DETECTION OF BIOMARKERS IN TEARS WITH FIBER OPTIC BIOSENSORS

Abstract

Tears play an important role in maintaining the normal functioning of the eyes. They protect the eye from the harmful effects of the environment and provide hydration. Despite the fact that tears mostly consist of water, their proteomic composition is very diverse and can vary depending on the emotional and physical condition of a person. In addition, collecting tears is not difficult and does not require invasive intervention. This fact makes tears an attractive material for research. Scientists are widely working on the study of the proteomic composition of tears and the discovery of new biomarkers of various diseases in them. The detection of biomarkers in tears has every chance of becoming a new branch of disease diagnosis. At the moment, a large number of biomarkers have already been found in tears and methods for their diagnosis are being actively developed. Biomarkers of diabetic retinopathy are among the most well-studied biomarkers in tears. LCN1 and VEGF are the most well-known representatives of biomarkers of others. In a normal state, the LCN1 protein is responsible for neutralizing harmful lipid molecules, but in pathological conditions, it causes prolonged inflammation. In turn, at normal concentrations, VEGF is responsible for the moderate development of new blood vessels, but at high concentrations, it causes pathological neovascularization. Determining changes in the concentrations of these proteins using fiber optic biosensors can be an effective way to diagnose diabetic retinopathy in the early stages. Fiber optic biosensors, such as semi-distributed interferometers have simple, fast and low-cost sensor fabrication technology, which makes them very attractive for use in the field of diagnostics. In the course of this study, semi-distributed interferometric (SDI) sensors for the detection of diabetic retinopathy biomarkers LCN1 and VEGF were developed. In the process of optimizing sensor development, it was determined that the LCN1 sensor works most effectively when it is functionalized at a concentration of anti-LCN1 antibodies of 8 µg/ml. The optimal concentration for sensor functionalization for VEGF was 10 µg/ml