Electrochemical and optical methods for detection of cystatin C as a biomarker of kidney disease.

The kidneys have vital functions in the body, including maintaining homeostasis and blood pressure, controlling water-electrolyte balance, and eliminating metabolic wastes. Early identification of renal dysfunction disease and selection of effective treatment methods reduce mortality in patients. Nowadays, Common indicators of kidney function lack the necessary specificity and sensitivity, but recent studies have reported that cystatin C (CysC) may be an ideal marker for glomerular filtration. CysC, known as a cysteine protease inhibitor, is synthesized by nucleated cells and is easily filtered due to its positive charge and low molecular weight. Also, the synthesis and secretion of CysC is a stable process that is not affected by dietary factors, enhanced protein catabolism, and renal conditions. Various studies have reported that measuring the level of CysC in the body's biological fluids is necessary for the treatment and diagnosis of a wide range of diseases, especially chronic kidney disease (CKD).Despite evidence that positive correlation between the high risk and/or progression of CKD and CysC, it's applied in clinical practice is still rare. Biosensors have been widely developed and researched as an effective method for the pharmaceutical, environmental, and medical fields. Biosensors are designed to create an effective electronic signal commensurate with the concentration of a particular biochemical.Recently, many studies have used biosensor techniques to detect CysC in kidneys and other diseases. In this study, we attempt to examine studies that have used different biosensor techniques for the detect CysC.