Using light to observe and understand physiological processes
Last Updated - 07/07/2016
Optical Biopsies using Optical Coherence Tomography
Optical coherence tomography (OCT) is a real time, non-invasive and non-contact imaging modality for translucent and transparent tissue capable of providing morphological images at the micron scale resolution at more than 1mm depth penetration.
First developed in 1991 for measuring the human retina, OCT's fields of application have been extended to a wide variety of tissues and non-biological structures. Conventional OCT is based on measuring the back reflection of light induced by changes of refractive index in the sample. Although the information gain of purely structural images is high, poor contrast can make structures difficult to be identified. Therefore OCT was extended to exploit other light properties for better contrast and quantitative measurements. In this context, we develop optical biopsies using OCT and new contrast agents such as chromatic dispersion and displacement.
The project will make use of the existing OCT systems based in Auckland and is funded by a Marsden grant
Bacteria are everywhere and are involved in many processes relevant to our everyday life, yet it is hard to monitor bacterial concentration accurately and in real time. Recently, the physics department, in collaboration with the microbiology department, has developed an all-fibre spectroscopic system called the optrode that is able to detect and quantify bacteria. It provides an alternative to the conventional plate count techniques with advantages of portability, sensitivity, near real-time measurements and ability to detect a highly dynamic range of bacterial concentrations in its natural environment.
The next challenge is to be able to identify specific types of bacteria. One avenue is to immobilise the microorganism using functionalised fibres or microfluidic devices.
This work is funded by a grant in collaboration with a company that is likely to commercialise the device. This research will be carried out in collaboration with microbiologists who will provide samples and knowledge of microorganisms and bacterial processes.
Nonlinear microscopy is a growing field with an ever-increasing range of applications and uses. Traditionally the sources required have been bulky laser systems, which restricted its use. Most recently we have demonstrated that compact fibre base sources offer a compelling alternative, and this project aims to further develop fibre based instruments into practical compact sources and then use them to demonstrate improved imaging of biological materials.
The student will begin by testing existing mode-locked fibre sources before designing and building an improved source optimised for imaging. Next they will look at including an all-fibre source into a traditional microscope before using their source for a range of imaging.
Second harmonic generation, Raman generation and other nonlinear techniques will be used to create a multi-modal tool that provides structural information with greater precision than conventional techniques.