posted on 2022-11-23, 15:22authored byKevin O'Dwyer
Many typical methods of studying particles within an aqueous solution use some form of control mechanism to limit sample variability. A common application in cytometry is the use of hydrodynamic focusing to confine the movement of particles to a narrow stream of flow through the optical focus. The purpose of the work presented in this thesis is to examine ways of studying features within a solution with minimal control of the internal motions of the features within the flow channel. Development of optical measurement systems without the use of hydrodynamic focusing would allow for reuse of samples limited in quantity, avoiding dilution by a buffer solution. Such a system would also more closely replicate an in-vivo system, and the analysis techniques that are developed could also be employed in an in-vivo system. Coherent Anti-Stokes Raman Scattering (CARS) is a nonlinear optical spectroscopy technique that can probe a sample for specific molecular vibrational bonds, as a means of chemical probing a specimen. It is a highly sensitive technique that can obtain information from a sample with a fast acquisition time. CARS is useful tool for obtaining chemical information from a sample, as it is a label-free technique, in that it probes the inherent chemical bonds present within a sample without the need for additional preparation of the sample through fluorescent dyes or other similar methods. However, as a nonlinear technique, it is very sensitive to changes in conditions in the sample. This makes the technique highly sensitive, but also can present problems in highly scattering dynamic systems. The design and implementation of custom built optical monitoring platforms allows for the widest possible freedom in the implementation of novel multimodal methods of sample analysis. The technical performance of the custom built CARS microscopy platform is interrogated through sample imaging. Means of improving the sensitivity of the CARS response in scattering solutions through use of multimodal optical monitoring systems to simultaneously multiple optical signals are investigated.
Funding
Using the Cloud to Streamline the Development of Mobile Phone Apps