采用核酸适配体作为特异性识别元件,SYBR Green I(SGI)荧光染料为信号输出单元,构建了黄曲霉毒素B1(AFB1)生物传感器,并对试验条件进行了优化.优化的试验条件如下:适配体互补链与适配体的物质的量比为1.5,SGI加入量为10 μL,适配体双链与SGI的作用时间为2 min,适配体与AFB1作用时间为14 min.结果表明,在AFB1质量浓度为0.1～1 000 μg·L-1时,荧光强度变化量与其质量浓度对数呈线性关系,检出限(3S/N)为0.081 μg·L-1.对实际玉米样品进行加标回收试验,回收率为95.2%～105%,测定值的相对标准偏差(n=7)均小于6.0%.与其他适配体传感器进行比较,该方法所构建的荧光适配体传感器对AFB1的检测具有操作简便、检测范围宽、灵敏度高、特异性强、成本低廉等优点,适合现场快速测定.
Preparation of Fluorescence Biosensor Based on Nucleic Acid Hybridization Reaction and Its Application in Aflatoxin B1 Detection
A biosensor for aflatoxin B1(AFB1)was constructed by using nucleic acid aptamer as the specific recognition element and SYBR Green I(SGI)fluorescent dye as the signal output unit.The test conditions were optimized,revealing the following optimal parameters:the molar ratio of the complementary chain of the aptamer to the aptamer was 1.5,the addition amount of SGI was 10 μL,the interaction time of the double-chain aptamer with SGI was 2 min,and the interaction time of the aptamer with AFB1 was 14 min.As shown by the results,when the mass concentration of AFB1 ranged from 0.1 μg·L-1 to 1 000 μg·L-1,the change in fluorescence intensity exhibited a linear relationship with the logarithm of its mass concentration,with detection limit(3S/N)of 0.081 μg·L-1.Test for recovery was made on actual corn samples by the standard addition method,giving results in the range of 95.2%—105%,with RSDs of the determined values(n=7)less than 6.0%.Compared to other aptamer sensors,this fluorescence aptamer sensor exhibited numerous advantages in AFB1 detection,including simplicity of operation,a wide detection range,high sensitivity,strong specificity,and low cost.Consequently,it was well-suited for rapid on-site determination.
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