Silver Nanocluster DNA Probes Detect MicroRNA

Any disease that assails a patient leaves genetic clues all over the victim, and because the profiles of micro ribonucleic acid (miRNA) vary by type of cancer, finding it proves beyond a reasonable doubt what is making the patient sick.

A chemist and a biologist from University of Copenhagen (Denmark) invented the detection method, which exploits a natural quality of genetic material. Together they figured out how to attach the light emitting molecules to DNA sensors for miRNA detection. When these luminous DNA-strands stick with microRNA-strands, their light is quenched, giving a very visible indication that the target miRNA is present in the sample.

A single DNA strand is made up of molecules, so called bases, ordered in a unique combination. When two strands join to form their famous double helix, they do so by sticking to complementary copies of themselves. Likewise, strands tailored to match particular miRNAs will stick to the real thing with uncanny precision.

The scientists tested their Silver Nano Cluster DNA probes with eight different types of genetic material and found that they work outright with six of them. They then fathomed how to fix the ones that did not perform. This indicates that their method will work in the detection of almost all types of miRNAs, also in all likelihood for cancer related miRNAs. The most widespread current miRNA detection method requires some 48 hours of laboratory work from raw samples. The new method can do the same job of detection within a maximum of six hours.

Tom Vosch, PhD, from the Department of Chemistry and senior coauthor of the study said, "We invented a probe that emits light only as long as the sample is clean. That is an unusually elegant and easy way to screen for a particular genetic target." The study was published on September 4, 2012, in the American Chemical Society journal ACSNano.

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