DNA-templated Au nanoclusters and MnO2 sheets: a label-free and universal fluorescence biosensing platform

Abstract A label-free and universal fluorescence biosensing paltform has been constructed for probing and recognizing biomolecular interactions based on the excellent fluorescent properties of poly(adenine) (poly A) DNA templated-Au nanoclusters (DNA-AuNCs) and the good quenching ability of MnO 2 sheets. Due to the high quenching efficiency of MnO 2 sheets, the luminescence of DNA-AuNCs was decreased. Because single-stranded DNA-AuNCs was adsorbed onto the surface of MnO 2 sheets through the physical absorption behavior between nucleobases of single-stranded DNA and the basal plane of MnO 2 sheets. When the target DNA was introduced, the DNA-AuNCs could hybridize with the target DNA and form double-stranded duplex DNA structures, which resulting in the desorption of DNA-AuNCs from the surface of MnO 2 sheets. Thus, the fluorescence signal of system was recovered. Similarly, in the presence of target substrate, aptamer-substrate complexes formed and resulted in the luminescence of DNA-AuNCs. By exploring DNA-AuNCs as signal reporter and MnO 2 sheets as the quencher, this strategy could avoid the complex labelling process of the DNA probe and offer the advantages of simplicity and cost efficiency.