Scientists at the University of Osaka have developed a method that could simplify the search for signs of life beyond Earth. They combine electrical signals and artificial intelligence to distinguish forms of amino acids at the level of individual molecules.
Amino acids exist in two mirror forms — L and D. In living organisms, L-forms predominate, while in nonliving processes they occur in roughly equal numbers. This difference has long been regarded as a possible biosignature, but previously it was difficult to detect over long distances.
The researchers used a nanogap between two extremely thin gold wires. When molecules pass through it, the electric current creates unique waveform patterns. Artificial intelligence analyzes these signals and distinguishes the L- and D-forms with an accuracy of more than 80 percent.
“By combining our nanogap tunneling technique with artificial intelligence, we were able to distinguish the L- and D-forms of amino acids with an accuracy of more than 80 percent,” said lead author Takahito Oshiro. He added that this is the first case of discriminating the chirality of amino acids at the level of a single molecule.
The method was tested on samples of the Murchison meteorite from Australia and soil from the Atacama Desert in Chile. The results proved comparable to traditional laboratory analyses.
The device is compact and does not require complex chemical reagents, so it could potentially be sent to other planets. But will it really help us understand whether there is life beyond Earth?
The work was published in the journal Nature Communications under the title “Chiral discrimination of amino acids in meteorite and desert soil extracts via single-molecule nanogap conductance.”
