Detecting Differences in DNA Strands using Nanotechnology

A sensitive yet uncomplicated method to detect differences in DNA strands using metal nanoparticle solutions has been developed by Roejarek Kanjanawarut and Xiaodi Su at the Institute of Materials Research and Engineering at A*STAR, Singapore. The method requires no modification of the surfaces of the nanoparticles, making it particularly fast and versatile to implement.

The researchers worked on the principle that aggregated and dispersed nanoparticles have different optical properties that make the solutions take on different colors. This means that the results of their tests can be displayed in minutes, and recorded qualitatively by the naked eye and quantitatively by a standard spectrometer.

The tendency of nanoparticles to aggregate in solution has been considered a drawback, and in previous approaches to use them for sensing, DNA strands were directly attached to the particles’ surfaces to prevent them clumping together. Kanjanawarut and Su turned the tables to take advantage of the natural propensity to aggregate as inspiration for their assays. Compared with the earlier nanoparticle- and chip-based DNA assays, the new method is cost-effective as it involves no time-consuming surface modifications, particle bioconjugation, biohazardous labeling or tedious assay procedures, explains Su.

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