Tetracyanoquinodimethane nanoparticles as an effective sensing platform for fluorescent nucleic acid detection

摘要

In this communication, we report on the use of tetracyanoquinodimethane nanoparticles (TNs) as an effective fluorescent sensing platform for nucleic acid detection for the first time. The general concept used in this approach is based on adsorption of fluorescently labeled single-stranded DNA (ssDNA) probe by TN, due to the strong π–π stacking between unpaired DNA bases and TN. As a result, the fluorophor is brought into close proximity of TN, leading to substantial fluorescence quenching via photoinduced electron transfer between fluorescent dye and TN. Upon presence of the target ssDNA, specific hybridization with the target takes place to form a double-stranded DNA (dsDNA). The helix cannot be adsorbed by TN due to its rigid conformation and the absence of unpaired DNA bases. Thus, the fluorophor is seperated from TN accompanied by fluorescence recovery. This fluorescence enhancement signals completion of the assay. It also suggests that this sensing platform can well differentiate perfect complementary and mismatched sequences. A detection limit as low as 1.5 nM was obtained...