Facile Determination of Sodium Ion and Osmolarity in Artificial Tears by Sequential DNAzymes

Eun Kim,Young-Pil Kim,Eun-Song Lee,Dong Lee

doi:10.3390/s17122840

Abstract

Despite high relevance of tear osmolarity and eye abnormality, numerous methods for detecting tear osmolarity rely upon expensive osmometers. We report a reliable method for simply determining sodium ion-based osmolarity in artificial tears using sequential DNAzymes. When sodium ion-specific DNAzyme and peroxidase-like DNAzyme were used as a sensing and detecting probe, respectively, the concentration of Na+ in artificial tears could be measured by absorbance or fluorescence intensity, which was highly correlated with osmolarity over the diagnostic range (R2 > 0.98). Our approach is useful for studying eye diseases in relation to osmolarity.

Highlights

Tears are an attractive target for disease diagnosis because they exist as a clear fluid and are excreted in response to metabolic and environmental cues
Osmolarity is a unit of osmotic concentration expressed as the number of osmoles (Osm) of solute per liter (L), and tear osmolarity is determined using an osmometers to measure the total concentration of all solutes including electrolytes in the tear fluid
We examined whether sodium ionsodium concentration was well-correlated above results, we examined whether ion concentration was with osmolarity in artificial tears

Summary

Introduction

Tears are an attractive target for disease diagnosis because they exist as a clear fluid and are excreted in response to metabolic and environmental cues. Dry eye is a commonly encountered symptom in humans and its incidence has increased considerably in recent years. Increased dryness in human tears can lead to eye diseases that damage the ocular surface and cause inflammation because of the instability of the tear film [1]. While individual objective tests prevail in the diagnosis of dry eye disease, tear osmolarity has been considered an alternative means for the rapid diagnosis of dry eye disease [2], as dry eye patients show increased tear osmolarity. It has been reported that ocular surface inflammation is accompanied by increased levels of osmolarity in the tear film of dry eye patients [3,4].

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Conclusion