DNA Aptamers for Rapid COVID-19 Testing: Interview with Steven Goh, CEO of Achiko and Dr. Michael Edel, Inventor of AptameX
Achiko, a company based in Switzerland, has developed AptameX, a saliva-based rapid COVID-19 test. The technology is based on DNA aptamers that are bound to gold nanoparticles. On binding with a viral protein the gold nanoparticles are released, causing a measurable color change. The test takes approximately 15 minutes in total, with the user spending just five minutes washing their mouth out and then providing a saliva sample.
PCR testing is the current gold standard for COVID-19, but it is not always practical to undergo such testing, and it is complex, time consuming, and costly to perform the PCR procedure hundreds of millions of times. These issues have created a niche for rapid testing techniques, such as antigen testing. Achiko reports that the AptameX test is more sensitive than antigen testing and cheaper and faster than PCR testing.
The test is paired with an app that allows users to receive their results and pay for the test, as well as provide evidence of their COVID-19 testing status.
See a video of the testing process below, which has been produced for the Indonesian market, where AptameX is manufactured and has received emergency approval:
Medgadget had the opportunity to speak with Steven Goh, CEO & Director of Achiko and Dr. Michael Edel, Inventor of AptameX.
Conn Hastings, Medgadget: Please give us an overview of the importance of rapid testing during the COVID-19 pandemic.
Steven Goh, Achiko: In our minds, it is increasingly apparent that vaccination alone may not win the battle against Covid-19. It will require a combination of testing, therapeutics and physical measures.
Rapid tests are a useful tool as part of a proactive approach to managing the pandemic when used together with vaccinations, masks and social distancing (as necessary). And unlike a PCR test, the rapid testing format is both cheaper and more convenient. Communities or countries with frequent mass testing can quickly identify positive cases that know to isolate at home and protect others. This approach limits the impact on economies, avoids lockdowns and allows people to retain freedom within a new normal.
However, there are design issues with current rapid testing. Antigen approaches have a limit in sensitivity and from what we understand of how Covid-19 is spreading, most may not be sensitive enough. Leaving healthcare professionals confronted with either a less practical and expensive PCR test or an insensitive rapid test that may miss most infections.
Medgadget: Do you think that non-invasive testing methods will increase test uptake?
Steven Goh: At the right price and performance combination, we believe that rapid tests may become as universal as a temperature check or brushing your teeth. We don’t believe the current tests are there yet, and it’s why we’re excited about AptameX.
Medgadget: How does the AptameX test work? How long does it take to obtain the test results?
Michael Edel, Achiko: In lieu of an antigen, AptameX uses DNA aptamers in a colormetric assay format.
DNA aptamers are conjugated to gold nanoparticles. Upon binding between the S1 virus protein from the saliva sample and the aptamer, gold nanoparticles are released. When gold nanoparticles are released, they aggregate causing a color change in the solution.
A UV-visible Spectrophotometer is used to detect the color change and software developed to analyze color change designates positive or negative results in under 15 minutes.
In time, the company is exploring other formats for other use cases and is looking forward to announcing those as and when they arise.
Medgadget: What are the advantages of this testing technology compared with other testing methods? How does it compare with PCR testing?
Michael Edel: PCR testing is the current gold standard. And published work (e.g. Eurosurveillance), cites a CT cutoff of typically around 32, far higher than where many rapid tests are able to detect a signal.
There are three areas thus for comparison:
- By sensitivity, testing in a 96 well plate format has yielded encouraging sensitivity numbers, materially greater than antigen-based formats, and the company is currently bringing that to market in a low cost and convenient cuvette format.
- A PCR test in its sensitivity may detect a positive well after the peak contagious period and when a patient is shedding dead virus. Whereas AptameX is based on a recent fresh and standardized saliva sample, which in a practical setting is to look for those currently infectious.
- Price and performance. The use of DNA aptamers allows for yet again an even lower cost test. Advantages in chemistry by stability, specificity and cost of production mean that the mass market may have access to a cheaper and more sensitive rapid test than others in the market.
Medgadget: Please describe the procedure for someone who takes the test.
Michael Edel: It’s a simple process where a patient goes to a health or medical facility to give a saliva sample. First the patient rinses with mouthwash, then rinses with water and then spits into a saliva collection cup.
The healthcare staff takes the collection cup and attaches a QR code to the collection tube. The staff then instructs the patient to pay for the test by scanning the QR code on the collection tube using the Teman Sehat User app. Once payment has been made, the healthcare staff delivers the sample to the laboratory for testing.
After processing, the test result will appear in the Teman Sehat User app in under 15 minutes.
The process of taking a saliva sample to it being analyzed in a lab using the AptameX test kit can be viewed here: https://bit.ly/APTXINA.
Medgadget: How do you envisage the test being used? Would this technology be suitable for routine testing to monitor someone’s COVID status, or as a precaution before large events?
Steven Goh: We believe that the tests have many practical applications. Ranging from mass public testing, to testing at high value workplaces, large public events, healthcare facilities, transport, tourism and recreation and many others.
Given the price / performance of the test, those that receive a positive test result would know to take the appropriate measures ranging from isolation to therapeutics, additional testing or any other measures.
Link: Achiko homepage…
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