In this study, we first selected DNA aptamers against HBsAg by immobilizing HBsAg on the surface of carboxylated MNPs. The ssDNA library of each selection round was prepared by asymmetric PCR amplification for the next selection round. To obtain aptamer sequences, the final selected products were purified by gel electrophoresis, and then cloned and sequenced. DNA aptamers that specifically bound to HBsAg were successfully obtained after 13 selection rounds. The selected aptamers were used to construct a chemiluminescence aptasensor based on magnetic separation and immunoassay to detect HBsAg from pure protein or actual serum samples. There was a linear relationship between HBsAg concentration and chemiluminescent intensity in the range of 1-200 ng/mL. The aptasensor worked well even in the presence of interfering substances, and was highly specific in the detection of HBsAg in serum samples, with a detection limit 0.1 ng/mL lower than the 0.5 ng/mL limit of an ELISA in use at the hospital. This aptasensor can contribute to better detection of hepatitis B virus infection. Furthermore, a gold nanoparticle-based colorimetric aptasensor for the detection of HBeAg was developed. The system allowed the DNA sensing with a sensitivity limit of 1×10<sup>-8</sup> M. This newly isolated aptamer could be modified to assist the both diagnosis and treatment of chronic hepatitis B.<br/>

Selection of HBsAg-specific DNA aptamers based on carboxylated magnetic nanoparticles and their application

251st National Meeting (2016)

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