Molecularly imprinted polymers (MIPs) are attracting substantial interest as artificial plastic antibodies because of their biometric capability for targeting small molecules. In this study, molecularly imprinted silica material-coated quantum dots (MIS-QDs) with selective recognition capability to okadaic acid (OA) were developed and characterized. The synthesized MIS-QDs with specific imprinting cavities exhibited excellent recognition capability similar to those of biological antibodies and high fluorescence (FL) quenching selectivity for OA. Furthermore, the MIS-QDs with unsaturated bonds were immobilized onto the surface of 96-well microplates by cold plasma-induced grafting. A novel direct competitive microplate assay strategy was then proposed. The FL quenching properties of the developed microplate assay showed an excellent linear relationship with OA in the range of 10.0-100.0 μg/kg with a correlation coefficient of 0.9961. The limit of detection for OA was 0.25 μg/kg in the shellfish samples. The mean quantitative recoveries were 92.5%-101.0% and 92.9%-101.3%, with relative standard deviations of <7.7% and 7.6% for pure solvents and purified shellfish samples, respectively. The established microplate assay strategy can be used as a rapid and high-throughput method for analyzing OA marine toxins in biological samples.
Keywords: Microplate assay; Molecularly imprinted material; Okadaic acid; Quantum dot.
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