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EP-4737006-A1 - ASSAY DEVICE AND TARGET MOLECULE TESTING METHOD

EP4737006A1EP 4737006 A1EP4737006 A1EP 4737006A1EP-4737006-A1

Abstract

An assay device configured to detect a target molecule includes: a pretreatment unit (100) having a circulation channel (105) which is a tubular passage through which a liquid circulates; and a bubble remover (112, 112a, 112b, 112c, 112d, 112e, 112f) configured to remove or capture bubbles mixed in the liquid circulating in the circulation channel by utilizing a difference in properties between liquid and gas. The target molecule is bound with a detection material for detecting the target molecule, and a cleaning is performed with a washing solution to separate unreacted substance that is not bound, as a pretreatment for detecting the target molecule.

Inventors

  • NAKAMURA, KAZUYA
  • NAKAGAWA, KAZUHISA
  • KADOI, MASARU

Assignees

  • DENSO CORPORATION

Dates

Publication Date
20260506
Application Date
20251009

Claims (11)

  1. An assay device configured to detect a target molecule, the assay device comprising: a pretreatment unit (100) having a circulation channel (105) which is a tubular passage through which a liquid circulates, in which the target molecule is bound with a detection material for detecting the target molecule and a cleaning is performed with a washing solution to separate unreacted substance that is not bound, as a pretreatment for detecting the target molecule; and a bubble remover (112, 112a, 112b, 112c, 112d, 112e, 112f) configured to remove or capture bubbles mixed in the liquid circulating in the circulation channel by utilizing a difference in properties between liquid and gas.
  2. The assay device according to claim 1, further comprising: a sensor (141) configured to perform sensing based on a substance generated by a reaction between the detection material and a reaction liquid; a sensor container (142) in which the sensor is provided; and a controller mechanism (143) configured to control the reaction liquid sealed in the sensor container to flow into and out of the circulation channel, wherein the controller mechanism draws a complex of the target molecule and the detection material bound with each other, after the cleaning, from the circulation channel into the sensor container by controlling the reaction liquid sealed in the sensor container into and from the circulation channel.
  3. The assay device according to claim 2, wherein a volume of the sensor container changes in accordance with a change in amount of the reaction liquid remaining in the sensor container when the reaction liquid sealed in the sensor container is controlled to flow into or out of the circulation channel by the controller mechanism.
  4. The assay device according to any one of claims 1 to 3, wherein the bubble remover (112a) has at least one set of an outlet (1121) through which the liquid circulating in the circulation channel flows out, a recess (1122) to receive and store the liquid flowing out of the outlet, and an inlet (1123) through which the liquid stored in the recess to flow into the circulation channel, and the outlet is located higher than the inlet in a height direction, in one set of the outlet, the recess, and the inlet.
  5. The assay device according to any one of claims 1 to 3, wherein at least a part of the circulation channel has an arc shape, and the bubble remover (112f) has a chamber structure in which a part of the circulation channel is bulged outwardly of the arc shape of the circulation channel.
  6. The assay device according to any one of claims 1 to 3, wherein the bubble remover (112e) includes a plurality of columnar structures having irregularities on a surface, inside the circulation channel.
  7. The assay device according to any one of claims 1 to 3, wherein the bubble remover (112b, 112c, 112d) has a chamber structure in which a part of the circulation channel is bulged upward in a height direction.
  8. The assay device according to claim 7, wherein the chamber structure has an air bubble outlet (1124) on an upper side in the height direction.
  9. The assay device according to claim 7 or 8, wherein the chamber structure includes a permeable membrane (1125) having selective permeability not to allow the liquid to pass through but allows the bubbles to pass through, the permeable membrane divides a space of the chamber structure in the height direction, and an upper space of the chamber structure upper than the permeable membrane in the height direction has a gas layer.
  10. A target molecule testing method to detect a target molecule, comprising: binding the target molecule to a detection material for detecting the target molecule, and cleaning with a washing solution to separate unreacted substance that is not bound, as a pretreatment process for detecting the target molecule, wherein the pretreatment process includes: circulating a liquid in a circulation channel (105) which is a tubular passage for circulating the liquid for the binding and the cleaning; and controlling bubbles to be captured or removed from the liquid by a bubble remover (112, 112a, 112b, 112c, 112d, 112e, 112f) by utilizing a difference in properties between liquid and gas.
  11. The target molecule testing method according to claim 10, further comprising: controlling a reaction liquid sealed in a sensor container (142) to flow into or out of the circulation channel by a controller mechanism (143), such that a complex of the target molecule and the detection material, after the cleaning, is drawn from the circulation channel into the sensor container; and sensing with a sensor (141) housed in the sensor container based on a substance produced by a reaction between the detection material and the reaction liquid.

Description

The present disclosure relates to an assay device and a target molecule testing method. A test called POCT (Point of Care Testing) is known, which shortens the time from when a sample is collected to when test results are obtained. Many of the assay devices used in POCT are based on the principles of immunoassay methods. Some immunoassay methods require a binding free (BF) separation, which is the separation of unreacted substances. JP 2013-536952 A discloses an assay cartridge in which binding of an analyte to a binder and subsequent washing are performed within a channel. In the technique of JP 2013-536952 A, a liquid sample containing an analyte is introduced into a cartridge through an inlet. In the technique of JP 2013-536952 A, the channel is a sealed system. In the technique disclosed in JP 2013-536952 A, air bubbles may be mixed into the sealed channel when the liquid sample is introduced. The details will be described as follows. If the analyte is trapped in the air bubbles, the air bubbles will inhibit the binding of the analyte and subsequent washing, reducing the accuracy of detection of the analyte. Furthermore, the technique disclosed in JP 2013-536952 A does not take into consideration stirring of the fluid within the channel. This can result in insufficient binding of the analyte within the channel. One objective of this disclosure is to provide an assay device and a target molecule testing method to make it easier for a target molecule to bind within a channel, when the target molecule is bound to a binding target and washed within the channel, and to reduce the inhibition of binding and washing of target molecule due to the inclusion of bubbles in the channel. The above objective is achieved by the combination of features described in the independent claims, and the dependent claims define further advantageous specific examples of the disclosure. The reference signs in parentheses in the claims indicate a correspondence relationship with specific means described in the embodiments described later as an aspect, and do not limit the technical scope of the present disclosure. In order to achieve the above-mentioned objective, an assay device of the present disclosure is used for detecting a target molecule, and includes a pretreatment unit in which the target molecule is bound to a detection material for detecting the target molecule, as a pretreatment for detecting the target molecule, and washing is performed using a washing solution to separate unreacted substance that has not been bound. The binding and washing are performed in the pretreatment unit. The pretreatment unit includes: a circulation channel which is a tubular passage for circulating a liquid used for the binding and the washing; and a bubble remover to remove or capture air bubbles from the liquid in the circulation channel by utilizing a difference in properties between liquid and gas. In order to achieve the above-mentioned objective, a target molecule testing method of the present disclosure is used for detecting a target molecule, and includes: a pretreatment process for binding the target molecule to a detection material for detecting the target molecule as a pretreatment for detecting the target molecule; and a washing process for separating unreacted substance not bound in the binding with a washing solution. The pretreatment includes: a circulation process for circulating a liquid in a circulation channel which is a tubular passage for circulating the liquid used for the binding and washing, where the binding and washing are performed; and a removal process for removing or capturing bubbles from the liquid in the circulation channel by a bubble remover to remove or capture bubbles by utilizing a difference in properties between liquid and gas. Accordingly, the binding with the detection material and the washing of unreacted substance, as pretreatment for detecting the target molecule, are performed in the circulation channel. Since the liquid is circulated in the circulation channel, the target molecule and the detection material in the circulation channel are more likely to be agitated by this circulation. This increases the chance of the target molecule binding to the detection material, making it possible to increase the rate at which the target molecule is bound to the detection material. Since the circulation channel is tubular, there is a possibility that bubbles mixed in the liquid in the circulation channel may circulate within the circulation channel together with the target molecule and the detection material. In contrast, according to the above configuration, the bubbles are removed from the liquid or captured by the bubble remover. By utilizing the difference in properties between liquid and gas, it is possible to separate the liquid from the bubbles. Thus, the bubble remover makes it possible to remove or capture bubbles from the liquid. Therefore, the bubble remover reduces the continuous contact of bubb