Tuning sensitivity of creatinine-imprinted polymers with new super-sensitive schlegelite nanocrystals for disposable electrochemical CKD diagnostics

Early diagnosis and monitoring of chronic diseases could alleviate the suffering of vulnerable people and prevent loss of lives, which largely depends on the availability of affordable and deliverable, yet sensitive analytical tools. We present a study aimed at optimizing the sensitivity of creatinine-imprinted polymers for disposable electrochemical sensors. For this purpose, various amounts of transition metal oxides with a layered structure, i.e., MoO3 (molybdite), V2O5 (shcherbinaite), and MoO3:V2O5 (schlegelite) nanocrystals, are embedded into a molecularly imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MIP) to create composite receptor layers on the surface of disposable, screen-printed Au electrodes. Cyclic voltammetry (CV) measurements demonstrate that these oxides remarkably improve the sensitivity of MIP toward creatinine, a key biomarker for renal malfunction. Compared to pure MIP, the sensitivity of MIP/MoO3, MIP/V2O5, and MIP/MoO3:V2O5 is enhanced by 113%, 121%, and 319%, respectively; thereby realizing the goal of developing highly sensitive and cost-effective electrochemical diagnostics for the chronic kidney diseases. Also, the MIP/MoO3:V2O5 sensor exhibits very low detection limits (90 nM), fast response times (<1 min), and a linear detection range (5-30 mu M) corresponding to the actual salivary concentration. Hence, these nanocrystallite-embedded electrochemical sensors have great potential for the diagnosis and monitoring of renal function.