Microchip electrophoresis array-based aptasensor for multiplex antibiotic detection using functionalized magnetic beads and polymerase chain reaction amplification

A microchip electrophoresis (MCE) array-based aptasensor for multiplex detection of antibiotics was developed using multi-capture DNA functionalized magnetic beads ([email protected]@assistantDNA) and polymerase chain reaction (PCR) for signal amplification. In this study, kanamycin (KANA) and chloramphenicol (CAP) were employed as model analytes. In the presence of a target, specific binding between the target and corresponding capture DNA (C-DNA) would induce the unwinding of double-strand structures, leading to the release of assistant DNA (A-DNA) into the supernatant after magnetic separation. The released A-DNA was co-amplified by PCR with an internal standard strand (I-DNA). After 20 cycles of PCR, the ratio (IA-DNA/II-DNA) between the above PCR products was proportional to the concentrations of the target with a detection limit of 0.0025 nM and 0.006 nM for KANA and CAP, respectively. Under optimal conditions, the method exhibited high sensitivity and selectivity for the targets, and the average detection time was about 1 min. Moreover, this assay was successfully employed to detect KANA and CAP in milk and fish samples with consistent results to that of enzyme-linked immunosorbent assay, suggesting that it is a promising platform for detecting small molecules in food by changing the corresponding aptamer.