Pd nanowires as new biosensing materials for magnified fluorescent detection of nucleic acid

The designed synthesis of new nanomaterials with controlled shape, composition, and structure is critical for tuning their physical and chemical properties, and further developing interesting analytical sensing devices. Herein, we presented that Pd nanowires (NWs) can be used as a new biosensing platform for high-sensitivity nucleic acid detection. The general sensing concept is based on the fact that Pd NWs can adsorb the fluorescently labeled single-stranded DNA probe and lead to substantial fluorescence quenching of dye, followed by specific hybridization with the complementary region of the target DNA sequence. This results in desorption of double-stranded DNA from Pd NWs surface and subsequent recovery of fluorescence. Furthermore, an amplification strategy based on Pd NWs for nucleic acid detection by using exonuclease III (Exo III) was demonstrated. The present dual-magnification sensing system combined Pd NWs with Exo III has a detection range of 1.0 nM to 2.0 μM with the detection limit of 0.3 nM (S/N = 3), which is about 20-fold higher than that of traditional unamplified homogeneous assays.