Since its invention in the 1600s, the microscope has enabled scientists to study biological systems previously invisible to understand structure and function. Fluorescence microscopy is a non-invasive and gentle technique that involves ‘tagging’ biological molecules of interest with fluorescent dyes (ranging from fluorescent proteins to chemically designed organic dyes) and measuring fluorescence emission. However, there exists a physical limit to the size of specimens that can be observed using fluorescence microscopy, this is known as the diffraction limit.
Due to the wave-like nature of light conventional microscopy is unable to resolve structures below ~250 nm in size due to diffraction. The challenge here is that many, if not most, biological processes occur below this limit and thus physical scientists must develop new optical techniques to study these processes. An additional problem is that most microscopes are limited to observing systems and structures in two-dimensions (x and y) and therefore cannot observe complex three-dimensional (x, y and z) structures.
My PhD addresses both the diffraction limit of light and observing biological systems in 3D. My research leverages the principles of super-resolution microscopy (SRM) to break through the diffraction limit and applies it to light field microscopy (LFM) to observe biological systems in three-dimensions. The result is Single Molecule Light Field Microscopy (SMLFM), which is achieved by adding an additional optical component, called a microlens array, to a traditional microscope. This tiny piece of glass is composed of many lenses that are used to observe the biological sample from multiple perspective views. Like how astronomers measure distances to stars using distances and angles, SMLFM uses this principle, called parallax, to deduce the 3D structure of a cell.
Not only does SMLFM acquire 3D information in a new way, it also enables a significant speed and depth advantage with a resolution of tens of nanometers (approx. 30 nm). After constructing and characterising a SMLFM platform in the Department of Chemistry, I work closely with collaborators across the university to address complex biological questions.
NanoDTC Associate, a2022