Synthesis of streptavidin-conjugated magnetic nanoparticles for DNA detection
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In this paper, we report a fabrication of streptavidin-coated magnetic nanoparticles used for DNA detection. Initially, amino-functionalized Fe3O4 nanoparticles with high saturation magnetization are prepared by a photopolymerization method using allylamine as monomer. It is followed by covalent immobilization of streptavidin onto the particle surface via a two-step reaction using glutaraldehyde as coupling agent. Streptavidin-coated magnetic nanoparticles are characterized and further tested for their ability to capture DNA target after binding biotinylated oligonucleotide probes. The results show that the products (~27.2 nm) have a maximum biotin-binding capacity of 0.71 nmol mg−1 when the immobilization reaction is conducted with a mass ratio of streptavidin to magnetic carriers above 0.2 in phosphate buffered saline (pH 7.4) for 24 h. In addition, highly negative ζ-potential and good magnetic susceptibility of the nanocomposites make them applicable for DNA collection and detection, which is verified by the results from the preliminary application of streptavidin-coated magnetic nanoparticles in DNA detection. Therefore, the magnetic nanoparticles provide a promising approach for rapid collection and detection of gene.
KeywordsMagnetic nanoparticles Streptavidin DNA detection Photopolymerization Saturation magnetization Zeta potential
This study was sponsored by the National Natural Science Foundation of China (Grant No. 21201151), Natural Scientific Foundation of Zhejiang Province (No. Y4100074, Y4090636, and Y4110025), Sci-Tech Research Projects of Jinhua (No. 2010-1-120 and 2010-1-069), and SRF for ROCS, SEM.