Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute-Constituent Laboratory of the Council of Scientific and Industrial Research, CSIR, Mysore 570020, India.
Anal Biochem. 2012 Aug 15;427(2):151-7. doi: 10.1016/j.ab.2012.05.020. Epub 2012 May 29.
A simple and stable RNA aptamer-based colorimetric sensor for the detection of vitamin B₁₂ using gold nanoparticles (AuNPs) has been proposed. Vitamin B₁₂ belongs to the B vitamin group and prevents pernicious anemia, which is caused by vitamin B₁₂ deficiency. A highly stable RNA aptamer that binds to vitamin B₁₂ was employed by structural modification of 2'-hydroxyl group of ribose to 2'-flouro in all pyrimidines indicated in lowercase in 35-mer aptamer (5' GGA Acc GGu GcG cAu AAc cAc cuc AGu GcG AGc AA 3'). Aggregation of AuNPs was specifically induced by desorption of the vitamin B₁₂ binding RNA aptamer from the surface of AuNPs as a result of the aptamer-target interaction, leading to the color change from red to purple. The level of detection of vitamin B₁₂ was 0.1 μg/ml by successful optimization of the amount of the aptamer, AuNPs, salts, and stability of the aptamer. Analysis of vitamin B₁₂ was carried out, and the observed recovery was 92 to 95.3% with a relative standard deviation in the range of 2.08 to 8.27%. The results obtained were compared with those of the ultraviolet-visible (UV-vis) spectrometry method. This colorimetric aptasensor is advantageous for on-site detection with the naked eye.
已提出一种基于简单稳定的 RNA 适体的比色传感器，用于使用金纳米粒子（AuNPs）检测维生素 B₁₂。维生素 B₁₂属于 B 族维生素，可预防因维生素 B₁₂缺乏引起的恶性贫血。通过对 35 -mer 适体（5' GGA Acc GGu GcG cAu AAc cAc cuc AGu GcG AGc AA 3'）中所有嘧啶的 2'-羟基核糖进行结构修饰，得到与维生素 B₁₂结合的高度稳定的 RNA 适体，其中小写字母表示 2'-氟。由于适体-靶相互作用，从 AuNPs 表面解吸与维生素 B₁₂结合的 RNA 适体，特异性诱导 AuNPs 聚集，导致颜色从红色变为紫色。通过成功优化适体、AuNPs、盐的用量和适体的稳定性，检测维生素 B₁₂的水平达到 0.1 μg/ml。进行了维生素 B₁₂的分析，观察到的回收率为 92%至 95.3%，相对标准偏差在 2.08%至 8.27%范围内。将所得结果与紫外可见（UV-vis）光谱法进行了比较。这种比色适体传感器有利于现场用肉眼进行检测。
