Adaptive optics stimulated emission depletion microscope for thick sample imaging

  • Piotr Zdankowski

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

Over the past few decades, fluorescence microscopy has proven to become the most widely used imaging technique in the field of life sciences. Unfortunately, all classical optical microscopy techniques have one thing in common: their resolution is limited by the diffraction. Thankfully, due to the very strong interest, development of fluorescent microscopy techniques is very intense, with novel solutions surfacing repeatedly. The major breakthrough came with the appearance of super-resolution microscopy techniques, enabling imaging well below the diffraction barrier and opening the new era of nanoscopy. Among the fluorescent super-resolution techniques, Stimulated Emission Depletion (STED) microscopy has been particularly interesting, as it is a purely optical technique which does not require post image processing. STED microscopy has proven to resolve structures down to the molecular resolution. However, super-resolution microscopy is not a cure to all the problems and it also has its limits. What has shown to be particularly challenging, was the super-resolution imaging of thick samples. With increased thickness of biological structures, the aberrations increase and signal-to-noise (SNR) decreases. This becomes even more evident in the super-resolution imaging, as the nanoscopic techniques are especially sensitive to aberrations and low SNR.

The aim of this work is to propose and develop a 3D STED microscope that can successfully image thick biological samples with nanoscopic resolution. In order to achieve that, adaptive optics (AO) has been employed for correcting the aberrations, using the indirect wavefront sensing approach. This thesis presents a custom built 3D STED microscope with the AO correction and the resulting images of thick samples with resolution beyond diffraction barrier. The developed STED microscope achieved the resolution of 60nm in lateral and 160nm in axial direction. What is more, it enabled super-resolution imaging of thick, aberrating samples. HeLa, RPE-1 cells and dopaminergic neuron differentiated from human IPS cells were imaged using the microscope. The results shown in this thesis present 3D STED imaging of thick biological samples and, what is particularly worth to highlight, 3D STED imaging at the 80μm depth, where the excitation and depletion beams have to propagate through the thick layer of tissue. 3D STED images at such depth has not been reported up to date.
Date of Award2018
LanguageEnglish
Awarding Institution
  • University of Dundee
Add any sponsors of the thesis researchEuropean Union
SupervisorJason Swedlow (Supervisor) & David McGloin (Supervisor)

Keywords

  • Microscopy
  • Fluorescence microscopy
  • Confocal microscopy
  • Super-resolution microscopy
  • Adaptive optics
  • Aberration correction
  • Thick sample imaging

Cite this

Adaptive optics stimulated emission depletion microscope for thick sample imaging
Zdankowski, P. (Author). 2018

Student thesis: Doctoral ThesisDoctor of Philosophy