# Dynamic Equilibria between DNA-Stabilized Silver Nanoclusters and Silver-Carrying DNA Strands

## TL;DR

This paper studies how DNA-stabilized silver nanoclusters interact with DNA strands, showing how their optical properties change with temperature and concentration.

## Contribution

The study reveals dynamic equilibria between DNA-AgNCs and Ag+-carrying DNA strands, showing how their interactions affect photophysical properties.

## Key findings

- Three distinct species of 13mer-AgNCs were identified based on concentration and temperature.
- The 16mer-stabilized AgNCs show temperature-dependent emission changes but no concentration-dependent shifts.
- Aggregation of (16mer)2-[Ag20]10+ was observed through time-resolved anisotropy.

## Abstract

DNA-stabilized silver nanoclusters (DNA-AgNCs) are versatile
emitters
whose photophysical properties are defined by the DNA template. In
this study, we explore the unusual temperature- and concentration-dependent
behavior of two NIR-emissive DNA-AgNCs: one stabilized by two 16-base
DNA oligomers (16mer), and another embedded within a 3-base shortened
version of these strands (13mer). Using a combination of optical spectroscopy
and mass spectrometry, we show that Ag+-carrying DNA strands
can reversibly attach to DNA-AgNCs and fine-tune their photophysical
properties. For 13mer-AgNC, we demonstrate the presence of three different
species, (13mer)2-[Ag20]10+, (13mer)3-[Ag27]17+, and (13mer)4-[Ag34]24+, depending on concentration and temperature.
For the AgNC stabilized by two 16-base DNA strands, (16mer)2-[Ag20]10+, emission wavelength and intensity
vary with temperature, although no significant concentration-dependent
spectral shifts are observed. While mass-spectrometry revealed the
existence of (16mer)3-[Ag27]17+,
time-resolved anisotropy uncovered the formation of aggregates of
(16mer)2-[Ag20]10+. These findings
demonstrate the presence of dynamic equilibria between Ag+-carrying DNA strands and DNA-AgNCs.