For reducing the steric hindrance and nonspecific binding of the target DNA, The dextran was used as an arm to immobilize on the surface of magnetic nanoparticles (MNPs). It was showed that magnetic separation was the best method in preparation of dextran-MNPs (DMNPs). Aspartic acid and aminated DNA probe were modified to the dextran immobilized on the surface of DMNPs one after another. These probe-DMNPs were applied to detect biotin-labeled PCR product of Ecoli. O157:H7 genome by hybridization. Then these complexes were bonded with streptavidin-modified alkaline phosphatase (ALP-SA). Finally the chemiluminescent signals were detected by adding 3-(2-spiroadamantane)-4-methoxy-4- (3-phosphoryloxy) phenyl-1, 2-dioxetane (AMPPD). The results showed that this method had a good specificity, and more sensitive than that of using MNPs as a solidoid carrier.

Preparation of dextran modified magnetic nanoparticle and its application in DNA detection

243rd National Meeting (2012)

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