基于磁性金属有机框架化合物-适配体探针的氯霉素仿生比色传感器研究

摘要

构建了一种基于磁性金属有机框架化合物( MOF)-适配体探针的仿生比色传感器，用于食品中氯霉素残留分析。首先将氯霉素( CAP)的适配体标记到Fe3 O4磁珠上获得捕获探针，进而采用该适配体的互补链标记到铁基MOF( Fe-MOF)上作为纳米示踪剂( MOF-cDNA)，将捕获探针和示踪剂杂交结合后，可获得铁磁性仿生复合探针。当氯霉素和此类探针孵育后，其与捕获探针上的适配体结合，将纳米示踪剂释放到溶液中，并经过磁分离后进入上清液。由于Fe-MOF具有过氧化物酶的性质，可以催化TMB-H2 O2系统显色，由此构建了一种高选择性的氯霉素比色传感器。在最佳反应条件下，本法对氯霉素的检测范围在0.001~10 ng/mL之间，最低检出限为0.3 pg/mL(S/N=3)，实际样品的加标回收率为86.9%~93.5%，且不受其它抗生素干扰。用此方法检测牛奶样品中氯霉素的结果与商业化ELISA方法一致。此类无酶标记仿生探针具有高催化活性且成本较酶标探针大大降低；该分析方法利用磁分离简化了前处理步骤，可用于奶制品中氯霉素的快速灵敏分析。%A colorimetric bionic aptasensor based on magnetic metal organic framework ( MOF ) compound-aptamer bionic probe was designed for detecting chloramphenicol ( CAP ) . In this assay, the aptamer was labeled on the magnetic beads as capture probe and its complementary strand ( cDNA ) was immobilized on MOF as the nanotracer composite probe, and the ferromagnetic biomimetic composite probe was obtained by hybridizing the capture probe with the tracer. When the composite probe solution was incubated with CAP, the aptamer on the capture probes preferentially combines with CAP, and the signal tag was substituted into supernatant after magnetic separation. The supernatant containing numerous MOF could efficiently catalyze tetramethylbenzidine ( TMB )-H2 O2 solution for the color development quantified by ultraviolet-visible spectroscopy. Under the optimal reaction conditions, the experimental results showed the CAP detection owned a linear range of 0 . 001-10 ng/mL and limit of detection was 0 . 3 pg/mL ( S/N=3 ) . The recoveries of standard addition in the actual samples were 86. 9% -93. 5% with no interference of other antibiotics. Besides, the results of this method for CAP detection in the milk samples agreed well with the ELISA results. Compared with the enzyme labeled probe, the non-enzyme labeled bionic probe using the magnetic separation greatly simplifies the pre-processing step, and it has many advantages such as high catalytic activity and low cost, and can be applied to the field detection of CAP in food with rapidity, high specificity and high sensitivity.