Optofluidic sorting of ultra-bright nanodiamonds

Biological imaging will advance when fluorescent markers overcome the limitations of toxicity and photo instability. Recent work by Brown [31] 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. A current restriction to the use of nanodiamonds in imaging applications is the brightness variations from particle-to-particle [14]. A new project at Macquarie University intends to improve the brightness uniformity of nanodiamond materials, using a sorting mechanism that impacts the defects embedded in the diamond. This thesis works towards the aims of the recently funded Discovery Project (DP170103010) to quantify the impact that defect variations have on the scattering force effect, and to develop a system for enriching the brightest particles. Fulfilling this aim required the development of a microfluidic device with an observable micro-channel and orthogonal laser accessibility. An optical setup was established to direct a high powered laser at a sample of particles that were suspended inside the channel. Microscopic images were recorded and the trajectories of each particle were tracked and recorded to quantify thebehaviour of the impacted particles [1].