Expanding the conjugation toolbox of DNA-stabilized silver nanoclusters with biotin-streptavidin

DNA-stabilized silver nanoclusters (DNA-AgNCs) combine molecular-scale dimensions with sequence-dependent optical properties, making them promising candidates for bioimaging applications. However, strategies for site-specific conjugation of DNA-AgNCs remain comparatively limited. Here, we expand the conjugation toolbox of DNA-AgNCs through biotin functionalization of previously developed single-stranded DNA-AgNC containing a [Ag₁₆Cl₂]⁸⁺ cluster. Incorporation of biotin either at 3' end or in the middle of the sequence, enabled selective immobilization of the resulting biotinylated DNA-AgNCs on streptavidin-coated poly(methyl methacrylate) (PMMA) microparticles. Importantly, biotin functionalization and subsequent particle attachment largely preserved the characteristic optical properties and fluorescence lifetimes of the DNA-AgNCs, while control experiments showed negligible nonspecific binding of the non-biotinylated DNA-AgNCs. These results demonstrated that biotin-streptavidin interaction provides a robust strategy for the modular functionalization of DNA-AgNCs without compromising their photophysical properties, opening opportunities for their integration into future bioimaging and sensing applications.