Mini route to amplify DNA
doi:10.1038/nindia.2010.79 Published online 14 June 2010
Nanoparticles of titanium dioxide can be useful for amplifying tiny segments of DNA, new research suggests. Such amplification of DNA — called polymerase chain reaction (PCR) — plays a vital role in DNA fingerprinting, the detection of bacteria or viruses, and the diagnosis of genetic disorders.
The first step of PCR, which utilises the reagents dimethyl sulphoxide, dithiothreitol, formamide and glycerol, is to separate double-stranded DNA into two pieces of single-stranded DNA by applying heat. An enzyme called 'Taq polymerase' then makes new strands using the original strands as templates.
To devise a cost-effective and efficient technique for PCR, the researchers chose inexpensive titanium dioxide nanoparticles. They dissolved the nanoparticles in sterile water to create a nanofluid, and then took a variety of DNA templates (mouse and human genomic DNA, and plasmid DNA). Under heating, the researchers then added the Taq polymerase to carry out PCR.
Besides significantly increasing the PCR yield, the nanoparticles also displayed excellent efficiency in reducing the PCR reaction time, helping to achieve a 50% reduction without compromising the yield.
The study showed that the nanoparticles were capable of conducting heat through the fluid much faster than a fluid without nanoparticles. This is important because heat-induced denaturation of genomic DNA is the very first step of PCR.
The researchers say that this nanoparticle-assisted PCR may be useful for the amplification of difficult-to-amplify DNA templates.
The authors of this work are from: Department of Biotechnology, Department of Mechanical Engineering and Department of Chemistry, Indian Institute of Technology Madras, Chennai, India.