Sensitive Detection of Serum Creatinine Based on β-Cyclodextrin-Ferrocenylmethanol Modified Screen-printed Electrode

Ferrocenylmethanol (Fc-OH) is included in β-cyclodextrin (β-CD) to form the β-CD-Fc-OH complex by host-guest supramolecular interaction. β-CD dissociates from the β-CD-Fc-OH complex due to the conversion of Fc-OH to Fc⁺-OH under a stimulus of oxidant. In our study, Fc-OH is oxidized after a series of enzymatic reactions of creatinine, which blocks the other means for oxidation of Fc-OH. And the background noise is reduced for testing for serum creatinine (sCr). The chronoamperometry signal for creatinine (with a constant potential -0.3 V vs. Ag/AgCl) increases linearly in the 1 - 1000 μM range, with a limit of detection as low as 0.5 μM. The amperometric potential of -0.3 V greatly prevents the interference of various redox substances in serum. The biosensor was used to test 120 clinical specimens and the results showed a linear correlation with the biochemical analyzer (R² = 0.9885). The biosensor could be applied to clinical trials and offers good prospects for clinical sCr detection.