Electrical Nanogap Chip Reportedly Distinguishes Amino-Acid Mirror Forms One Molecule at a Time

Distinguishing mirror forms through current between gold nanowires

According to ScienceAlert, an international team led by the University of Osaka used two closely spaced gold nanowires on a microchip to measure tunneling-current changes as amino-acid molecules passed through a nanogap.

Machine learning was used to identify L- and D-form amino acids—mirror-image forms whose balance can help indicate whether amino acids have biological or non-biological origins. The researchers reported over 80% accuracy and said tests on Murchison meteorite and Atacama Desert soil samples captured major features of amino-acid composition comparably to conventional methods.

Amino-acid chirality can be analyzed with liquid chromatography–mass spectrometry, which the report says requires bulky equipment, larger samples, and multiple chemical processes. The supplied evidence does not provide a like-for-like performance comparison beyond the reported sample tests.

The reported result establishes single-molecule electrical discrimination of L- and D-form amino acids and reports more than 80% accuracy for the technique.

Sample collection and further development remain necessary

A compact method that uses fewer molecules and less sample preparation than the approach described in the report could eventually be useful for chemical analysis in space missions. The report stresses that further testing and development are needed, and that samples would still need to be collected for analysis.