Dendritic DNA–porphyrin as mimetic enzyme for amplified fluorescent detection of DNA

•A dendritic DNA–porphyrin superstructure was successfully assembled.•The dendritic DNA–porphyrin mimic demonstrated excellent peroxidase-like catalysis.•The enhanced fluorescence signal was obtained.•This strategy for DNA detection showed high sensitivity and simplicity.•The label-free dendritic DNA provided a universal sensing platform.

In this work, a novel dendritic DNA–porphyrin superstructure was designed as mimetic enzyme for the amplified fluorescent detection of DNA. The dendritic DNA superstructure was in situ assembled with three auxiliary DNAs via hybridization chain reaction. With groove interaction between iron porphyrin (FeTMPyP) and double-stranded DNA, the dendritic DNA superstructure is capable to gather abundant FeTMPyP molecules to form dendritic DNA–FeTMPyP mimetic enzyme. Using tyramine as a substrate, the dendritic DNA–FeTMPyP demonstrated excellent peroxidase-like catalytic oxidation of tyramine into fluorescent dityramine in the presence of H2O2. Based on an amplified fluorescence signal, a signal on strategy is proposed for DNA detection with high sensitivity, good specificity and practicability. The assembly of porphyrin with dendritic DNA not only provided the new avenue to construct mimetic enzyme but also established label-free sensing platform for a wide range of analytes.

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