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  • Development of POCT using CAs-CHIP (Platform)

Development of POCT using CAs-CHIP (Platform)

Individual technology development for the CAs-CHIP platform

The constituent technology of the CAs-CHIP platform that makes POCT possible is described in detail below.

 

CAs-CHIP testing kit

The CAs-CHIP test kit has two main components: the CAs-CHIP including a test reagent (the main component is a PCR primer pair for detecting a specific target) prepared in advance to match the test target, and the cartridge that protects it. The cartridge features a structure that allows it to easily insert the sample for analysis, and a mechanism that efficiently and uniformly transfers heat from the dedicated PCR unit (described later) to the CAs-CHIP. The cartridge is compatible with high-speed PCR.



Fig. 10

 

Quick sample pretreatment kit

In addition to increasing PCR speed by using the CAs-CHIP, in order to speed up the whole testing process, we are also developing technology that allows nucleic acid (DNA or RNA) extraction from a specimen in a short time.



Fig. 11
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For instance, we are developing a kit to extract and purify DNA or RNA from various biological specimens, such as blood and body fluids or sputum within minutes. In normal clinical examination, a purification kit that uses silica beads or magnetic beads is commonly used, but as complicated processes and operations are required such as heating or centrifugation, extracting the nucleic acid from the specimens takes time and effort (from about one hour to several hours).

Further, in the case of a simple extraction kit that can extract nucleic acid from the sample in about 10 minutes, disabling the PCR inhibitors from the sample that are left in the nucleic acid extraction solution through just a simple extraction process is difficult. Therefore, we have made original improvements to the existing simple nucleic acid extraction and purification methods, and have developed a technology for isolating and purifying the DNA or RNA from the sample within a few minutes.



Fig. 12
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High-speed PCR unit

In a typical PCR, by repeating three types of temperature in order about 20 to 30 times (thermal cycles), the original DNA is amplified to about 1 million to 10 billion times.



Fig. 13
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As mentioned, the PCR method performs gene amplification through a very simple process, but because it is difficult to achieve high-speed temperature cycles with traditional technology, there was a limit to how much the reaction time could be shortened. However, as CAs-CHIPs have a very small thermal capacity, it is possible to increase the speed of the thermal cycle by using the CAs-CHIP as a reaction vessel.
In this context, we are developing a CAs-CHIP dedicated high-speed thermal cycle unit that can achieve rapid temperature changes through a simple mechanism.



Fig. 14
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Amplified testing unit

DNA fragments amplified by PCR become fluorescent when using an intercalator.



Fig. 15
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In the screening unit that we develop, we have incorporated a high sensitivity camera to shoot the fluorescence that increases in strength together with the amplification of DNA fragments. The presence or absence of amplification of DNA can be visualized, thus making it possible to confirm whether the DNA sequence of interest in the sample exists or not.
In other words, we can find the eight capillaries from the CAs-CHIP in the captured image, and we can determine the presence or absence of DNA amplification by measuring the intensity of fluorescence in each capillary.



Fig. 16
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