Nano RNA aptamer wire for analysis of vitamin B12

A simple and stable RNA aptamer-based colorimetric sensor for the detection of vitamin B-12 using gold nanoparticles (AuNPs) has been proposed. Vitamin B-12 belongs to the B vitamin group and prevents pernicious anemia, which is caused by vitamin B-12 deficiency. A highly stable RNA aptamer that binds to vitamin B-12 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 B-12 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 B-12 was 0.1 mu g/ml by successful optimization of the amount of the aptamer, AuNPs, salts, and stability of the aptamer. Analysis of vitamin B-12 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. (C) 2012 Elsevier Inc. All rights reserved.