EP3964292A1

EP3964292A1 - Enclosed unit for biological sample processing and uses thereof

Info

Publication number: EP3964292A1
Application number: EP20305989.4A
Authority: EP
Inventors: Clarence Deffaud
Original assignee: Interhealth
Current assignee: Interhealth
Priority date: 2020-09-07
Filing date: 2020-09-07
Publication date: 2022-03-09

Abstract

The present invention relates to an enclosed unit 1 for biological sample processing comprising a support 2 with a housing 3 for receiving a reaction tube 5 containing a biological sample to process and guide means movable with respect to the support, so that said displacement pulls out a protruding plug 4 of the reaction tube placed in the housing of the support and allows a reagent 8 to fall into the reaction tube. Advantageously, the guide means are movable in translation or in rotation with respect to the support.

Description

TECHNICAL FIELD

The invention relates to a totally enclosed unit for biological sample processing, such as nucleic acid detection using nucleic acid thin-layer chromatography (test strip) technique, and to a method implementing biological sample processing in a totally enclosed detection unit.

PRIOR ART

Nucleic acid testing has been increasingly developed in the field of screening and diagnosis of infectious diseases and genetic disorders. Nucleic acid testing assays comprises three main steps, consisting of extraction of nucleic acid, genome amplification, and amplicon detection. Polymerase Chain Reaction (PCR) is a highly efficient technique for in vitro amplification of specific nucleic acid fragments by using the principle of denaturation and renaturation of nucleic acid in the presence of in vitro polymerases. For example, PCR detection of various pathogens has become one of the most important means for diagnosis of infectious diseases. However, due to the powerful efficiency of PCR amplification and the method used for PCR product detection (agarose gel electrophoresis), contamination between laboratorial amplification products is extremely liable to occur, which further leads to false positives in detection, and finally, complete confusion of PCR assay results. Similarly, Loop-mediated isothermal amplification (LAMP) is also commonly used for nucleic acid amplification. In contrast to the PCR technology, in which the reaction is carried out with a series of alternating temperature steps or cycles, LAMP is carried out at a constant temperature, and does not require a thermal cycler.
An essential requirement for assays based on nucleic acid amplification is protection from amplicon contamination. The elimination of PCR or LAMP false positives resulted from contamination between laboratorial amplification products, open-tube detection is prohibited after amplification. There is thus a need for totally enclosed units, wherein both nucleic acid amplification and detection may be performed without any opening between these steps. More generally, there is a need for totally enclosed unit for biological sample processing, which does not require tube opening between the treatment step of the biological sample and the detection step of the target component in the biological sample.

SUMMARY OF THE INVENTION

It is the purpose of the present invention to provide an enclosed unit for biological sample processing comprising

a support with at least one housing for receiving a reaction tube containing a biological sample to process;
guide means able to be displaced with respect to the support, so that said displacement pulls out a protruding plug of the reaction tube placed in the at least one housing of the support and allows a reagent to fall into said reaction tube.

Advantageously, the enclosed unit of the present invention comprising several (e.g. two or more) housings for receiving each a reaction tube containing a biological sample to process, the displacement of the guide means allowing to pull the protruding plugs of each reaction tubes placed in the housings of the support and to fall a corresponding reagent into each reaction tube. Accordingly, several biological sample processing may be carried out simultaneously.
In a first embodiment, the enclosed unit further comprises a protective cap mounted rotatably on the support, said protective cap comprising at least one chamber for receiving the reagent, and the guide means are fixed within an inner volume of said protective cap, said guide means comprising at least one set of holes comprising a first hole for receiving a protruding plug of a reaction tube placed in the housing of the support and a second hole for a reagent.
In a particular embodiment, the support further comprises at least one housing for a protruding plug that closes an opened end of the chamber, the second hole of at least one set of holes on the guide means receiving and pulling out said protruding plug.
In a second embodiment, the support comprises a top part with at least one chamber for receiving a reagent and a base part with at least one housing for receiving a reaction tube, at least one chamber for the reagent being disposed substantially above at least one housing for a reaction tube, and the guide means extend transversally between the top part and the base part of the support, said guide means being mounted slidably with respect to said top part and base part of the support.
These enclosed units are particularly suited for nucleic acid detection, such as by PCR or LAMP
It is also the purpose of the present invention to provide a method for processing at least one biological sample while preventing cross-contamination with an enclosed unit according to the invention, comprising the steps of

placing at least one biological sample within a reaction tube and closing said reaction tube with a protruding plug;
placing the reaction tube in a housing in the support of the enclosed unit;
moving the guide means in such a way that the guide means pulls out the protruding plug and a reagent disposed above the reaction tube falls into said opened reaction tube;
observing the result of the reaction between the reagent and the biological sample.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1A and 1B represent an enclosed unit according to a first embodiment of the invention, view in cross section along a longitudinal plan, illustrating the rotational movement of the guide means allowing to bring the biological sample in communication with a test strip (i.e. the reagent);
Figures 2A and 2B represent an enclosed unit according to an alternative to the embodiment of Figures 1A and 1B, view in cross section along a longitudinal plan, illustrating the rotational movement of the guide means allowing to bring the biological sample in communication with a test strip (i.e. the reagent);Figures 3A and 3B represent the guide means and the housing for the biological sample according to Figures 1A and 1B or Figures 2A and 2B, viewed from above (the rest of the unit being disregarded);
Figures 4A and 4B represent an enclosed unit according to a second embodiment of the invention, view in cross section along a longitudinal plan, illustrating the translation of the guide means allowing to bring the biological sample in communication with a test strip (i.e. the reagent);
Figures 5A and 5B represent the guide means and the reaction tube according to Figures 4A and 4B viewed from above (the rest of the unit being disregarded).

DETAILED DESCRIPTION OF THE INVENTION

By working on a solution to provide a device suitable for processing one or more biological samples, in particular suitable for amplifying and detecting nucleic acids from sample(s) in conditions limiting contaminations, the inventors have developed a totally enclosed unit, wherein at least one biological sample to process can be brought into communication with a reagent without potentially contaminant manipulations.
More particularly, the inventors have developed an enclosed unit comprising

a support with a housing for receiving a reaction tube containing a biological sample to process;
guide means movable with respect to the support, so that said displacement pulls out a protruding plug of the reaction tube placed in the housing of the support and allows a reagent to fall into the reaction tube.

In the context of the present invention, a reagent refers to a substance, compound or product to be added to the biological sample to test if a reaction occurs, e.g. by revealing the presence of a target compound. The reagents may be used in a chemical reaction to detect, measure or make other substances. For instance, the reagent is a chromogenic reagent that reacts with specific chemical groups in the biological sample with the formation of a colored compound in situ. In case of chemical reagent, the reagent is preferably in lyophilized or solid form. Alternatively, the reagent may be a test strip, i.e. a band, piece or strip of paper or other material used for biological testing.
The enclosed unit of the present invention, in use, is advantageously sealed from the external environment. Thus, processing a biological sample may be carried out with low risk of contamination from the environment or to the environment.
The enclosed unit of the present invention may be used for processing any biological sample, particularly liquid sample such as saliva, blood, urine, cell suspension, etc. Preferably, the enclosed unit of the present invention is dedicated to be used for on-site nucleic acid testing. In such a test, a liquid sample is processed by a number of steps to amplify the nucleic acid, after which the processed sample is tested for the presence of a target nucleic acid by use of a test strip (i.e. reagent). The enclosed system is particularly advantageous to prevent contamination with contaminant nucleic acids.
According to the invention, the guide means are movable relative to the housing receiving the reaction tube. The displacement of the guide means allows the opening of the reaction tube and the reagent to be in overlapping relationship with the opened reaction tube.
Preferably, the reagent is introduced in the reaction tube under influence of gravity. In the position where the reagent is not in overlapping relationship with the opened reaction tube, the reagent is maintained within its chamber by a barrier, which is removed or displaced when the guide means are displaced. Gravity can act on the reagent when the barrier is displaced and the guide means are held in an appropriate position with respect to the reaction tube. Thereby, the reagent falls within the reaction tube and contacts the biological sample.
In a particular embodiment, the reagent is a test strip. Advantageously, the test strip is maintained substantially vertically with respect of the support and the reaction tube. In a particular embodiment, the test strip is housed in a similarly-dimensioned chamber in the protective cap or the top part of the support. If need be, retention means are provided in the chamber or on the guide means to maintain the test strip vertically.
In a particular embodiment, the guide means are movable in translation with respect to the support. In another embodiment, the guide means are movable in rotation with respect to the support.
The guide means comprise access means which can open into or be aligned with the opened reaction tube for providing access of the reagent to the reaction tube.
Advantageously, the unit comprises sealing means for sealing the entire unit from the external environment. Such sealing means may help prevent contamination of the sample during processing. In a preferred embodiment, during processing of the sample, the inner volume of the support is sealed from the external environment, i.e. the unit provides a closed system and the sample cannot escape from the unit. Such closed unit helps eliminate contamination from external sources, and at the same time protects the external environment from contamination with the processed biological sample. This is particularly important when processing involves the amplification of nucleic acid.
The sealing means may comprise any suitable means for sealing the support from the external environment while still allowing reagent to access to the reaction tube. Sealing may be achieved by the abutment of the guide means with respect to the support. In particular, the displacement of the guide means with respect to the support from an opened position to a closed position isolates an inner volume of the support from external environment.
Advantageously, when the biological processing gives a visual result, the wall of the chamber receiving the test strip may be substantially transparent so that the result of the analysis can be seen without any need to open the unit.
In a particular embodiment, the enclosed unit comprises several housings for receiving several reaction tubes, and the guide means comprise several sets of holes, which can each open into or be aligned with a reaction tube for providing access of a reagent to said reaction tube. Such embodiment allows to process simultaneously several biological samples.
The invention further provides a kit comprising an enclosed unit as exposed above and one or more reagents, particularly one or more test strips.
Specific embodiments of the invention will now be described by way of example, with reference to the drawings.
A first embodiment is illustrated by figures 1A, 1B, 2A, 2B and 3A, 3B, wherein same references are used to designate same elements.
According to this first embodiment, an enclosed unit 1 for biological sample processing comprises a support 2 comprising a housing 5 for receiving a reaction tube 3. Advantageously, the housing 5 is formed integrally within the support 2. The reaction tube 3 may be closed by a protruding plug 4.
The enclosed unit 1 further comprises a protective cap 6, mounted rotatably on the support 2. The protective cap 6 comprises a chamber 7 for receiving a test strip 8 (i.e. reagent).
In the embodiment illustrating Figures 1A and 1B, the chamber 7 has an opening 14 at an end, or extremity, of said chamber located outside the protective cap 6. Accordingly, the test strip 8 may be loaded in the chamber 7 at any time, by said opening 14, which is advantageously closable by a plug 9.
In the embodiment illustrating Figures 2A and 2B, the extremity of the chamber 7 located outside the protective cap 6 is closed. The chamber 7 comprises an opposed end 15, located within the protective cap 6, which may be used for loading the test strip 8 in the chamber 7, before to close the unit 2 with the protective cap 6. As illustrated Figure 2A, said opened end 15 is closed by a protruding plug 16 located in a second housing 17 in the support 2.
To use the unit 1, a reaction tube 3 closed by a protruding plug 4 is placed in the housing 5 of the support 2. Then, the protective cap 6 is placed above the support 2. The support 2 and the protective cap 6 are circular and rotatably engageable with each other. In order to close the unit, the protective cap 6 is moved in a circular path with respect of the support 2.
Advantageously, the mating between the support 2 and the protective cap 6 is a locking mate that cannot be broken once made. This may ensure a secure containment of the contents of the unit during processing.
Guide means 10 are fixed within an inner volume of the protective cap 5. As illustrated figures 3A and 3B, the guide means 10 comprise or consist in a disk 11 comprising a first hole 12 for receiving and pulling out the protruding plug 4 of the reaction tube 3 and a second hole 13 for receiving and maintaining the test strip 8 substantially vertically with respect to the support 2. The diameter of the first hole 12 is greater than the diameter of the protruding plug 4.
In a first position (Figures 1A? 2A and 3A), the first hole 12 is in overlapping relationship with the reaction tube 3 and the protruding plug 4 of the reaction tube 3 is engaged through said first hole 12. The second hole 13 is above a flate surface of the support (figure 1A) or above the second housing 17 of the support 2 (figure 2A) so that the protruding plug 16 located within the second housing 17 is engaged through said second hole 13.
In the embodiment illustrated figures 1, 2 and 3, the first hole 12 and the second hole 13 are diametrically opposed on the disk 11, so that a rotation of 180° must be performed to move the first and second holes 12, 13 to place the second hole 13 in overlapping relationship with the reaction tube 3 (figures 1B and 2B). Of course, the holes 12, 13 may be arranged differently on the disk 11, e.g. separated of 90°, so that alternative rotations may be performed to position the second hole 13 in overlapping relationship with the reaction tube 3, e.g. a rotation of 90°. As well apparent for the skilled person, the unit 1 may comprises several housings for reaction tubes and the guide means may comprise several sets of holes, in order to carry out several biological sample analysis simultaneously. The position of the sets of holes on the guide means may be adapted easily to the number of sets of holes and reaction tubes.
Advantageously, the rotation of the protective cap 6 simultaneously seals the protective cap 6 on the support 2, in order to isolate the inner volume of the support from external environment.
The rotation of the protective cap 6 results in a corresponding rotation of the guide means 10, which leads to the tearing of the protruding plug 4 of the reaction tube 3, and optionally of the protruding plug 16 of the chamber 7 (figures 2A and 2B). The reaction tube 3 lays opened and the second hole 13 becomes aligned with the opened reaction tube 3, so that the test strip 8 falls by the action of gravity within the reaction tube 3. The protruding plug 4 of the reaction tube 3, and optionally of the protruding plug 16 of the chamber 7 (figures 2A and 2B) is/are displaced at the diametral opposite of the guide means 10.
According to the invention, retention means, on the chamber 7 of the protective cap 6 and/or on the guide means 10, may help to maintain the test strip 8 substantially vertically with respect to the support 2 and the reaction tube 3. Generally speaking, the test strip 8 is advantageously maintained vertically during all the processing, to optimize the sample analysis and results visualization.
Advantageously, the unit may be a non-reusable, one-shot disposable unit. In such case, the unit may comprise sealing means that irrevocably close the protective cap on the support and isolate the inner volume from the external environment. Alternatively, the unit may be a reusable unit, which may be provided with several test strips to be used for successive analysis.
This enclosed unit 1 may be used for implementing a method for processing a biological sample while preventing cross-contamination.
In a particular embodiment, this method comprises the steps:

placing a biological sample within a reaction tube 3 and closing said reaction tube with a protruding plug 4;
placing the reaction tube 3 in the housing 5 of the support 2 of the enclosed unit 1;
closing the support 2 with the protective cap 6;
placing a test strip 8, or any other suitable reagent, into a chamber 7 of the protective cap 6, so that the test strip 8 is maintained substantially vertically with respect to the support;
rotating the protective cap 6 on the support 2, said rotation leading to a corresponding rotation of the guide means 10, so that the protruding plug 4 is pulled out the reaction tube 3 and the test strip 8 is moved over the reaction tube 3 and falls into said reaction tube;
observing the detection result, e.g. target nucleic acid detection.

According to the invention, the test strip 8 may be placed in the chamber 7 before or after the closure of the support 2 with the protective cap 6.
A second embodiment is illustrated by figures 4A, 4B and 5A, 5B.
According to this second embodiment, an enclosed unit 20 for biological sample processing comprises a support 21 comprising a top part 22 and a base part 23.
The top part 22 comprises a chamber 24 for receiving a test strip 25 (i.e. reagent). Advantageously, the dimensions of the chamber 24 are similar to the dimensions of the test strip 25 so that the test strip is maintained substantially vertically in the chamber 24 with respect to the support 21 and a reaction tube 27.
The base part 23 comprises a housing 26 for receiving a reaction tube 27, closed by a protruding plug 28.
The support 23 has an access port for introduction of the reaction tube 27 within the housing 26 (not represented). For example, the reaction tube is translated to the housing in the support. This allows to introduce the reaction tube to the housing without the need for opening the unit. Advantageously, the access port is protected by a seal, to ensure that the unit is free of contamination prior to introduction of the sample.
Guide means 29 extend transversally between the top part 22 and the base part 23 of the support 21, said guide means 29 being mounted slidably with respect to said top part 22 and base part 23 of the support 21.
In this embodiment, the guide means 29 comprise or consist in a push-rod which comprises successively a first hole 30 for receiving and pulling out the protruding plug of a reaction tube and a second hole 31 for receiving the reagent (Figures 5A and 5B). As well illustrated in the figures, the first hole 30 is opened onto one extremity of the push-rod (i.e. it leads up to one extremity of the push-rod) to form a clamp able to receive and pull out the protruding plug of the reaction tube.
The first hole 30 extends from a first end 34 of the push rod 29, in a longitudinal direction with respect to a longitudinal axis A. The second hole 31 extends in a transversal direction with respect to the longitudinal axis A (figures 5A and 5B).
To use the unit 20, the reaction tube 27, closed by the protruding plug 29 is first engaged in the housing 26. The test strip 25 is loaded in the chamber 24 when the push rod 29 is engaged in a first position (figure 4A), wherein an upper part 32 of the push rod 29 closes the communication between an opening 33 of the chamber and the base part 23. The opening 33 of the chamber is in overlapping relationship with the housing 26 and the reaction tube 27. The test strip 25 is maintained in the chamber 24 by way of the upper part 32 of the push-rod 29.
Then, the push-rod 29 is pushed in translation within the support 21. This translation brings the first hole 30 in contact with the protruding plug 28 and a further translation allows to snatch the protruding plug 28 from the reaction tube 27. The translation is performed until the second hole 31 is in overlapping relationship with the opening 33 of the chamber 24.
Thereby, the test strip 25 can fall by the action of gravity through the second hole 31 within the reaction tube 27 (figure 4B). Advantageously, the dimensions of the second hole 31 are substantially similar to the dimensions of the opening 33 of the chamber 24. The test strip 25 is maintained substantially vertically during all the processing, to optimize the sample analysis and result visualization.
As well apparent for the skilled person, the unit 20 may comprises several housings for reaction tubes and the guide means may comprise several sets of holes, in order to carry out several biological sample analysis simultaneously. The position of the sets of holes on the guide means may be adapted easily to the number of sets of holes and reaction tubes.
This enclosed unit 20 may be used for implementing a method for processing a biological sample while preventing cross-contamination.
In a particular embodiment, this method comprises the steps of:

placing the biological sample within a reaction tube 27 and closing said reaction tube with a protruding plug 28;
placing the reaction tube in a base part 23 of the support 21 of the enclosed unit 20;
placing a test strip 25 into a chamber 24 in a top part 22 of the support, so that the test strip is maintained substantially vertically above the reaction tube;
translating the guide means 29 within the support, said translation leading to a grubbing-up of the protruding plug 28 from the reaction tube by a first hole 30 of said guide means and a second hole31 comes above the opened reaction tube so that the test strip falls into said reaction tube;
observing the detection result, e.g. target nucleic acid detection.

Claims

Enclosed unit (1, 20) for biological sample processing comprising
- a support (2, 21) with at least one housing (5, 26) for receiving a reaction tube (3, 27) containing a biological sample to process;

- guide means (10, 29) movable with respect to the support, so that said displacement pulls out a protruding plug (4, 28) of the reaction tube placed in the at least one housing of the support and allows a reagent (8, 25) to fall into said reaction tube.
The enclosed unit for biological sample processing according to claim 1, wherein the guide means are movable in translation or in rotation with respect to the support.
The enclosed unit for biological sample processing according to claim 1 or 2, wherein the displacement of the guide means with respect to the support from an opened position to a closed position isolates an inner volume of the support from external environment.
The enclosed unit for biological sample processing according to any one of claims 1 to 3, wherein the reagent is a test stip.
The enclosed unit for biological sample processing according to any one of the previous claims, wherein the support comprises two or more housings for receiving each a reaction tube containing a biological sample to process, the displacement of the guide means allowing to pull the protruding plugs of each reaction tubes placed in the housings of the support and to fall a corresponding reagent into each reaction tube.
The enclosed unit for biological sample processing according to any one of the previous claims, wherein the enclosed unit further comprises a protective cap (6) to be mounted rotatably on the support, said protective cap comprising at least one chamber (7) for receiving the reagent, and wherein the guide means are fixed within an inner volume of said protective cap, said guide means comprising at least one set of holes (12, 13) comprising a first hole (12) for receiving a protruding plug (4) of a reaction tube (3) placed in the housing (5) of the support (2) and a second hole (13) for a reagent (8).
The enclosed unit for biological sample processing according to claim 6, wherein the guide means comprise or consist in a disk (11) comprising at least one set of holes (12, 13) comprising a first hole (12) for receiving and pulling out the protruding plug of a reaction tube and a second hole (13) for receiving and maintaining a test strip substantially vertically with respect to the support.
The enclosed unit for biological sample processing according to claim 7, wherein the first and second holes of a set of holes (12, 13) are diametrically opposed on the disk.
The enclosed unit for biological sample processing according to any one of claims 6 to 8, wherein the support further comprises at least one housing (17) for a protruding plug (16) that closes an opened end (15) of the chamber, the second hole (13) of at least one set of holes on the guide means receiving and pulling out said protruding plug.
The enclosed unit for biological sample processing according to any one of claims 1 to 5, wherein the support (21) comprises a top part (22) with at least one chamber (24) for receiving a reagent (25) and a base part (23) with at least one housing (26) for receiving a reaction tube (27), at least one chamber (24) for the reagent being disposed substantially above at least one housing (26) for the reaction tube, and wherein the guide means (29) extend transversally between the top part and the base part of the support, said guide means being mounted slidably between said top part and base part of the support.
The enclosed unit for biological sample processing according to claim 10, wherein the guide means comprise or consist in a push-rod which comprises at least one set of holes (30, 31) comprising successively a first hole (30) for receiving and pulling out the protruding plug of a reaction tube and a second hole (31) for receiving the reagent.
A method for processing at least one biological sample, preferably a target nucleic acid detection, more preferably by use of PCR or LAMP, while preventing cross-contamination, with an enclosed unit according to any one of claims 1 to 11, said method comprising the steps of
- placing at least one biological sample within a reaction tube and closing said reaction tube with a protruding plug;

- placing the at least one reaction tube in a housing in the support of the enclosed unit;

- moving the guide means in such a way that the guide means pulls out the protruding plug and a reagent disposed above the reaction tube falls into said opened reaction tube;

- observing the result of the reaction between the reagent and the biological sample.
The method according to claim 12, wherein the enclosed unit is according to any one of claims 6 to 8, comprising the steps of
- placing at least one biological sample within a reaction tube and closing said reaction tube with a protruding plug;

- placing said reaction tube in the housing in the support of the enclosed unit;

- closing the support with the protective cap;

- placing a test strip into a chamber of the protective cap, so that the test strip is maintained substantially vertically with respect to the support;

- rotating the protective cap on the support, said rotation leading to a corresponding rotation of the guide means so that the protruding plug is pulled out the reaction tube and the test strip is moved over the reaction tube and falls into said reaction tube;

- observing the detection result.
The method according to claim 12, wherein the enclosed unit is according to claim 9, comprising the steps of
- placing at least one biological sample within a reaction tube and closing said reaction tube with a protruding plug;

- placing said reaction tube in the housing in the support of the enclosed unit;

- placing a reagent in the housing in the protective cap and closing the opened end of the housing with a protruding cap;

- closing the support with the protective cap so that the protruding cap of the housing for the reagent is located within the corresponding housing in the support, through the second hole of a set of holes on the guide means;

- rotating the protective cap on the support, said rotation leading to a corresponding rotation of the guide means so that both the protruding plug of the reaction tube and the protruding plug of the housing for the reagent are pulled out and the test strip is moved over the reaction tube and falls into said reaction tube;

- observing the detection result.
The method according to claim 12, wherein the enclosed unit is according to any one of claims 10 to 11, comprising the steps of
- placing at least one biological sample within a reaction tube and closing said reaction tube with a protruding plug;

- placing the reaction tube in the base part of the support of the enclosed unit;

- placing a test strip into a housing in the top part of the support, so that the test strip is maintained substantially vertically above the reaction tube;

- translating the guide means within the support, said translation leading to a grubbing-up of the protective cap from the reaction tube by the first hole of said guide means and the second hole comes above the opened reaction tube so that the test strip falls into said reaction tube;

- observing the detection result.
A kit for processing at least one biological sample, preferably a target nucleic acid detection, more preferably by use of PCR or LAMP, while preventing cross-contamination, said kit comprising an enclosed unit according to any one of claims 1 to 11, and one, two or more reagents, preferably one, two or more test strips.