Development and characterization of an electrochemical sensor using molecularly imprinted polymer based on a gold screen-printed electrode for the detection of creatinine and glucose in human urine and saliva

The development of noninvasive and enzyme-free devices is nowadays very popular in medical research due to their affordable cost and also to bypass the restrictions because of the measurements requiring blood. For this purpose, this work presents the development of noninvasive electrochemical sensors operating in secreted human physiological fluids, namely, urine and saliva. The proposed electrochemical devices are based on molecularly imprinted polymer (MIP) for the detection of two analytes (creatinine and glucose) that are very important in understanding kidney diseases. The challenges facing research in this field are to bypass classical techniques which are either cumbersome, expensive, or invasive. Indeed, biomimetic receptors are designed on screen-printed gold electrodes using two different ways (sandwich and electropolymerization). Here, electrochemical and morphological characterizations were performed. On the one hand, cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy have allowed to visualize the electrochemical behavior of the proposed MIP sensors. On the other hand, scanning electron microscopy coupled with energy-dispersive spectroscopy and atomic force microscopy have allowed to study the surface properties, thereby obtaining very promising metrological properties. In a wide linear range of 0.1–1 μg/mL, a low detection limit of 0.016 ng/mL was reached for the creatinine sensor. For glucose detection, an Limit Of Detection (LOD) of 0.59 μg/mL was obtained in the working range from 0.5 to 50 μg/mL. Using partial least squares regression, the two MIP sensors were satisfactorily applied for the practical detection of both analytes in urine and saliva while referring to the Jaffé method and a glucometer, respectively.