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

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 MnO2 sheets. Due to the high quenching efficiency of MnO2 sheets, the luminescence of DNA-AuNCs was decreased. Because single-stranded DNA-AuNCs was adsorbed onto the surface of MnO2 sheets through the physical absorption behavior between nucleobases of single-stranded DNA and the basal plane of MnO2 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 MnO2 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 MnO2 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. (c) 2017 Elsevier B.V. All rights reserved.