A&P Seminar - Pratik Shah

The Analytical and Physical Seminar Series presents: Pratik Shah
Roskilde University

Host: Devleena Samanta

Title: Dynamic DNA–Silver Nanocluster Interactions for Responsive Biosensing and Imaging

Location: NHB 1.720
 

Biosensing technologies capable of detecting molecular signals inside living cells are essential for advancing both diagnostics and basic cell biology. DNA has emerged as a versatile scaffold in this space due to its programmable structure, biocompatibility, and ease of functionalization. Yet, in most DNA–nanomaterial systems, the DNA serves as a passive template. In contrast, our work with DNA-stabilized silver nanoclusters (DNA/AgNCs) reveals a unique, reciprocal interaction—where the DNA structure dynamically tunes the optical properties of the AgNCs, and the AgNCs, in turn, reshape the DNA into novel non-canonical conformations. This mutual feedback mechanism acts like a “molecular handshake,” where both the DNA and nanocluster adjust to one another, unlocking unique modes of sensing. We exploit this dynamic to rationally design Hoogsteen triplex DNA motifs that modulate AgNCs fluorescence in response to pH changes. Through detailed structural and biochemical analysis, we show how AgNCs organize within triplex scaffolds and reversibly alter their emission properties. Building on this, we’ve developed responsive biosensors for microRNA and reactive oxygen species (ROS), enabling potential applications in live-cell imaging. Our results establish a new design approach in DNA nanotechnology, where structural and functional integration between scaffold and signal element enables the development of dynamic nanosensors. These advances open opportunities for intracellular biosensing, imaging, and programmable nanodevice design.