A Novel DNA Extraction Method Using Monoclonal Anti-DNA Bound To Colloidal-gold Beads

With the development of the polymerase chain reaction(PCR), there are many methods for extracting DNA before amplification. However, difficulties are encountered with environmental specimens, such as soil, dust, sewage—small specimen and lots of PCR inhibitors contained, which dramatically effect the sensitivity of PCR. Conventional ways to extraction DNA utilize either glass beads or phenol-chloroform. Using small glass beads is messy and need protease digestion, whereas phenol-chloroform extraction is harmful. To overcome these problems, an immuno-affinity method has been developed. In 1997, Adrian R.Gelsthorpe[11] reported a method using monoclonal anti-DNA and magnetic beads. In our studies, we use monoclonal anti-DNA bound to collidiol-gold beads(which called immnocolliodal-gold) and is extremely efficient in extracting DNA from environmental specimens before amplification by PCR. The irnmunoaffinity method we use is extremely efficient in extracting DNA at low concentration, also, the beads carrying the DNA/anti-DNA complexes can be added directly to a PCR mixture without elution, and the presence of PCR inhibitors in specimens has no effect on amplification. When applied to serial dilution bacteria suspension, the detection of limit can be 100 CFU/mL, and the sensitivity of detecting artificial soil sample and milk sample were 101 and 100 CFU/mL. The immunoaffinity method described here can sever as a sensitive and practicable method for extracting DNA , particularly where samples have low concentrations of DNA or where the material is in poor condition.