Colloidal gold-polystyrene bead hybrid for chemiluminescent detection of sequence-specific DNA.
A sensitive chemiluminescent (CL) detection of sequence-specific DNA has been developed by taking advantage of a magnetic separation/mixing process and the amplification feature of colloidal gold labels. In this protocol, the target oligonucleotides are hybridized with magnetic bead-linked capture probes, followed by the hybridization of the biotin-terminated amplifying DNA probes and the binding of streptavidin-coated gold nanoparticles; the nanometer-sized gold tags are then dissolved and quantified by a simple and sensitive luminol CL reaction. The proposed CL protocol is evaluated for a 30-base model DNA sequence, and the amount as low as 0.01 pmol of DNA is determined, which exhibits a 150 x enhancement in sensitivity over previous gold dissolution-based electrochemical formats and an enhancement of 20 x over the ICPMS detection. Further signal amplification is achieved by the assembly of biotinylated colloidal gold onto the surface of streptavidin-coated polystyrene beads. Such amplified CL transduction allows detection of DNA targets down to the 100 amol level, and offers great promise for ultrasensitive detection of other biorecognition events.
Fan
Aiping
A
School of Pharmacy, Fudan University, Shanghai, China.
Lau
Choiwan
C
Lu
Jianzhong
J
D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D001483:Base Sequence; D004247:DNA / Q000032:analysis*; D015342:DNA Probes; D017979:Gold Colloid; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D049329:Nanostructures; D011137:Polystyrenes; D012680:Sensitivity and Specificity; D019809:Streptavidin
D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D015342:DNA Probes; D017979:Gold Colloid; D011137:Polystyrenes; C030325:anthrax toxin; D004247:DNA; D019809:Streptavidin