<aside> <img src="https://prod-files-secure.s3.us-west-2.amazonaws.com/ad281bfa-2e4c-463c-b4cc-31d5b7796dae/d38eb9e9-dc7a-4aab-bc1d-2c506885b88c/reader_diagnostics_platform-500x500-1.png" alt="https://prod-files-secure.s3.us-west-2.amazonaws.com/ad281bfa-2e4c-463c-b4cc-31d5b7796dae/d38eb9e9-dc7a-4aab-bc1d-2c506885b88c/reader_diagnostics_platform-500x500-1.png" width="40px" /> Igloo reader combines several technologies in one device: colorimetry, fluorescence and time-resolved fluorescence(TRF). A set of LEDs is used for radiation and a high-speed camera is used to measure the intensity of signal. Such a technique allows reading colorimetric and fluorescence tests, as well as tests with dry chemistry. Combination of two-dimensional images with computer vision allows you to read lines and/or dots. This makes Igloo highly versatile for reading 300+ tests available on market and the world's first portable readers for multiplex assays (microarray).
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One example of such a test is a standard pregnancy test. Its principle is based on the examination of the light absorption coefficient in both the test and control lines. During the reaction, an antigen-antibody complex forms along with a dye. The intensity of light absorption in the test line increases with higher concentrations of the substance under examination. These types of tests are commonly employed to detect infections, drugs, and various other substances.
Unlike colorimetry, fluorescent markers based on Eu particles (Europium) are used as the dye. Such a dye absorbs radiation with a wavelength of 320-340 nm and emits light at 615 nm. To the naked eye, it appears as a red glow.
The advantages of using Eu particles compared to other fluorescent markers lie in their long afterglow time, which can be detected by a detector without a filter. The figure below shows a comparison between regular fluorescence with short afterglow time and TRF technology. The use of TRF allows for increased accuracy of results and sensitivity of analyte detection compared to standard colorimetric and fluorescent methods.
Microarray technology is a further development of lateral flow tests. The distinctive feature is the use of dots instead of lines, which allows for an increase in the number of tests on one cassette. An example of a multiplex test for 4 allergies is presented below. The use of dots makes it possible to reduce the amount of antibodies and reagents, which reduces the cost of the test. A large number of tests can be combined, for example, for food allergies, studying immune status (concentration of antibodies to viruses or bacteria), investigating sensitivity to antibiotics. Also, with the help of this technology, dry chemistry can be applied for biochemical analysis.
<aside> 💡 The tech uniqueness of igloo - reading 2D images using time-resolved fluorescence method.
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| Colorimetry | Fluorescence | Time-resolved fluorescence (TRF) | Microarray TRF | |
|---|---|---|---|---|
| Limit of detection | + | ++ | +++ | +++ |
| Accuracy | + | ++ | +++ | +++ |
| Naked eye | Yes | No | No | No |
| Availability tests on the market | +++ | ++ | ++ | - |
| Multiplex assays | 4 | 4 | 4 | 20-40 |
| Igloo unique solution | No | No | No | Yes |
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