State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University , Ningbo, 315211, PR China.
J Agric Food Chem. 2017 Jul 19;65(28):5731-5740. doi: 10.1021/acs.jafc.7b02139. Epub 2017 Jul 7.
A mimicking-enzyme-based colorimetric aptasensor was developed for the detection of kanamycin (KANA) in milk using magnetic loop-DNA-NMOF-Pt (m-L-DNA) probes and catalytic hairpin assembly (CHA)-assisted target recycling for signal amplification. The m-L-DNA probes were constructed via hybridization of hairpin DNA H1 (containing aptamer sequence) immobilized magnetic beads (m-H1) and signal DNA (sDNA, partial hybridization with H1) labeled nano Fe-MIL-88NH-Pt (NMOF-Pt-sDNA). In the presence of KANA and complementary hairpin DNA H2, the m-L-DNA probes decomposed and formed an m-H1/KANA intermediate, which triggered the CHA reaction to form a stable duplex strand (m-H1-H2) while releasing KANA again for recycling. Consequently, numerous NMOF-Pt-sDNA as mimicking enzymes can synergistically catalyze 3,3',5,5'-tetramethylbenzidine (TMB) for color development. The aptasensor exhibited high selectivity and sensitivity for KANA in milk with a detection limit of 0.2 pg mL within 30 min. The assay can be conveniently extended for on-site screening of other antibiotics in foods by simply changing the base sequence of the probes.
基于模拟酶的比色适体传感器用于牛奶中卡那霉素（KANA）的检测，该传感器使用磁性环-DNA-NMOF-Pt（m-L-DNA）探针和催化发夹组装（CHA）辅助的目标循环进行信号放大。m-L-DNA 探针通过固定在磁性珠上的发夹 DNA H1（包含适体序列）与信号 DNA（sDNA，与 H1 部分杂交）的杂交构建，并用纳米 Fe-MIL-88NH-Pt（NMOF-Pt-sDNA）标记。在存在 KANA 和互补发夹 DNA H2 的情况下，m-L-DNA 探针分解并形成 m-H1/KANA 中间体，该中间体触发 CHA 反应形成稳定的双链体（m-H1-H2），同时再次释放 KANA 以进行循环利用。因此，大量的 NMOF-Pt-sDNA 作为模拟酶可以协同催化 3,3',5,5'-四甲基联苯胺（TMB）显色。该适体传感器对牛奶中的 KANA 具有高选择性和灵敏度，检测限为 0.2 pg mL，在 30 分钟内即可完成检测。通过简单改变探针的碱基序列，该方法可以方便地扩展用于食品中其他抗生素的现场筛选。
