Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer

The tear film, consisting of the aqueous and lipid layers, maintains the homeostasis of the ocular surface; therefore, when disturbed, it can cause dry eye, which affects millions of people worldwide. Understanding the dynamics of the tear film layers is essential for developing efficient drug deliv...

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Main Authors: Sidra Sarwat, Fiona Stapleton, Mark D. P. Willcox, Peter B. O’Mara, Maitreyee Roy
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/7/552
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author Sidra Sarwat
Fiona Stapleton
Mark D. P. Willcox
Peter B. O’Mara
Maitreyee Roy
author_facet Sidra Sarwat
Fiona Stapleton
Mark D. P. Willcox
Peter B. O’Mara
Maitreyee Roy
author_sort Sidra Sarwat
collection DOAJ
description The tear film, consisting of the aqueous and lipid layers, maintains the homeostasis of the ocular surface; therefore, when disturbed, it can cause dry eye, which affects millions of people worldwide. Understanding the dynamics of the tear film layers is essential for developing efficient drug delivery systems for dry eye disease. Quantum dots (QDs) offer the potential for real-time monitoring of tear film and evaluating its dynamics. Hydrophilic silicon QDs (Si-QDs) have already been optimised to image the aqueous layer of the tear film. This study was conducted to optimise hydrophobic Si-QDs to image the lipid layer of the tear film. Si-QDs were synthesised in solution and characterised by transmission electron microscope and spectrofluorophotometry. The fluorescence emission of Si-QDs was monitored in vitro when mixed with artificial tears. The cytotoxicity was assessed in cultured human corneal epithelial cells using an MTT assay following 24 h of exposure. Si-QDs were 2.65 ± 0.35 nm in size and were non-toxic at <16 µg/mL. Si-QDs emitted stable green fluorescence for 20 min but demonstrated aggregation at higher concentrations. These findings highlight the potential of hydrophobic Si-QDs as a biomarker for the real-time imaging of the tear film lipid layer. However, further research on surface functionalisation and preclinical evaluations are recommended for enhanced solubility and biocompatibility in the ocular surface.
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spelling doaj-art-3d6f5546ba9c4641a0d7ea9d33ad5fc02025-08-20T02:15:46ZengMDPI AGNanomaterials2079-49912025-04-0115755210.3390/nano15070552Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid LayerSidra Sarwat0Fiona Stapleton1Mark D. P. Willcox2Peter B. O’Mara3Maitreyee Roy4School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney 2052, AustraliaSchool of Optometry and Vision Science, University of New South Wales (UNSW), Sydney 2052, AustraliaSchool of Optometry and Vision Science, University of New South Wales (UNSW), Sydney 2052, AustraliaElectron Microscope Unit, School of Chemistry, Mark Wainwright Analytical Centre, University of New South Wales (UNSW), Sydney 2052, AustraliaSchool of Optometry and Vision Science, University of New South Wales (UNSW), Sydney 2052, AustraliaThe tear film, consisting of the aqueous and lipid layers, maintains the homeostasis of the ocular surface; therefore, when disturbed, it can cause dry eye, which affects millions of people worldwide. Understanding the dynamics of the tear film layers is essential for developing efficient drug delivery systems for dry eye disease. Quantum dots (QDs) offer the potential for real-time monitoring of tear film and evaluating its dynamics. Hydrophilic silicon QDs (Si-QDs) have already been optimised to image the aqueous layer of the tear film. This study was conducted to optimise hydrophobic Si-QDs to image the lipid layer of the tear film. Si-QDs were synthesised in solution and characterised by transmission electron microscope and spectrofluorophotometry. The fluorescence emission of Si-QDs was monitored in vitro when mixed with artificial tears. The cytotoxicity was assessed in cultured human corneal epithelial cells using an MTT assay following 24 h of exposure. Si-QDs were 2.65 ± 0.35 nm in size and were non-toxic at <16 µg/mL. Si-QDs emitted stable green fluorescence for 20 min but demonstrated aggregation at higher concentrations. These findings highlight the potential of hydrophobic Si-QDs as a biomarker for the real-time imaging of the tear film lipid layer. However, further research on surface functionalisation and preclinical evaluations are recommended for enhanced solubility and biocompatibility in the ocular surface.https://www.mdpi.com/2079-4991/15/7/552tear film lipid layerdry eye diseasehydrophobic quantum dotsfluorescence imaging
spellingShingle Sidra Sarwat
Fiona Stapleton
Mark D. P. Willcox
Peter B. O’Mara
Maitreyee Roy
Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer
Nanomaterials
tear film lipid layer
dry eye disease
hydrophobic quantum dots
fluorescence imaging
title Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer
title_full Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer
title_fullStr Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer
title_full_unstemmed Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer
title_short Hydrophobic Silicon Quantum Dots for Potential Imaging of Tear Film Lipid Layer
title_sort hydrophobic silicon quantum dots for potential imaging of tear film lipid layer
topic tear film lipid layer
dry eye disease
hydrophobic quantum dots
fluorescence imaging
url https://www.mdpi.com/2079-4991/15/7/552
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AT markdpwillcox hydrophobicsiliconquantumdotsforpotentialimagingoftearfilmlipidlayer
AT peterbomara hydrophobicsiliconquantumdotsforpotentialimagingoftearfilmlipidlayer
AT maitreyeeroy hydrophobicsiliconquantumdotsforpotentialimagingoftearfilmlipidlayer