The cell is a fundamental yet complicated unit of biology; a dynamic system of interacting processes. To observe these processes, it is necessary to develop a contrast mechanism that isolates the behaviour under study from the natural cell contrast. Commonly this is achieved by labelling with single fluorescent entities; however, due to the inherent photochemical properties of single quantum emitters the photon rate is fundamentally limited and furthermore prone to blinking and bleaching. Recently, metallic nanoparticles have gained significant interest as biological labels as they do not suffer from these limitations as they scatter light proportional to the incident power. However, the applied power can not be infinitely increased as cells are sensitive to photodamage. As such, it is important to develop a technique capable of detecting weakly scattered signals at low incident optical powers. We have recently shown the detection of 5 nm gold nanoparticles at low incident power (< 1μW) under a technique we have termed Interferometric Cross-Polarization Microscopy (ICPM). Toward the goal of metallic nanoparticle detection in biological material, herein we characterise the complex Point Spread Function (cPSF) of ICPM and show its capacity for optical sectioning. We develop a model for the detection sensitivity of ICPM to elucidate the detection capabilities and areas of potential application. Building from these chapters, we show how the technique may be applied to colocalise weak scattering signals of individual nanodiamonds against their fluorescent signatures from embedded NV- centres. And finally, we apply ICPM to the detection of metallic nanoparticles in HeLa cells.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:702752 |
| Date | January 2016 |
| Creators | Miles, Benjamin T. |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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