June 2021
Volume 62, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2021
Utilization of metal complexes in the tears biomarkers assay
Author Affiliations & Notes
  • Ilias Milionis
    Department of Chemistry, University of Ioannina, Greece
    Eye Clinic, University Hospital Ioannina, Ioannina, Epirus, Greece
  • Christina N Banti
    Department of Chemistry, University of Ioannina, Greece
  • Koralia Sarakinou
    Department of Chemistry, University of Ioannina, Greece
  • Sotiris Hadjikakou
    Department of Chemistry, University of Ioannina, Greece
  • Footnotes
    Commercial Relationships   Ilias Milionis, None; Christina Banti, None; Koralia Sarakinou, None; Sotiris Hadjikakou, None
  • Footnotes
    Support  none
Investigative Ophthalmology & Visual Science June 2021, Vol.62, 1312. doi:
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      Ilias Milionis, Christina N Banti, Koralia Sarakinou, Sotiris Hadjikakou; Utilization of metal complexes in the tears biomarkers assay. Invest. Ophthalmol. Vis. Sci. 2021;62(8):1312.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose : Reduced urea concentration, could lead to disorganization and decompose of the tear film which is related with Ocular Surface Diseases (OSD). Moreover, urea is an indicator for OSD, such as Dry Eye Syndrome (DES). Recent epidemiological studies show that DES is a common disorder, which appears especially in the elderly population, affecting up to 20 % of adults. The lack of clinical symptoms makes the diagnosis of DES very difficult. Nowadays, a colorimetric enzymatic method for determining urea is used in cell and tissue culture supernatants, urine, plasma, serum, and other biological samples. Therefore the development of new urea assay is a matter of research interest.

Methods : Copper(II) - urea complexes Cu2(CH3COO)4U2 (1) and Cu(NO3)2U4 (2), (U= urea) have been synthesized and characterized. Compounds 1-2 were used for the qualitative and quantitative determination of urea by Thin Layer Chromatography (TLC) densitometry assay and Fluorescence Spectroscopy:.

Results : For the determination of urea in tears, the graphs of the TLC spots intensity vs the concentration of standard solutions of 1 and 2 are used. The concentrations of 1 and 2 vs spot's intensity (Int) are linearly fitted. Tears were collected using Whatman paper and they were added into DMSO solution which contain copper(II) salts. The content of urea in the sample is determined by the complex:Urea molar ratio in 1 and 2. The quenching (by 66 (1) or 48 (2) %) at the energy emitted when the tears/DMSO solution were incubated with copper acetate or nitrate is also correlated with DES diagnosis.

Conclusions : The concentration level of urea in the tear fluid is a diagnostic biomarker for the detection of the dry eye syndrome (DES). The complexes 1 and 2 are used for their chromatographic and spectroscopic characteristics which consequently lead to the identification and determination of urea in tears. Although more experiments should be carried out before a reliable method could be established, however, the importance of urea in eye disorders diagnosis makes TLC-densitometry and fluorescence spectroscopy a possible candidate for the development of a novel urea assay

This is a 2021 ARVO Annual Meeting abstract.


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