Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
University of Chinese Academy of Science, Beijing, 100049, China.
Mikrochim Acta. 2018 Nov 7;185(12):534. doi: 10.1007/s00604-018-3067-0.
A competitive colorimetric assay has been established to detect chloramphenicol (CAP). It is based on the use of colloidal and electrostatically stabilized aptamer-modified gold nanoparticles (GNPs). The CAP aptamer is modified by a sequence of 5 adenosine groups to anchor it on the surface of GNPs. It can competitively capture two compounds, viz. D-(-)-threo-2-amino-1-(4-nitrophenyl)-1,3-propanediol (CAP-base, with a positive charge) and CAP (which is uncharged). The capture of the positively charged CAP-base triggers the aggregation of modified GNPs in salt-containing solution, and this causes a color change from red to purple. However, in the presence of CAP and CAP-base, the capture of the uncharged CAP weakens this color change by a competing process for capture. Thus, the concentration of CAP is associated with the degree of deaggregation of GNPs and can be quantified by the ratio of absorbances at 620 nm and 520 nm. The assay has a 22 nM limit of detection in acidic solution, and the response is linear in the range of 0.20 to 3.20 μM CAP concentration. This assay was successfully applied to the determination of CAP in spiked environmental water samples. Conceivably, this method has a wide scope in that it may be applied to a wide range of analytes if respective aptamers are available. Graphical abstract Schematic presentation of a competitive non-cross linking deaggregating method for detecting chloramphenicol. The surface charge of polyA-Apt@GNPs and its aggregation degree (purple) are determined by the charge of target. (CAP-base: precursor of CAP; PolyA-Apt@GNPs: 5'-polyA-modified DNA aptamer functionalized gold nanoparticles.).
建立了一种竞争性比色测定法来检测氯霉素 (CAP)。它基于使用胶体和静电稳定的适配体修饰的金纳米颗粒 (GNPs)。CAP 适配体通过 5 个腺苷序列修饰，以将其锚定在 GNPs 表面。它可以竞争性地捕获两种化合物，即 D-(-)-threo-2-氨基-1-(4-硝基苯基）-1,3-丙二醇（带正电荷的 CAP-base）和 CAP（不带电荷）。带正电荷的 CAP-base 的捕获在含盐溶液中引发修饰的 GNPs 的聚集，这导致颜色从红色变为紫色。然而，在存在 CAP 和 CAP-base 的情况下，由于捕获的竞争过程，不带电荷的 CAP 的捕获削弱了这种颜色变化。因此，CAP 的浓度与 GNPs 的解聚集程度相关，并可以通过在 620nm 和 520nm 处的吸光度比来定量。该测定法在酸性溶液中的检测限为 22nM，响应在 0.20 至 3.20μM CAP 浓度范围内呈线性。该测定法成功地应用于加标环境水样中 CAP 的测定。可以想象，如果有相应的适体，这种方法的应用范围很广，因为它可以应用于广泛的分析物。 图表抽象 用于检测氯霉素的竞争性非交联解聚集方法的示意性表示。聚 A-Apt@GNPs 的表面电荷及其聚集度（紫色）由目标的电荷决定。（CAP-base：CAP 的前体；聚 A-Apt@GNPs：5'-聚 A 修饰的 DNA 适体功能化金纳米颗粒）。
