Fast Detection with High Sensitivity and Selectivity
Fast hybridization kinetics is one of the key features of DNA microarrays fabricated on NB slides. Both sides of the NB slides are coated with trillions of NanoCones™, cone-shaped organic chemical compounds. The apexes of NanoCones are functionalized with a NHS (N-hydroxyl succinimidyl) or aldehyde groups for attaching probe molecules with amino groups. These NanoCones can minimize steric hindrance and electrostatic disturbance by regularly controlling lateral spacing between surface-immobilized molecules, and eventually enhance binding kinetics between probe and target molecules.
The NB9 NHS slide was compared with two market leading slides for a DNA microarray assay to detect single base mutations of hot spots of p53 tumor suppress gene. The result demonstrated that the NB9 NHS slide showed up to 10 times enhanced sensitivity and up to 400% improved selectivity than other slides. In addition to this superiority, the NB9 NHS slide allows much faster detection than others. Even 10 min hybridization time in this study is sufficient to detect target DNAs with good reliability.
In this study a plasmid DNA including exon 5, 6, 7 and 8 of p53 gene was extracted from E. coli., and 32 ng of the plasmid DNA was labeled with a fluorescence dye during a random priming method. The random priming is known to increase the amount of target DNA 10 to 100 times in spite of much lower amplification yield than a PCR method. This labeled target DNA was used for hybridization on DNA microarrays. Hybridization was performed with a MAUI hybridization machine (BioMicro). The fluorescence images were acquired by a confocal laser scanner, ScanArray Lite (GSI Lumonics) and each fluorescence signal was analyzed by Imagene 4.0 software (Biodiscovery). For fair comparison, all processes were performed by following the protocols that the companies recommended in their user guides, and each company’s printing buffer was utilized.