State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
Talanta. 2018 Sep 1;187:27-34. doi: 10.1016/j.talanta.2018.04.072. Epub 2018 Apr 25.
An ultrasensitive colorimetric aptasensor was developed for antibiotics detection, with chloramphenicol (CAP) as model target, using DNAzyme labeled Fe-MIL-88-Pt as novel peroxidase mimic signal tags and target-triggered circular strand-displacement polymerization (CSDP) for signal amplification. The system consists of two components which can partially hybridize with each other: one is capture probe which was formed through immobilizing hairpin DNA containing aptamer sequence on magnetic beads (MB-cDNA), another is signal tag which was constructed through labeling single strand DNAzyme (G-quadruplex/Hemin) which can partially hybrid with cDNA on platinum nanoparticles functionalized Fe-MIL-88 (MIL-88-Pt-DNAzyme). All components of MIL-88, Pt and DNAzyme in the tag can act as peroxidase mimic to triply catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by HO into a blue-colored oxidized TMB (oxTMB) for the colorimetric readout. Thus distinctive signal can be observed by naked eye even in presence of 0.02 nM tags. In the presence of target and primer, cDNA loop can open to form cDNA/CAP intermediates, enabling primer to hybridize with the exposed sequences of the cDNA, which initiated target assisted CSDP recycles. Then numerous signal tags were released into supernatant to catalyze TMB for color development. There was a liner relationship between the absorbance and the concentration of CAP in the range of 0.1 pM (0.0323 pg/mL) to 1000 pM (323 pg/mL) with the detection limit of 0.03 pM (0.0097 pg/mL). The ultra-high sensitivity was ascribed to the multiplex catalytic activities from the tags and CSDP based signal amplification. Furthermore, this method can produce signals being observed by naked eye to facilitate in-situ detection and be further extended to detect other antibiotics in food just by simply replacing cDNA on the sensing system.
开发了一种超灵敏的比色适体传感器，用于抗生素检测，以氯霉素 (CAP) 为模型目标，使用 DNAzyme 标记的 Fe-MIL-88-Pt 作为新型过氧化物酶模拟信号标签，并采用靶触发循环链置换聚合 (CSDP) 进行信号放大。该系统由两个可以部分杂交的组件组成：一个是含有适体序列的发夹 DNA 固定在磁性珠上形成的捕获探针 (MB-cDNA)，另一个是信号标签，它通过标记可以与铂纳米粒子功能化 Fe-MIL-88 上的 cDNA 部分杂交的单链 DNAzyme (G-四链体/Hemin) 构建而成 (MIL-88-Pt-DNAzyme)。标签中的所有 MIL-88、Pt 和 DNAzyme 成分都可以作为过氧化物酶模拟物，三重催化 HO 将 3,3',5,5'-四甲基联苯胺 (TMB) 氧化成蓝色氧化 TMB (oxTMB)，用于比色读出。因此，即使在存在 0.02 nM 标签的情况下，也可以用肉眼观察到独特的信号。在存在靶标和引物的情况下，cDNA 环可以打开形成 cDNA/CAP 中间体，使引物与 cDNA 暴露的序列杂交，从而引发目标辅助 CSDP 循环。然后，大量的信号标签被释放到上清液中，以催化 TMB 显色。在 0.1 pM（0.0323 pg/mL）至 1000 pM（323 pg/mL）的范围内，吸光度与 CAP 的浓度呈线性关系，检测限为 0.03 pM（0.0097 pg/mL）。超高灵敏度归因于标签和基于 CSDP 的信号放大的多重催化活性。此外，该方法可以产生肉眼可观察到的信号，便于原位检测，并通过简单更换传感系统上的 cDNA 进一步扩展到检测食品中的其他抗生素。
