Detection of mercury(II) ions (Hg2+) in water by a nanobiosensor
By: Wu, Wen-he; Hong, Xiao-lan; Xiang, Xu-wu; Yao, Xiao-yan; Pan, Ting-ting; Xiong, Jun; Lu, Jian-xin
A nanobiosensor for rapid colorimetric detecting Mercury(II) Ions (Hg2+) in water by mercury-specific oligonucleotides (MSOs) probe and gold nanoparticles was developed. The nanobiosensor was assembled by adsorbing the optimized MSOs on the surface of gold nanoparticles. A direct colorimetric probe of Hg2+ which relied on the T-T mismatches in DNA duplexes was used to selectively and strongly capture Hg2+. Hg2+ induces the aggregation of gold nanoparticles with appropriate amt. of salts, resulting the colorchange (red to blue). The diam. and concn. of the gold nanoparticle prepn. were 15 nm and 2.97 nmol/L, resp. Truncated MSOs (9 bp) showed the similar Hg2+binding activity. The optimum concn. of the NaNO3 soln. was 0.5 mol/L. The nanobiosensor could detect Hg2+ in a range of 10-1000 μmol/L within few minutes and the specificity was 100%. A new nanobiosensor is developed successfully for rapid colorimetric detecting Hg2+ in water, avoiding either MSOs labeling or gold nanoparticles modification. This technique is simple, convenient and rapid detecting method with high sensitivity and specificity.