Designing nanobarcode DNA based on gold and magnetic nanoparticles for detection of Pseudomonas aeruginosa

Bio-barcode DNA based on gold nanoparticle (GNPs) as a new generation of a biosensor for detection of biological science studies. The biosensor is of very importance in rapid and sensitive detecting of microorganisms. Exotoxin A (ETA) is the most toxic virulence factor of Pseudomonas aeruginosa. ETA has ADP-ribosylation activity and inhibitory effects on the protein synthesis of host cells. In the present study, we developed a nanobarcode DNA technology for detection of trace P. aeruginosa ETA. The GNPs were conjugated with the first target-specific DNA probe 1 (1pDNA) and Barcode DNA, which there were acted as a signal reporter and biosensor. The magnetic nanoparticles (MNPs) were conjugated with the second target specific DNA probe 2 (2pDNA) that was able to recognize the other end of the target DNA. After binding the nanoparticles with the target DNA, the following complex structure was formed: MNP 2pDNAtDNA-1pDNA-GNP-bDNA. The complex was isolated by a magnetic field. After dissolved complex in dithiothreitol (DTT) solution, the Barcode DNAs were released from the complex. This bio-barcode DNA was detected by fluorescence spectrophotometry. The results showed that the barcode DNA assay has fast, high sensitivity (the detection limit, 1.2 ngmL-1), good selectivity for detection of ETA. Also, the regression analysis showed that the barcode DNA assay was a good linear relationship (ΔF=0.57 [target DNA] + 21.31, R2=0.9984) between the fluorescent intensity and the target DNA concentration.

کلیدواژه ها:

Bio-barcode DNA ، MNPs ، GNPs ، Pseudomonas aeruginosa