A novel detection method for DNA point mutation using QCM based on Fe3O4/Au core/shell nanoparticle and DNA ligase reaction

A novel detection method for DNA point mutation using quartz crystal microbalance (QCM) based on DNA ligase reaction and Fe3O4/Au core/shell nanoparticle probes has been proposed in this paper. We used the synthesized core/shell nanoparticles to realize the isolution of DNA probes and amplification of the detection signal. The detailed investigation of the synthesized core/shell nanoparticle by transmission electron microscopy (TEM) and UV–vis spectroscopy was performed in order to elucidate the morphology and properties of the nanocomposites. After the DNA ligase reaction and denaturing at an elevated temperature, the biotin-modified probe reacts with avidin on the electrode surface for the perfect match target, causing a change of the crystal frequency, while actually no frequency change for mismatch target would recorded. Point mutation discrimination could be achieved successfully. The present approach has been demonstrated with the identification of a single-base mutation in –28 site of artificial β-thalassemia gene, and the wild-type and mutant type were successfully discriminated. A detection limit of 4.6 × 10−10 mol/L of oligonucleotides was achieved. Owing to its ease of operation and low detection limit, it was expected that the proposed procedure might hold great promise in both research-based and clinical genomic assays.