Silver clusters with ~10 atoms develop within single-stranded DNA and become optical chromophores.  We consider their electronic spectra from two perspectives.  First, DNA structure controls cluster emission.  We use a DNA template with two components: the 3' sequence hybridizes with target oligonucleotides and the 5' sequence forms specific silver clusters. These composite strands exclusively harbor a cluster that absorbs at 400 nm with limited emission. When a target hybridizes with these single-stranded conjugates, cluster absorption shifts and strong emission develops. We consider the associated DNA structural and cluster spectral transformation via a range of experimental techniques.  Second, cluster emission can be enhanced when co-illuminated with low-energy light that optically depopulates the fluorescence-limiting dark state. We consider different emissive clusters and use kinetic modeling to understand the photophysical models that underlie the fluorescence enhancement.  These studies are aimed at developing new chromophores for sensitive detection in high background environments. <br/>

DNA-Encapsulated silver cluster chromophores

253rd National Meeting (2017)

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