Department of Chemistry, Pohang University of Science and Technology, Pohang, Gyungbuk, South Korea.
Anal Bioanal Chem. 2012 Feb;402(6):2153-61. doi: 10.1007/s00216-011-5662-3. Epub 2012 Jan 7.
A gold nanoparticle based dual fluorescence-colorimetric method was developed as an aptasensor to detect ampicillin using its single-stranded DNA (ssDNA) aptamer, which was discovered by a magnetic bead-based SELEX technique. The selected aptamers, AMP4 (5'-CACGGCATGGTGGGCGTCGTG-3'), AMP17 (5'-GCGGGCGGTTGTATAGCGG-3'), and AMP18 (5'-TTAGTTGGGGTTCAGTTGG-3'), were confirmed to have high sensitivity and specificity to ampicillin (K(d), AMP7 = 9.4 nM, AMP17 = 13.4 nM, and AMP18 = 9.8 nM, respectively). The 5'-fluorescein amidite (FAM)-modified aptamer was used as a dual probe for observing fluorescence differences and color changes simultaneously. The lower limits of detection for this dual method were a 2 ng/mL by fluorescence and a 10 ng/mL by colorimetry for ampicillin in the milk as well as in distilled water. Because these detection limits were below the maximum residue limit of ampicillin, this aptasensor was sensitive enough to detect antibiotics in food products, such as milk and animal tissues. In addition, this dual aptasensor will be a more accurate method for antibiotics in food products as it concurrently uses two detection methods: fluorescence and colorimetry.
一种基于金纳米粒子的双荧光比色法被开发为一种适体传感器，用于检测氨苄西林，其单链 DNA（ssDNA）适体是通过基于磁珠的 SELEX 技术发现的。经过筛选的适体 AMP4（5'-CACGGCATGGTGGGCGTCGTG-3'）、AMP17（5'-GCGGGCGGTTGTATAGCGG-3'）和 AMP18（5'-TTAGTTGGGGTTCAGTTGG-3'）对氨苄西林具有高灵敏度和特异性（K(d)，AMP7 = 9.4 nM，AMP17 = 13.4 nM，AMP18 = 9.8 nM）。5'-荧光素亚胺（FAM）修饰的适体被用作双探针，同时观察荧光差异和颜色变化。该双方法的检测下限为在牛奶和蒸馏水中，氨苄西林的荧光检测为 2 ng/mL，比色检测为 10 ng/mL。由于这些检测限低于氨苄西林的最大残留限量，因此该适体传感器足以检测食品（如牛奶和动物组织）中的抗生素。此外，这种双适体传感器将是一种更准确的食品中抗生素检测方法，因为它同时使用了两种检测方法：荧光和比色法。
