Slowest part of COVID tests ‘eliminated’ with Israeli single-molecule method

Nano team at the Technion says it can check molecules one by one, meaning labs won’t need to spend hours ‘amplifying’ samples to generate more material for analysis

Nathan Jeffay is The Times of Israel's health and science correspondent

A throat swab for a coronavirus test. (Galina Sandalova via iStock by Getty Images)
A throat swab for a coronavirus test. (Galina Sandalova via iStock by Getty Images)

Israeli nanotechnologists say that they have found a way to examine molecules one by one for coronavirus, and eliminate the most time-consuming process in COVID-19 test analysis.

In regular virus testing, lab teams need to massively increase the number of molecules they have from each patient’s sample, through a process known as amplification. That typically takes between one and two hours, and requires special chemicals. Millions of molecules are needed before a sample can be analyzed.

But the method just developed in Haifa, tested, and outlined in the peer-reviewed journal ACS Nano, requires just 100 molecules, eliminating all need for amplification, bio-engineer and nanotechnology expert Amit Meller told The Times of Israel Monday.

“We have developed a way to pass molecules, one by one, through a tiny nano hole,” said Meller, of the Technion-Israel Institute of Technology. “The hole is called a nanopore, and isn’t new, but this is the first time it has been deployed for RNA testing for the coronavirus.”

Bio-engineer and nanotechnology expert Amit Meller from the Israel Institute of Technology, holding the nano-chip device that contains the nanopore (courtesy of the Israel Institute of Technology)

He said that as well as being used for the coronavirus, his analysis method can be deployed in screening for secondary cancers, and said he hopes to see it quickly commercialized for both uses. He said the key is that it retains a level of precision in analysis of ribonucleic acid, RNA, “which is essential in both contexts we studied – RNA biomarkers of metastatic cancer and the SARS-CoV-2 virus.”

His method starts in exactly the same way as existing tests: The patient is swabbed, their sample is dissolved in liquid, and their ribonucleic acid, or RNA, is converted to DNA, which is suitable for screening. But instead of amplifying the sample, it is immediately examined with the nanopore, one molecule at a time, and lab workers assess whether a cancer biomarker or SARS-CoV-2 is present, and if so, in what quantity.

Using the nano method, the quantity of chemicals needed is reduced by 100-fold compared to regular lab analysis, according to Meller. “Our advances will potentially cause a significant reduction in the cost of testing,” he said.

An illustration of molecules entering the nanopore used by Israeli scientists developing new system for analyzing coronavirus test samples. (illustration by Amit Meller)

Discussing the benefits of eliminating amplification in COVID-19 and cancer screening, he said: “Current lab methods can’t look at individual molecules, so amplification is needed, which doesn’t just take time, but also reduces accuracy.

“If you think of when you try to amplify a very quiet sound using an audio amplifier, you end up getting extra interference and noise, which is exactly what happens when amplifying for coronavirus tests. This is why results aren’t always accurate. Because we are eliminating amplification, we expect our method to boost accuracy.”

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