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

Abstract

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 KNO₃ 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 KNO₃, 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 KNO₃, 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.