Abstract:
A sample preparation device for reducing a concentration of one or more concomitant components of a sample and/or increasing a concentration of one or more desired sample components is described.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. provisional application No. 60/551,787, filed Mar. 11, 2004, which application is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a sample preparation device as well as to related methods.  
       BACKGROUND  
       [0003]     One of the common difficulties in performing bio-assays is preparing a sample for testing. Raw samples can be obtained from a bodily fluid, bodily waste, or from a swab that is subsequently placed in a buffer solution to release collected cells, DNA, and varying amounts of extraneous matter collected during the swabbing. Current sample preparation techniques can be expensive, labor intensive, time consuming, and can rely heavily on human participation.  
         [0004]     Preparation of raw samples for testing typically includes clean up steps, such as forcing the sample through various sizes and types of filters to trap, isolate, screen, or sort out particles that range down to micron and sub-micron sizes. During preparation, samples can be contaminated or otherwise rendered unusable due to handling or simple human error. Proper sample concentration and clean-up reduces clogging especially when used with micro-scale structures.  
         [0005]     The recent arrival of point of care devices for use in clinics and doctors&#39; offices has increased the need for a simple, yet robust preparation device that a non-technician can use to perform the critical step of sample preparation at the ‘point of care.’ This creates an intense need for a device to simplify sample preparation and concentration while maintaining the integrity of the sample.  
         [0006]     Current sample preparation and concentration methods usually involve a syringe and a single size filter for each clean up step. Such filters utilize a single direction of fluid flow, and are typically operated using the injection stroke of a syringe to filter out large particles. The sample is filtered through different, successively smaller filters such as by fitting the filters to a different syringe. Each time the filter is changed, technician time increases and the possibility of sample contamination also increases.  
       SUMMARY  
       [0007]     The present invention relates to a sample preparation device as well as to related systems and methods. In general, the result of the sample preparation is to provide a processed sample having a reduced amount of concomitant components relative to an unprocessed sample and/or a processed sample that is enriched in one or more desired sample components relative to an unprocessed sample.  
         [0008]     In some embodiments, the invention relates to a device that includes distinct passages having different (e.g., separate) intake/outflow openings and valves. Sample can pass in only one direction along each passage.  
         [0009]     In some embodiments, the device is configured to process a sample using both the intake and output motions of a syringe. For example, the intake motion can draw a sample through a first passage of the device and the output motion of the syringe can expel the sample through a second, different passage of the device. This can be performed, for example, without detaching the device from the syringe.  
         [0010]     In some embodiments, one or more of the passages can filter the sample and/or one or more of the passages can enrich the sample.  
         [0011]     In some embodiments, the device includes an integral pressure device such as a syringe as opposed to being designed for use with a stand-alone pressure device.  
         [0012]     The device can include fittings that are compatible with standard syringes, and can be disposed of with standard biomedical waste. The device allows safe injection of samples into micro-fluidic devices without overwhelming such microfluidic devices with excessive pressure.  
         [0013]     In some embodiments, a sample processing device includes a body defining a first passage configured to allow passage of fluid in only a first direction with respect to the body and a second passage configured to allow passage of fluid in only a second, different direction with respect to the body. A fluid retention member is disposed along at least one of the first and second passages. The fluid retention member is configured to retain fluid that passes along the first and second passage so that the amount of fluid that exits the passage is less than the amount of fluid that entered the passage. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  shows an embodiment of a sample preparation device. 
     
    
     DETAILED DESCRIPTION  
       [0015]     Referring to  FIG. 1 , a sample preparation device  10  is configured to process a sample including (a) at least one desired sample component, e.g., one or more polynucleotides or other biological material, one or more cells, viruses, or other microorganisms and, typically, (b) one or more concomitant components, e.g., one or more polynucleotides or other biological material, cells, viruses, or other microorganisms, tissue, particulates and the like. The desired and concomitant components of the sample can be entrained in a fluid (e.g., a liquid). Typical samples include blood and samples generated from tissue swabs and other tissue samples such as by combining a tissue or cell sample with buffer. Device  10  processes such samples to provide a processed sample including: (a) a reduced amount (e.g., none) of concomitant components (if present in the original sample) relative to the amount of a desired sample component(s), (b) a processed sample enriched in the desired sample component(s) relative to an amount of fluid entraining the desired sample component, or (c) a processed sample having both of these properties.  
         [0016]     Device  10  includes a body  12  defining a first end  13 , a second end  15 , a first passage  14  and a second passage  16 . Body  12  is shown as bulb shaped but may have other configurations (e.g., cylindrical, rectangular, or onion shaped). First passage  14  has a first opening  18  and a second opening  20 . Second passage  16  has a first opening  22  and a second opening  24 . In general, first passage  14  provides a passage for the intake of a sample by device  10 , whereas the second passage  16  provides a passage for the output of a processed sample by device  10 . A wall  18  isolates first and second passages  14 ,  16  from one another such that desired sample components and, generally, other material cannot pass between the passages except via openings thereof.  
         [0017]     First and second ends  13 ,  15  of device  10  include a fitting  53  (e.g., a Luer loc fitting) so that device  10  can be coupled to other devices (e.g., to a syringe, a source of sample, or to another processing device).  
         [0018]     Second opening  20  of first passage  14  includes a valve  36  configured to allow fluid and particles to exit first passage  14  via second opening  20  and to limit or prevent entry of fluid and particles to first passage  14  via second opening  20 . Second opening  24  of second passage  16  includes a valve  38  configured to allow fluid to exit second passage  16  via second opening  24  and to limit or prevent entry of fluid and particles to second passage  16  by second opening  24 . Valves  36  and  38  are generally one-way valves.  
         [0019]     In use, a vacuum source (e.g., a syringe  50 ) is mated with second opening  20  of first passage  14  and first opening  22  of second passage  16 . The first end  18  of first passage  14  and the second opening  24  of the second passage  24  are contacted with a sample (e.g., a sample to be processed). A plunger  55  of syringe  50  is withdrawn to apply a reduced pressure to second opening  20  of first passage  14  and to first opening  22  of second passage  16 . Valve  38  at second opening  24  of second passage  16  closes to prevent sample from entering the second passage. Sample is drawn into first passage  14  through first opening  18 , drawn along first passage  14 , and then withdrawn from first passage  14  through second opening  20  and valve  36 . The exiting sample typically enters a reservoir of the vacuum source (e.g., a barrel  52  of syringe  50 ).  
         [0020]     The plunger of syringe  50  is then depressed to apply pressure to sample within barrel  52 . Valve  36  closes to prevent material from reentering first passage  14 . Sample is pushed into second passage  16  through first opening  22 , pushed along second passage  16 , and pushed from second opening  24  through valve  38  to exit device  10 . Second passage  16  can have smaller dimensions (e.g., a smaller radial cross section) than first passage  14 . The smaller cross section can reduce the force required to move material through the second passage.  
         [0021]     Sample is typically subjected to at least one processing step (e.g., enrichment of desired sample components and/or concomitant component reduction or removal as by filtration) while traveling through each of the first and second passages.  
         [0022]     In embodiments configured to at least reduce the relative amount of concomitant sample components, device  10  can include at least one and optionally a plurality of retention elements  26  configured to retain concomitant components of the sample while allowing passage of desired sample components. For example, retention elements, e.g., filters  28 ,  30 ,  32 , and  34 , can retain particles having a size greater than the size of the desired sample component(s). Filters  28 ,  30 ,  32 , and  34  may be, for example, a torturous path filter or a screen or mesh type filter. The type of filter in each device depends upon the components of the sample and the filtration requirements. Filters  28 ,  30 ,  32 , and  34  generally retain particles of decreasing size. First sample passage  14  can have greater dimensions, e.g., a greater radial cross section, than second passage  16  to allow filters disposed along first passage  14  to have a greater surface area than if the passages had the same size cross sections.  
         [0023]     It should be noted that filters  28 ,  30 ,  32 , and  34  may also (or alternatively) be configured as adsorptive filters configured to adsorb and/or bind one of the desired sample component(s) and concomitant sample components to a greater extent than the other. Filters  28 ,  30 ,  32 , and  34  can be formed of any material compatible with samples to be processed.  
         [0024]     In embodiments configured to provide a processed sample enriched in the desired sample component(s) relative to the amount of fluid, device  10  can include a fluid retention member  40  configured to retain fluid of the sample to a greater extent than the one or more desired sample components. For example, retention member  40  can comprise a porous network capable of retaining a given amount of fluid. The porous network can be hydrophilic. The porous network can comprise a ceramic medium, such as moderately or hard fired alumina, or a porous glass medium. Other suitable materials include polymers, e.g., polytetrafluoroethylene or polyethylene, configured as porous networks.  
         [0025]     The void volume of the porous medium can be at least 15%, at least 25%, or at least 30% of the porous network. Retention member  40  is generally configured to minimize retention of the desired sample component. For example, the pore size can be selected to be smaller than the size of the desired sample component. Retention member  40  can include a layer, e.g., a coating, configured to minimize association, e.g., adsorption, by the retention member  40  of the desired sample component.  
         [0026]     As an alternative to or in combination with a porous network, retention member  40  can comprise an absorptive medium configured to retain water by absorption such as through solvation. Preferred absorptive media comprise a plurality of chemical constituents, e.g., hydroxyl groups, organic acid groups, hydrogen bonding groups, ionic groups, and the like, with which water can associate. Exemplary polymers include acrylates, e.g., sodium polyacrylate, cellulose, e.g., carboxymethylcellulose and hydroxyethylcellulose, and acrylamide polymers. The absorptive medium can comprise a substantial amount of cross linked material.  
         [0027]     In some embodiments, device  10  is configured to receive a sample having a liquid volume of at least about 500 microliters (e.g., at least about 1000 microliters, at least about 2000 microliters, at least about 5000 microliters) into opening  18  of first passage  14 . In some embodiments, device  10  is configured to receive a sample having a liquid volume of no more than about 750 microliters (e.g., no more than about 1500 microliters, no more than about 2500 microliters, no more than about 10000 microliters) into opening  18  of first passage  14 .  
         [0028]     In some embodiments, device  10  is configured to provide (e.g., from second opening  24  of second passage  16 ) a processed sample having a liquid volume of no more than about 90% (e.g., no more than about 80%, no more than about 65%, no more than about 50%, no more than about 25%) of the liquid volume of the sample introduced into opening  18  of first passage  14 . At least some (e.g., most or essentially all) of the remaining liquid is retained by one or more retention members of device  10 . Because the one or more retention members retain liquid preferentially to the desired sample material, the processed sample can be enriched in the desired sample material by at least about 10% (e.g., at least about 20%, at least about 35%, at least about 50%, at least about 75%, or more) as compared to the sample introduced to first opening  18  of first passage  14 .  
         [0029]     Device  10  can be formed of material including but not limited to metal, polymer, e.g., plastic, polytetrafluoroethylene, nylon, or any other polymer, co-polymer or synthetic type material that is sufficiently inert with respect to desired sample materials. Components of device  10 , e.g., valves and filters as discussed below, can be secured using, e.g., laser or ultrasonic welding, adhesives including epoxies, solder, heat staking, press fitting, and the like.  
         [0030]     Other embodiments are within the claims.