Quantification of scattering forces in a microfluidic channel

Biological imaging will advance when fluorescent markers overcome the limitations of toxicity and photo instability. Recent work by Brown indicates that fluorescent nanodiamonds avoid these limitations, as the carbon composition of the diamond removes toxicity and the embedding of defects in the diamond lattice increases photo stability. The current limitation to the use of nanodiamonds in imaging applications is the brightness variations from particle-to-particle. A new project at Macquarie University aims to improve the brightness uniformity of nanodiamond materials using optical forces to sort particles by brightness. This thesis targets the first aim of the recently funded Macquarie project (DP170103010) which is to quantify the effect of scattering forces on nanomaterials. Fulfilling this aim required the development of a microfluidic device that was capable of observing nanomaterials and of enabling laser access. Particles in the channels of the developed devices were observed under the impact of a high powered laser and video data was analysed to track and map the trajectory of each particle. The experiment did not observe an optical force as the particles were not significantly impacted by the path of the laser. We believe that insufficient laser power was entering the channel due to the shallow height of the optical access. Future work on this project will require additional control of the laser setup and a redesign of the devices' optical accessibility.