10In this work, sensor based on a new molecularly imprinted polymer (MIP) for creatinine (Cre) 11 detection, using screen-printed gold electrodes (Au-SPE), was developed. A carboxylic 12 polyvinyl chloride (PVC-COOH) layer was first deposited on Au-SPE surface. The creatinine 13 molecules were attached to the surface of Au-SPE/PVC-COOH. Afterward, the polymerization 14 of acrylamide and N, N' methylenebisacrylamid filled vacant spaces around them. The 15 subsequent templates removal left binding sites within the polymer which are capable of 16 selectively recognizing creatinine at different concentrations. To test the sensitivity of this 17 Biosensor, the same procedure without creatinine was performed on a gold non-imprinted 18 polymer (Au-SPE/NIP). Their retention and molecular-recognition properties were 19 qualitatively investigated by means of three instrumental techniques: voltammetry (cyclic 20 voltammetry (CV) and differential pulse voltammetry (DPV)), electrochemical impedance 21 spectroscopy (EIS), and UV-Visible spectrophotometry (UV-Vis). The obtained results indicate 22 that the MIP had a specific recognition ability for creatinine, while other structurally related 23 compounds, such as urea or glucose, could not be recognized on the MIP. In addition, the 24 biosensor was tested on volunteers with different creatinine urine levels and seemed a 25 promising tool for screening creatinine in point-of-care. Moreover, Partial Least Squares 26 (PLS) analysis was used to obtain a correlation between the predicted creatinine 27 concentrations from voltammetric measurements and concentrations measured by Jaffe's 28 reaction as a reference method. The EIS and DPV biosensor responses show a limit of detection 29 of 0.016 ng/mL and 0.081 ng/mL, respectively, with a linear range from 0.1 ng/mL to 1 µg/mL.
30This study provides a promising strategy to fabricate sensor devices based on MIPs with highly 31 selective recognition ability, simplicity of operation, small size and low cost. 32 Keywords: Molecular imprinted polymers (MIP), screen-printed gold electrodes, creatinine, 33 biosensor, human urine.34 35 3
Introduction
36The analysis of biological fluids, as blood, skin emanations, feces, saliva or even urine is 37 becoming a common practice to find out particular patient pathologies. One of the most used 38 fluids is urine, a multi-component complex system, from which the chemical composition can 39 be related to several pathologies [1,2]. One of the urine components in concern is creatinine 40 molecule, chemically designated as 2-amino-1-methyl-2-imidazoline-4-one. It can be found in 41 human urine as result of creatine or creatine phosphate metabolism, after muscle contraction.
42In mammals, creatinine is the end product of creatine metabolism in the skeletal muscles to the 43 release of energy and is removed from the body by renal excretion at a relatively constant rate 44 [3]. The normal levels for creatinine concentrations in urine and blood are ranging from 500 to 45 1500 µg/mL and from 700 to 12...
