Molecularly imprinted polymer dual electrochemical sensor for the one-step determination of albuminuria to creatinine ratio (ACR)

The urinary albumin to creatinine ratio (ACR) is a convenient and accurate biomarker of chronic kidney disease (CKD). An electrochemical sensor for the quantification of ACR was developed based on a dual screen-printed carbon electrode (SPdCE). The SPdCE was modified with carboxylated multiwalled carbon nanotubes (f-MWCNTs) and redox probes of polymethylene blue (PMB) for creatinine and ferrocene (Fc) for albumin. The modified working electrodes were then molecularly imprinted with coated with polymerized poly-o-phenyl-enediamine (PoPD) to form surfaces that could be separately imprinted with creatinine and albumin template molecules. The seeded polymer layers were polymerized with a second coating of PoPD and the templates were removed to form two different molecularly imprinted polymer (MIP) layers. The dual sensor presented recog-nition sites for creatinine and albumin on different working electrodes, enabling the measurement of each an-alyte in one potential scan of square wave voltammetry (SWV). The proposed sensor produced linear ranges of 5.0-100 ng mL-1 and 100-2500 ng mL-1 for creatinine, and 5.0-100 ng mL-1 for albumin. LODs were 1.5 & PLUSMN; 0.2 ng mL-1 and 1.5 & PLUSMN; 0.3 ng mL-1, respectively. The dual MIP sensor was highly selective and stable for seven weeks at room temperature. The ACRs obtained using the proposed sensor compared well (P > 0.05) with the results from immunoturbidimetric and enzymatic methods.