Design and fabrication of fluorescence based nanobiosensor for detection of transgenic plants

Detection of foreign genes in genetically modified (GM) plants is very important for proving the effectiveness of genetic engineering procedure and determination of GM plants. In the present study a very sensitive and convenient fluorescence nanobiosensor for rapid detection of GM crops based on Fe3O4/Au core/shell nanoparticles was developed. Specific site of 35S CaMV, a well studied gene promoter in plant genetic engineering was used as the DNA sequence target. The core/shell Fe3O4/Au magnetic nanoparticles were synthesized to utilize their magnetic properties and improve their DNA functionalization. Fe@Au nanoparticles were functionalized by bounding of single stranded DNA (ssDNA) probe through sulfhydryl group at 5ʹ phosphate end. Then complementary target ssDNA were hybridized with immobilized ssDNA probe. Methylene blue was selected as a fluorescence probe. It was shown that methylene blue had significant interaction with hybridized DNA. Upon the addition of the target ssDNA, fluorescence intensity decreased in linear range by concentration of ssDNA from 3×10-7 to 2.2×10-9 M with detection limit of 1.2×10-10 M. The nanobiosensor enabled us to detect the transgenic crops through convenient and reliable simple method.