An ultrasensitive method for the detection of gene fragment from transgenics using label-free gold nanoparticle probe and dynamic light scattering.

The detection of transgenic products is of great significance for the development of transgenic technique. In this paper, we developed a simple, rapid and ultrasensitive method for the detection of sequence-specific Nopaline synthase (NOS) gene from the transgenic plants using label-free gold nanoparticle (NP) probe and dynamic light scattering (DLS) technology. Gold NPs were stable in NaCl solution with the presence of NOS gene probe. On the contrary, they were aggregated in NaCl solution when the probe sequence was hybridized with target sequence. The change in the size of gold NPs can be detected by DLS technology with high sensitivity. Under the optimal conditions, the average hydrodynamic diameter of gold NPs was linear with the concentration of the target sequence ranging from 1.0×10(-13)mol L(-1) to 5.0×10(-9)mol L(-1), with a detection limit of 3.0×10(-14)mol L(-1) (S/N=3). The relative standard deviation (at 1.0×10(-9)mol L(-1) of target sequence) was 4.8% (n=11). The result shows that gold NPs-based DLS method has great potential in the analysis of transgenic products.