Detecting the presence of specific DNA strands in small patient blood samples could revolutionize the diagnostics of many diseases. Now researchers at Uppsala University in Sweden have developed a technique that may provide extremely high sensitivity and specificity when looking for specific strands of DNA.
The technology involves growing a DNA strand between two electrodes and attaching gold nanoparticles to the strand. The DNA strand is made so that it will couple with the second electrode only in the presence of a specific DNA string. Once connected, the gold nanoparticles lining the newly formed bridge allow for an electric current to flow between the electrodes, signaling the presence of the target string. To demonstrate the effectiveness of the new technology, the team used it to detect 10 ng of Escherichia coli bacteria in a laboratory sample.