JP2007526477A - Bicomponent fiber core - Google Patents

Abstract

A bicomponent fiber core is provided for use in processing the analyte fluid. A bicomponent fiber core is a self-supporting fluid having a plurality of constricted bicomponent fibers that are bundled and bonded together at a plurality of spaced apart contact points Including a substrate that permeates through. Each bicomponent fiber has a fiber structure that includes a first fiber component and a second fiber component formed from a polyamide material. The fiber defines a tortuous fluid flow path through the substrate that is collectively permeable to fluid, and the fiber structure includes a substrate through which at least a portion of the first fiber component is in contact with and permeable to the analyte fluid. It is configured to control the flow of analyte fluid through it.

Description

  The present invention relates generally to hygroscopic wicks and, more particularly, to bicomponent fiber cores adapted to permeate an analyte fluid into an assay device.

  A variety of analytical devices are known that provide analysis results that are fast and minimize user skill and impact for use in home, office, clinic, hospital or physician surgery. An example of this is a test device or assay for pregnancy and conception period (ovulation). In such a device, the number of operations to obtain results is usually minimized.

A typical analytical device includes a housing, a reaction medium disposed in the housing and causing a chemical reaction for analysis thereon, and a wick that collects and transports the fluid to be analyzed to the reaction medium. In general, the analytical device only requires that the collection part of the device is in contact with a sample (eg, a urine sample for pregnancy testing), after which no further action of the user is required. The sample is conveyed from the collection part through the wick to the reaction medium. By observing the change of the reaction medium or the substrate carrying the reaction medium, an analysis result is provided. The analysis results are ideally observable within a few minutes after sampling.
US Pat. No. 5,607,766 US Pat. No. 5,620,641 US Pat. No. 5,633,082

  The actual analytical technique used to obtain the results typically determines the presence or absence of various analytes in the organism's tissues and fluids and / or quantifies the amount of the analyte. Many current diagnostic tests are performed using blood, urine, cage material, saliva, or tissue biopsy. However, tests based on these materials substantially cause privacy breaches and carry substantial safety risks (especially in blood tests). Improved analytical devices are required to allow transport and analysis of fluid samples at high speed and with high control. This analytical device will depend on improved core material and structure.

  The present invention provides a core that uses a bicomponent fiber in which at least one of the fiber components is a polyamide material. An exemplary embodiment of the present invention provides a bicomponent fiber core for use in processing an analyte fluid. A bicomponent fiber core is a plurality of crimped bicomponent fibers that are bundled together and coupled to each other at a plurality of spaced apart contact points And includes a substrate that is permeable to a self-supporting fluid. Each bicomponent fiber has a first fiber component and a second fiber component formed from a polyamide material. The bicomponent fiber defines a twisted fluid flow path through a substrate that is collectively permeable to fluid, and the fiber structure includes at least a portion of the first fiber component in contact with the analyte fluid. And configured to control fluid flow of the analyte through the fluid permeable substrate.

  The invention may be more fully understood by reading the following detailed description with reference to the accompanying drawings, in which reference numerals are used to identify the elements. The present invention provides a bicomponent fiber core that is particularly adapted for use in devices requiring rapid controlled fluid transport. This core is particularly adapted for use in analytical devices that require the transport of an analyte fluid. As used herein, the term analyte fluid means a fluid sample, where the fluid sample analyzes the presence of one or more analytes in the fluid sample and / or in the fluid sample. Quantify the amount of one or more analytes present.

  The core of the present invention can be formed from bicomponent fibers and the structure and material components of the core can be adapted to provide special fluid transport performance for specific analytes and analyte fluids.

  Bicomponent fibers are used to some extent in core and medical analytical devices. However, many conventional analytical devices are composed of low-cost monocomponent fibers, which are low density polyethylene (LDPE), polypropylene (PP), high density polyethylene (HDPE), ultra high molecular weight polyethylene (UHMW), polypropylene. (PP), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyester, and polyether sulfonic acid (PES). In fact, materials such as nylon 6 have been found to be normally usable, and in fact their natural hydrophilic behavior can be favorable. However, the use of nylon materials has not been supported in part by cost in such one-component applications. It has also been found that nonwoven hydrophilic structures formed from nylon are often not self-supporting. Further, the nylon manufacturing process often requires additional processing to avoid accidental moisture absorption by the nylon fiber. In some instances, this process requires a dedicated drying step. Also, the physical and mechanical properties of the spun nylon fiber are susceptible to changes over time (aging effects).

  Conventional inexpensive polymers such as polyolefins and polyesters are currently used to form the core of analytical devices, but have two drawbacks. (1) The polymers require additional materials, such as surfactants, to provide sufficient fluid transport performance. (2) Without functionalization, derivatization, or modification, the polymers Does not provide a reaction field for other auxiliaries. Because of these shortages, the possibility of using nylon as a natural hydrophilic core material was studied. The core embodiment of the present invention utilizes a bicomponent fiber having natural hydrophilic properties by using a polyamide material in the fiber structure. The structure of these fibers is adapted to provide an optimum amount of polyamide material that maintains the desired flow characteristics for the final core product.

  In general, the use of bicomponent fibers in hydrophilic structures is well known in the art. For example, US Pat. No. 5,607,766 issued on March 4, 1997, US Pat. No. 5,620,641 issued on April 15, 1997, May 27, 1997. U.S. Pat. No. 5,633,082, which is incorporated herein by reference in its entirety, but having a thermoplastic material core coated with a polyethylene terephthalate sheath The manufacture and use of a fiber is disclosed. These patents note that such fibers are particularly useful in the manufacture of elongated, highly porous elements, whose core is used to transport all fluids to the test side of a diagnostic device. In the core to be done.

  However, the prior art does not disclose a core structure formed from a fiber that has at least one polyamide group component and is joined by a crimped bicomponent fiber. The core embodiment of the present invention is a self-supporting structure formed from such a fiber. The term “bicomponent”, as used herein, refers to the use of two polymers having different chemistries that are located in separate cross-sectional areas in the fiber structure. The two polymers are disposed substantially uniformly in different regions of the cross-section of the bicomponent fiber, and the fiber extends continuously along the length of the bicomponent fiber. Other configurations of bicomponent fibers are possible, but the more common bicomponent fiber types are “side-by-side” and “sheath-core” types. The first type was so named because the two polymer materials form a cross-sectional configuration that is literally juxtaposed. In a “sheath-core” bicomponent fiber, the sheath of one polymer material is spun to completely enclose and surround the core of another polymer material, usually a low shrinkage, high strength thermoplastic polymer material. Yes.

  The core structure of the present invention can be formed from parallel or sheath-core bicomponent fibers that include at least one polyamide fiber component. The polyamide fiber component can be any of nylon 6, nylon 6,6, nylon 4, nylon 6,10, nylon 11, nylon 12, or various nylons having hydrophilic sites such as polyethylene glycol and / or polyethylene oxide diamine. It can be selected from the group consisting of copolymers. In some examples, both bicomponent fiber components can be polyamides selected from the group described above.

  The one or more polymers of the second fiber component may depend on the bicomponent fiber type. In a parallel fiber, the first fiber component is formed from a polyamide material and the second fiber component can be formed from a material selected from the group including, but not limited to, polyolefins, polyesters, polyamides, polysulfonates, and the like. In the sheath-core fiber, the sheath component is formed from a polyamide material, and the core component is not limited, but polyamide (nylon 6, nylon 6,6 and other nylons), polyester (polyethylene terephthalate, polybutylene terephthalate, polypropylene It can be formed from thermoplastic polymer materials selected from the group comprising terephthalate and polylactic acid) and polyolefins (syndiostatic, isotactic polypropylene and polyethylene).

  From the above, it is noted that both parallel and sheath-core bicomponent fibers can have a first component of one polyamide material and a second component of another polyamide material. Thus, embodiments of the core of the present invention may be formed, for example, from a sheath-core fiber having a core component of nylon 6 and a sheath component of nylon 6,6.

  As discussed in more detail later, it has been found that the content and fiber structure of both sheath-core and parallel fiber types has a significant impact on certain properties of the final core product. It has also been found that the fiber material content and fiber structure can be selected to provide the desired core properties and, in effect, can be optimized based on various design criteria. .

  The bicomponent fiber used in embodiments of the present invention can be manufactured by many common techniques. Such techniques include the usual melt spinning process in which a molten polymer is pumped under pressure to a spinning head and a number of continuous fibers are extruded from a spinneret orifice. For melt spinning, only polymers with melting temperatures below the decomposition temperature such as nylon, polypropylene, etc. are available, where the polymer material can be melted and extruded to form fibers without decomposition. Other polymers, such as acrylic resins, cannot be dissolved without breaking or breaking down. The above polymers can be dissolved in a suitable solvent (eg, acetate ester in acetone), usually 20% polymer and 80% solvent. In the wet spinning process, the aqueous solution is pumped at room temperature, passes through the spinneret, and is submerged in a liquid (eg, water) bath, where the solvent is soluble and solidifies the polymer fiber. It is also possible to dry spin the fiber in hot air rather than a liquid bath to evaporate the solvent and form a skin on the fiber surface.

  After spinning, the fiber is generally thinned by pulling it from the spinning device at a rate faster than the extrusion rate. The fiber can be thinned by taking the fiber on a nip roll that rotates at a speed faster than the draw speed, or between nip rolls operating at different speeds. Depending on the nature of the polymer, the fiber can be drawn out in this way, making it more crystallized and stronger.

  It can also be thinned using a melt-blowing process. In this process, the fiber is thinned by contact with a fluid such as high velocity air as the fiber exits the spinneret orifice. The effect of the fluid is to draw the fiber into fine filaments. These filaments can be collected for subsequent processing as a fiber entangled fabric on a continuously moving surface such as a conveyor belt or drum surface. This process, known as “melt blowing”, is particularly industrially important in the manufacture of many products because of its ability to thin the fiber while it is still molten.

  Any of the processes described above can be used to produce a bicomponent fiber for use with the core of the present invention. One skilled in the art can appreciate that the actual process used for a given fiber can depend on the composition and composition of the fiber. Regardless of the method of forming the bicomponent fiber, the bicomponent fiber is then collected and passed through one or more processing sections, where the fiber is a continuous free-standing porous core having a constant cross-section. Are combined and molded to produce the element.

  The core element is then further processed and / or divided into individual core elements. Each core element is a self-supporting structure formed as a network of continuous coupled fibers. This network of fibers provides a twisted gap passage for the fluid passage by capillary action, and for the substance trapped in and / or trapped in the fluid passing through the gap. Provides a twisted gap passageway.

  With reference to FIG. 1, a manufacturing process for forming a bicomponent fiber core element according to an embodiment of the present invention will now be discussed in detail. The process begins at step S100. In step S110, a plurality of bicomponent fibers having at least one polyamide fiber component are provided. Each fiber is typically provided in a separate bobbin, and the fiber is drawn from the bobbin through a supply roll. The fiber can alternatively be provided as a tow or as a melt blown, spun bonded, or unwoven roving. In step S120, the fiber is drawn from a temperature and humidity controlled draw box where the fiber is heated and drawn at a predetermined draw ratio. In the illustrated embodiment, the predetermined draw ratio may be about 1.5 to 1 to about 6 to 1, and preferably about 2.5 to 1 to about 3.5 to 1.

  In step S130, a crimp can be formed in the fiber. Prior to crimping, the collected fibers form a plurality of continuous straight fiber elements. When the fiber is crimped, the fiber becomes multidimensional and has the effect of increasing the bulk and loft of the final core product. Further, the crimping increases the uniformity of the core substrate structure, in particular the uniformity of the capillaries that create a twisted fluid path through the core product. The crimping can be done by mechanical means, or it can be done in a bicomponent fiber configuration that self-winds. Mechanical crimping can be applied to any fiber type, and viewing the fiber from above and / or from the side tends to produce a zigzag or sawtooth pattern. Any suitable mechanical crimping process can be used to practice the present invention.

  Self-contracting fibers are generally bicomponent fibers in which the two fiber components have different shrinkage / extension characteristics. Typically, one of the fiber components (usually the sheath-core component of the core fiber) has a higher melting temperature, lower shrinkage and higher strength than the second component. As a self-contracting fiber becomes heated and can soften, the difference in behavior of the two components causes the fiber to deform or constrict in a predictable manner. Depending on the choice of component materials and the cross-sectional shape of the two fiber components, the desired three-dimensional deformation can be introduced.

  For both parallel and sheath-core bicomponent fibers, the self-winding action of the fiber can be affected by the material used in the fiber component and the relative cross-sectional area of the two components. A particularly preferred self-contracting fiber configuration cross section is illustrated in FIG. As shown, the fiber 10 is a sheath-core fiber and the core component 12 and the sheath component 14 are both substantially circular in cross section (respective outer radius radii R1, R2) but are not coaxial. Such fibers can be represented as eccentric sheath-cores. The eccentricity of the fiber can be defined as the ratio of the offset X between the centers of the two components and the outer radius of the fiber equal to the outer radius R1 of the sheath component. The eccentricity and the relative cross-sectional area of the two components can be changed to change the degree of deformation when the fiber can be crimped. The fibers used in the core of the present invention typically have an eccentricity in the range of approximately 0.1 to approximately 0.5.

  When a self-contracting fiber is used in the process of FIG. 1, the action to achieve the collected fiber constriction is to pass the fiber through the drawer to stretch the fiber and then to disturb the air injection. In that region, which can include a step through the flow region, the fiber becomes softer and can usually take on a self-contracting fiber pattern. This multi-dimensional fiber deformation mixes the fibers and forms the desired free standing core downstream.

  In step S140, the mixed and crimped fiber is drawn through an oven or other heating device, where the temperature is at or near the melting temperature of at least one of the two fiber components. In a preferred embodiment, the fiber is a sheath-core fiber and the oven temperature is set at or near the melting temperature of the polyamide sheath material to at least partially melt the sheath material. The environment within the oven is carefully controlled to ensure uniform heating of the fiber. In step S150, the mixed fiber is drawn through a heated sizing die, where mixed and crimped fibers are separated at various intervals along the length of the molten fiber component. Contact each other. In the cooling process of step S160, the fibers remain coupled at these contact points, thereby producing a self-supporting fiber structure. The fiber can be cooled at ambient conditions, or it can be cooled with cooled air or cold fluid through the drawn fiber structure through the next cooling die, depending on the specifics of the process. In the preferred embodiment where the fiber is a sheath-core fiber, the fiber structure bonds are formed at various points along the polyamide sheath portion of the fiber.

  At this point in the process, a crimped bicomponent fiber is formed in a continuous core substrate structure. Although generally rectangular, it is understood that the cross-section of the continuous core substrate can be any geometric shape. In step S170, the continuous core substrate structure is cut to a desired length to form a separated core substrate. An exemplary final product core 100 is displayed in FIG. 3 (scale not shown). The core 100 has a rectangular fluid-permeable core substrate 100 and is formed from bicomponent fibers 120 that are generally aligned, three-dimensionally mixed, joined, and crimped. The process ends at step S190.

  In some examples, it may be preferable for the final core product to add or coat the additive material. Typical additive materials can include, for example, screening agents, surfactants and reactants. The additive may be incorporated by coating or dipping the core substrate structure with the additive solution before and after cutting. In a particular embodiment, a pump can be used to apply the additive in solution to the formed core element. The amount of additive added to the wick can be controlled by the concentration of the additive in the aqueous solution, the pump speed, and the speed of the wick through the solution. An elongated die can be used to remove excess additive. The core structure is then dehydrated by generally well known means.

  As with all core embodiments of the present invention, the final product of the method described above is a self-supporting network of bicomponent fibers coupled together. This network defines a twisted flow path for a fluid path through the core. As is well known, structures so formed can provide a means for transporting fluids without the use of fluid mobility other than capillary action. Thus, the degree of capillary action and the flow rate of a given fluid is determined by the degree of surface energy at the capillary boundary of the gap through the fiber structure. Without the use of enhancing additives such as surfactants, the capillary surface energy will be determined by the polymer material used in the fiber. The overall fluid transport performance of the core can be influenced by the uniformity of the mixed fiber structure established by crimping the fiber.

  As noted previously, polyamide materials, particularly nylon, are naturally hydrophilic (ie, have a natural high surface energy when compared to other common fiber materials such as polyolefins and polyesters). Thus, the use of a nylon fiber component in the core structure can provide a fairly high fluid flow rate without the use of additives that increase the flow rate. In the bicomponent fiber structure of the present invention, at least some of the exposed fiber surfaces that form the capillary boundary are provided by the polyamide fiber component of the bicomponent fiber. All sheathed surfaces are provided by the polyamide in a sheath formed from a sheath-core fiber with a polyamide sheath and in a core formed from a parallel fiber having both components formed from a polyamide material. In a core formed from parallel fibers, if only one fiber component is a polyamide, the degree of natural capillary flow potential is relative to the surface area manifested by the polyamide component when compared to the surface area manifested by the non-polyamide component. Can be determined by the specific surface area.

  Thus, it is understood that the core structure of the present invention can provide a significant degree of fluid flow potential. It is also understood that in embodiments incorporating the sheath-core fiber type, the degree of flow potential is essentially independent of the volume of the polyamide in the fiber sheath as long as a sufficient fiber surface area of nylon is maintained. Can do. Thus, the amount of polyamide material in the fiber can be minimized for an inexpensive core material. Thus, the sheath-core fiber configuration can provide significant advantages, in which all of the exposed fiber surface can be formed by a nylon sheath that forms only a portion of the total fiber material. If only surface energy is the only consideration, the core fiber can be formed using the minimum amount of polyamide material required to completely coat the core component.

  However, there are other considerations in selecting the amount and configuration of the polyamide fiber component. For example, for a given polyamide material, the coupling capacity of a bicomponent fiber to form the free standing core substrate of the present invention can be related to the amount of polyamide material used. This is especially true for a sheath with a polyamide sheath-core fiber. Also, as previously discussed, the use of crimped fibers, particularly self-crimped fibers, affects the core transport properties because the bonded fiber structure and the twisted flow formed thereby. This is because it affects the uniformity of the passage. As noted above, the crimping behavior of self-crimping fibers is generally not only a function of the relative stretch (or shrinkage) of the two fiber components, but also the relative cross-sectional area of these components. It is therefore also a function of the relative amount of material.

  As a result, under certain circumstances, there may be an incentive to increase the amount of polyamide material in the bicomponent fiber beyond the minimum amount required to produce a particular polyamide material surface. Thus, the amount of polyamide material used may be based on complex design constraints, including parameters based on surface energy requirements, structural uniformity and connectivity. However, it may also be desirable to minimize the amount of polyamide material required to meet these limitations. The present invention provides tailoring the fiber shape to meet these one or more design criteria.

  For a given polyamide material and fiber type, the surface area of the flow is essentially determined by the required fluid transport performance. The remaining performance parameters may be related to the polyamide component ratio of the bicomponent fiber. As used herein, the term “polyamide component ratio” refers to the unit length of a bicomponent fiber (or weight) per unit length of polyamide (or volume) that provides the polyamide surface of the core capillary. , Mean the ratio of total weight per volume). In a bicomponent fiber having a first fiber component of polyamide and a second fiber component of non-polyamide, the polyamide component ratio is a first per unit length divided by the total fiber weight per unit length. It is readily understood that the ratio is by weight of the components. Also, a bicomponent fiber with a given polyamide sheath and high polyamide component ratio can have some surface energy and binding properties, but it can easily be quite expensive due to the high proportion of polyamide material Can be understood. On the other hand, fibers with a low polyamide component ratio can be low cost, but have coupling problems and may not provide sufficient polyamide surface area. It is noted that some bicomponent fibers have two components formed from a polyamide material and the polyamide component ratio is as high as 1.0.

  For a given bicomponent fiber type, the actual cross-sectional shape of the fiber can be determined by a combination of polyamide surface area requirements and polyamide component ratio. If a self-crimping fiber is used, the crimping behavior also acts as a factor.

  Based on the above, it can be appreciated that the bicomponent fiber core of the present invention can be optimally combined for a particular combination of core performance characteristics. The substrate that is permeable to the bicomponent fiber core fluid may be formed from a plurality of bicomponent fibers that are coupled together at spaced contact points. In all of the cores of the present invention, the fibers collectively define a twisted three-dimensional fluid flow path through the core substrate. The bicomponent fiber comprises a fiber structure that includes first and second fiber components, each having a separate cross-sectional region that extends continuously along the length of the bicomponent fiber. The fiber includes at least a polyamide material. Typically, the fiber has a first component formed from a polyamide material and a second component not formed from a polyamide, and in some embodiments, the second component is different from the first component polyamide. It can be a polyamide material with properties. The shape of the bicomponent fiber may be specially adapted to provide a polyamide component ratio to provide a final core structure adapted to meet predetermined design requirements.

  There may be several variations depending on the particular polyamide material used, but acceptable cores are from crimped bicomponent fibers with polyamide component ratios ranging from about 0.10 to about 0.50. It is determined that it can be manufactured. In a preferred embodiment, the core can be made from a crimped bicomponent fiber having a polyamide component ratio in the range of about 0.20 to about 0.35. In the most preferred embodiment, the core can be made from a crimped bicomponent fiber having a polyamide component ratio in the range of about 0.25 to about 0.30.

[Example]
The core structure was successfully formed from bicomponent fibers with different polyami content levels and shapes. The processing method described above is used to create a core from a self-contracting sheath-core bicomponent fiber, the core fiber component of which is polyethylene terephthalate (DuPont 4441), and the sheath fiber component is nylon 6 (Ultraamide BASF BS403N). The fiber was formed using a conventional two-component melt spinning technique using a spin pack with 288 individual filaments. The filaments were spun to 25 dpf (denier per filament) and each package was creeled to provide a final core product of sufficient density. The collected yarn was drawn at a draw rate of 3.5 at 150-160 ° C. to introduce a self-contracting fiber structure. The yarn was then pulled through an oven at 200-235 ° C. through a heated die to form a free standing core with a rectangular cross section of 2.45 mm × 11.5 mm.

  Two sets of cores were manufactured, both having an outer diameter of 38 μm. In the first set, the core fiber is formed with a core diameter of 29.4 μm and an eccentricity of 0.45 to produce a polyamide component ratio of 0.40. In the second set, the core fiber was formed with a core diameter of 32.9 μm and an eccentricity of 0.27 to produce a polyamide component ratio of 0.25. Both sets of cores provided a well-coupled free-standing fluid permeable substrate with substantially similar fluid transport properties far exceeding conventional untreated bicomponent fiber cores.

  The core of the present invention has wide applicability and can be used in any fluid transport application. They are particularly adapted for use in analytical devices that can be used in medical applications. Thus, the core of the present invention can be used for the transport of any practical analyte fluid, including biological analyte fluids such as urine, blood, and saliva. The core of the invention can also be used in an analytical device to detect one or more analytes, including but not limited to human chorionic gonadotropins (which are frequently used as pregnancy markers). hormones such as hCG), antigens, enzymes, HIV antibodies, HTLV antibodies, Helicobacter pylori antibodies, hepatitis antibodies, measles antibodies, hepatitis antigens, terponemes antibodies, antibodies to hosts or infectious agents, including but not limited to cardiolipin , Lecithin, cholesterol, lipopolysaccharide, sialic acid, parotitis antibody, rubella antibody, cotinine, cocaine, benzoylecgonine, benzodiazepine, tetrahydrocanabinol, nicotine, ethanol theophylline, phenytoin, acetaminophen, lithium, diazepam , Nortriptyline hydrochloride, Secobar Growth elements I such as tar, phenobarbital, theophylline, testosterone, estradiol, 17-hydroxyprogesterone, progesterone, thyroxine, thyroid stimulating hormone, follicle stimulating hormone, luteinizing hormone, transforming growth factor α, epidermal growth factor, insulin And II, including pathological cell markers including growth hormone release inhibitor, IGA and sex hormone binding globulin, and glucose, cholesterol, caffeine, cholesterol, corticosteroid binding globulin, PSA or DHEA binding globulin Including other analytes.

  While the above figures and description illustrate exemplary embodiments of the invention, it is understood that the invention is not limited to the arrangements disclosed herein. The present invention may be specifically expressed in other specific forms without departing from the spirit or essential attributes thereof.

4 is a flowchart of a process for manufacturing a bicomponent fiber core according to an embodiment of the present invention. 1 is a cross-sectional view of a sheath-core bicomponent fiber that can be used in embodiments of the present invention. FIG. FIG. 3 is a perspective view in which the dimensions of the core of a two-component fiber according to an embodiment of the present invention are not described.

Claims (21)

A binary fiber core for use in processing an analyte fluid comprising:
A self-supporting fluid permeable substrate comprising a plurality of bundled and compressed bicomponent fibers coupled to each other at a plurality of spaced apart contact points; Including
Each bicomponent fiber has a fiber structure including a first fiber component and a second fiber component formed from a polyamide material;
The bicomponent fiber defines a twisted fluid flow path through a substrate that collectively transmits the fluid;
The fiber structure is configured to control flow of the analyte fluid through a substrate that is in contact with and permeable to the analyte fluid in at least a portion of the first fiber component.
A two-component fiber core characterized by that.   The polyamide material is selected from the group consisting of nylon 6, nylon 6,6, nylon 4, nylon 6,10, nylon 11, nylon 12, and copolymers thereof. Bicomponent fiber core as described.   The second fiber component includes at least one of nylon 6, nylon 6,6, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polylactic acid, polypropylene, and polyethylene. Bicomponent fiber core as described.   2. The bicomponent fiber core of claim 1 wherein the bicomponent fiber is self-contracted.   A core of a continuous two-component fiber in which the first fiber component forms a sheath of a two-component fiber continuous along the length direction of the two-component fiber, and the second fiber component is surrounded by the sheath The bicomponent fiber core of claim 1, wherein:   The bicomponent fiber core of claim 1 wherein the fiber structure is adapted to provide a predetermined polyamide component ratio.   7. The bicomponent fiber core of claim 6, wherein the predetermined polyamide component ratio is in the range of about 0.10 to about 0.50.   7. The bicomponent fiber core of claim 6 wherein said predetermined polyamide component ratio is in the range of about 0.20 to about 0.35.   7. The bicomponent fiber core of claim 6, wherein the predetermined polyamide component ratio is in the range of about 0.25 to about 0.30.   The bicomponent fiber core of claim 1, wherein the analyte fluid is one of urine, blood, serum and saliva. A binary fiber core for use in processing an analyte fluid comprising:
Bundled self-contracted bicomponent fibers that pass through a self-supporting fluid formed from the bicomponent fibers joined together at a plurality of spaced apart contact points Including a substrate to be
Each bicomponent fiber has a fiber structure that includes a continuous thermoplastic fiber core material and a continuous fiber sheath surrounded by the continuous thermoplastic fiber core material;
The continuous fiber sheath is formed from a sheath material selected from the group consisting of nylon 6, nylon 6, 6, nylon 4, nylon 6, 10, nylon 11, nylon 12, and copolymers thereof;
The bicomponent fiber defines a twisted fluid flow path through a substrate that collectively transmits the fluid;
The fiber structure is configured to control fluid flow of the analyte through a substrate that is permeable to the fluid;
A two-component fiber core characterized by that.   The continuous thermoplastic fiber core material includes at least one of nylon 6, nylon 6,6, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polylactic acid, polypropylene and polyethylene. 12. A bicomponent fiber core according to claim 11.   13. A bicomponent fiber core according to claim 12, wherein the fiber structure is adapted to provide a predetermined polyamide component ratio.   14. The bicomponent fiber core of claim 13, wherein the predetermined polyamide component ratio is in the range of about 0.10 to about 0.50.   14. The bicomponent fiber core of claim 13, wherein the predetermined polyamide component ratio is in the range of about 0.20 to about 0.35.   14. The bicomponent fiber core of claim 13, wherein the predetermined polyamide component ratio is in the range of about 0.25 to about 0.30. A binary fiber core for use in processing an analyte fluid comprising:
A self-supporting fluid permeable substrate formed of a plurality of bicomponent fibers coupled to each other at a plurality of spaced apart contact points;
The plurality of bicomponent fibers define a twisted fluid flow path through the substrate that collectively transmits the fluid;
Each bicomponent fiber comprises a fiber structure including first and second fiber components;
Each having a separate cross-sectional area extends continuously along the length of the binary fiber;
The first fiber component is formed from a polyamide material;
The fiber structure is adapted to provide a predetermined polyamide component ratio equal to the ratio of the first fiber component weight per unit volume to the total fiber weight per unit volume;
A two-component fiber core characterized by that.   18. The polyamide material according to claim 17, wherein the polyamide material is selected from the group consisting of nylon 6, nylon 6, 6, nylon 4, nylon 6, 10, nylon 11, nylon 12, and copolymers thereof. Bicomponent fiber core as described.   The second fiber component includes at least one of nylon 6, nylon 6,6, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polylactic acid, polypropylene, and polyethylene. Bicomponent fiber core as described.   The first fiber component forms a sheath of a bicomponent fiber that is continuous along the length of the bicomponent fiber, and the second fiber component is a continuous bicomponent fiber surrounded by the sheath. 18. A bicomponent fiber core according to claim 17 forming a core.   18. The bicomponent fiber core of claim 17, wherein the analyte fluid is one of urine, blood, serum and saliva.

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