JP-WO2023219148-A5 -

Dates

Publication Date

20260508

Application Date

20230512

Description

When a fluid is introduced into a fluid device , i.e., a flow channel device, voids or dead spaces are likely to occur, particularly in the corners of the space. Furthermore, due to wall resistance, the target solution may be introduced to the relatively central part of the volume, while the previous liquid remains near the walls. This results in an unbalanced solution distribution within the fluid device. As long as the volume of the fluid device is large, the impact of these problems on the measurement results is small, and measurements can be performed in areas where these problems do not occur. In other words, these problems can be ignored. However, as fluid devices become smaller, the generation or retention of air voids, or the uneven distribution of the target solution, increases relative to the measurement area or volume, and the behavior of the fluid in the microspace becomes more pronounced. Therefore, these problems can have a substantial impact on the measurement results or efficiency of microfluidics. However, such problems are just examples, and the issues of this disclosure described below are not limited to these. Therefore, in microfluidic devices, there is a need to reduce the generation or retention of voids and improve the fluid exchange efficiency. This disclosure describes and provides a microfluidic device , i.e., a flow channel device, that suppresses or avoids these or other problems. As used herein, 0 o'clock refers to the angular position in the disk -shaped space where the fluid flowing from the fluid inlet substantially enters the disk- shaped space. Alternatively, 0 o'clock may be defined as the direction from the center of the disk- shaped space toward the connection point of the fluid inlet to the disk- shaped space. 0 o'clock may also be defined as the radial direction perpendicular to the circumferential direction at the time of fluid introduction. The introduced fluid, or at least a portion thereof, flows circumferentially near the circumference of the disk-shaped space. In this specification, this flow direction is defined as clockwise. In some embodiments, the inclined inlet and outlet may be connected to the same bottom surface of the disk-shaped space. Hereinafter, the bottom surface of the disk-shaped space includes the bottom surface of the cylinder that defines the disk-shaped space. In some embodiments, the inclined inlet may be connected to a first bottom surface (one bottom surface) and the outlet may be connected to a second bottom surface (the other bottom surface). In some embodiments, the two bottom surfaces do not necessarily have to be parallel. For example, the bottom surfaces do not have to be flat. For example, at least a portion of them may be cone-shaped (convex or concave relative to the disc- shaped space). For example, one bottom surface of the cylinder may be configured to move away from the other bottom surface near the fluid inlet (convex cone). This makes it easier for bubbles in the disc- shaped space to escape through the fluid outlet. For example, one bottom surface of the cylinder may be configured to move closer to the other bottom surface near the fluid inlet (concave cone). The fluid introduced into the disc- shaped space is more likely to flow near the circumference. This can strengthen the water flow on the circumferential side, which has a relatively small solution exchange rate, and increase the solution exchange rate. As used herein, "optical measurement" generally refers to determining the optical properties of a substance using an optical element or device. In some embodiments, optical measurements of the substance of interest may be performed . In some aspects, the properties of a substance bound to or associated with the substance of interest (hereinafter, not necessarily the substance of interest itself, but a substance chemically, biologically, or physically bound to or associated with the substance of interest (e.g., a reagent)) may be measured. The properties of a reagent may also be measured. The reagent may be referred to as the "substance of interest." Figure 1B shows the same fluid device 100 as in Figure 1A, and uses it to illustrate an example of fluid flow 151 within the disk-shaped space 120. After the fluid 151 enters the disk-shaped space 120 through the fluid inlet 130, it flows along its circumference (see dashed line 152). However, the fluid outlet 140 is located in the center of the disk-shaped space 120. Therefore, the fluid shown by the dashed line 152 , having flowed along the circumference, does not complete a full circuit, but rather leaves the circumference, for example, from around the 6 o'clock to 9 o'clock position. The fluid shown by the dashed line 152 then flows towards the fluid outlet 140 in the center of the disk-shaped space 120, or is pulled towards the fluid outlet 140. As a result, a liquid surface 153 is formed, and a space 154 where no liquid exists (sometimes called a bubble) is formed beyo