Energy Transfer Between i-Motif DNA Encapsulated Silver Nanoclusters and Fluorescein Amidite Efficiently Visualizes the Redox State of Live Cells.

The redox regulation, maintaining a balance between oxidation and reduction in living cells, is vital for cellular homeostasis, intricate signaling networks, and appropriate responses to physiological and environmental cues. Here, a novel redox sensor, based on DNA-encapsulated silver nanoclusters (DNA/AgNCs) and well-defined chemical fluorophores, effectively illustrating cellular redox states in live cells is introduced. Among various i-motif DNAs, the photophysical property of poly-cytosines (C)-encapsulated AgNCs that sense reactive oxygen species (ROS) is adopted.

Tailed-Hoogsteen Triplex DNA Silver Nanoclusters Emit Red Fluorescence upon Target miRNA Sensing.

MicroRNAs (miRNAs) are small RNA molecules, typically 21‒22 nucleotides in size, which play a crucial role in regulating gene expression in most eukaryotes. Their significance in various biological processes and disease pathogenesis has led to considerable interest in their potential as biomarkers for diagnosis and therapeutic applications. In this study, a novel method for sensing target miRNAs using Tailed-Hoogsteen triplex DNA-encapsulated Silver Nanoclusters (DNA/AgNCs) is introduced.

Silver Nanoclusters Serve as Fluorescent Rivets Linking Hoogsteen Triplex DNA and Hairpin-Loop DNA Structures.

Greater understanding of the mutual influence between DNA and the associated nanomaterial on the properties of each other can provide alternative strategies for designing and developing DNA nanomachines. DNA secondary structures are essential for encapsulating highly emissive silver nanoclusters (DNA/AgNCs). Likewise, AgNCs stabilize secondary DNA structures, such as hairpin DNA, duplex DNA, and parallel-motif DNA triplex.

Noncanonical Head-to-Head Hairpin DNA Dimerization Is Essential for the Synthesis of Orange Emissive Silver Nanoclusters.

DNA secondary structures, such as dimers and hairpins, are important for the synthesis of DNA template-embedded silver nanoclusters (DNA/AgNCs). However, the arrangement of AgNCs within a given DNA template and how the AgNC influences the secondary structure of the DNA template are still unclear. Here, we introduce a noncanonical head-to-head hairpin DNA nanostructure that is driven by orange-emissive AgNCs.

Structural Influence on the Post-Clustering Stability of DNA/AgNCs Fluorescence.

DNA-encapsulated Silver Nanoclusters (DNA/AgNCs) based sensors have gained increasing attention in past years due to their diverse applications in bioimaging, biosensing, and enzymatic assays. Given the potential of DNA/AgNCs for practical applications, the systematic studies of the fluorescent stability over an extended period is necessary. However, the correlation between nucleic acid properties and the long-term stability of DNA/AgNCs is less known.

The structural shift of a DNA template between a hairpin and a dimer tunes the emission color of DNA-templated AgNCs.

The scaffolding DNA sequence and the size of silver nanoclusters (AgNCs), confined in a DNA template are the key parameters in determining the fluorescent properties of DNA-stabilized silver nanoclusters (DNA/AgNCs). In addition, we suggest here that the structural shift of a DNA hairpin-dimer is as important as the DNA sequence in determining the emission wavelength of DNA/AgNCs. Furthermore, we show that the structural shift post AgNC formation can be triggered by incubation time and pre-AgNC formation under salt conditions.