Direct and highly sensitive impedimetric detection of creatinine in artificial urine using photopolymerized boronic-functionalized imprinted polymers films

Highly sensitive creatinine (Cre) detection in complex urinary matrices remains challenging because of nonspecific interference and limited molecular selectivity. Here, a boronic acid-functionalized molecularly imprinted polymer (MIP) electrode was developed for label-free electrochemical impedance spectroscopy (EIS) detection of Cre in undiluted artificial urine. A Cre-imprinted film containing 4-vinylbenzeneboronic acid (4-VBBA) was photopolymerized on a vinyl-functionalized Au electrode to enhance molecular recognition. The optimized MIP electrode exhibited a linear dynamic range of 5-250 nM, a sensitivity of 0.027 nM^-1, and a limit of detection (LOD) of 1.63 nM. Its sensitivity was 6.75-fold higher than that of the non-imprinted polymer (NIP). Incorporation of 4-VBBA further increased the sensitivity from 0.020 to 0.027 nM^-1 and improved the selectivity coefficients from 3.12 to 5.76 to 4.49-8.57. The Cre response remained well preserved in the presence of a 10-fold excess of individual interferents. The sensor also demonstrated high fabrication reproducibility (RSD, 2.15%), operational repeatability over ten regeneration cycles (RSD, 2.67%), and analytical recoveries of 98.69-101.55%. These results establish the 4-VBBA-functionalized MIP as a robust and highly selective recognition interface for sensitive Cre sensing in complex urine-like matrices.