Patent Publication Number: US-2019194588-A1

Title: Partitioning device for creating a competitive assay platform

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/599,890, filed Dec. 18, 2017, the content of which is incorporated herein by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     This invention was made with government support under Grant No. DMR1149931 awarded by the National Science Foundation. The government has certain rights in the invention. 
    
    
     BACKGROUND 
     Several previous in vitro co-culture systems have been developed to study interaction and selective uptake of substances such as nanoparticles with various cell types. However, these systems make it relatively difficult to incorporate more than two cell types, and additional labeling techniques must be employed to distinguish various cell types. Thus, there is a need in the art for improved systems and methods for studying selective uptake of substances by cell cultures. 
     SUMMARY 
     Various implementations of competitive assay platforms can be used to study selective uptake of substances (e.g., nanoparticles, drugs, heavy metals, chemicals) in three dimensional (3D) cultures. In some implementations, the platform includes a partitioning device that divides a volume of a well into multiple compartments for receiving different 3D cultures. In certain implementations, the partitioning device is separately formed from and fits into a well of a standard cell culture well plate or other type of well structure. In other implementations, the partitioning device is integrally formed with the well surfaces (e.g., a bottom surface and side surface(s) of the well are integrally formed in one molding process with the partitioning device). In some implementations, the partitioning device is made of biocompatible polymers (e.g., poly(lactic acid) (PLA)). And, in some implementations, the partitioning device may be made using additive manufacturing. A substance, such as nanoparticles, may be introduced into the well to evaluate selective uptake of the substance by the 3D cultures. Because of its broad utility, this platform can be easily adapted with standard culture substrates in a range of tissue-like environments and, thus, can be readily utilized by laboratories studying nanoparticle-cellular interactions. 
     In addition, this technology could be broadly applied for fundamental studies of preferential cellular decisions in physiologically relevant 3D environments. 
     Various implementations include a partitioning device for creating at least three separate three-dimensional cultures for studying selective uptake of a substance in the cultures. The partitioning device is disposable in a well that is defined by a bottom surface through which a central axis of the well extends and at least one side surface that extends axially from the bottom surface. The partitioning device includes a first wall, a second wall, and a third wall. 
     The first wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges are opposite and spaced apart from each other, the first and second side edges are opposite and spaced apart from each other, and the first and second divider surfaces are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces. 
     The second wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the second wall portion are opposite and spaced apart from each other, the first and second side edges of the second wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the second wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the second wall portion. 
     The third wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the third wall portion are opposite and spaced apart from each other, the first and second side edges of the third wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the third wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the third wall portion. 
     The lower edge of the first, second, and third wall portions are disposable on a bottom surface of a well. The first side edges of the first, second, and third wall portions are disposable against at least one side surface of the well. The first and second divider surfaces of the first, second, and third wall portions at least partially define first, second, and third compartments. 
     In some implementations, the second side edges of the first, second, and third wall portions intersect each other. 
     In some implementations, the first side edges of the first, second, and third wall portions are coupled to each other by a coupling wall, the coupling wall being disposable against at least one side surface of the well. 
     In some implementations, the partitioning device further includes a center wall having a perimeter forming a closed shape, and the center wall is sealingly disposable between the second side edges of the first, second, and third wall portions. 
     In some implementations, each of the first wall portion, the second wall portion, and the third wall portion are planar. 
     In some implementations, the first wall portion, the second wall portion, and/or the third wall portion are integrally formed. 
     In some implementations, the partitioning device further includes a fourth wall portion. The fourth wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the fourth wall portion are opposite and spaced apart from each other, the first and second side edges of the fourth wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the fourth wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the fourth wall portion. The first side edge of the fourth wall portion is disposable against at least one side surface of the well, and first and second divider surfaces of the first, second, third, and fourth wall portions at least partially define the first, second, and third compartments and a fourth compartment. 
     In some implementations, the partitioning device comprises a biocompatible material. In some implementations, the biocompatible material comprises a polymer. In some implementations, the biocompatible material comprises polylactic acid. In some implementations, the biocompatible material comprises polycaprolactone. 
     In some implementations, the partitioning device comprises a non-biocompatible material. 
     In some implementations, the compartments have equal volumes. 
     In some implementations, the wall portions of the partitioning device are solid. 
     In some implementations, the wall portions of the partitioning device prevent flow of a pourable culture substrate between the compartments. In some implementations, the wall portions of the partitioning device comprise one or more openings through which uptake materials flow between the compartments. In some implementations, the wall portions of the partitioning device comprise a membrane through which uptake materials flow between the first and second compartments. 
     In some implementations, the partitioning device is created using additive manufacturing. 
     In some implementations, the partitioning device further includes at least one well. The at least one well is defined by a bottom surface through which a central axis extends and at least one side surface extending axially from the bottom surface. The first, second, and third wall portions are disposed within the well. In some implementations, the lower edges of the first, second, and third wall portions are disposed against the bottom surface of the well, and the first side edges of the first, second, and third wall portions are disposed in contact with at least one side surface of the well. 
     In various other implementations, a competitive assay system includes at least one well and a partitioning device. The at least one well is defined by a bottom surface through which a central axis extends and at least one side surface extending axially from the bottom surface. 
     The partitioning device is disposed within the at least one well. The partitioning device includes a first wall, a second wall, and a third wall. The first wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges are opposite and spaced apart from each other, the first and second side edges are opposite and spaced apart from each other, and the first and second divider surfaces are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces. 
     The second wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the second wall portion are opposite and spaced apart from each other, the first and second side edges of the second wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the second wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the second wall portion. 
     The third wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the third wall portion are opposite and spaced apart from each other, the first and second side edges of the third wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the third wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the third wall portion. 
     The lower edge of the first, second, and third wall portions are disposed against the bottom surface of a well. The first side edges of the first, second, and third wall portions are disposed in contact with at least one side surface of the well. The first and second divider surfaces of the first, second, and third wall portions at least partially define first, second, and third compartments. 
     In some implementations, the second side edges of the first, second, and third wall portions intersect each other. 
     In some implementations, the first side edges of the first, second, and third wall portions are coupled to each other by a coupling wall, the coupling wall being disposable against at least one side surface of the well. 
     In some implementations, the partitioning device further includes a center wall having a perimeter forming a closed shape, and the center wall is sealingly disposable between the second side edges of the first, second, and third wall portions. 
     In some implementations, the partitioning device is separately formed from the side surface and bottom surface of the well such that the partitioning device is removably disposable within the well. 
     In some implementations, each of the first, second, and third wall portions of the partitioning device are planar. 
     In some implementations, the partitioning device further includes a fourth wall portion. The fourth wall portion has a lower edge and an upper edge, first and second side edges, and first and second divider surfaces that are opposite and spaced apart from each other. The first side edge of the fourth wall portion is disposed in contact with at least one side surface of the well, and the divider surfaces of the wall portions define the first, second, and third compartments and a fourth compartment. 
     In some implementations, the partitioning device comprises a biocompatible material. In some implementations, the biocompatible material comprises a polymer. In some implementations, the biocompatible material comprises polylactic acid. In some implementations, the biocompatible material comprises polycaprolactone. 
     In some implementations, the partitioning device comprises a non-biocompatible material. 
     In some implementations, the compartments have equal volume. 
     In some implementations, the wall portions of the partitioning device are solid. 
     In some implementations, the partitioning device is integrally formed with at least one side surface and/or bottom surface of the well. 
     In some implementations, the wall portions of the partitioning device prevent flow of a pourable culture substrate between the compartments. In some implementations, the wall portions of the partitioning device comprise one or more openings that allow for the flow therethrough of an uptake substance between the compartments. In some implementations, the wall portions of the partitioning device comprise a membrane that allow for the flow therethrough of an uptake substance between the compartments. 
     In some implementations, the partitioning device is created using additive manufacturing. 
     Various other implementations include a method for creating a competitive assay system. The method includes (1) inserting a partitioning device into a well in a culture well plate. The well is defined by a bottom surface through which a central axis extends and at least one side surface extending axially from the bottom surface. 
     The partitioning device includes a first wall, a second wall, and a third wall. The first wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges are opposite and spaced apart from each other, the first and second side edges are opposite and spaced apart from each other, and the first and second divider surfaces are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces. 
     The second wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the second wall portion are opposite and spaced apart from each other, the first and second side edges of the second wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the second wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the second wall portion. 
     The third wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the third wall portion are opposite and spaced apart from each other, the first and second side edges of the third wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the third wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the third wall portion. 
     The lower edge of the first, second, and third wall portions are disposed against the bottom surface of the well. The first side edges of the first, second, and third wall portions are disposed in contact with at least one side surface of the well. The first and second divider surfaces of the first, second, and third wall portions define first, second, and third compartments in the well. 
     The method further includes (2) inserting a first pourable culture substrate including a first culture within the first compartment, (3) inserting a second pourable culture substrate including a second culture within the second compartment, wherein the first culture is different than the second cell culture, (4) inserting a third pourable culture substrate comprising a third culture within the third compartment, wherein the first and second cultures are different than the third culture, (5) removing the partitioning device from the well after the pourable culture substrates have solidified, and (6) introducing an uptake substance inside the well such that the uptake substance contacts each of the solidified culture substrate. 
     In some implementations, the second side edges of the first, second, and third wall portions intersect each other. 
     In some implementations, the first side edges of the first, second, and third wall portions are coupled to each other by a coupling wall, and the coupling wall is disposable against at least one side surface of the well. 
     In some implementations, the partitioning device further includes a center wall having a perimeter forming a closed shape, wherein the center wall is sealingly disposable between the second side edges of the first, second, and third wall portions. 
     In some implementations, the partitioning device is created using additive manufacturing. 
     In some implementations, the first, second, and third cultures comprise cell cultures. In some implementations, the first, second, and third cultures comprise bacterial cultures. 
     In some implementations, the first, second, and third pourable culture substrates comprise hydrogels. 
     Various other implementations include a method for creating a competitive assay system. The method includes (1) providing a partitioning device in a well in a culture well plate. The well is defined by a bottom surface through which a central axis extends and at least one side surface extending axially from the bottom surface. 
     The partitioning device includes a first wall, a second wall, and a third wall. The first wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges are opposite and spaced apart from each other, the first and second side edges are opposite and spaced apart from each other, and the first and second divider surfaces are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces. 
     The second wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the second wall portion are opposite and spaced apart from each other, the first and second side edges of the second wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the second wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the second wall portion. 
     The third wall portion has an upper edge, a lower edge, a first side edge, a second side edge, and first and second divider surfaces. The upper and lower edges of the third wall portion are opposite and spaced apart from each other, the first and second side edges of the third wall portion are opposite and spaced apart from each other, and the first and second divider surfaces of the third wall portion are opposite and spaced apart from each other and extend between the upper and lower edges and the first and second side surfaces of the third wall portion. 
     The lower edge of the first, second, and third wall portions are disposed against the bottom surface of the well, and the first side edges of the first, second, and third wall portions are disposed in contact with at least one side surface of the well. The first and second divider surfaces of the first, second, and third wall portions define first, second, and third compartments in the well. 
     The method further includes (2) inserting a first pourable culture substrate comprising a first culture within the first compartment, (3) inserting a second pourable culture substrate comprising a second culture within the second compartment, wherein the first culture is different than the second culture, (4) inserting a third pourable culture substrate comprising a third culture within the third compartment, wherein the first and second cultures are different than the third culture, and (5) introducing an uptake substance inside the well such that the uptake substance flows through the partitioning device and contacts each of the solidified culture substrates. 
     In some implementations, the second side edges of the first, second, and third wall portions intersect each other. 
     In some implementations, the first side edges of the first, second, and third wall portions are coupled to each other by a coupling wall, and the coupling wall is disposable against at least one side surface of the well. 
     In some implementations, the partitioning device further includes a center wall having a perimeter forming a closed shape, and the center wall is sealingly disposable between the second side edges of the first, second, and third wall portions. 
     In some implementations, the partitioning device is created using additive manufacturing. 
     In some implementations, the first, second, and third cultures comprise cell cultures. In some implementations, the first, second, and third cultures comprise bacterial cultures. 
     In some implementations, the first, second, and third pourable culture substrates comprise hydrogels. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Example features and implementations are disclosed in the accompanying drawings. However, the present disclosure is not limited to the precise arrangements and instrumentalities shown. 
         FIG. 1  is a perspective view of a competitive assay platform in accordance with one implementation. 
         FIG. 2  is a perspective view of a competitive assay platform in accordance with another implementation. 
         FIG. 3  is an example flow chart of a method of using the competitive assay platform of  FIG. 1  according to one implementation. 
         FIG. 4  is a perspective view of a competitive assay platform in accordance with another implementation. 
     
    
    
     DETAILED DESCRIPTION 
     The following is a description of various implementations of a competitive assay platform to evaluate selective uptake of substances in three dimensional cultures, such as cell cultures, bacterial cultures, etc. 
     Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present claims. In the drawings, the same reference numbers are employed for designating the same elements throughout the several figures. A number of examples are provided, nevertheless, it will be understood that various modifications can be made without departing from the spirit and scope of the disclosure herein. As used in the specification, and in the appended claims, the singular forms “a,” “an,” “the” include plural referents unless the context clearly dictates otherwise. The term “comprising” and variations thereof as used herein is used synonymously with the term “including” and variations thereof and are open, non-limiting terms. Although the terms “comprising” and “including” have been used herein to describe various implementations, the terms “consisting essentially of” and “consisting of” can be used in place of “comprising” and “including” to provide for more specific implementations and are also disclosed. 
       FIG. 1  shows one implementation of the competitive assay platform  100  with a partitioning device  120  disposed in a well  110 . The well  110  has a bottom surface  112 , a central axis  114 , and a side surface  116 . The bottom surface  112  and the side surface  116  define a well volume. The central axis  114  of the well  110  extends through the bottom surface  112  of the well  110 , and the side surface  116  extends axially from the bottom surface  112 . An edge of the side surface  116  opposite the bottom surface  112  defines an opening into the well  110 . While the well  110  in  FIG. 1  is cylindrically shaped and has a single side surface  116 , a well having another prismatic shape and having more than one side surface could also be used. It is also understood that a well can be any study apparatus that can be utilized for studying competition, including cell culture well plates, petri dishes, etc. 
     The partitioning device  120  includes a first wall portion  130 , a second wall portion  140 , and a third wall portion  150 . Each of the first  130 , second  140 , and third wall portions  150  has an upper edge  132 ,  142 ,  152 , a lower edge  133 ,  143 ,  153 , a first side edge  134 ,  144 ,  154 , a second side edge  135 ,  145 ,  155 , a first divider surface  136 ,  146 ,  156 , and a second divider surface  137 ,  147 ,  157 , respectively. The upper  132 ,  142 ,  152  and lower edges  133 ,  143 ,  153 , respectively, are opposite and spaced apart from each other, the first  134 ,  144 ,  154  and second side edges  135 ,  145 ,  155 , respectively, are opposite and spaced apart from each other, and the first  136 ,  146 ,  156  and second divider surfaces  137 ,  147 ,  157 , respectively, are opposite and spaced apart from each other and extend between the upper  132 ,  142 ,  152 , the lower edges  133 ,  143 ,  153 , and the first  134 ,  144 ,  154  and second side edges  135 ,  145 ,  155 , respectively. The second side edges  135 ,  145 ,  155  of each of the first  130 , second  140 , and third wall portions  150 , respectively, intersect each other.  FIG. 1  shows the wall portions  130 ,  140 ,  150  being integrally formed with each other, but it is understood that the wall portions  130 ,  140 ,  150  could also be separately formed and coupled together. 
     The partitioning device  120  of  FIG. 1  is shown inserted into the well  110  with the lower edge  133  of the first wall portion  130 , the lower edge  143  of the second wall portion  140 , and the lower edge  153  of the third wall portion  150  of the partitioning device  120  disposed on (e.g., abutting) the bottom surface  112  of the well  110 . The first side edge  134  of the first wall portion  130 , the first side edge  144  of the second wall portion  140 , and the first side edge  154  of the third wall portion  150  are disposed against (e.g., abutting) the side surface  116  of the well  110 . Thus, when the partitioning device  120  is inserted into the well  110 , the second divider surface  137  of the first wall portion  130  and the first divider surface  146  of the second wall portion  140  define a first compartment  170 . The second divider surface  147  of the second wall portion  140  and the first divider surface  156  of the third wall portion  150  define a second compartment  172 . And, the first divider surface  136  of the first wall portion  130  and the second divider surface  157  of the third wall portion  150  define a third compartment  174 . The wall portions  130 ,  140 ,  150  of  FIG. 1  are designed such that the first  170 , second  172 , and third compartments  174  have equal volumes. The first  130 , second  140 , and third wall portions  150  shown in  FIG. 1  are planar, but the wall portions in other implementations of the partitioning device can be any other shape. 
     The wall portions  130 ,  140 ,  150  of the partitioning device  120  can be made from a biocompatible material such as a polymer (e.g., polylactic acid, polycaprolactone). However, the wall portions  130 ,  140 ,  150  can also be made from any non-biocompatible material. 
     The partitioning device  120  can be created using additive manufacturing, or any other means known in the art. The partitioning device  120  of  FIG. 1  is solid and separately formed from the side surface  116  and bottom surface  112  of the well  110  so that the partitioning device  120  can be inserted into the well  110 , and later removed from the well  110 , as described below, before an uptake substance is introduced into the well  110 . However, the partitioning device  120  may be integrally formed with the side surface(s)  116  and/or bottom surface  112  of the well  110  in some implementations. And, in some implementations, the wall portions can define holes or include a membrane. The holes or membrane are sized such that the culture substrate does not flow outside the respective compartment, but the uptake material inserted in the compartments is able to flow freely among each of the compartments through the holes or membrane. 
     The partitioning device  120  shown in  FIG. 1  has three wall portions  130 ,  140 ,  150 . However, in other implementations, the partitioning device  120  can have more wall portions to form additional compartments.  FIG. 2  depicts another implementation of a competitive assay platform  200  with a partitioning device  220  similar to the partitioning device  120  shown in  FIG. 1 , but the partitioning device  220  of  FIG. 2  comprises a fourth wall portion  260 . Similar to the other wall portions  230 ,  240 ,  250 , the fourth wall portion  260  has an upper edge  262 , a lower edge  263 , a first side edge  264 , a second side edge  265 , a first divider surface  266 , and a second divider surface  267 . The second side edge  265  of the fourth wall portion  260  intersects the second side edges  235 ,  245 ,  255  of the first  230 , second  240 , and third wall portions  250 , respectively. The first side edge  264  of the fourth wall portion  260  is disposed against the side surface  116  of the well  110 . Thus, when the partitioning device  220  is inserted into the well  110 , the second divider surface  237  of the first wall portion  230  and the first divider surface  246  of the second wall portion  240  define a first compartment  270 . The second divider surface  247  of the second wall portion  240  and the first divider surface  256  of the third wall portion  250  define a second compartment  272 . The second divider surface  257  of the third wall portion  250  and the first divider surface  266  of the fourth wall portion  260  define a third compartment  274 . And, the second divider surface  267  of the fourth wall portion  260  and the first divider surface  236  of the first wall portion  230  define a fourth compartment  276 . 
       FIG. 3  shows the steps for an example method for creating a competitive assay system  300 . In step  310 , a partitioning device, such as partitioning devices  120 ,  220  described above in relation to  FIGS. 1 and 2 , is inserted into a well. The partitioning device is inserted into the well such that the bottom edges of the wall portions are disposed against the bottom surface of the well, and the first side edges of the wall portions are disposed against the side surface(s) of the well, and the second side edges of the wall portions intersect each other. In this way, the divider surfaces of the wall portions define multiple compartments in the well. 
     In step  320 , different pourable culture substrates capable of setting as solids are inserted into each compartment, respectively, with each culture substrate and respective compartment containing a different culture. Pourable culture substrates can include any substance that can take a liquid form and subsequently solidify or partially solidify, for example, hydrogels, slurries, suspensions, solutions, etc. The culture substrates can contain various types of cultures, including cell cultures, bacterial cultures, etc. 
     Once the culture substrates have solidified, the partitioning device is removed from the well such that the culture substrates remain in place in the well, which is shown as step  330 . In step  340 , an uptake substance is introduced inside the well and is in contact with each of the solidified culture substrates. 
     Because each compartment has an equal volume and because equal volumes of culture substrates are inserted into each compartment, the culture substrates have equal surface areas for uptake of the uptake substance. 
     As mentioned above, in some implementations, the wall portions of the partitioning device can define holes or define a membrane, and the holes or membrane may be sized and/or selected such that the culture substrates inserted within each compartment are prevented from flowing outside each respective compartment, but an uptake material inserted in the compartments can flow freely between each of the compartments. In these implementations, the step of removing the partitioning device from the well can be eliminated and the partitioning device can be left in the well during the introduction of the uptake substance inside the well. 
       FIG. 4  depicts another implementation of a competitive assay platform  400  with a partitioning device  420  similar to the partitioning device  120  shown in  FIG. 1 , but the second side edges  435 ,  445 ,  455  of the first, second, and third wall portions  430 ,  440 ,  450  of the partitioning device  420  of  FIG. 4  do not intersect each other. The partitioning device  420  shown in  FIG. 4  also includes a coupling wall  490 . The coupling wall  490  shown in  FIG. 4  includes three coupling wall segments  492 ,  494 ,  496 . Each of the three segments  492 ,  494 ,  496  of the coupling wall  490  couple a pair of adjacent first side edges  434 ,  444 ,  454  of the first, second, or third wall portions  430 ,  440 ,  450  to each other. Thus, a first segment  492  of the coupling wall  490  couples the first side edge  434  of the first wall portion  430  and the first side edge  444  of the second wall portion  440 , a second segment  494  of the coupling wall  490  couples the first side edge  444  of the second wall portion  440  and the first side edge  454  of the third wall portion  450 , and a third segment  496  of the coupling wall  490  couples the first side edge  456  of the third wall portion  450  and the first side edge  434  of the first wall portion  430 . Each of the segments  492 ,  494 ,  496  of the coupling wall  490  are positioned such that the segments  492 ,  494 ,  496  of the coupling wall  490  are disposable against the side surface  416  of the well  410 , which is shown in the dotted line of  FIG. 4 . 
     Although the coupling wall  490  shown in  FIG. 4  includes multiple segments  492 ,  494 ,  496 , in some implementations, the coupling wall includes one continuous wall coupled to the ends of the first side edges of the first, second, and third wall portions. In other implementations that include a partitioning device including more than three wall portions, the coupling wall includes any number of segments such that a segment couples the first edges of each set of adjacent wall portions. Although the segments  492 ,  494 ,  496  of the coupling wall  490  shown in  FIG. 4  have an arcuate cross section as viewed in a plane parallel to the lower edges  433 ,  443 ,  453  of the first, second, and third wall portions  430 ,  440 ,  450 , in other implementations, the coupling walls may have any other shape such that the first edges of each set of adjacent side walls are coupled and the partitioning device is disposable within the well. 
     The competitive assay platform  400  shown in  FIG. 4  also includes an annular center wall  480  defining a center compartment  482 . The annular center wall  480  is sized such that the annular center wall  480  is sealingly disposable between the second side edges  435 ,  445 ,  455  of the first, second, and third wall portions  430 ,  440 ,  450 . Thus, a culture substrate or uptake substance introduced into the first compartment  470 , the second compartment  472 , the third compartment  474 , or the center compartment  482  is prevented from flowing into any of the other compartments. The annular center wall  480  is separately formed from the second side edges  435 ,  445 ,  455  of the first, second, and third wall portions  430 ,  440 ,  450  such that the annular center wall  480  is removable from the well  410  separately from the remainder of the partitioning device  420 . However, in other implementations, the annular center wall is integrally formed with the second side edges of the first, second, and third wall portions. Although the annular center wall  480  shown in  FIG. 4  has a circular cross section as viewed in a plane parallel to the lower edges  433 ,  443 ,  453  of the first, second, and third wall portions  430 ,  440 ,  450 , in other implementations, the cross section of the center wall as viewed in a plane parallel to the lower edges of the first, second, and third wall portions may have another shape, such as a triangle, a square, a pentagon, an oval, or any other closed shape. 
     In use, culture substrates are inserted into each of the first, second, and third compartments  470 ,  472 ,  474 , as described above with respect to  FIG. 3 . An uptake substance is then inserted into the center compartment  482 . Once the culture substrates have solidified, the annular center wall  480  is removed from the well  410  such that the uptake substance is introduced to the solidified culture substrates in each of the first, second, and third compartments  470 ,  472 ,  474 . In this implementation, the remainder of the partitioning device  420  (the first, second, and third wall portions  430 ,  440 ,  450 , and the coupling wall  490 ) can remain within the well  410 . 
     Example 
     A partitioning device, like the partitioning device  220  shown in  FIG. 2  with four wall portions, was created using 3D printing. The partitioning device was manufactured using a biocompatible poly(lactic acid) (“PLA”) polymer which fits snuggly into a well of a standard cell culture  12  well plate. The partitioning device was used to create four competing compartments in 3D hydrogels (e.g., polyacrylamide hydrogels, collagen hydrogels), which subsequently permitted evaluation of selective nanoparticle uptake to test for competition. The compartments enabled incorporation of four different cell types, which were tested for selective nanoparticle uptake. 
     Four different cell types—(1) HepG2 liver cells, and breast cancer cells, (2) MDA-MB-231BR (a brain metastasizing variant of the triple negative breast cancer cell line MDA-MB-231), (3) MDA-MB-231, and (4) SKBr3—were seeded at 7,500 cells per gel compartment using Collagen-I hydrogels (5 mg/mL) in a single well of a 12 well plate. The cell-gel constructs were then incubated with 75 μg/mL of quinic acid-coated ultrasmall iron-oxide nanoparticles for three days followed by Prussian blue staining to evaluate cellular uptake. 
     The results of the uptake testing were as expected. Significant uptake of these nanoparticles was noted for HepG2 liver cells, followed by MDA-MB-231BR, and MDA-MB-231. No significant uptake was noted for SKBr3 cells. These results demonstrate the feasibility of the partitioning device disclosed herein. 
     A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the claims. Accordingly, other implementations are within the scope of the following claims. 
     Disclosed are materials, systems, devices, methods, compositions, and components that can be used for, can be used in conjunction with, can be used in preparation for, or are products of the disclosed methods, systems, and devices. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutations of these components may not be explicitly disclosed, each is specifically contemplated and described herein. For example, if a device is disclosed and discussed each and every combination and permutation of the device, and the modifications that are possible are specifically contemplated unless specifically indicated to the contrary. Likewise, any subset or combination of these is also specifically contemplated and disclosed. This concept applies to all aspects of this disclosure including, but not limited to, steps in methods using the disclosed systems or devices. Thus, if there are a variety of additional steps that can be performed, it is understood that each of these additional steps can be performed with any specific method steps or combination of method steps of the disclosed methods, and that each such combination or subset of combinations is specifically contemplated and should be considered disclosed.