WO2014139139A1

WO2014139139A1 - Sample tube assembly

Info

Publication number: WO2014139139A1
Application number: PCT/CN2013/072671
Authority: WO
Inventors: Weiming Yu
Original assignee: Gene Era Biotech Co. Ltd.
Priority date: 2013-03-15
Filing date: 2013-03-15
Publication date: 2014-09-18

Abstract

The sample tube assemblies with improved seal are provided.

Description

SAMPLE TUBE ASSEMBLY

Field of the Invention

[1] The present invention generally relates to sample tubes for handling liquid reagents, and particularly to sample tubes with improved seal and especially suitable for sample preparation and storage.

Background of the Invention

[2] Molecular biology experiments are conducted at ever increasing throughputs and automation in low reaction volumes and often require high temperature conditions and robotic handling. Frequently, biological samples to be analyzed are only available in small quantities. Moreover, the need for reducing reagent costs especially in commercial settings demands minimization of reaction volumes. When heated, e.g., in PCR experiments, low volume reactions are particularly sensitive to loss of liquid. Therefore, improved seal in sample tubes will result in increased consistency in experiments with low reaction volumes and lead to costing saving.

Summary of the Invention

[3] The present invention provides sample tube assemblies with improved seal. Using such sample tube assemblies in PCR reactions effectively prevents leaks and reduces loss of reaction volume.

[4] Accordingly, in a first aspect, the present invention provides a sample tube assembly comprising a sealing cap, and a hollow vessel body having an upper wall section. The upper wall section comprises a proximal section defining the opening of the hollow vessel body and in juxtaposition a distal section, which includes a supporting layer that has a greater hardness, as measured according to ASTM test D 2240, than that of the proximal section. When the sealing cap engages the hollow vessel body for closing the opening, the sealing cap removably engages, and is in sealing contact with, the proximal section and optionally also the distal section. Preferably, the sample tube also includes a flexible strap having opposite ends that are respectively connected with the hollow vessel body and the sealing cap.

[5] In another aspect, the present invention provides a sample tube strip having a plurality of hollow vessel bodies arranged symmetrically in a linear array whereby their axes are in parallel. Each of a plurality of hollow vessel bodies has an upper wall section which comprises a proximal section defining the opening of the hollow vessel body and also a distal section. The distal section comprises a supporting layer having a greater hardness, as measured according to ASTM test D 2240, than that of the proximal section. Preferably, a linear array of a plurality of sealing caps is also included. Each sealing cap is adapted to fit the opening of the hollow vessel body, and when removably engages the opening becomes in sealing contact with the proximal section of the upper wall section of the hollow vessel body. Any two adjacent sealing caps can be connected by a tether.

[6] In yet another aspect, the present invention provides a multiwell plate assembly, e.g., a multiwell microtiter plate assembly comprising a plate body having therein a plurality of wells (e.g., 36, 48, 96, 192 or 364) each having an opening, a closed bottom, and a side wall extending between the opening and the bottom. At least one of the plurality of wells has an upper wall section which comprises a proximal section defining, at its edge portion, the opening of the well. The well also has a distal section having a supporting layer with a greater hardness than the proximal section, as measured according to ASTM test D 2240. Preferably, the multiwell plate further includes a plurality of sealing caps each removably engages, and is in sealing contact with, the proximal section for closing the opening, and any two adjacent sealing caps are connected by a tether or a sheet.

[7] In the various aspects of the present invention, preferably, the proximal section is a monolayer structure. In some embodiments of the sample tube assembly, the sample tube strip and the multiwell plate assembly, the proximal section is a monolayer and the distal section comprises at least a sealing layer permanently joined to the supporting layer. In some specific embodiments, a sealing layer is on an outer peripheral surface of the distal section. In other specific embodiments, a sealing layer is on an inner peripheral surface of the distal section. In some specific embodiments, the distal section comprises a tri-layer structure having two supporting layers sandwiching a sealing layer. [8] Generally, the proximal section and the sealing layer are elastic and flexible while the supporting layer is relatively hard and rigid. The supporting layer has a greater hardness (as measured according to ASTM test D 2240) than the sealing layer and the proximal section. Preferably, the upper wall section is generally cylindrical, and the proximal section, the sealing layer and the supporting layer are coaxial and concentric. Also preferably, the sealing layer and the supporting layer are permanently joined together. The supporting layer generally has a hardness (ASTM test D 2240) of at least 10 Shore A greater than that of the proximal section and/or the sealing layer.

[9] The sealing layer may be coextensive with and covers the entire surface of the supporting layer, or alternatively an annular ring covering a portion of the supporting layer, but around the entire circumference of the portion. Preferably the sealing layer and/or the proximal section are directly molded onto the supporting layer. The sealing cap may be in engagement with the proximal section and optionally also the sealing layer of the upper wall section to hermetically seal the vessel/well.

[10] In the various aspects and the embodiments thereof, the proximal section and sealing layer may have a compression factor of from about 1.5: 1 to about 3: 1, or a compression set of less than about 30%, preferably less than 20%, more preferably less than 10%, and most preferably less than 5%, as measured according to ASTM D395 Method B. The sealing layer and proximal section may have a hardness of from about 30 to about 90 Shore A, preferably about 35 to about 80 Shore A, about 40 to about 80 Shore A, about 40 to about 70 Shore A, more preferably about 40 to about 50 or 60 Shore A, as measured by ASTM test D 2240. For example, the sealing layer and proximal section may be made of one or more polymer materials chosen from the group consisting of polyethylene (PE) (especially low density polyethylene or LDPE), polyurethane (PU), thermoplastic polyurethanes (TPU), thermoplastic elastomers (TPE), thermoplastic polyolefin (TPO), styrenic thermoplastic elastomers (S-TPEs), thermoplastic rubber (TPR), poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS), thermoplastic vulcanizates (TPV), styrene-butadiene-styrene (SBS), flexible PVC (elPVC), etc.

[11] In the various aspects and the embodiments thereof, the supporting layer may have a hardness of greater than about 30 Shore D, as measured by ASTM test D 2240. In some embodiments, the supporting layer has a hardness of from about 30 to about 90 Shore D, as measured by ASTM test D 2240. Examples of polymer materials for forming the supporting layer include, but are not limited to, polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and polystyrene (PS).

[12] In preferred embodiments, the supporting layer has a hardness (ASTM test D

2240) of at least 5, preferably at least 10 Shore A greater than the sealing layer and the proximal section.

[13] In preferred embodiments, each sample tube or well can contain a total volume of from about 0.1ml to about 2.0 ml of liquid. In preferred embodiments, all materials used for the sample tube assembly are heat stable and can withstand heat at a temperature of up to 100°C.

[14] Also, in the various aspects and the embodiments thereof, the proximal section may have a longitudinal length from about 1 mm to about 5 mm. Additionally, the sealing layer if present, forms an annular region that extends axially, and preferably continuously, along at least 10%, 20%, 30%, 40%, 50%, 60%, 70% or at least 80% of the entire length of the upper wall section of the vessel body. Preferably, the sealing layer is coextensive with and covers the entire surface of the upper wall section of the vessel body or of the substantially cylindrically shaped member of the sealing cap. Alternatively, the sealing layer may be in a form of an annular convexity covering a portion of the supporting layer but around the entire circumference of the portion, preferably at the lower edge portion of the cylindrically shaped member, or at the upper edge portion of the upper wall section. In some embodiments, there may be two or more coaxial annular rings (e.g., an O-ring) spaced axially apart.

[15] In yet another aspect, a plastic sample tube is provided comprising a generally cylindrically shaped plastic hollow vessel body having a plastic upper wall section defining at its edge portion the opening of the hollow vessel body. The sample tube further includes a plastic sealing cap having a (1) generally cylindrically shaped sealing member adapted to removably fit the opening of the hollow vessel body and (2) a top cover closing one end of the sealing member. The sealing member has a smaller hardness compared to the top cover, as measured according to ASTM test D 2240, and preferably a smaller hardness compared to the hollow vessel body.

When the sealing cap engages the hollow vessel body for closing the opening, the cylindrically shaped member is in sealing contact with a peripheral surface of the upper wall section.

Preferably the sealing member is a skirt having a monolayer sheet made of a polymeric composition with a hardness at least 5, preferably at least 10 Shore A smaller than that of the top cover. Also preferably the sealing member is made of a resilient material and has a compression set of less than about 10%, as measured according to ASTM D395 Method B. In some embodiment, the sealing member has a sealing lip around the sealing member.

[16] The foregoing and other advantages and features of the invention, and the manner in which the same are accomplished, will become more readily apparent upon consideration of the following detailed description of the invention taken in conjunction with the accompanying examples, which illustrate preferred and exemplary embodiments.

Brief Description of the Drawings

[17] Figure 1 is a cross-sectional side view of one preferred embodiment of a sample tube assembly;

[18] Figure 1A is a sectional view of an enlarged portion of the upper wall section shown in Figure 1 ;

[19] Figure IB a cross-sectional side view of the sample tube assembly in Figure 1 when the sealing cap closes the vessel body;

[20] Figure 1C is a sectional view of an enlarged portion of the upper part shown in

Figure IB;

[21] Figure 2 is a cross-sectional view of an embodiment of a sample tube strip;

[22] Figure 2A is an expanded view of section A in Figure 2;

[23] Figure 2B is an expanded view of section B in Figure 2;

[24] Figure 2C is a cross-sectional side view of the sample tube strip in Figure 2 except in a sealed position;

[25] Figure 2D is an expanded view of section A in Figure 2C;

[26] Figure 2E is a perspective view of a multiwell plate assembly with each well having a structure similar to a tube in Figure 2;

[27] Figure 2F is an expanded view of section A in Figure 2E;

[28] Figure 3 is a cross-sectional view of another embodiment of a sample tube strip;

[29] Figure 3 A is an expanded view of section A in Figure 3;

[30] Figure 3B is a cross-sectional side view of the sample tube strip in Figure 3 except in a sealed position;

[31] Figure 3C is an expanded view of section B in Figure 3B; [32] Figure 3D is a prospective view of a multi-tube plate assembly with each tube having a structure similar to a tube in Figure 3;

[33] Figure 3E is an expanded view of section A in Figure 3D;

[34] Figure 4 is a perspective view of another embodiment of a multiwell plate;

[35] Figure 4A is an expanded view of section A in Figure 4;

[36] Figure 4B is a cross-sectional side view of the multiwell plate in Figure 4 except that a sealing lid is also shown;

[37] Figure 4C is an expanded view of section A in Figure 4B;

[38] Figure 4D is a cross-sectional side view of the multiwell plate in Figure 4 except in a sealed position;

[39] Figure 4E is an expanded view of section B in Figure 4D; and

[40] Figure 5 is a cross-sectional side view of an embodiment of a sample tube assembly.

Detailed Description of the Invention

[41] Accordingly, the present invention provides a sample tube assembly with improved seal.

[42] Referring to Figure 1, an illustrative embodiment of the present invention is shown. Sample tube assembly 100 includes a hollow vessel body 102 for containing either solid or liquid reagents. Vessel body 102 has a closed bottom and at its top an opening 104, which is defined by a substantially cylindrical upper wall section 106. Sample tube assembly 100 also includes a sealing cap 108, which may be separate and detached from vessel body 102, or optionally may be connected to the vessel body 102 through a tether that is preferably flexible.

[43] Sealing cap 108 includes a cylindrical skirt 110 and an inner lip 112 that is substantially concentric with the cylindrical skirt 110. Sealing cap 108 also includes top cover 122 closing one end of cylindrical skirt 110 and inner lip 112. An expanded view of the upper wall section 106 is illustrated in Figure 1A. It has a proximal section 114 and a distal section 116. Proximal section 114 defines opening 104 of hollow vessel body 102, and is a monolayer structure. Distal section 116, on the other hand, is a bilayer structure including a supporting layer 118 and a sealing layer 120. Supporting layer 118 has a greater hardness, as measured according to ASTM test D 2240, than that of proximal section 114 and that of sealing layer 120. [44] Thus, when sealing cap 108 seals vessel body 102 as shown in Figure IB and

Figure 1C, inner lip 112 of sealing cap 108 removably engages upper wall section 106.

Specifically, as shown in Figure 1C, both inner lip 112 and the inner surface of top cover 122 engage, and are in sealing contact with, proximal section 114 of the upper wall section 106. The softer proximal section 114 helps to improve the sealing effect when it is engaged with inner lip 112 and the inner surface of top cover 122. Preferably, proximal section 114 and the sealing layer 120 are integrally formed in the same molding process, and permanently joined to supporting layer 118. More preferably, proximal section 114, sealing layer 120 and supporting layer 118 are interlocked together as shown in Figure 1C.

[45] In another aspect, the present invention provides a sample tube strip having a plurality of hollow vessel bodies arranged symmetrically in a linear array whereby their axes are in parallel. Figure 2 shows a cross-sectional view of an embodiment of a sample tube strip. Specifically, sample tube strip 200 includes a plurality of (e.g., 8 or 12) hollow vessel bodies 202 with adjacent hollow vessel bodies optionally connected with linker 204. As in the sample tube described in Figures 1, each hollow vessel body 202 includes a closed bottom 206 and an upper wall section 208. Optionally, a sealing lid 210 is included forming a sample tube strip assembly 212. Sealing lid 210 has a plurality of sealing skirt 214 and a top cover 216 closing one end of the plurality of sealing skirt 214.

[46] Figure 2A is an expanded view of the upper wall section 208 in Figure 2. As shown in Figure 2A, upper wall section 208 defines at its edge the opening 218. Upper wall section 208 includes a proximal section 220 and a distal section 222, which has a bilayer structure with a supporting layer 224 permanently joined to sealing layer 226. Optionally, proximal section 220 and sealing layer 226 are molded integrally as one piece. Supporting layer 224 has a greater hardness, as measured according to ASTM test D 2240, than that of proximal section 220 and that of sealing layer 226.

[47] Figure 2B is an expanded view of a portion of sealing lid 210 showing a sealing skirt 214 and a portion of top cover 216 closing one end of sealing skirt 214.

[48] Figure 2C shows the sample tube strip assembly 212 in a closed position with each sealing skirt inserted into a hollow vessel body. Figure 2D is an expanded view of section A in Figure 2C and illustrates the tight seal of one tube. Specifically, in the sealed position, sealing skirt 214 is removably inserted into a vessel body through opening 218, and both top cover 216 and sealing skirt 214 engage and are in sealing contact with the proximal section 220. Preferably sealing skirt 214 also engages and is in sealing contact with sealing layer 226. The softer proximal section 220 and sealing layer 226 impart greater sealing effect.

[49] Figure 2E illustrates a multitube assembly or rather a multiwell plate including a plurality of (e.g., 36-, 48-, 96-, 192-, 384-well PCR plate) tubes or wells, with each well or tube having a hollow vessel body having an upper wall section as provided above in the context of the sample tube or sample tube strip. This point should be amply clear from the expanded view of section A in Figure 2E that is shown in Figure 2F. Optionally, a sealing lid is also provided having a plurality of sealing skirts and a top cover as described above in the context of the sample tube strip, except that the plurality of sealing skirts are arranged such that each can removably engage a tube or well when the sealing lid closes the multi-tube assembly or multiwell plate.

[50] Figure 3 is a cross-sectional view of another embodiment of the present invention.

A sample tube strip is shown having a plurality of hollow vessel bodies arranged symmetrically in a linear array whereby their axes are in parallel. Sample tube strip 300 includes a plurality of (e.g., 8 or 12) hollow vessel bodies 302 with adjacent hollow vessel bodies optionally connected with linker 304. As in the sample tube described in Figures 1, each hollow vessel body 302 includes a closed bottom 306 and an upper wall section 308. Optionally, a sealing lid 310 is included forming a sample tube strip assembly 312. Sealing lid 310 has a plurality of sealing skirt 316 and a top cover 314 closing one end of the plurality of sealing skirt 316.

[51] An expanded view of the upper wall section 308 in Figure 3 is shown in Figure 3A. As shown in Figure 3A, upper wall section 308 defines at its edge the opening 318. Upper wall section 308 includes a proximal section 320 and a distal section 322, which has a bilayer structure with a supporting layer 324 permanently joined to sealing layer 326. In contrast to that shown Figure 2A, the sealing layer 326 is on the outer surface and the supporting layer 324 is on the inner surface. Supporting layer 324 has a greater hardness, as measured according to ASTM test D 2240, than that of proximal section 320 and that of sealing layer 326. Optionally, proximal section 320 and sealing layer 326 are molded integrally as one piece.

[52] Figure 3B shows the sample tube strip assembly 312 in a closed position with the opening of each hollow vessel body closed off by the top cover of the sealing lid. Figure 3C is an expanded view of section B in Figure 3B and illustrates the tight seal of one tube or well. Specifically, in a sealed position, part of upper wall section 308 is removably inserted into sealing skirt 316 such that both sealing skirt 316 and top cover 214 engage and are in sealing contact with the proximal section 320. Preferably sealing skirt 316 also engages and is in sealing contact with sealing layer 326. The softer proximal section 320 and sealing layer 326 impart greater sealing effect.

[53] Figure 3D illustrates a multitube assembly or rather a multiwell plate including a plurality of (e.g., 36-, 48-, 96-, 192-, 384-well PCR plate) tubes or wells, with each well or tube having a hollow vessel body having an upper wall section as provided above in the context of Figures 3-3C. This point should be clear from the expanded view of section A in Figure 3D that is shown in Figure 3E. Optionally, a sealing lid is also provided having a plurality of sealing skirts and a top cover as described above in the context of Figures 3-3C, except that the plurality of sealing skirts are arranged such that each can removably engage a tube or well when the sealing lid closes the multi-tube assembly or multiwell plate.

[54] Figure 4 illustrates another embodiment of the multiwell plate of the present invention. As shown in Figure 4, multiwell plate 400 comprises four walls 402 forming a support skirt 404 having a top deck 406 and a bottom 408. Integral with top deck 406 are the upper rim and opening of an array of symmetrically arranged tubes or wells (410) with parallel axes. Figure 4A is an expanded view of the section C in Figure 4. Figure 4B shows a cross- sectional side view of the multiwell plate shown Figure 4. Specifically, as shown in Figure 4C, multiwell plate 400 has a wall 412 as part of support skirt 404 (shown in Figure 4), which has a top deck 406. Integral with the skirt and top deck are a plurality of wells 410. Each well comprises a closed bottom 414, and a side wall 416 extending upward therefrom having an upper wall section 418 defining an opening 420 of the well. Additionally shown is a sealing lid 422 which has an array of sealing skirt 424 and a top cover 426 closing one of each of the array of sealing skirts 424. Sealing lid 422 is adapted to cover and seal the multiwell plate 400 and the two together form a multiwell plate assembly 428. Details of the upper wall section 418 are illustrated in Figure 4D which is an expanded view of Section A in Figure 4C. Referring to Figure 4D, upper wall section 418 includes a proximal section 430 at the very edge of the upper wall section defining opening 420 of the well. Upper wall section 418 also has a distal section 432, which is a trilayer structure having two sealing layers 434 sandwiching a supporting layer 436. Supporting layer 436 has a greater hardness, as measured according to ASTM test D 2240, than that of proximal section 430 and that of sealing layer 434. Optionally, proximal section 430 and both sealing layers 434 are molded integrally as one piece and preferably permanently joined to supporting layer 436. Preferably, proximal section 430 and both sealing layers 434 are retentively molded onto supporting layer 436.

[55] Figure 4D shows multiwell plate assembly 428 shown in Figure 4B in a closed position with the opening of each well closed off by the top cover of the sealing lid 422. Figure 4E is an expanded view of section B in Figure 4D and illustrates the tight seal of one well.

Specifically, in a sealed position, sealing skirt 424 is removably inserted into a well such that both sealing skirt 424 and top cover 426 engage and are in sealing contact with the proximal section 430. Preferably sealing skirt 424 also engages and is in sealing contact with sealing layer 434. The softer proximal section 430 and sealing layer 434 impart greater sealing effect.

[56] Figure 5 shows a sample tube assembly according to yet another aspect of the invention. Specifically, Figure 5 is a cross-sectional side view of a sample tube assembly 500. Sample tube assembly 500 includes a hollow vessel body 502 for containing either solid or liquid reagents. Vessel body 502 has a closed bottom and at its top an opening 504, which is defined by a substantially cylindrical upper wall section 506 having a supporting layer. Sample tube assembly 500 also includes a sealing cap 510, which may be separate and detached from vessel body 502, or optionally may be connected to the vessel body 502 through a tether that is preferably flexible.

[57] Sealing cap 510 includes a cylindrical sealing member 512. At the upper rim of cylindrical sealing member 512 is a transverse wall or top cover 518. The sealing member is a monolayer having a smaller hardness compared to the top cover, as measured according to ASTM test D 2240. As such, sealing cap 510 snug fits upper wall section 506 such that the softer sealing member 512 is in sealing contact with the inner peripheral surface of upper wall section 506 to provide a tight seal, and preferably fluid-tight seal, as shown in Figure 5.

[58] In preferred embodiments, cylindrical sealing member 512 has an outwardly protruding (preferably circumferential) sealing lip 520 at the lower edge of cylindrical skirt 112 opposite the top cover 518. Sealing lip 122 is essentially a peripheral, annular ridge of a certain outwardly axial extension at the lower edge of sealing member 512. Also in preferred embodiments, the edge portion of the upper wall section 506 defining the opening 504 has an upwardly flaring, conical inside surface 534 to facilitate the insertion of the sealing cap into the vessel body. Preferably, as shown in Figure 5, the upper rim of cylindrical sealing member 512 is embedded in the transverse wall or top cover 518. More preferably, as shown in Figure 5, sealing member 512 has a flange 514 (preferably circumferential) extending outwardly and joined to top cover 518, and preferably embedded within top cover 518.

[59] In any one of the sample tube assemblies illustrated above, the two contacting surfaces (i.e., one on the sealing cap and the other on the upper wall section of the vessel body) may be smooth. Alternatively, however, the two surfaces for sealing contact may be corrugated, having grooves and ridges, and sealing is accomplished by screwing the sealing cap onto the hollow vessel body.

[60] In various embodiments of the sample tube assembly, strip and multiwell plate, the vessel body generally has a lower wall section joining the substantially cylindrical upper wall section described above. In some embodiments, the lower wall section may be a thin-walled tapered or conical section with an angle of about 10 to about 20 degrees to form a closed dome- shaped bottom of the vessel body. In preferred embodiments, the sample tube assembly is particularly suited for thermocyling reactions such as PCR, and the walls of the vessel body may have a thickness of from about 0.008 to about 0.015 inches. The lower wall section may be thinner and may have a thickness of from about 0.008 to about 0.012 inches, while the upper wall section may be thicker with a thickness of from about 0.010 to about 0.015 inches. The supporting layer may have a thickness of from about 0.008 to about 0.06 inches.

[61] In preferred embodiments, the sample tube may have a volume sufficient to contain from about 50 μΐ to less than about 1 ml of liquid, preferably less than about 0.5 ml of liquid.

[62] Generally speaking, in the various aspects of the present invention, the supporting layer has a greater hardness (as measured according to ASTM test D 2240) than the proximal section, the sealing layer and the sealing member. In preferred embodiments, the supporting layer has a hardness (ASTM test D 2240) of at least 5, preferably at least 10 Shore A greater than the sealing layer, the proximal section and the sealing member of the sealing cap. Preferably, the supporting layer have a different polymeric composition than that of the sealing layer, the proximal section and the sealing member.

[63] The sealing layer, the proximal section and the sealing member of the sealing cap may have a compression set of less than about 30%, preferably less than 20%, more preferably less than 10%, and most preferably less than 5%, as measured according to AST D395 Method B. They may have a hardness of from about 30 to about 90 Shore A, preferably about 35 to about 80 Shore A, about 40 to about 75 or 80 Shore A, about 40 to about 70 Shore A, more preferably about 40 to about 50 or 60 Shore A, as measured by ASTM test D 2240. Examples of polymer materials useful for forming the sealing layer, the proximal section and the sealing member of the sealing cap include, but are not limited to, polyethylene (PE) (especially low density polyethylene or LDPE), polyurethane (PU), thermoplastic polyurethanes (TPU), thermoplastic elastomers (TPE), thermoplastic polyolefin (TPO), styrenic thermoplastic elastomers (S-TPEs), thermoplastic rubber (TPR), poly[styrene-b-(ethylene-co-butylene)-b- styrene] (SEBS), thermoplastic vulcanizates (TPV), styrene-butadiene-styrene (SBS), flexible PVC (elPVC), etc. In preferred embodiments, the sealing layer is made of one or more of TPE, TPU and PVC, preferably TPE or TPU or both.

[64] The parts of the sample tube assembly, sample tube strip and multiwell plate other than the sealing layer, the proximal section and the sealing member of the sealing cap are generally intended to be supportive and to maintain the shape and rigidity. In some

embodiments, the supporting layer may have a hardness of greater than about 20 Shore D or greater than about 30 Shore D, as measured by ASTM test D 2240. In some embodiments, the supporting layer has a hardness of from about 30 to about 90 Shore D, as measured by ASTM test D 2240. In some embodiments, the supporting layer has a compression set of at least about 20%, or at least 30%. Examples of polymer materials for forming the supporting layer include, but are not limited to, polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and polystyrene (PS).

[65] Preferably, the polymer material for the sealing layer, the proximal section and the sealing member of the sealing cap and the polymer material for the supporting layer are chosen such that the two polymer materials may interact with each other under the molding or bonding conditions such that the sealing layer, the proximal section and the sealing member of the sealing cap can be retentively attached onto the supporting layer or the transverse wall of the sealing cap. In preferred embodiments, the sealing layer, the proximal section and the sealing member of the sealing cap are made of one or more polymer materials selected from the group of TPE, TPV and PVC, and the supporting layer is made of one or more polymers chosen from the group of polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and polystyrene (PS).

[66] In preferred embodiments, the sample tube has a total volume of from about

0.1ml to about 2.0 ml. In preferred embodiments, all materials used for the sample tube assembly are heat stable and can withstand heat at a temperature of up to 100°C.

[67] Preferably, the sealing layer is coextensive with and covers the entire surface of the upper wall section of the vessel body. Alternatively, the sealing layer may be in a form of an annular convexity covering a portion of the supporting layer but around the entire circumference of the portion. In some embodiments, there may be two or more coaxial annular rings (e.g., an O-ring) spaced axially apart which are preferably retentively molded onto the supporting layer.

[68] The various embodiments of the sample tube assemblies can be adapted into sample tube strips or multiwell plates, e.g., in industry standard formats, i.e. 36-, 48-, 96-, 192-, 384-well PCR plates. Essentially, in a sample tube strip, a plurality (e.g., 4, 8 or 12) of hollow vessel bodies in one of the embodiments described above may be arranged symmetrically in a linear array whereby their axes are in parallel. The adjacent two of these vessel bodies may optionally be connected through a strip. Similarly, in a multiwell microtiter plate, a plurality (e.g., 36, 48, 96, 192 or 384) of hollow vessel bodies of the same design as in one of the embodiments described above may be arranged in a multiwell plate format, according to standard formats in the industry. The designs and manufacturing methods of microtiter plates are well known in the art, and may be found in e.g., US Patent Nos. 5,710,381 and 5,475,610, both of which are incorporated herein by reference. For example, a 96-well microtiter plate is a tray with a width of 3 5/8 inches and a length of 5 inches and containing 96 identical sample wells in an 8 well by 12 well rectangular array. Thus, each well of the microtiter plate of the present invention has the same design as the vessel body in one of the above embodiments of the sample tube assembly. Additionally the plate also includes a plurality (e.g., 4, 8, 12, 96) of the corresponding sealing caps in that same embodiment arranged in an array, and any two adjacent members of the plurality of caps being connected by a tether or sheet. The caps are arranged such that their axes are in parallel. Each of the plurality of sealing caps removably engages the upper wall section of a vessel body. [69] In preferred embodiments, the supporting layer and the sealing layer and/or proximal section should be permanently joined together. In preferred embodiments, the monolayer sealing member shown in Figure 5 and the transverse wall of the sealing cap are permanently joined together. This means that they are not easily separable, and cannot be easily removable from each other. The sample tube assembly, sample tube strip and multiwell plate of the present invention may be made by conventional processes, e.g., plastic-injection molding or spray-on process. In preferred embodiments, the proximal section and/or sealing layer may be directly and retentive ly molded onto the supporting layer such that the proximal section and/or sealing layer can be retained securely on top of the supporting layer. Alternatively, the proximal section and/or sealing layer may be adhered to the supporting layer through a bonding material. The proximal section (and/or sealing layer) and the supporting layer may be molded together by a dual component plastic injection molding process. Alternatively, the sample tube assembly is made by a two-step molding: the parts of the sample tube assembly other than the proximal section and/or sealing layer are first molded, by e.g., plastic injection molding, and then the proximal section and/or sealing layer are directly and retentively molded onto the supporting layer.

[70] All publications and patent applications mentioned in the specification are indicative of the level of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. The mere mentioning of the publications and patent applications does not necessarily constitute an admission that they are prior art to the instant application.

[71 ] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A plastic sample tube assembly comprising:

a sealing cap; and

a hollow vessel body having an upper wall section which comprises a proximal section defining the opening of the hollow vessel body and a distal section, wherein said distal section comprises a supporting layer having a greater hardness, as measured according to ASTM test D 2240, than said proximal section, and wherein when said sealing cap engages said hollow vessel body for closing said opening, said sealing cap removably engages, and is in sealing contact with, said proximal section.

2. The sample tube of Claim 1, further comprising a flexible strap having opposite ends that are respectively connected with said vessel body and said cap.

3. A sample tube strip, comprising

a plurality of hollow vessel bodies arranged symmetrically in a linear array whereby their axes are in parallel, each having an upper wall section which comprises a proximal section defining the opening of the hollow vessel body and a distal section, wherein said distal section comprises a supporting layer having a greater hardness, as measured according to ASTM test D 2240, than said proximal section; and

a linear array of a plurality of sealing caps each in sealing contact with the proximal section of the upper wall section of one of said plurality of hollow vessel bodies.

4. A multiwell plate assembly comprising:

a plate body having therein a plurality of wells each having an opening, a closed bottom, and a side wall extending therebetween, wherein at least one of said plurality of wells has an upper wall section which comprises a proximal section defining, at its edge portion, the opening of the well, and a distal section, wherein said distal section comprises a supporting layer having a greater hardness, as measured according to ASTM test D 2240, than said proximal section.

5. The multiwell plate of Claim 4, further comprising a plurality of sealing caps each removably engages, and is in sealing contact with, said proximal section for closing said opening.

6. The plastic sample tube assembly of Claim 1 or 2, the sample tube strip of Claim 3, or the multiwell plate assembly of Claim 4 or 5, wherein said proximal section is a monolayer and said distal section comprises at least a sealing layer permanently joined to said supporting layer, wherein said supporting layer has a greater hardness, as measured according to ASTM test D 2240, than the sealing layer.

7. The plastic sample tube assembly or the sample tube strip or the multiwell plate assembly of Claim 6, wherein said sealing layer is on an outer peripheral surface of said distal section.

8. The plastic sample tube assembly or the sample tube strip or the multiwell plate assembly of Claim 6, wherein said sealing layer is on an inner peripheral surface of said distal section.

9. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the supporting layer has a hardness (ASTM test D 2240) of at least 10 Shore A greater than that of the proximal section or the sealing layer.

10. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the supporting layer has a polymeric composition that is different from that of the sealing layer or the proximal section.

12. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the proximal section or the sealing layer has a compression set of less than about 10%, as measured according to ASTM D395 Method B.

13. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the sealing layer and proximal section have a hardness of from about 30 to about 90 Shore A, and the supporting layer has a hardness of greater than about 30 Shore D, as measured by ASTM test D 2240.

14. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the proximal section and the sealing layer are independently made of TPE, TPU or both, and wherein the supporting layer is made of one or more chosen from the group of

polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and polystyrene (PS).

15. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the supporting layer has a compression set of at least about 20%, or at least 30%.

16. The sample tube assembly any one of Claims 1, 2, and 6-8, or the sample tube strip of any one of Claims 3, and 6-8, or the multiwell plate assembly of any one of Claims 4-8, wherein the proximal section and the sealing layer is retentively molded onto the supporting layer.

17. A plastic sample tube comprising:

a substantially cylindrically shaped plastic hollow vessel body having a plastic upper wall section defining at its edge portion the opening of the hollow vessel body; and

a plastic sealing cap having a substantially cylindrically shaped sealing member adapted to removably fit the opening of the hollow vessel body and a top cover closing one end of said sealing member, wherein said sealing member has a smaller hardness compared to said top cover, as measured according to ASTM test D 2240, and wherein when said sealing cap engages said hollow vessel body for closing said opening, said cylindrically shaped member is in sealing contact with a peripheral surface of said upper wall section.

18. The plastic sample tube of Claim 17, wherein the sealing member is made of a resilient material and has a compression set of less than about 10%, as measured according to

ASTM D395 Method B.

19. The sample tube of Claim 17, wherein the sealing member has a sealing lip around said sealing member.