The tear fluids from three healthy individuals and three patients with diabetes mellitus were examined using atomic force microscopy-infrared spectroscopy (AFM-IR) and Fourier transform infrared spectroscopy (FTIR). The dried tear samples showed different surface morphologies: the control sample had a dense network of heart-shaped dendrites, while the diabetic sample had fern-shaped dendrites. By using the AFM-IR technique we identified spatial distribution of constituents, indicating how diabetes affects the structural characteristics of dried tears. FTIR showed that the dendritic structures gradually disappeared over time due to glucose-induced lysozyme damage. The tear fluid from diabetes mellitus patients has a higher concentration of glucose, which accelerates the breakdown of lysozyme and, as a result, the quick loss of the dendritic structure. Our study shows that analysis of dry tear fluid can be promising technique for the detection of glycated proteins that reveal long lasting hyperglycemia and diabetes mellitus.

Bruker Nano Surfaces and Metrology Östliche Rheinbrückenstrasse 49 76187 Karlsruhe Germany

Department of Magnetism Institute of Experimental Physics Slovak Academy of Sciences Watsonova 47 Košice 040 01 Slovakia

Department of Medical and Clinical Biochemistry Faculty of Medicine Pavol Jozef Šafárik University in Košice Košice Slovakia

Department of Public Health and Hygiene Faculty of Medicine Pavol Jozef Šafárik University in Košice Šrobárová 2 Košice 041 80 Slovakia

Institute of Physics Department of Condensed Matter Physics Faculty of Science Pavol Jozef Šafárik University in Košice Park Angelinum 9 Košice 041 54 Slovakia

Měřicí technika Morava s r o Babická 619 664 84 Zastávka Czech Republic

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