A novel fluorescent DNA sensor system based on polydopamine modified MgAl-layered double hydroxides

In this work, a novel fluorescent DNA sensor system based on polydopamine (PDA) modified layered double hydroxides (Mg/Al-LDH) was designed and PDA-co-LDH composites were examined for DNA sensing owing to their fluorescence quenching capability. We demonstrated that the fluorescence of ssNDA could be effectively quenched after mixing with PDA-co-LDH composites, while the fluorescence could be recovered after the target DNA was added to form dsDNA. Based on the fluorescence changes, the target DNA can be facilely and quantitatively determined by the DNA sensor system. Based on 3σ method, the detection limit is calculated to be as low as 1.0 pM. Moreover, PDA-co-LDH composites have an excellent sensitivity and selectivity that can discriminate the complementary and mismatched target sequences even for the single-base mismatched target sequences. More importantly, this DNA sensor system could be expected for detection of many other molecules through design DNA sequences. [Display omitted] •Preparation of polydopamine coated LDH•These resultant PDA modified LDH could be utilized for DNA fluorescent sensors•The procedure for preparation of PDA-co-LDH is simple, facile and universal•These PDA-co-LDH may be used for other applications