Methodology for MC-LR detection using surface plasmon resonance of the gold nanorods-aptamer complex in aqueous solutions

Abstract

By high concentration sodium chloride system, the high affinity of the aptamer-based gold nanorod was used as the sensing material for selective detection of Microcystin-LR (MC-LR). The combination of MC-LR and aptamer resulted in red shift in the absorption peak of the gold nanorods. As the increasing of MC-LR, the structure of the aptamer adsorbed on the gold nanorods changed, reducing the exposure of the bases and causing the gold nanorods to aggregate under the induction of salt solution. MC-LR concentration was measured according to the change of A798/A560 ratio of gold nanorods. In order to verify the accuracy of the nano method, the concentration of MC-LR in different growth periods was detected by comparing with that of liquid chromatography–mass spectrometry. The results showed that the aptamer-based colorimetric system had fast and sensitive detection performance with a linear range of 0.5 nM–8 μM and the detection limit reached 0.2 nM. In one month of short-term culture, the concentration of MC-LR detected by gold nanorods existed in the cell and kept increasing. That indicated that the modified gold nanorod method could detect MC-LR with high recovery and sensitivity in the actual environment.