Combination of functionalized nanoparticles and polymerase chain reaction-based method for SARS-CoV gene detection

Rapid and sensitive detection of SARS associated coronavirus is critical for early diagnosis and control of severe acute respiratory syndrome. This study describes a method for the detection of SARS associated coronavirus gene by the combination of functionalized nanoparticles and PCR-based assay. In this method, the target cDNA of SARS associated coronavirus was firstly captured and enriched from the mixture of target cDNA and non-target cDNA by the use of the functionalized silica coated superparamagnetic nanoparticles. Additionally, the enriched target cDNA were amplified through a general symmetry PCR and then was selectively isolated from the double strands PCR products by applying the silica coated superparamagnetic nanoparticles again. Finally, we detected the amplified target cDNA by employing the functionalized silica coated fluorescent nanoparticles as signaling probes with a sandwich hybridization format. The results show that the target cDNA can be assayed successfully with a detection limit of 2.0 x 10(3) copies and the nonspecific amplification could be inhibited. In addition, the detection procedure is rapid and can be completed in less than 6 h. Our results suggest that this approach will provide promising prospects for other pathogens detection.