Study Of Novel Tetracyclines Detection Methods Using Aptamers

Tetracyclines residuals in animal products and water take great threatens to human health via the food chain, which have already caused a high attention of society. In order to ensure the food safety, developing rapid and effective analysis methods to monitor tetracyclines residuals have important reality significance. In the research paper, two novel sensor methods were established using the aptamers, they are aptamer resonance scattering(RS) method and aptamer colorimetric method. The detailed research contents are shown as follow:(1) Resonance Scattering(RS) method based on aptamer and catalytic activity of nanogold. In the presence of tetracycline, aptamer combined to tetracycline, the naked nanogold got aggregation when the Na Cl existence. The aggregated nanogold had lower catalytic capacity and catalyzed Fehling reaction yielding smaller Cu2 O cubic. The system had lower RS signals. In the absence of tetracycline, nanogold dispersed evenly in the system, and catalyzed the Fehling reaction yielding bigger Cu2 O cubic. The system had higher RS signals. Under the optimization reaction conditions, the linear equation was △I620nm= 1.4793 CTET + 107.69(R2 = 0.998) and the limit of detection was calculated as 11.6 nM. The results indicated that this method has good sensitivity and selectivity to tetracycline.(2) Colorimetric method based on aptamer and PAH efficiently aggregated nanogold. In the presence of tetracycline, a macromolecule complex tetracycline-aptamer-PAH formed and the aggregation capacity of PAH to nanogold reduced. At this time, the solution color was light red. However, in the absence of tetracycline, the system could not form the macromolecules and the PAH also had higher aggregation capacity to nanogold. The solution color was light blue. Under the optimization conditions, the linear equation was Y=2.23X+1.0296, the correlation coefficient was 0.9924 and the limit of detection was calculated as 95 nM. The results manifested that the colorimetric method has good selectivity and sensitivity to tetracycline.(3) Standard addition recovery experiments. The two novel methods were applied to analyze the real milk sample. The recoveries of RS method were 105 % ~ 109 %, and the relative standard deviation(RSD) were 1.9 % ~ 4.2 %. The recoveries of colorimetric method were 108 % ~ 117 %, and the RSD were 2.9 % ~3.6 %. These indicated that the two novel methods had good accuracy and repeatability.