DEVELOPING AN OPTICAL FIBER BIOSENSOR FOR THE DETECTION OF KIM-1 PROTEIN

Abstract

Kidney Injury Molecule-1 (KIM-1) is a protein within the cell membrane that experiences increased expression in the proximal tubules of kidneys following ischemia. This protein belongs to the TIM (T-cell immunoglobulin mucin) family, but unlike other TIM proteins, it is produced mainly in the renal tubular epithelial cells. The baseline expression of KIM-1 in healthy organs is minimal, making it a valuable biomarker for the early identification of renal injury due to its significantly enhanced production during the initial stages of renal injury. Additionally, it is more sensitive than Blood Urine Nucleotide or creatinine as a marker. Recent studies have shown that urinary KIM-1 outperforms all other renal proteins in efficiency (Assadi & Sharbaf, 2019). The FDA qualified it as a biomarker of AKI, a devastating clinical problem with high mortality rates. AKI patients have a high risk of mortality, repetitive cardiovascular events, and risk of long-term chronic kidney disease. Screening and early detection is very important. Although KIM-1 has been established as a biomarker for AKI, the limited availability of assays restricts its use in diagnosis. Therefore, an unmet clinical need exists to develop an assay specific to the given protein. In the current work, we propose the use of a novel type of optic fiber biosensor, called a semi-distributed interferometer (SDI). These fibers are characterized by their ease of manipulation, rapid fabrication, and anticipated capacity for heightened sensitivity and specificity toward KIM-1, primarily attributed to the ability of fibers for functionalization in accordance with the protein of interest. We aim to build and characterize a semi-distributed interferometer-based optical fiber biosensor sensitive and specific to KIM-1 biomarker levels. It is hypothesized that the developed SDI-based optical fiber biosensor will considerably elevate the detection and quantification of KIM-1 levels in bodily fluids. To accomplish intended outcome, we established and optimized the optical fiber biosensor based on the SDI through functionalization, assessed its sensitivity to the KIM-1 biomarker level and made some experiments to assess its specificity towards the KIM-1 biomarker levels in the samples of artificial urine. This study revealed that SDI-based platform can be used to detect the KIM-1 protein. This novel biosensor concept not only provides a simplified fabrication process but also offers remarkable advantages, including resistance to electromagnetic interference and the ability to function effectively in a compact and durable form factor. The utilization of this cutting-edge technology promises to revolutionize the detection of biomarkers, particularly KIM-1, in bodily fluids such as urine. Detecting such important biomarker as KIM-1 molecule using freshly developed biosensor than available technologies (ELISA, lateral flow assay) could lower the time needed to perform its measurement and analyze biological specimens having lower levels of the analyte. The results of this study have significant implications for various fields, especially in clinical diagnostics and biomedical research. The semi-distributed interferometer-based optical fiber biosensor fabricated here could be used as a foundation for the development of sensors with the potential of earliest detection of AKI.