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bioRxiv · 10.1101/2020.12.09.411876

Evaluation of optically tailored fluorescent silicon quantum dots for bioimaging of the tear film

Sarwat, S.·Stapleton, F.·Willcox, M. D. P.·O'Mara, P.·Tilley, R.·Gooding, J.·Roy, M.
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Abstract

This experimental study aimed to investigate the feasibility of using silicon quantum dots doped with transition metals: scandium, copper and zinc as contrast agents for eventual application for the study of the tear film in eyes. Si-QDs were synthesized and characterized by transmission electron microscopy, photoluminescence, absorbance and transient absorption measurements. The fluorescence of Si-QDs was investigated when combined with TheraTears(R) (a balanced electrolyte formula for dry eye therapy). An optical imaging system composed of a modified slit lamp biomicroscope combined with a high-resolution Zyla sCMOS camera, SOLIS software, custom-made optical mounts and emission filters (460 nm, 510 nm and 530 nm) were used for in vitro imaging of Si-QDs with TheraTears(R). The average size of Si-QDs was 2.65 nm. In vitro imaging of Sc-Si-QDs and Cu-Si-QDs indicated their stable and bright fluorescence with TheraTears(R). Sc-Si-QDs were significantly brighter compared to Cu-Si-QDs and Zn-Si-QDs, and the Zn-Si-QDs showed a tendency to clump in TheraTears(R). The fluorescence of the Si-QDs was detected down to a concentration of 0.01 {micro}g/mL within a total volume of 5 {micro}L. Cu-Si-QDs and Sc-Si-QDs showed brighter fluorescence than Zn-Si-QDs. However, Zn-Si-QDs and to a lesser extent, Cu-Si-QDs showed some aggregation at specific concentrations. Sc-Si-QDs are proposed as a better option for further development as an in vivo bioimaging agent to study the tear film dynamics.

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Sarwat, S., Stapleton, F., Willcox, M. D. P., O'Mara, P., Tilley, R., Gooding, J., Roy, M.. 2020-12-09. Evaluation of optically tailored fluorescent silicon quantum dots for bioimaging of the tear film. https://doi.org/10.1101/2020.12.09.411876

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