Design of a Functionalized Nonenzymatic Electrochemical Sensor with a Ternary MXene Nanocomposite to Identify Creatinine in Various Biological Samples

In muscle tissue, creatinine is a byproduct of creatine phosphate, which supplies energy to the muscles and is consistently filtered through the glomerulus in the kidney. In real-time and point-of-care medical diagnostics, creatinine testing can be a component of a larger panel of diagnostics used to evaluate general health and recognize any issues such as diabetes or hypertension. Consequently, we developed an enzyme-free electrochemical biosensor that enables rapid, small-volume detection of creatinine. In our biosensor, the use of active materials like MXene, SiO₂, and ZnO, which have a high surface area and semiconducting properties, offers high sensitivity and is enhanced by the addition of chitosan for its superb biocompatibility and functional group (-OH, -NH₂) interactions with creatinine molecules that enhance selectivity. We investigated the characterization and electrochemical properties of the SiO₂-MXene-SnO₂-chitosan nanocomposite using spectroscopical and electrochemical instruments. The electrochemical analyses exhibit robust sensitivity to low concentrations (0.05 μM) of creatinine within a potential range of -0.1 to 0.1 V. This enzyme-free biosensor presented a better selectivity range (0.05 μM-0.40 μM) with a correlation coefficient (R²) of 0.978 in PBS. In addition, this sensor has better reproducibility and stability for 25 days in its electrochemical analytical performance.