Lateral flow test strips for mercury ions detection based on combination of oligonucleotide-modified gold nanoparticles and chelation by glutathione

Heavy metal pollution is still of actual task despite on many developments. The growth in nanotechnology allowed for application of nanoparticles modified with receptor molecules for selective or group-selective recognition of concrete metal ions. One of these molecules are aptamers which consist of nucleotides linked in necessary order. In our investigation new aptamer-based assay format for mercury ions has been developed. It is based on lateral flow technique with working nitrocellulose membrane and immobilized reagents as corresponding test zones. Two reagents have been applied to form the detectable complex on the membrane. Conjugate of bovine serum albumin with glutathione was immobilized on the nitrocellulose membrane to form the test zone as catching agent. Freshly prepared gold nanoparticles were conjugated with G,T-rich oligonucleotide as recognition agent. A linear relationship between the change in the color intensity of the corresponding test zones and the concentration of Hg2+ ions in the range from 5 to 1000 ng/mL was observed. Visual limit of mercury detection was of 10 ng/mL. Total duration of the analysis is 5 min. Thus, the developed technique is promising for Hg2+ detection in different water sources to confirm their safety.