Abstract:
An apparatus configured to enable the concentration of paramagnetic and/or superparamagnetic materials in a fluid for the purpose of examining such materials. The apparatus includes a magnet container arranged to be located proximate to a material container containing the materials to be examined. The magnet container includes therein a fluid and one or more magnets. The magnet container further includes means for controlling the movement of the one or more magnets in the fluid to allow the attraction of the paramagnetic and/or superparamagnetic materials in the material container to the one or more magnets as they travel in the magnet container so as to concentrate those materials. Several options for controlling the movement of the one or more magnets are described, including fluid viscosity selection, magnet shape and size selection, the use of an inclined pathway and the use of an inclined plane.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparatuses and methods for detecting hemozoin in a fluid. More particularly, the present invention relates to the detection of hemozoin in a fluid using a magnetic attraction element. 
     2. Description of the Prior Art 
     Current methods for detecting malaria in blood specimens are time consuming and costly, or lack clinical or analytical sensitivity and may not be environmentally friendly. A significant impediment to effective testing is the inability to obtain sufficient quantity of biomarker material early enough in the development of the disease to carry out effective treatment as soon as would be preferable. It is desirable to have an apparatus and related detection method that can be used to concentrate biomarker material effectively and in a timely manner. While the cost and timeliness of malaria testing is of significance, the present invention is not limited solely to the detection of that disease. Instead, the present invention is directed to the concentration of magnetic and paramagnetic biomarkers suitable for use in the detection of any condition of interest that requires the evaluation of magnetic and/or paramagnetic biomarkers. 
     As an aspect of the desired functionality of the present invention, it is noted that hemozoin is an attractive biomarker for malaria determination. Hemozoin is a paramagnetic material. As a result, it is attracted to a magnetic field. The present invention takes advantage of this characteristic to address the limitation of a lack of sufficient biomarker material to use in current malaria testing methods inexpensively and/or timely manner. 
     SUMMARY OF THE INVENTION 
     The present invention is an apparatus and related method that can be used to concentrate paramagnetic and/or superparamagnetic particles for the purpose of analyzing the collected particles as biomarkers. The apparatus includes one or more magnets that are positioned proximate to a container including a material to be evaluated. The material container may be a vial or a tube, for example. The material container includes a fluid to be analyzed, such as a blood specimen, for example, that includes paramagnetic and/or superparamagnetic material. The one or more magnets are positioned in relation to the material so as to enable the attraction thereto of the paramagnetic and/or superparamagnetic materials in the fluid. Such materials gather in the vicinity of the magnets and are thereby concentrated in the material container. A material of interest may be analyzed once the concentration thereof has reached a detectable level, which detectable level is a function of the material to be analyzed. 
     As noted, the apparatus of the present invention enables the concentration of magnetically susceptible particles contained in fluid in the material container. The one or more magnets are positioned with respect to the material container such that as the magnet moves, whether inside or outside of the container, any paramagnetic and/or superparamagnetic material contained in the fluid is attracted to the one or more magnets and thereby moves with the one or more magnets. The ability to concentrate desirable levels of material in the container for analysis purposes is dependent upon magnet strength, the size and magnetic attraction characteristics of the material under evaluation, the viscosity of the fluid containing the material, the proximity of the magnet to the material and the rate of movement of the magnet with respect to the fluid in the container. The apparatus of the present invention is established in multiple embodiments, each of which is configured to manage the movement of the magnet with respect to the fluid. 
     The present invention may be used to concentrate biomarker materials of interest that are themselves paramagnetic and/or superparamagnetic. In other words, the invention may be used directly with such materials. In addition, if there is an interest in concentrating materials without magnetic characteristics, the present invention may still be used to accomplish that goal. Specifically, the fluid containing a sample that includes a non-magnetic analyte of interest may be placed in the material container. Paramagnetic particles containing ligand-binding molecules are also inserted into the material container. The ligand-binding materials are selected for their ability to bind to the non-magnetic analyte of interest. As a result of that combination, a complex of paramagnetic material, binder and non-magnetic analyte of interest is formed. The material container including that complex is positioned adjacent to the magnet container as described herein and the one or more magnets are caused to be moved in a regulated manner so as to attract and concentrate the composition at an end of the material container. The material container alone or the combination of the material container and the magnet container can then be inverted, if needed, to position the complex near an opening of the material container for removal and insertion into an assay device. Alternatively, the complex may be evaluated without removing it from the material container. 
     The movement of the magnet may be regulated in two primary ways in the present invention. First, the one or more magnets may be placed in a separate magnet container, which magnet container is placed adjacent to the material container. The magnet container includes a fluid of selectable viscosity. The magnetic container is positioned so that the one or more magnets are allowed to descend by gravitational force from an upper section of the container to a lower section of the container. The viscosity of the fluid in the magnet container and the size and shape of the one or more magnets within that fluid dictate the rate of descent. As the one or more magnets descend, particles with magnetic characteristics in the material container that is adjacent to the magnet container move toward the inner perimeter of the material container and also descend at a rate substantially matching the descent of the one or more magnets in view of the magnetic attraction. The magnetically-susceptible particles are concentrated at the bottom of the material container when the one or more magnets reach the bottom of the magnet container, provided the magnets and the fluid containing the magnets are selected to establish a descent rate that enables enough particles in the material container to be attracted and concentrated for analysis purposes. The concentrated particles are then evaluated, either directly in the material container or they are moved to some type of test bed, including but not limited to, a microscope slide, an assay device, a separate vial or tube. 
     A second way of managing magnet movement in the apparatus of the present invention with respect to material in a material container also uses gravity to move the magnet down through the magnet container but regulates that movement with reduced dependency on the viscosity of the fluid within the magnet container. The fluid could be a gas such as air or it could be a liquid. One variant takes advantage of the Lenz Law, wherein a portion or all of the magnet container is made of Aluminum. Alternatively, the magnet container includes an Aluminum component to cause the magnet to slow. The other variant is the inclusion in the magnet container of a non-vertical incline that the magnet travels down. In that configuration, the magnet does not make a direct-line trip to the bottom of the magnet container. Instead, the incline extends the time period for the magnet to move from the top to the bottom of the magnet container, resulting in an overall slower velocity on that trip from top to bottom. Either of these two variants permit the use of a less viscous and less expensive fluid, e.g., water or a salt or sugar solution but not limited thereto. For the first such variant, the material container may be positioned adjacent to the magnet container. For the second such variant, the material container could also be positioned adjacent to the magnet container or the magnet container could be annular, with the material container positioned at the center of the annulus. 
     A third way of managing magnet movement in the apparatus of the present invention with respect to material in a material container also uses gravity to move the magnet down through the magnet container regulates that movement through movement of the entire magnet container. Specifically, one or more magnets are located within a fluid of selectable viscosity in the magnet container. The material container is placed on an incline. The magnet container is of a shape that permits it to roll down the incline. For example, the magnet container may be a round jar. The magnet container is positioned on top of the material container at its highest point on the incline and allowed to roll down the incline while on top of the material container. The angle of the incline, the viscosity of the fluid in the magnet container and the characteristics of the one or more magnets dictate the velocity of the magnet container moving down the incline. That velocity is therefore selectable and may be adjusted as needed to ensure that there is sufficient time to attract any paramagnetic and/or superparamagnetic particles in the material container to the magnet container to allow concentration of a desired amount of those particles at the lowest point of the material container positioned on the incline. The desired amount of particles to be attracted and concentrated is dependent on the evaluation to be conducted and the characteristics of the particles. 
     The combination of the one or more magnets and magnet movement regulation yields effective paramagnetic and/or superparamagnetic biomarker concentration. This combination may be used to concentrate for analysis hemozoin, for example, as part of a substantially less costly malaria test. It can also be used to concentrate other biomarker materials of interest. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a first embodiment of the apparatus for detecting paramagnetic and/or superparamagnetic materials of the present invention. 
         FIG. 2  is a side view of a second embodiment of the apparatus for detecting paramagnetic and/or superparamagnetic materials of the present invention. 
         FIG. 3  is a bottom view of a third embodiment of the apparatus for detecting paramagnetic and/or superparamagnetic materials of the present invention positioned on an inclined plane substrate. 
         FIG. 4A  is a top view of a set of capillary tubes including one in the center of the set that is a material container retaining a fluid with a paramagnetic material dispersed therein on the inclined plane substrate.  FIG. 4B  is a top view showing the apparatus of  FIG. 3  rolling on the capillary tubes of  FIG. 4A . 
         FIG. 5  is a top view of a portion of the set of capillary tubes of  FIGS. 4A and 4B  after the apparatus of  FIG. 3  was rolled down the inclined plane over the set of capillary tubes showing the paramagnetic material concentrated at the lower end thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is an apparatus and related method for concentrating paramagnetic and/or superparamagnetic materials in a container for the purpose of evaluating those materials. The apparatus includes the combination of a magnet container and a materials container. The magnet container contains therein one or more magnets of selectable size and shape. The magnet container also includes a fluid of selectable viscosity that is arranged to aid in managing the rate of movement of the one or more magnets in the magnet container. The materials container includes a fluid within which an analyte of interest, such as a biomarker, for example, resides. The analyte has paramagnetic and/or superparamagnetic characteristics or is coupled to a material that has paramagnetic and/or superparamagnetic characteristics. The magnet container is positioned in proximity to the material container and configured to cause controlled movement of the one or more magnets. That controlled magnet movement causes corresponding movement of the analyte in the material container in a way that results in concentration of the analyte at an end of the material container, thereby enhancing the ability to evaluate the analyte. 
     A first embodiment of an apparatus  10  for concentrating an analyte is shown in  FIG. 1 . The apparatus  10  includes a magnet container  12  and a material container  14 . The magnet container  12  includes a first end  16  and a second end  18 . Either or both of the first end  16  and the second end  18  includes a removable cap  20 . The cap  20  may be removed to allow delivery of a fluid  22  and a magnet  24  into an interior  26  of the magnet container  12 . The fluid  22  is of selectable viscosity and type. For example, the fluid  22  may be corn syrup but is not limited thereto. The magnet  24  represents one or more magnets. The magnet  24  is of selectable size, shape and magnetic strength. For example, the magnet  24  may be spherical, discoidal or disk-shaped with concave or convex surfaces but is not limited thereto. Its exterior dimensions must be smaller than the interior dimensions of the magnet container  12  to ensure that the magnet  24  will move within the magnet container  12  such as when, for example, the magnet container  12  is first resting on the first end  16  and then rotated so that it is resting on the second end  18 , causing the magnet  24  to move from the second end  18  to the first end  16  through the fluid  22 . The selection of the fluid  22  and the magnet  24  determines the rate of movement of the magnet  24  from one end of the magnet container  12  to the other end. 
     The material container  14  includes a first end  28  and a second end  30 . The material container  14  may be a vial or a tube, such as a capillary tube that may include caps at either or both of the first end  28  and the second end  30 . As can be seen from  FIG. 1 , the material container  14  has a cross section that is significantly smaller than a cross section of the magnet container  12 , and that the material container  14  is directly attached to the magnet container  12  along the length of the magnet container  12 . It is to be understood that the cross section of the material container  14  is made at a right angle to the longitudinal axis of the material container  14  and that the cross section of the magnet container  12  is made at a right angle to the longitudinal axis of the magnet container  12 . At least one of the caps may be removable to allow delivery of a fluid  34  therein. The fluid  34  may be aspirated into the material container  14  in a conventional manner. The fluid  34  is one under examination. Specifically, the fluid  34  includes at least one analyte to be analyzed. In particular, with respect to the present invention, the fluid  34  includes at last one material having a paramagnetic and/or superparamagnetic characteristic. The material container  14  is arranged for placement adjacent to the magnet container  12 . 
     A desirable portion of the paramagnetic and/or superparamagnetic material in the fluid  34  is attracted to the magnet  24  in the magnetic container  12  given the proximity of the material container  14  to the magnet container  12 . As the magnet  24  moves through the fluid  22  from one end to the other of the magnet container  12 , the magnetically attracted materials in the material container  14  move with it. When the magnet  24  reaches the terminus of its travel in the magnet container  12 , paramagnetic and/or superparamagnetic materials in the material container  14  have completed a similar travel condition. For example, if the material container  14  has been joined to the magnet container  12  such that the first end  16  of the magnet container  12  is aligned with the first end  28  of the material container  14  and the magnet  24  is located in the vicinity of the second end  18 , then when the magnet container  12  and the material container  14  are rotated 180 degrees vertically, the magnet  24  moves from the second end  18  to the first end  16 . At the same time, magnetically attracted material in the fluid  34  moves toward the magnet  24  and in a corresponding path in the material container  14  from the second end  30  the first end  28 . The concentrated magnetically attracted material at the first end  28  may be examined therein or the material may be removed from the material container  14  for remote evaluation. The apparatus  10  provides an effective, efficient and inexpensive way to gather material for evaluation in a faster way than has been possible, particularly with respect to certain biomarkers of interest that otherwise must be slowly or expensively collected. 
     A second embodiment of an apparatus  100  for concentrating an analyte is shown in  FIG. 2 . The apparatus  100  includes a magnet container  102 , a material container  104  and an incline pathway  106 . The magnet container  102  includes a first end  108  and a second end  110 . The first end  108  includes a removable cap  112 . The second end  110  has an opening  114  for insertion therein of the material container  104  and the incline pathway  106 , as well as a fluid  116  and a magnet  118  into an interior  120  of the magnet container  102 . The fluid  116  is of selectable viscosity and type. For example, the fluid  102  may be corn syrup or water but is not limited thereto. The magnet  118  represents one or more magnets. The magnet  118  is of selectable size and magnetic strength, and must be shaped to allow it to move down the incline pathway  106 . For example, the magnet  118  may be a sphere or a discoid. Its exterior dimensions must be smaller than the interior dimensions of the magnet container  102  to ensure that the magnet  118  will move within the magnet container  102  such as when, for example, the magnet container  102  and the material container  104  are joined together and the combination is rotated. 
     The material container  104  includes a first end  122  and a second end  124 . The first end  122  is threaded or otherwise configured to allow its removable insertion into opening  114  of the first end  108  of the magnet container  102 . The second end  124  includes a cap  128  that is threaded or otherwise configured to enable its removable joining to the second end  110  of the magnet container  102 . The magnet container  102  and the material container  104  are shown in  FIG. 2  separated from one another, but when the first end  122  of the material container  104  is coupled to the port  126  of the magnet container  102  while the cap  128  is coupled to the second end  110 , the apparatus  100  is a unitary structure with the material container  104  contained within the interior  120  of the magnet container  102 . The opening  114  of the magnet container  102  does not extend completely through the cap  112  so that a fluid under examination in the material container  104  is retained therein when the magnet container  102  and the material container  104  are coupled together. 
     The incline pathway  106  is a helix-shaped structure sized to fit in the interior  120  of the magnet container  102  with its exterior dimensions small enough to fit within the magnet container  102  but large enough so that the magnet  118  can only travel on the incline pathway  106  as it traverses from one end of the magnet container  102  to the other without falling off the incline pathway  106 . The incline pathway  106  is of an annular configuration with a portal  130  arranged to retain therein the material container  104 . The incline pathway  106  may be separate from or joined to the material container  104 . A fluid under examination may be aspirated into the material container  104  in a conventional manner. The fluid includes at least one analyte to be analyzed. In particular, with respect to the present invention, the fluid includes at last one material having a paramagnetic and/or superparamagnetic characteristic. 
     When the fluid under examination is in the material container  104  and the material container  104  is in the magnet container  102  and that combination is rotated 180 degrees, the magnet  118  moves down the incline pathway  106 . Its rate of descent through the magnet container  102  is determined by its size and shape, as well as the angle of the include pathway  106  and the viscosity of the fluid  116 , all of which are selectable to manage that rate of descent. As the magnet  118  moves on its controlled descent, a desirable portion of paramagnetic and/or superparamagnetic material in the fluid in the material container  104  is attracted to the magnet  118  moving downwardly with it. When the magnet  118  reaches the terminus of its travel in the magnet container  102 , paramagnetic and/or superparamagnetic materials in the material container  104  have completed a similar descent to the second end  124  of the material container  104 . The concentrated magnetically attracted material at the second end  124  may be examined therein or the material may be removed from the material container  104  for remote evaluation. The apparatus  100  provides an effective, efficient and inexpensive way to concentrate material for evaluation in a faster way than has been possible, particularly with respect to certain biomarkers of interest that otherwise must be slowly or expensively collected. 
     A third embodiment of an apparatus  200  for concentrating an analyte is shown in  FIG. 3 . The apparatus  200  includes a magnet container  202  and an incline plane  204 . The magnet container  202  includes a housing  206 , a cap  208 , a magnet  210  and a fluid  212 . The cap  208  is removably coupled to the housing  206 , such as with threading of an exterior of the housing  206  and threading of an interior of the cap  208 . The cap  208  may be removed from the housing  206  for insertion therein of the magnet  210  and the fluid  212 . The fluid  212  is of selectable viscosity and type. For example, the fluid  212  may be corn syrup but is not limited thereto. The magnet  210  represents one or more magnets. The magnet  210  is of selectable size, shape and magnetic strength. For example, the magnet  210  may be disk-shaped or spherical. Its exterior dimensions must be smaller than the interior dimensions of the magnet container  202  to ensure that the magnet  210  will move within the magnet container  202  when the magnet container  202  moves. The selection of the fluid  212  and the magnet  210  determines the rate of movement of the magnet  210  down the incline plane  204 . The housing  206  is preferably round or otherwise configured to enable its descent down the incline plane  204 . The incline plane  204  may be any substrate having a first end  214  that is relatively higher than a second end  216  so that gravity may be used to effect the descent of the housing  206  from the first end  214  to the second end  216  when the magnet container  202  is placed on its side and positioned near the first end  214  of the incline plane  204 . For example and without limitation, the substrate may be a form of container that retains therein the material container and that is configured to allow passage of the magnet container over it. 
     As has been noted, the viscosity of the fluid  212  and the configuration of the magnet  210  dictate the rate of descent of the magnet container  202  and, therefore, the rate of descent of the magnet  210 . An analysis of three different magnets was conducted to determine the impact of those characteristics, if any, on the rate of descent of the magnet container  202  down the incline place  204 . In all three examples, the fluid  212  in the housing  206  was corn syrup and the magnetic strength of the three example magnets was the same. A first magnet was disk-shaped with a ¼-inch diameter, a second magnet was disk-shaped with a ⅜-inch diameter, and a third magnet was disk-shaped with a ½-inch diameter. It was discovered that the ¼-inch and the ½-inch magnets traveled 7.5 centimeters down the incline plane having a 3.3-degree angle of descent at nearly identical times of about 26.5 seconds, while the ⅜-inch magnet took 263 seconds to complete the same course. That experiment confirmed that the rate of descent of the magnet container  202  and, therefore, the magnet  210  can be managed to a selectable effect dependent on fluid  212  and magnet  210  chosen. 
     The apparatus  200  can be used with a material container containing a fluid having an analyte of interest, wherein the analyte may be paramagnetic, superparamagnetic or linked to a paramagnetic and/or superparamagnetic binder.  FIGS. 4A, 4B, and 5  show what can be accomplished using the apparatus  200 . Three capillary tubes are shown in those drawings placed on the incline plane  204  extending from the first end  214  to the second end  216 . Outer tubes  220  and  222  were empty while center tube  224  was filled with water containing one-micron paramagnetic particles  226  available from Polysciences, Inc. It can be seen in  FIG. 4A  that the paramagnetic particles  226  in tube  224  are widely dispersed throughout the tube  224 . The magnet container  202  including the ⅜-inch magnet was placed on its side on top of the three capillary tubes at the first end  214  of the incline plane  204 . The magnet container  202  was released and allowed to move over the three tubes as shown in  FIG. 4B . It traveled in a stop-and-start fashion as the movement of the magnet  210  closest to the incline plane  204  lagged behind the movement of the housing  26 . By the time the magnet container  202  reached the second end  216  of the incline plane  204 , a substantial quantity of the paramagnetic particles  226  were concentrated at the second end  216  of the incline plane  204 , as shown in  FIG. 5 . It can be seen from the results of this experiment that the apparatus  200  provides an effective, efficient and inexpensive way to concentrate material for evaluation in a more rapid manner than has been possible, particularly with respect to certain biomarkers of interest that otherwise must be slowly or expensively collected. 
     The present invention has been described with respect to various example embodiments. Nevertheless, it is to be understood that various modifications may be made without departing from the spirit and scope of the invention as described by the following claims.