Feasibility of Silicon Quantum Dots as a Biomarker for the Bioimaging of Tear Film

This study investigated the fluorescence and biocompatibility of hydrophilic silicon quantum dots (SiQDs) that are doped with scandium (Sc-SiQDs), copper (Cu-SiQDs), and zinc (Zn-SiQDs), indicating their feasibility for the bioimaging of tear film. SiQDs were investigated for fluorescence emission by the in vitro imaging of artificial tears (TheraTears (R)), using an optical imaging system. A trypan blue exclusion test and MTT assay were used to evaluate the cytotoxicity of SiQDs to cultured human corneal epithelial cells. No difference was observed between the fluorescence emission of Sc-SiQDs and Cu-SiQDs at any concentration. On average, SiQDs showed stable fluorescence, while Sc-SiQDs and Cu-SiQDs showed brighter fluorescence emissions than Zn-SiQDs. Cu-SiQDs and Sc-SiQDs showed a broader safe concentration range than Zn-SiQDs. Cu-SiQDs and Zn-SiQDs tend to aggregate more substantially in TheraTears (R) than Sc-SiQDs. This study elucidates the feasibility of hydrophilic Sc-SiQDs in studying the tear film's aqueous layer.

Automated summary

This study investigated the fluorescence and biocompatibility of hydrophilic silicon quantum dots doped with scandium, copper, and zinc, indicating their potential for bioimaging of tear film. The results showed that there was no difference in fluorescence emission between scandium-doped and copper-doped silicon quantum dots at any concentration. In addition, scandium and copper-doped quantum dots exhibited brighter fluorescence emissions than zinc-doped quantum dots, and they had a wider safe concentration range.