Functionalized magnetic nanoprobe-based aptasensor for on-site detection of kanamycin in water by a personal glucose meter.

In this work, the nanomagnetic probe was prepared by condensation of carboxylated kanamycin (Kana) aptamers with aminated nanomagnetic Fe3O4 beads, which was coupled with invertase-labeled complementary DNA (cDNA) for sensitive and convenient detection of Kana in water samples by a personal glucose meter (PGM). In the absence of Kana, there was no PGM signal recorded because formed nanomagnetic probe was removed by magnetic separation. Conversely, the aptamer could recognize Kana specifically and released cDNA into supernatant. After the addition of sucrose, it was hydrolyzed into glucose by invertase. Detection of Kana was indirectly achieved based on the relationship between glucose concentration and the PGM indication. Furthermore, a miniaturized portable device was constructed by integrating the components using 3D printing technology. Under optimal conditions, rapid detection of Kana within the concentration range of 1-200 nM was achieved, with a detection limit (3σ/k) of 0.28 nM. Moreover, the proposed aptasensor was characterized in terms of selectivity, reproducibility and stability. Finally, it was applied to the determination of Kana in water with recoveries from 99% to 103%. All these results indicated that the proposed aptasensor is simple, rapid, selective, and sensitive, and it could potentially serve as an effective approach for the on-site determination of Kana in water samples.