A MIP/ITO with electrochromic properties for selective monitoring of carvedilol in human biofluids: towards a green dual-mode electrochemical/visual sensor.

The widespread prevalence of cardiovascular diseases and their profound impact on quality of life have underscored the critical need for accurate monitoring of cardiac medications and precise dosage control. In this study, an electrochromic sensor has been designed and fabricated using aniline as the electrochromic material and carvedilol as the template molecule. The sensing mechanism is based on molecular imprinting on the surface of an indium tin oxide (ITO) electrode, enabling selective recognition of the analyte according to its shape and size. The proposed sensor demonstrates a linear response for carvedilol detection over the concentration range of 1 to 700 nM, with a detection limit of 0.33 nM and a sensitivity of 0.0318 μA nM-1. Moreover, the resulting surface color variations range from green to blue, creating a unique color pattern confirmed by RGB indexes, serving as a key for the naked-eye detection of carvedilol. The sensor exhibits excellent stability, selectivity, and cost-effectiveness. Analytical performance has been validated using human urine and blood samples, yielding satisfactory recoveries and precision and demonstrating the potential of the proposed sensor for convenient analysis of carvedilol in biological matrices. Furthermore, the method has been evaluated using two widely accepted international greenness assessment tools, confirming its environmental compatibility.