nanoimaging and topographic data permits quantification of chemical complexity at the nanoscale, enabling the analysis of biochemical heterogeneity in mammalian cancer cells on the scale of subcellular features.
      530Scopus© Citations 25
  • Publication
    The Effect of Ag Nanoparticles on Surface-Enhanced Luminescence from Au Nanovoid Arrays
    Studies comparing the effect of adding two different nanoparticle compositions on the plasmonic properties of Au nanovoid arrays were undertaken. Surface-enhanced resonance luminescence and surface-enhanced resonance Raman studies comparing dispersed Ag nanoparticles and Ag nanoparticle aggregates on gold nanovoid arrays were undertaken. These studies showed that using Ag nanoparticle aggregates increased both luminescence and Raman efficiency relative to when dispersed nanoparticles were used; in addition, these studies also showed that adding dispersed Ag nanoparticles supported a more reproducible enhancement in luminescence and Raman across the substrate compared to using Ag nanoparticle aggregates. Finite element analysis simulations indicated that surface plasmon polariton distribution in the sample was affected by the presence of the Ag nanoparticles on the Au nanovoid array.
      459Scopus© Citations 25
  • Publication
    Sub-wavelength infrared imaging of lipids
    (Optical Society of America, 2011-01) ; ; ;
    Infrared absorption spectroscopy of lipid layers was performed by combining optics and scanning probe microscopy. This experimental approach enables sub-diffraction IR imaging with a spatial resolution on the nanometer scale of 1, 2-dioleoyl-sn-glycero-3-phosphocholine lipid layers.
      346Scopus© Citations 18
  • Publication
    Surface-enhanced Raman scattering from small numbers of purified and oxidised single-walled carbon nanotubes
    Surface enhanced resonance Raman scattering (SERRS) has been applied to investigate defects in purified and carboxylated single-walled carbon nanotubes (SWCNTs). For both samples SERRS spectra with temporal fluctuating peak intensities and positions in the range of 1000 to 1350 cm-1 have been observed. A series of peaks in this window were observed to coincide with peak positions that have been assigned to arise from Stone-Thrower-Wales and heptagonal-pentagonal intramolecular junction defects on the nanotubes surface. Two possible origins for these fluctuating spectral features are discussed ie the presence of Stone-Thrower-Wales defects in SWCNTs or amorphous carbon impurities.
      495Scopus© Citations 27