Reduced Graphene Oxide Nanosheets Enhance the Sensitivity of p-Cresyl Sulfate Detection Using a Molecularly Imprinted Polymer-Based Electrochemical Sensor

p-Cresyl sulfate (PCS) is readily absorbed in the bloodstream due to bacterial activity, which leads to the production of PCS using dietary tyrosine and phenylalanine by the bacteria residing in the gut. This molecule is responsible for maintaining the human health system and controlling the development of several diseases related to obesity, diabetes, cardiovascular diseases, chronic kidney diseases (CKDs), inflammatory bowel diseases, etc. Therefore, it is necessary to detect the level of PCS in urine or blood samples, which helps to identify CKDs. In this article, a poly(methacrylic acid) (PMAA)-based molecularly imprinted polymer (MIP) is used to develop a point-of-care device for PCS detection using an indigenously fabricated screen-printed carbon electrode. MIP is modified by further incorporating reduced graphene oxide (rGO) in the PMAA matrix, and the formations of PMAA@rGO-NIP and PMAA@rGO-MIP are confirmed by Fourier transform infrared spectroscopy analysis. A comparison in electrochemical sensing of PCS by PMAA-MIP and PMAA@rGO-MIP was performed, and better sensitivity (0.116 mu A/ng mL cm(-2)) and a wide linear range of detection were obtained in the case of PMAA@rGO-MIP because of the presence of the conductive rGO nanosheets. The obtained results were compared using ultra-performance liquid chromatography-tandem mass spectrometry to validate the accuracy of the fabricated sensor. The interferent study was also performed to show the selectivity of the developed sensor PMAA@rGO-MIP toward PCS, which was further used to quantify PCS in the spiked-in human urine sample model.