Detection of Silver Ions Using Dielectrophoretic Tweezers-Based Force Spectroscopy

Understanding of the interactions of silver ions (Ag⁺) with polynucleotides is important not only to detect Ag⁺ over a wide range of concentrations in a simple, robust, and high-throughput manner but also to investigate the intermolecular interactions of hydrogen and coordinate interactions that are generated due to the interplay of Ag⁺, hydrogen ions (H⁺), and polynucleotides since it is critical to prevent adverse environmental effects that may cause DNA damage and develop strategies to treat this damage. Here, we demonstrate a novel approach to simultaneously detect Ag⁺ satisfying the above requirements and examine the combined intermolecular interactions of Ag⁺-polycytosine and H⁺-polycytosine DNA complexes using dielectrophoretic tweezers-based force spectroscopy. For this investigation, we detected Ag⁺ over a range of concentrations (1 nM to 100 μM) by quantifying the rupture force of the combined interactions and examined the interplay between the three factors (Ag⁺, H⁺, and polycytosine) using the same assay for the detection of Ag⁺. Our study provides a new avenue not only for the detection of heavy metal ions but also for the investigation of heavy metal ions-polynucleotide DNA complexes using the same assay.