Low-Cost Saliva-based Biosensor For Cancer Detection

More and more biomarkers that can help in the early diagnosis of diseases like cancer are being discovered every year, but often the effective application relies on having diagnostic methods that are both affordable and as least invasive as possible. This is definitely true in the case of breast cancers, where the standard diagnostic method after seeing something ‘odd’ on a scan is to perform a biopsy so that a tissue sample can be tested in a laboratory. What [Hsiao-Hsuan Wan] and colleagues demonstrate in a recently published research article in the Journal of Vacuum Science & Technology B is a way to use saliva on disposable test strips to detect the presence of cancer-related biomarkers. Best of all, the system could be very affordable.

The two biomarkers tested in this experiment are HER2 (in 10 – 30% of breast cancer cases) and CA 15-3, both of which are indicative of a variety of cancers, including breast cancers. According to the researchers, the levels of these biomarkers in saliva can be correlated to those in blood serum. Where other biosensors may include the read-out circuitry – making those disposable and expensive – here the disposable part is the test strips which are plated with electrodes.

(a) Output drain voltage waveform for pure artificial saliva and HER2 protein diluted in saliva from 10−7 to 10−15 g/ml. (b) Output digital reading from PCB under different HER2 protein concentrations. (Credit: Wan et al., 2024)
(a) Output drain voltage waveform for pure artificial saliva and HER2 protein diluted in saliva from 10−7 to 10−15 g/ml. (b) Output digital reading from PCB under different HER2 protein concentrations. (Credit: Wan et al., 2024)

Each test strip is processed by exposing it to monoclonal antibodies for the target biomarker. When the resulting strip is then exposed to a series of pulses, any antigen-antibody complexes will stretch and contract, causing a measurable change in the electrical signal. This signal is then amplified by a MOSFET, after which the data can be analyzed. According to the reported results, the experimental results matched with the (anonymized) samples from both healthy volunteers and patients with breast cancer.

Whether a saliva-based test like this will replace most biopsies remains to be seen, but if the saliva-blood serum correlation holds up in further testing, it might provide a quick and non-invasive way to test for these and other biomarkers, whether for cancer or other diseases.

12 thoughts on “Low-Cost Saliva-based Biosensor For Cancer Detection

    1. You can’t expect PhD candidates to actually put in proper work for all the papers they produce! You’re not meant to take anything but the text seriously /s

      Just a while ago someone tried to get a paper with AI generated image (complete with garbled text) of a rat with massive testicles peer reviewed. And guess what? No one had a problem, it achieved peer review status without a problem

      Link: https://www.frontiersin.org/articles/10.3389/fcell.2023.1339390/full

      Academia. Never fails to disappoint.

      1. I don’t know anything about the journal publishing it, but holy hell if the figures I’m seeing are the ones used in the original paper before its retraction, that should be the end of it.

    2. The only thing really odd is the “pattern generator” section.

      Assuming the paper is legit (a big assumption) I’d say it’s most likely they refused hardware they had sitting around the lab from some previous thing. When I was a grad student it wasn’t unusual at all to have 20-year old hardware sitting disused in a corner. If you’re a grad student who knows something about protein sensing and nothing about hardware, your advisor might point you to that board in the corner and say “why don’t you see if you can make that work”. Doesn’t matter if it was designed to do 14 things you’re not using, if you can correct it to do the one thing you need for your paper, you’re off to the races. Even better if you can just reuse the diagram from the previous student’s paper which described the hardware, since you never managed to understand half of it….

      1. Found it! Your photo is actually a different but almost identical looking board, for another earlier article which shares a number of authors: https://publishing.aip.org/publications/latest-content/point-of-care-biosensor-rapidly-detects-oral-cancer/ and the older article is https://doi.org/10.1116/6.0002175

        You can see that the oled screen on the bottom right has a different board color and that the chips in the newer article appear to be soldered to it.

    1. This accurately detects something that 10% of breast cancer patients have. So what exactly is the market use case. Take this test if it comes up positive you probably have cancer if it comes up negative that means nothing. Unless the test is <$5 after research and manufacturing costs I can't see many people paying for it.

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