Robust Electrochemical Sensing Techniques for Serum Creatinine Biosensor

Abstract

Creatinine is an important biomarker for evaluating the renal function and its concentration in serum can be utilized for early detection of kidney disease, thyroid disorders, and muscular dystrophy. Accurate, reliable, and decentralized testing of creatinine has become vital owing to the rising trajectory of Chronic Kidney Disease and its associated risk factors diabetes and hypertension. The conventional analytical techniques to estimate serum creatinine are limited by its non-specificity, prevalent in the optical Jaffe assay, and the high costs, involved in the enzymatic assays. This has led to intensive research efforts in developing an accurate, robust, and sensitive sensor for estimating the concentration of creatinine in serum with cost-effective solutions. This underlies the focus of the thesis as it primarily discusses various approaches and challenges faced in developing the intended sensor. The primary challenge in estimation of serum creatinine is posed by its reduced concentration in the complex matrix of blood, which is constituted by varied proteins, whole cells, immunoglobulins, ions, and other metabolites. The electro-inactivity of creatinine further complicates the measurement by an electrochemical route. This necessitates selection of a redox probe that has an inherently high selectivity for creatinine to address both issues. In this thesis, we have explored non-enzymatic and enzymatic approaches for its detection. One of the non-enzymatic approaches, involves utilization of a transition metal iron that has an affinity for creatinine. The other non-enzymatic approach involves electrochemical estimation of creatinine by picric acid that is already utilized in the optical Jaffe reaction. Both the approaches provide reliable estimation of creatinine in saline and prove the feasibility of estimation of the reduced concentrations of serum creatinine by non-enzymatic techniques. The enzymatic approach involves one-step hydrolysis of creatinine by creatinine deiminase...