A facile double-signal ratiometric sensor of creatinine based on silver nanoparticles/thionine acetate/Mxenes with intrinsic self-calibration property

In this work, a ratiometric double signals electrochemical sensing platform was constructed for creatinine (Cre) analysis employing silver nanoparticles (AgNPs)@ MXenes/thionine acetate (THAT) composites. The synthesis of MXenes/THAT composites was utilized to modify on the surface of a screen-printed electrode (SPE) via dripping coating, followed by the electro-deposition of AgNPs. While the anodic current of the AgNPs decreased in the presence of Cre due to the competive reaction for forming metal complexes, the current of THAT remained invariant, which attained a ratiometric response. Under optimized conditions, the response current ratio ( I Ag /I THAT ) decreases while the concentration of Cre increased linearly between 0 ∼ 1.2 mM, with 0.01 μM as a adaptive detection limit. It provided a new sensing platforming for employing double-signals nanostructures with remarkable stability and sensitivity to design ratiometic sensors for analysis of Cre in human urine samples with real-time.