Artificial molecular recognition material based biosensor for creatinine by electrochemical impedance analysis

An electrochemical impedimetric sensor based on molecular imprinted polymer (MIP) has been developed for the detection of creatinine. Creatinine MIP was prepared by using the functional monomer methylacrylate and cross-linker ethylene glycol dimethacrylate in presence of the template creatinine. The resultant polymer was washed with water, methanol and 1 M HCl to extract the template from the polymer matrix. Formations of MIP, NIP (non-imprinted polymer) and template extraction were confirmed with vibrational Raman spectroscopic analysis. MIP incorporated carbon paste electrodes were used to develop a sensor for creatinine by applying electrochemical impedance spectroscopy (EIS) as transduction principle. Charge-transfer impedance (Rct) of the sensor system was determined in the absence and presence of creatinine. Interestingly, magnitude of Rct was found to increase with increasing concentrations of creatinine, which suggests the accumulation of creatinine into the polymer matrix. From the calibration plot, the low-detection-limit value was found to be ~20 ng mL−1. The MIP electrode showed very good selectivity towards the specific recognition of creatinine in the presence of possible interferents like l-ascorbic acid and l-tryptophan. From the observations, we can conclude that the prepared imprinted polymer works successfully as an artificial biomolecular recognition element.