An international team of researchers led by Osaka University in Japan has developed a compact electrical method for detecting signs of life beyond Earth. It focuses on the chirality of amino acids — their "mirror-image" L and D forms.
Traditional approaches such as liquid chromatography-mass spectrometry require bulky equipment and large samples. The new device uses a microscopic gap between two gold nanowires on a chip.
When a solution containing amino acids enters the gap, a tunneling current arises — a quantum effect in which electrons "seep" across the gap. Changes in the current make it possible to distinguish between the forms of the molecules.
Machine learning helps identify the L and D forms with an accuracy of more than 80 percent. This is the first case of discriminating the chirality of amino acids at the single-molecule level.
The method has already been tested on samples from the Atacama Desert in Chile and the Murchison meteorite in Australia. The results proved comparable to traditional analyses, but require less preparation and fewer molecules.
The device is compact and could be suitable for installation on probes and rovers. The researchers note that it is capable of working with chemically complex samples, including those relevant to astrobiology.
The work has been published in Nature Communications. "These results lay the foundation for future applications in research related to the search for life," the authors write.
But will the sensor be able to handle molecules it has never encountered? The next stages of development will show how universal the approach proves to be.
For now, the technology is ready for further testing both on Earth and in space. If life is ever detected on another planet, it may be precisely this kind of chip that plays a key role in that discovery.
