Analytical method for the determination of the absorption coefficient of DNA-stabilized silver nanoclusters

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DNA-stabilized silver nanoclusters (DNA-AgNCs) are biocompatible emitters formed by silver atoms and cations encapsulated in DNA oligomers. Here, we present an analytical approach to calculate the molar absorption coefficient (ϵ) of these systems, which consists of combining UV-Vis spectroscopy, electrospray ionization-mass spectrometry (ESI-MS), and inductively coupled plasma-optical emission spectrometry (ICP-OES). ESI-MS enables the determination of the number of silvers bound to the DNA strands, whereas ICP-OES allows measurement of the total amount of silver in solution. The data is used to calculate the concentration of DNA-AgNCs and together with UV-Vis absorbance, allows for the calculation of ϵ. We compare the obtained ϵ with the experimental values previously determined through fluorescence correlation spectroscopy (FCS) and theoretical estimates based on the ϵ of the DNA itself. Finally, the experimental radiative decay rates (kf) and ϵ values are evaluated and compared to those typically found for organic fluorophores, highlighting the molecular-like nature of the DNA-AgNC emission.

OriginalsprogEngelsk
TidsskriftNanoscale
ISSN2040-3364
DOI
StatusAccepteret/In press - 2024

Bibliografisk note

Funding Information:
G. R., C. C., V. R., and T. V. acknowledge funding from the Villum Foundation (VKR023115), the Independent Research Fund Denmark (0136-00024B) and the Novo Nordisk Foundation (NNF22OC0073734). We thank Tatiana Yuli Morante Bligaard and the Center for High Entropy Alloy Catalysis (DNRF 149) for providing access to ICP-OES.

Publisher Copyright:
© 2024 The Royal Society of Chemistry.

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