DETERMINATION OF NANOMOLAR LEVELS OF MERCURY(II) BY EXPLOITING THE SILVER STAIN ENHANCEMENT OF THE AGGREGATION OF APTAMER-FUNCTIONALIZED GOLD NANOPARTICLES

Authors：Chen Beibei; Wang Zebo; Hu Dongxue; Ma Qingqing; Guo Zhiyong^*; Jiang Xiaohua; Wang Sui

Source：ANALYTICAL LETTERS, 2014, 47(5): 795-806.

DOI：10.1080/00032719.2013.853183

• Aptamer
• Biosensor
• Gold nanoparticles
• Mercury(II) ions
• Silver stain enhancement

An ultrasensitive method for the determination of mercury(II) ions was developed based on mercury(II)-induced strong and selective binding of thymine-thymine mismatches between aptamers on gold nanoparticles and a signal amplification effect caused by a silver stain. The gold nanoparticles were first coated with a single-stranded DNA aptamer rich in thymine. In the presence of mercury(II), the functionalized gold nanoparticles aggregated due to the formation of thymine-Hg(II)-thymine complexes resulting in a largely reduced surface area of the gold nanoparticles when exposed to silver ions during staining. Therefore, fewer silver ions were reduced, and the average grey values, as measured by a scanner, were lower. The average grey values were linearly related to the logarithm of mercury(II) concentration from 1 to 500nM. In addition, there were no significant interferences by common metal ions due to the high specificity of the interaction between mercury(II) and the aptamer. The method offers high sensitivity, good selectivity, and the absence of large equipment that makes it suitable for field analysis.

• Institution
  深圳职业技术学院; 宁波大学