Filter components

Abstract

A filtration system, a filter assembly, and a method for using the filter assembly to determine the presence or absence of microorganisms in a fluid filtered through the filter assembly are disclosed.

Description

Background Art

[0001] A common method for determining the presence of microorganisms in a fluid comprises collecting a fluid sample in a first container and subsequently transferring it to a filter device comprising a filter element. The sample is then passed through a filter element that is capable of capturing microorganisms larger than a certain size. After filtering the sample, the filter element with the captured microorganisms is transferred to a culture dish containing a nutrient solution that supports microbial growth. The nutrient solution permeates the filter element and reaches the microorganisms, enabling the microorganisms to be cultured on the filter element. However, there is a need for an improved filter device.

[0002] The present invention is intended to improve at least some of the shortcomings of the prior art. These and other advantages of the present invention will be apparent from the description set forth below. Summary of the Invention

[0003] One aspect of the present invention provides a filter assembly comprising: (a) a sample reservoir for holding a fluid sample to be filtered, the sample reservoir having an open top end, an open bottom end, and at least two inwardly facing arms disposed at the open bottom end, the sample reservoir having a resilient sidewall; (b) a fluid port, the fluid port being in fluid communication with the sample reservoir; (c) a porous microorganism capture filter element, the porous microorganism capture filter element being disposed across a flow path between the sample reservoir and the fluid port, the porous microorganism capture filter element being releasably retained by the at least two inwardly facing arms; (d) an absorbent pad disposed below the porous microorganism capture filter element and the at least two inwardly facing arms, and disposed across the flow path between the sample reservoir and the fluid port; and (e) a base removably mounted to the sample reservoir, the base comprising the fluid port and a support surface for supporting the absorbent pad; wherein, after the base is removed from the sample reservoir, the resilient sidewall is compressed to release the porous microorganism capture filter element from the at least two inwardly facing arms.

[0004] In another aspect of the present invention, a filtration system is provided that includes an aspect of a filtration assembly, and an incubation assembly including an incubation plate and an incubation plate cover.

[0005] In other aspects, methods are provided for determining the presence or absence of at least one microorganism in a fluid using an incubation assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1Ais a diagram showing an exploded view of a filtration system, wherein according to one aspect of the present invention, the filtration system includes a filtration device, the filtration device including a reservoir and a porous microorganism-entrapment filter element, the reservoir including a resilient sidewall and an inwardly facing arm slidably attached to the reservoir, wherein according to another aspect of the present invention, the filtration system includes a filtration assembly, the filtration assembly including the filtration device and an absorbent pad, and a base, and according to another aspect of the present invention, the filtration system further includes an incubation assembly, the incubation assembly including an incubation plate and an incubation plate cover, the incubation assembly for treating the porous microorganism-entrapment filter element after filtration; Figure 1B is a diagram showing the bottom of the reservoir; Figure 1C It is shown that Figure 1A A view of the inside of the bracket of the arm is shown; Figure 1D It shows Figure 1C A diagram showing the outside of the arm.

[0007] Figures 2A to 2C is a diagram showing the initial assembly of a filtration device according to an aspect of the present invention prior to filtration, wherein the reservoir is inverted and the porous microorganism-entrapment filter element is placed on the open bottom of the reservoir and held by the arms. Figure 2A The filter element is shown aligned with the bottom of the reservoir; Figure 2B A slidably attached arm is shown about to slide in the direction of the arrow, and Figure 2C The arms are shown sliding to hold the filter element in place.

[0008] Figures 3A to 3E is a diagram showing the filtration assembly, including the assembled filter device, after sterilization, before preparation for filtration, and before placement in a vacuum manifold. Figure 3A Yes Figure 2C an exploded view of the receptacle with the retained filter element shown aligned with the absorbent pad and base; Figure 3B shows an absorbent pad engaged in a base (in cross-section) prior to placement of the absorbent pad with retained filter element in the base; Figure 3C shows a cross-sectional view of an assembled filter device with a pad and base; Figure 3D shows a perspective view of the assembled filter device; and Figure 3E A bottom view of the base is shown.

[0009] Figures 4A to 4C is a diagram showing the assembled filter device aligned with the incubation plate after filtration and removal from the base, wherein the incubation plate has cutouts in opposing portions of the incubation plate sidewalls for receiving the arms on the receptacles. Figure 4A shows a top perspective view, Figure 4B shows a cross-sectional view of an incubation plate, and Figure 4CIt is shown that compressing the resilient side walls of the reservoir causes the arms to move outward, thereby releasing the filter element into the incubation plate.

[0010] Figure 5 is a diagram showing a released filter element in an incubation plate, about to be covered by an incubation plate, for incubation. DETAILED DESCRIPTION

[0011] According to one aspect of the present invention, a filter assembly is provided, the filter assembly comprising: (a) a sample reservoir for holding a fluid sample to be filtered, the sample reservoir having an open top end, an open bottom end, and at least two inwardly facing arms disposed at the open bottom end, the sample reservoir having a resilient sidewall; (b) a fluid port in fluid communication with the sample reservoir; (c) a porous microorganism capture filter element disposed across a flow path between the sample reservoir and the fluid port, the porous microorganism capture filter element being releasably retained by the at least two inwardly facing arms; (d) an absorbent pad disposed below the porous microorganism capture filter element and the at least two inwardly facing arms and disposed across the flow path between the sample reservoir and the fluid port; and (e) a base removably mounted to the sample reservoir, the base comprising the fluid port and a support surface for supporting the absorbent pad; wherein after the base is removed from the sample reservoir, the resilient sidewall is compressed to release the porous microorganism capture filter element from the at least two inwardly facing arms.

[0012] In another aspect of the present invention, a filtration system is provided that includes an aspect of a filtration assembly, and an incubation assembly including an incubation plate and an incubation plate cover.

[0013] In other aspects, methods are provided for determining the presence or absence of at least one microorganism in a fluid using an incubation assembly.

[0014] For example, in one aspect, a method for determining the presence or absence of at least one microorganism in a fluid is provided, the method comprising: passing the fluid through one aspect of a filtration assembly; detaching a sample reservoir having a retained porous microorganism-capture filter element from a base; releasing the porous microorganism-capture filter element from the sample reservoir into an incubation plate; incubating the released porous microorganism-capture filter element; and determining the presence or absence of at least one microorganism on the porous microorganism-capture filter element.

[0015] Advantageously, aspects of the present invention are used for microbiological testing with minimal manipulation of the filter element after filtration. For example, after filtration, the filter element is released from the reservoir and placed in a receiving plate without requiring an operator to touch the filter element manually or with pliers. Thus, the process can be referred to as "touch-free."

[0016] Each component of the present invention will now be described in more detail below, wherein like components have like reference numerals.

[0017] Figure 1A An aspect of a filtration system 2000 is shown in FIG. 2 , which includes an aspect of a filter assembly 1000 , which includes an aspect of a filter device 500 .

[0018] The illustrated aspect of the sterilizable filtration device 500 includes a sample receptacle 100 for holding a fluid sample to be filtered, the sample receptacle having an open top end 101, an open bottom end 102 (at Figure 1B and Figure 2A , having opposing straight portions 102A and opposing curved portions 102B), a resilient sidewall 110 and at least two inwardly facing arms 150A, 150B arranged at the open bottom end (see also Figure 1C and Figure 1D ), the at least two inwardly facing arms are shown attached to opposing portions of the sidewall. Filter device 500 includes a porous microorganism-entrapment filter element 501 having an upstream surface 501A and a downstream surface 501B.

[0019] In preferred aspects, Figure 1A 、 Figure 2B and Figure 2C As shown, inwardly facing arms 150A, 150B are slidably attached to opposing portions of sidewall 110 by brackets 160A, 160B, respectively. In some applications, the slidable arrangement improves the sealing of the filter element with the open bottom end of the receptacle.

[0020] When necessary, such as Figure 1A As shown, the reservoir may include struts 170A, 170B including a pair of protrusions 171A, 171B (see Figure 1B and Figure 2A The pair of protrusions 171B of the bracket 160A and the corresponding pair of recessed portions on the bracket 160A and 160B are connected. Figures 1A to 1C A pair of recesses 172A on bracket 160A is shown, and a pair of recesses on bracket 160B (not shown) engage, thereby allowing an operator assembling the filter assembly to hear and / or feel the engagement to notify the operator that the filter element is assembled as intended. Figures 1A to 1D and Figure 2A For reference, the aspect shown has a shoulder 161A on its inner surface (same for bracket 160B) that fits and slides within the gap between the outer surface of the reservoir and the inner surface of the projection.

[0021] like Figures 2A to 2CAs shown, in one aspect, the filter assembly can be assembled by inverting the reservoir 101, placing the filter element 501 in contact with the bottom end 102, and slidingly moving the brackets 160A, 160B so that the arms 105A, 150B hold the filter element against the bottom end 102. In one aspect, the open bottom end has generally oval open ends, such as opposed straight portions 102A and opposed curved portions 102B, as shown. Figure 2A In some applications, this provides an improved sealing of the upstream surface of the filter element against the open bottom end of the receptacle.

[0022] Figure 1A The illustrated aspect of the also sterilizable filter assembly 1000 further includes an absorbent pad 1030 disposed beneath the porous microorganism-entrapment filter element 500 and the at least two inwardly facing arms 150A, 150B, and a base 1050 including a support surface 1051 for the absorbent pad, the base also including a fluid port 1075 (at the Figures 3A to 3C and Figure 3E ). Preferably, the support surface for supporting the absorbent pad in the base comprises a plurality of ribs, for example to improve sealing and liquid transfer.

[0023] The filtration assembly has a fluid flow path between the sample reservoir 100 and the fluid port 1075 in the base 1050, wherein the porous microorganism-capturing filter element and the absorbent pad are disposed across the flow path to allow the fluid to be filtered to pass through the porous microorganism-capturing filter element and the absorbent pad. In some aspects, at least a portion of the downstream surface of the filter element (e.g., the portion of the surface not in contact with the arms) contacts the absorbent pad.

[0024] The absorbent pad is more porous than the filter element and provides mechanical support to the filter element during filtration. The absorbent pad may comprise a layer of mesh, paper, or fabric. A variety of pads are suitable and commercially available.

[0025] The base is removably mounted to the sample reservoir. In one aspect, there is a friction fit or press fit between the base and the bottom of the sample reservoir, wherein the top of the base and the bottom of the sample reservoir have corresponding oval shapes with opposing straight portions (1052A, base; 102A, bottom of reservoir) and opposing curved portions (1052B, base; 102B, bottom of reservoir) to ensure proper alignment.

[0026] Where desired, the receptacle and base may include features such as to provide an audible "click" when assembled so that the operator recognizes that they are properly engaged. Figure 1B Two structures 107C and 107D on the reservoir are shown, each comprising a lip and a groove which engage with half rings 1057C and 1057D on the base (in FIG. Figure 1A and Figure 3A shown in ).

[0027] As will be discussed in greater detail below, although the aspect of the filtration system 2000 shown in FIG1 also includes an incubation assembly 700 having an incubation plate 750 and an incubation cover 775, the incubation assembly is not used during filtration of the fluid.

[0028] Preferably, the filter device 500 (as described with respect to Figures 2A to 2C ) and are packaged and sterilized (e.g. by irradiation, such as gamma irradiation) together with the pad and base, and the incubation plate and incubation cover are packaged and sterilized separately, and the user obtains two packages.

[0029] The assembled filter device 500 and pad 1030 are as follows Figures 3A to 3D 1050 as shown, thereby providing the filter assembly 1000. Typically, the filter assembly 1000 is placed in a filter manifold (such as a vacuum manifold, not shown), the reservoir is filled with fluid, and a vacuum is applied, causing the fluid to pass through the filter element and pad and port 1075 ( Figure 3E The bottom of the base including port 1075 is shown).

[0030] The filter device 500 is then removed from the base and Figures 4A to 4C As shown, the incubation plate 750 is aligned with the incubation plate, which preferably contains a microbial growth medium, such as, for example, agar, wherein the plate receives the released element. The incubation plate 750 preferably has an upwardly raised surface 751 and includes a plurality of ribs that can be used to indicate how much growth medium has been added to the plate, wherein the ribs are immersed in the growth medium.

[0031] The incubation plate 750 (which may be a conventional culture dish) has side walls 752. Preferably, as shown in FIG. Figure 4A As shown (see also Figure 4C ), the side walls have opposing cutouts 752A, 752B that align with the arms 150A, 150B once the base 102 is placed in the incubation plate 750. Figure 4CFor reference, when the operator compresses the part of the elastic sidewall 110 of the reservoir, arms 150A, 150B move outwards, thereby the filter element 501 is released into the incubation plate. After removing the reservoir, the incubation cover 775 can be placed above the incubation plate containing the filter element, and the filter element can be incubated for a desired time period and analyzed for the presence or absence of one or more microorganisms. It is known in the art to be used for incubating and analyzing the various techniques of one or more microorganisms. A technology is provided in ASTM F838-15 (" Standard Test Method for Bacterial Retention of Membrane Filters Used for Determining Liquid Filtration ").

[0032] The filter element (eg, membrane) may have any suitable pore structure, for example, pore size (e.g., as evidenced by bubble point, or K-values ​​such as described in U.S. Patent No. 4,340,479). L The filter elements may be characterized by a pore size (e.g., as determined by capillary condensation flow porosimetry), mean flow pore (MFP) size (e.g., when characterized using a porosimeter such as the PorvAir porosimeter (PorvAir, Norfolk, UK) or a porosimeter commercially available under the trademark POROLUX (Porometer.com, Belgium)), pore grade, pore diameter (e.g., when characterized using a modified OSU F2 test such as that described in U.S. Patent No. 4,925,572), or removal grade. Typically, the filter elements have a pore size in the range of 0.1 μm to 5 μm, preferably in the range of 0.2 μm to 0.8 μm, for example, pore sizes of 0.2 μm, 0.45 μm, and 0.8 μm.

[0033] The porous microorganism capture filter element preferably comprises at least one filter medium that is compatible with the fluid being filtered and can remove the microorganism of being paid close attention to from the fluid.The filter medium can be any desired type, such as microporous membrane or fiber element of various materials, or for example filter paper.The various filter media that are used for microbiological research are commercially available, and any such filter medium can be used as the porous microorganism capture filter element together with the present invention.The filter medium can capture microorganisms in any desired manner, for example according to size, by adsorption and / or affinity binding.The filter medium that is used for microbiological research is a flat diaphragm normally, but the porous microorganism capture filter element does not need to have any specific shape.Typical filter media comprises for example polyvinyl sulfone and modified cellulose.

[0034] The reservoir, arms, and base can be made of any suitable rigid impermeable material compatible with the fluid being processed, including any impermeable thermoplastic material (e.g., made by injection molding). In preferred aspects, these components are made of polymers, such as acrylic, polypropylene, polystyrene, or polycarbonate resins, in certain aspects.

[0035] The components may be produced via additive manufacturing (sometimes referred to as "additive layer manufacturing" or "3D printing").

[0036] Typically, the incubation plate and lid are made from polymer or glass, and are typically both made from the same material for ease of use.

[0037] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0038] The use of the terms "one" and "a kind of", as well as "the" and "at least one" and similar indicators in the context of describing the present invention (particularly in the context of the following claims) should be interpreted as covering the singular and plural, unless otherwise specified herein or the context is clearly contradictory. Unless otherwise specified herein or the context is clearly contradictory, the use of the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B") should be understood to mean one item (A or B) selected from the listed items or any combination of two or more of the listed items (A and B). Unless otherwise specified, the terms "comprise", "have", "include" and "contain" should be understood as open terms (i.e., meaning "including but not limited to"). Unless otherwise specified herein, the description of the range of values ​​herein is intended only to be used as a shorthand method for individually referring to each independent value falling within the range, and each independent value is incorporated into the specification as if individually narrated herein. Unless otherwise specified herein or the context is clearly contradictory, all methods described herein can be performed in any suitable order. Unless otherwise specified, the use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better illustrate the invention and does not limit the scope of the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0039] The preferred aspects of the present invention are described herein, including the best mode known to the inventor for implementing the present invention. After reading the foregoing description, variations of those preferred aspects may become apparent to those of ordinary skill in the art. The inventor expects that the skilled person will appropriately adopt such variations, and the inventor wishes to practice the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalents of the subject matter recited in the appended claims as permitted by applicable law. In addition, unless otherwise indicated herein or otherwise clearly contradicted by context, the present invention encompasses any combination of the above-mentioned elements in all possible variations thereof.

Claims

1. A filter assembly, comprising: (a) a sample receptacle for holding a fluid sample to be filtered, the sample receptacle having an open top end, an open bottom end, and at least two inwardly facing arms disposed at the open bottom end, the sample receptacle having resilient sidewalls; (b) a fluid port in fluid communication with the sample reservoir; (c) a porous microorganism-capturing filter element disposed across the fluid path between the sample reservoir and the fluid port, the porous microorganism-capturing filter element being releasably retained by the at least two inwardly facing arms; (d) an absorbent pad disposed beneath the porous microorganism-entrapment filter element and the at least two inwardly facing arms and positioned across the flow path between the sample reservoir and the fluid port; (e) a base removably mounted to the sample receptacle, the base comprising the fluid port and a support surface for supporting the absorbent pad; wherein, after the base is removed from the sample receptacle, the resilient sidewall is compressed to release the porous microorganism-entrapment filter element from the at least two inwardly facing arms.

2. The filter assembly according to claim 1, wherein The open bottom end of the sample receptacle has opposing straight portions and opposing curved portions.

3. The filter assembly according to claim 1, wherein The at least two inwardly facing arms are slidably attached to the sample receptacle. 4 . A filtration system, comprising the filtration assembly according to claim 1 , and an incubation assembly comprising an incubation plate and an incubation plate cover.

5. The filtration system according to claim 4, wherein: The incubation plate comprises agar.

6. A method for determining the presence or absence of at least one microorganism in a fluid, the method comprising: Passing the fluid through the filter assembly according to any one of claims 1 to 3; detaching the sample receptacle with the retained porous microorganism-entrapment filter element from the base; releasing the porous microorganism-capturing filter element from the sample reservoir into an incubation plate; incubating the released porous microorganisms to capture the filter element; as well as The presence or absence of at least one microorganism on the porous microorganism-entrapment filter element is determined.

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