We investigated the effects of DNA probe length on the performance of a dynamics-based electrochemical metal ion (E-ION) Hg(II) sensor. A systematic comparison of three versions of the Hg(II) sensor fabricated using oligothymine (oligo-T) probes of different lengths (6, 12, and 18 bases) is presented here. Independent of the probe length, the sensing mechanism of the sensor remains the same. It is based on the specific interactions between Hg(II) and thymine (T), formation of the T-Hg(II)-T complexes rigidifies the methylene blue (MB)-modified oligo-T probes, resulting in a concentration-dependent reduction in the MB signal. Although there are noted differences in sensor characteristics such as the limit of detection and dynamic range, all three sensors have demonstrated to be specific and selective. Thus, depending on the specific sensor properties that are required for the analysis, a shorter or longer oligo-T probe should be employed. With further optimization, this sensor could find applications in real time detection of Hg(II) in environmental samples.
- Electrochemical metal ion sensors
- alternating current voltammetry
- methylene blue
ASJC Scopus subject areas
- Analytical Chemistry