Plate Nº 94 · recorded October 10, 2026
Space & AstronomyReported finding
AI-Powered Nanogap Sensor Detects Life's Molecular Handedness
Osaka University researchers distinguished mirror-image amino acids with over 80% accuracy using a single-molecule electrical sensor, testing it on meteorite and desert soil samples.
By Nathan Brooks3 min read606 words
In brief
- The Osaka team distinguished L- and D-form amino acids with over 80% accuracy using AI plus a gold nanowire tunneling sensor.
- The method identified amino acids in the Murchison meteorite (Australia) and Atacama Desert soil (Chile) as well as traditional methods.
- Living organisms use almost exclusively L-form amino acids, making the L/D ratio a potential biosignature of life.
- The study is set to be published in Nature Communications (2026), DOI: 10.1038/s41467-026-77947-6.
A single-molecule electrical sensor developed at the University of Osaka can tell left- and right-handed amino acids apart with over 80% accuracy — a capability that could one day help spacecraft detect signs of extraterrestrial life. The study is set to be published in Nature Communications (2026).
The technique worked not only on purified molecules in the lab. When the team analyzed a fragment of the Murchison meteorite from Australia and soil from Chile's Atacama Desert, it captured the major features of amino acid composition about as well as conventional laboratory methods do.
Why do mirror-image molecules signal life?
Amino acids — the building blocks of proteins — come in two mirror-image forms, called L and D, that share the same chemical formula. Biology is picky about which form it uses. In living organisms, almost all amino acids appear exclusively in the L-form, while sugars exist in the D-form.
Nonliving chemical and physical processes are not so selective. They produce L- and D-forms in roughly equal amounts.
That imbalance makes the ratio of L- to D-forms — the L/D ratio — a potential biosignature: a measurable chemical clue that something is, or was, alive. This is why amino acids are a prime target for astrobiology research within our solar system and beyond.
How does the electrical detection work?
Traditional methods measure amino acids in large groups of molecules, which creates practical challenges for space missions. Instruments need to be sensitive yet compact, and that combination has proven difficult to achieve.
The Osaka team took a different route: electrical detection. This approach is simpler, less sensitive to vibrations, and avoids chemical reagents altogether.
The method works like this:
- Individual molecules pass through a tiny gap between two gold nanowires.
- Each passage generates an electrical tunneling current — a faint flow of electrons across the gap.
- The L- and D-forms of an amino acid produce different current waveforms.
- The researchers can therefore count molecules of each form directly, one at a time.
Artificial intelligence plays a key role in reading those signals.
"By combining our nanogap tunneling technique with artificial intelligence, we were able to distinguish between the L- and D-forms of amino acids with over 80% accuracy," said lead author Takahito Oshiro. "This is the first discrimination of amino acid chirality at the single-molecule level and constitutes a fundamental advance in chemical sensing."
Did it work on real-world samples?
Real astrobiological samples rarely contain a single tidy molecule type. They are complex mixtures of many different compounds, so the team needed to show the sensor could pick out amino acids from that chemical noise.
They tested two natural samples:
- Extract from the Murchison meteorite, which fell in Australia
- Soil samples from the Atacama Desert in Chile
"Our method was comparable to traditional methods, as both were capable of capturing the major features of amino acid composition," explained senior author Masateru Taniguchi.
What are the limitations?
The results are preliminary in an important sense: the accuracy, at just over 80%, leaves room for error, and the tests so far covered only two natural sample types. Whether the instrument can withstand the rigors of a space mission — radiation, temperature swings, launch vibration — remains untested.
Still, the direction is promising. The researchers hope these developments will lead to compact, electrically based instruments that future missions could carry to search for life beyond Earth.
Publication details
The study, "Chiral discrimination of amino acids in meteorite and desert soil extracts via single-molecule nanogap conductance," appears in Nature Communications (2026), DOI: 10.1038/s41467-026-77947-6. The University of Osaka provided the research.
via Phys.org Space & Astronomy (Source)
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