Solid-State Nanopore Analysis of DNA-Templated Silver Nanoclusters: Voltage-Dependent Translocation and Electrolyte Stability.

We investigate the translocation behaviors of fluorescent silver nanoclusters templated in 20- and 37-nucleotide-long DNA strands (DNA/AgNCs) through solid-state nanopores in various electrolyte solutions (1 M KNO(3) and 1 M KCl with 10 mM Tris). Using nanopores with diameters of 2.6, 3.1, 3.6, 4.8, and 5.6 nm, we analyze the stability and translocation characteristics of the DNA/AgNCs across electrolyte conditions ranging from pH 7.6 to 8.4 and applied voltages from 200 to 400 mV. Our findings reveal that AgNCs remain stable in KNO(3), resulting in distinct translocation signatures, whereas they dissociate in KCl, resulting in translocation signatures similar to bare DNA. We reveal how nanopore size and buffer conditions influence translocation behavior, providing a more comprehensive understanding of the DNA/AgNC dynamics. Conductance measurements and the corresponding nanopore diameters confirm the presence of stable AgNCs in KNO(3), with significant current blockades indicative of near-pore clogging events. Additionally, our data highlight that nanopore technology can differentiate DNA/AgNCs from bare DNA based on their translocation patterns, emphasizing the potential for advanced biosensing applications. This fundamental understanding of AgNC behaviors, combined with insights from pore-size-dependent and pH-dependent translocation patterns, not only enhances our knowledge of metallo-DNA structures but also strengthens the potential of nanopore-based analyte differentiation and biosensing applications.