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Stacy Copp - University of California, Irvine

Host:  Lauren Zarzar (865-1316)

"DNA as an architect for atomically precise silver nanoclusters"

Abstract: DNA is a programmable building block for sequence-encoded nanomaterials whose structure-property relationships are governed by Nature’s base pairing rules. By exploiting metal-nucleic acid chemistry, we can significantly expand the “sequence-structure-property” relationships of DNA-based nanomaterials beyond the rules that Nature provides. This talk focuses on one such promising direction: atomically precise and programmable DNA-templated metal nanoclusters with bright fluorescence and promise for addressing challenges in biophotonics. DNA oligomers can template atomically precise silver nanoclusters (Ag-DNAs) that come in a diversity of bright, sequence-selected fluorescence colors. While Ag-DNAs hold promise for bioimaging and biosensing, their structure-property relationships have remained elusive. By combining high-throughput experiments and machine learning models with analytical studies of single nanocluster species, we show how nucleobase sequence selects the structures and colors of Ag-DNAs. This approach enables the design of new DNA template sequences for Ag-DNAs that emit light in the near-infrared tissue transparency window, a key area of need for bioimaging. Finally, I will discuss how we are using native mass spectrometry and circular dichroism spectroscopy to advance understanding of Ag-DNA ligand chemistry. Our discovery of a new class of Ag-DNAs with halide ligands has recently enabled the first electronic structure calculations for Ag-DNAs and presents new opportunities to expand these emitters for biophotonics applications.