基于荧光共振能量转移的核酸适配体传感器检测环丙沙星

A fluorescence resonance energy transfer-based aptasensor for the detection of ciprofloxacin

建立了一种基于荧光共振能量转移(FRET)的核酸适配体传感器,并用于检测实际水体和牛奶中的环丙沙星(CIP)。为了防止羧基荧光素(FAM)被CIP猝灭,FAM和四甲基罗丹明(TAMRA)分别标记在互补单链DNA(FAM-cDNA)和适配体(TAMRA-APT),通过DNA杂交发生FRET,TAMRA有效猝灭FAM的荧光。CIP加入后,其与FAM-cDNA发生亲和力竞争反应,CIP与TAMRA-APT形成结构更稳定的CIP/TAMRA-APT复合物,使体系FAM的荧光恢复。在优化条件下,本方法对CIP表现出高灵敏度和高选择性,检测浓度线性范围为0.01~1μmol/L,检出限为6 nmol/L;对实际水样和牛奶的加标回收率为90.4%~113.2%,相对标准偏差为1.8%~11%。该荧光适配体传感器具有成本低、灵敏度高、特异性好等优点,在环境中CIP残留快速检测方面具有良好的应用潜力。

A fluorescence resonance energy transfer(FRET)-based aptasensor was established for the detection of ciprofloxacin(CIP)in water and milk.The fluorescence of carboxyfluorescein(FAM)could be effectively quenched by tetramethylrhodamine(TAMRA)based on the FRET occurred by the hybridization of TAMRA-labeled aptamer(TAMRA-APT)with fluorescein-labeled complementary DNA(FAM-c DNA).However,CIP could compete with FAM-c DNA in affinity,which means after its addition to form a more stable CIP/TAMRA-APT complex with TAMRA-APT,FAM-c DNA was released,leading to the fluorescence of FAM system recovered.As a result,the aptasensor showed high sensitivity and selectivity for CIP detection.Under the optimal conditions,the linear range of CIP concentrations for the method was 0.01-1μmol/L,and the detection limit was 6 nmol/L.Furthermore,the recoveries of the spiked water and milk samples were 90.4%-113.2%,and the relative standard deviations(RSDs)were 1.8%-11%.The fluorescent aptasensor,with low cost,high sensitivity and specificity,has good application potential in the rapid detection of CIP residues in the environment.