A dual-mode of electrochemical-colorimetric biosensing platform for kanamycin detection based on self-sacrifice beacon and magnetic separation technique.

In this work, iron-based metal organic frameworks (Fe-MOF) are used as a self-sacrifice beacon to produce Prussian blue (PB). Then, a dual-mode electrochemical-colorimetric biosensing platform for kanamycin (KAN) detection is established considering the prominent redox activity and blue color of PB. CoFe2O4 magnetic nanobeads (CoFe2O4 MBs) are employed for immobilization and separation of the signal beacon in the complex matrix, and the combination between CoFe2O4 MBs and magnetic electrodes simplifies the electrochemical testing process. The linear range of the electrochemical mode is 0.1 nM-1.0 μM with a detection limit of 39 pM, and that of the colorimetric mode is 10 nM-2.0 μM with a detection limit of 3.6 nM. Furthermore, the dual-mode strategy shows satisfactory specificity and enhanced applicability for KAN detection in real samples. Compared with known dual-mode determination methods, the proposed design employs the same reaction to produce two signal output modes, thus eliminating the effect of different reactive pathways on the outcome and in turn promoting greater accuracy.