Patent Application: US-201213728865-A

Abstract:
cell and organ cultures provide a micro - environment with respect to nutrients , gas exchange , and scaffolding in order to encourage specific cell function , and in some cases to mimic in - vivo cellular expression under in - vitro conditions . we describe apparatus and methods to chemically , spatially , and temporally measure diffusible molecules produced , or used by cells or tissues in culture . in this manner , mechanisms of cell - cell interaction and other chemical signaling , detailed biochemical pathways , and the action of potential pharmaco - therapy agents can be better understood at a molecular level . in addition to basic science , the technical advantages of process monitoring and control can be applied to optimize culture products in bioreactors . embodiments of this device are intended to simulate and monitor the behavior of vascular capillary beds in higher species vascular systems .

Description:
the current invention describes devices and methods intended to monitor ( and additionally ) control the behavior of selected samples of cells , tissues , or micro - organisms . the invention comprises ; a controlled input media delivered to a selected sample 3 . said input media is delivered by an input means 2 in order to elicit or stimulate a response from the said sample or simply provide nutrients to just develop stasis of the sample cells . fig1 is intended to illustrate the general flow of input media 1 to the sample 3 , whereby the output from the sample is collected by an output means 4 and monitored by one or more monitoring means 5 . said media 1 is delivered to said sample 3 by one or more input means 2 . a wide variety of alternatives embodiments for each component in fig1 are listed in fig2 . we envision that this invention will input a variety of input media 1 ; including but not limited to , reagents , nutrients , drugs , gases , blood , output from upstream cultures , output from a natural environment , buffers , stimulants , retardants , and pollutants . we envision that the variety of embodiments of this invention will utilize a number of alternative input means ; including , pumped fluids streams , pumped fluid streams across an aperture array , pumped fluid streams across a membrane or fritted interface , conductance via diffusion across selective membrane , conductance via electrodynamic forces across electrostatic aperture array , convection supplying material to input barrier , input barrier such as membrane , tube , array , or other selective material ( e . g . artificial skin ), but not limited to bundles of permeable tubes that are interspersed within the sample . the sample 3 intended for evaluation and control with this invention includes , but is not limited to cells , tissues , micro - organisms , cell cultures , tissue cultures , viruses , bacteria , collected samples from a biological ( e . g . bio - hazards or bio agents ), and cells supported upon a substrate material . the products of biological activity resulting from said sample responding to said input media is collected by output means 4 and delivered to monitoring means 5 . the said output means of this invention is envisioned to comprise one or more alternatives ; including , aperture arrays , addressable aperture arrays ( mechanical ), addressable aperture arrays ( electrostatic ), frits , filters , tubes , permeable tubes , membranes , but not limited to bundles of permeable tube . it is a primary intention of this invention to monitor the output collected from the said sample via the output means 5 . alternatives for monitoring said sample output involve collection , separation , and detection of one or more components of the sample output stream , including , but not limited to chromatography , mass spectrometry , electrophoresis , spectroscopy , and electrochemistry . this invention generally describes a means of controlled input of input media that are intended to induce or stimulate a response from a given sample cell , tissue , or organism . the result of the high precision with respect to flow , positioning , and composition of input media enables the evaluation of sample bio - activity by monitoring the output products of biological behavior . precise spatial and temporal control and measurement of both input and output components results in unique information regarding the behavior of the sample cells by direct or differential measurement . alternatively , monitoring output products from sample cells can also be used to feedback and control the input media ( or medias ) in order to control the output of the sample cells . there is no limit to the combination of input media components in terms of composition and flow from single or multiple input streams . a preferred embodiment is schematically illustrated in fig3 . the media reservoir 6 containing input media 1 is delivered to sample 3 by input means 2 comprising a peristaltic pump 7 . the media input 8 is delivered through entrance aperture array 9 to culture volume 10 containing sample 3 . said sample comprising cells , tissues , or micro - organisms respond to said input media with biological activity that results in both absorption of at least some of the input media and subsequently the output of products of said biological activity . the output products are passed through membrane 12 through observation barrier 14 . said barrier comprising an array of apertures direct the product output 16 toward downstream chemical or physical monitoring means 5 . the said output is directed to sample conditioning means 20 via output sampling pump 18 . sample output monitoring is accomplished by separating output components with chromatograph 22 and analyzing with mass spectrometer 24 . we envision no restriction on the breadth of alternatives for chromatographic separation or mass spectrometry analysis ; including , but not limited to ms / ms , icp / ms , gc / ms , lc / ms , ic / ms , and any number of parallel or serial techniques that are used to characterize both organic and inorganic species resulting from biological activity . additionally , this embodiment is intended to incorporate mechanical positioning control 26 of both media input 8 and product output 16 . these components facilitate the positional and temporal control of both input of input media to the sample and output of product output . one operation of this assembly uses two aperture arrays 9 and 14 to define an active organ or cell culture volume 10 is shown as viewed from the z - axis . a reservoir of oxygenated nutrients and other co - factors is delivered to the culture assembly through the action of a peristaltic pump 6 . one array is used to disperse oxygenated nutrient evenly into the active culture volume . this active volume can be of any configuration including a void volume , or scaffolding or tube arrays of any type . the exit from the culture volume in fig3 consists of a membrane supported by an aperture array . each hole in the array is a receiver for flow of liquid phase that is a composite of the components externally added to the system in excess of that used by the cells , plus the components generated by the cells in culture local to that particular exit hole . the flow from these holes when analyzed individually and the resulting data reassembled constitutes a chemical map of the diffusible molecules consumed and generated in a specific area of the culture . this map may be used in combination with the histology of the sample in organ culture , or with the various cell lines used in cell culture . the net balance of components consumed and produced can in experimental design be compared with variations in physiologic and physiochemical conditions . in the case where the histology or inoculation regions are known and chemical relationship information reflecting those regions is sufficient , it may be most straight - forward to analyze a limited number of the hole flows in a discrete fashion . in this case , small capillaries may be inserted into the hole array at selected addresses to remove a portion of the liquid flow outside the assembly . alternatively , the apparatus may be capable of translation in the x - y plane with respect to discrete sampling apertures . the discrete sampling apertures maintain sealing surfaces such that the flow from target sample points can be individually diverted or combined for any number of purposes . the locations of these sampling apertures may be varied in relation to the culture volume and one another . the use of multiple sampling tubes or apertures allow for the study of event driven chemical changes and their kinetics as a function of cell type and cell - cell interaction . these measurements are also important to facilitate the determination of potential reactive metabolites in the drug development process . when discrete samples for hole locations are produced , a variety of traditional sample preconcentration , cleanup , separation methods and analytical instrument sample introduction designs can be used for on - line process level measurements . biological matrix samples are very complex and sample conditioning , such as solid phase extraction techniques , are important to enrich certain components in preference to others . additional stages of sample conditioning may be interposed after the observation barrier but within the device prior to analysis . a plurality of aperture arrays can be positioned downstream from the observation barrier with gaps between which constitute a gate or switch . sample may be selectively moved across stages ( gaps ) using hydrostatic ( pressure ), electrokinetic ( voltage ), or other mechanical means ( valves ) of gating sample . in the case of electrokinetic sampling the internal hole surface can be tailored using surface coating materials to establish a dielectric where a voltage drop across the two outside x - y planes of the array can be established . the inside structure of the hole can also be modified to include membranes , porous plugs , stationary phases , etc . to achieve desired conditions for solute migration . the rims of each hole on each x - y plane can be metalized and traced to edges for addressing individual channels . the array of holes are individually addressable such that a potential can be applied to a selected channel , or set of channels , where solutes are sampled preferentially from designated channels in the observation barrier array and advanced through the train . the sampling aperture arrays can also be used to achieve analyte mixture separation or sample preconcentration using electrophoretic or field amplified sample stacking ( fass ) methods ( 8 , 9 ). these means can be used in combination with control of both pressure and flow , including stop flow . this alternate preferred embodiment with additional stages is schematically illustrated in fig4 . the media reservoirs 6 a and 6 b containing input media 1 can selectively and independently deliver differential media to sample 3 by input means 2 comprising peristaltic pumps 7 a and 7 b . the media is delivered through entrance aperture array 9 to culture volume 10 containing sample 3 . said sample comprising cells , tissue , or micro - organisms respond to said input media with biological activity that results in both absorption of at least some of the input media and subsequently the output of products of said biological activity . the output products are passed through observation barrier 14 whereby output media is directed toward media or solvent outlet 36 . this direction of flow can be facilitated by downstream pumping . some of the products of bio - activity of sample cells may directed away from outlet 36 flow by being induced to pass through addressable array 28 . the product species can be induced to flow across the addressable array by electrostatic forces , mechanical forces , and / or pressure . at the downstream side of the addressable array 28 solvent input 38 is accomplished to condition the sample for detection with the mass spectrometer . solvent input 38 may comprise a wide variety of solvent and solvent modifier alternatives . said input 38 entrains the product output from addressable array 28 and directs the flow through addressable array 30 to be sampled for downstream monitoring through movable sampling aperture 12 resulting in product output 16 . the product output 16 is directed to sampling valving means 20 under the influence of output sampling pump 18 . in this embodiment , the conditioning means 20 can switch the product output flow into a preconcentration step 40 and a cleanup step 42 . an example of this would involve solid phase extraction to concentrate and desalt sample in order to optimize the response of sample output components . sample output monitoring is accomplished by separating output components with chromatograph 22 and analyzing with mass spectrometer 24 . we envision no restriction on the breadth of alternatives for chromatographic separation or mass spectrometry analysis ; including , but not limited to ms / ms , icp / ms , gc / ms , lc / ms , ic / ms , and any number of parallel or serial techniques that are used to character both organic and inorganic species resulting from biological activity . additionally , this embodiment is intended to incorporate mechanical positioning control 26 of both media input 8 and product output 16 as illustrated in fig3 . these components facilitate the positional and temporal control of both input of input media to the sample and output of product output . in this embodiment , a plurality of outputs 16 may be incorporated into the device . the additional arrays , or x - y plane sampling apertures , can also be used for ion generation using atmospheric pressure ionization or desorption ionization electrospray methods . fig5 illustrates a system using two downstream aperture arrays and a x - y translation stage populated with sampling apertures . the system can load sample from the observation barrier through either hydrostatic pressure , electrokinetic , or mechanical means , perform preconcentration and electrophoretic separation of the sample mixture , and optionally perform electrospray ionization if the translation stage sampling aperture comprises a spray nozzle . in this embodiment an exit for the culture media , or downstream solvent , is provided radially at the gap between the observation aperture and addressable array 1 . an additional flow stream consisting of an appropriate solvent for analysis and / or preconcentration is introduced radially at the gap between addressable array 1 and addressable array 2 . the flows and pressures of the media input and the solvent input can be controlled and switched to generate optimum conditions for a particular sampling state . addressable array 2 can be used for sample separation using electrophoretic methods . the state table shown in fig6 illustrates one example of the functional modes of the system where sample is preconcentrated , separated , and ionized by electrospray . in this example we show the sampling of positive ions and neutrals capable of migrating toward a negative applied potential . both addressable arrays are dielectrics and can be controlled at independent potentials . rather than using a translational stage for discrete sampling , any embodiment of the device can have as its final stage an array of electrospray nozzles to accommodate each channel of flow , or for combinations of channels . the general use of such a device is based on control of conditions for ion sampling or generation in order to selectively analyze samples . in this case , on a practical basis , to focus ions from such a broad source , such as described and into a single analytical instrument , ion funneling ion optics are used . this alternate preferred embodiment is schematically illustrated in fig5 . the media reservoir 6 containing input media 1 is delivered to sample 3 by input means 2 comprising a peristaltic pump 7 . the media input 8 is delivered through entrance aperture array 9 to culture volume 10 containing sample 3 . said sample comprising cells , tissue , or micro - organisms the respond to said input media with biological activity results in absorption of at least some of the input media and subsequently the output of products of said biological activity . the output products are passed through observation barrier 14 whereby output media is directed toward media or solvent outlet 36 . this direction of flow can be facilitated by downstream pumping . some of the products of bio - activity of sample cells may directed away from outlet 36 flow by being induced to pass through addressable array 28 . the product species can be induced to flow across the addressable array by electrostatic forces , mechanical forces , and / or pressure . at the downstream side of the addressable array 28 solvent input 38 is accomplished to condition the sample for detection with the mass spectrometer . solvent input 38 may comprise a wide variety of solvent and solvent modifier alternatives . said input 38 entrains the product output from addressable array 28 and directs the flow through addressable array 30 to be sampled for downstream monitoring through electrospray needle array 44 . discrete and individually addressable electrospray needles are actuated through applying a needle potential relative to the electrospray counter - electrode 46 . electrospray ionization produces sample product ions that are directed to mass spectrometer 24 . additional stages in this embodiment may alternatively include conditioning of sample streams to desalt , enrich , and further modify the sample downstream from the sample region with mobile phase components , buffers , modifiers , electrolytes , and ion - pairing reagents . downstream modification is intended to be completely isolated from the sample environment as to not effect the biological activity of the sample . an additional preferred embodiment is schematically illustrated in fig7 b . with this embodiment input media 1 are pumped into a tubular bed comprising a bundle of permeable tubes 60 connected to the input flow via permeable tube union 62 . the sample 3 with this embodiment is interspersed throughout the tubular bed of permeable tubes . the passage of input media and the collection of output products in accomplished by movement out of and into the said tubes . this simple tubular bed device has fluid mechanical and mass transfer similarities to the schematic illustration of a capillary bed supplying blood to human tissue in fig7 a . monitoring means for output from the tubular bed can be accomplished by any number of liquid detection systems , including , but not limited to lc / ms , ms / ms , icp / ms , gc / ms , and ic / ms . an additional preferred embodiment is schematically illustrated in fig8 . with this embodiment input media 1 are pumped into a tubular bed comprising a bundle of permeable tubes 60 connected to the input flow via permeable tube union 62 . the sample 3 with this embodiment is interspersed throughout the tubular bed of permeable tubes . the passage of input media and the collection of output products in accomplished by movement out of and into the said tubes . this more complex tubular bed device incorporates two separate input and output flow streams in contrast to fig7 b . the input means 2 is shown as a bed of permeable tubes 60 . the output means 4 is shown as a bed of permeable tubes 60 oriented at 90 degrees relative the input means . sample is interspersed between both input and output bundles in order to have good spatial distributions of input media through the sample and representative spatial collection of the output products of biological activity of the sample . the output means 4 bundles deliver product species to monitoring means 5 . in addition , the flow through both input and output streams can be optionally recirculated by recirculation loops 70 and 72 . another option with this embodiment is the addition of collection sampling of input and output streams 74 , 76 , and 78 . the sampling of these streams at various locations before and after the sample enables real - time monitoring of the composition of the stream composition and feedback control of the input media composition based on measured results . the ultimate outcome of this configuration can be real - time closed loop feedback control of the activity of the sample biological activity . addressable aperture array embodiments —( as seen in fig3 , 4 , and 5 ) a component part of fig3 , and 5 are a number of uses of addressable arrays . addressable arrays are intended to allow controlled transport of sample through a specific aperture within an array of aperture or general transport across the entire array . we envision a number of embodiments for aperture arrays to segregate , control , and select materials moving through the device . we envision two type of aperture arrays , namely , simple and addressable . simple arrays are surfaces with a plurality of holes across a transport surface that enable transmission of material from one layer to the next as illustrated in fig9 c . there is no selectivity in the x - y dimension with this array 100 , however , differential transport can be facilitated by pressure differences ( controlling flow between layers ) or electrostatics ( applying a voltage between metal aperture array separated by an insulator layer . note that electric fields will only directly influence motion of sample “ ions ”. indirectly , momentum from moving ions can be imparted to neutral sample species . addressable aperture arrays have the added control and flexibility of influencing the transport of material through discrete and selectable apertures across the array surface . we envision a number of alternative embodiments of addressable arrays ; including , mechanical and electrostatic control . fig9 a and 9 b describe an electrostatically controlled addressable aperture array . with this embodiment sample ions flow through specified apertures based on applied voltages to the specified apertures . ( e . g . apertures 1 and 3 do not transmit , apertures 2 and 4 transmit ) this illustration shows a three layer aperture array with upstream electrode layer 92 , intermediate electrode layer 93 , and downstream electrode layer 96 . layer 93 comprises discrete electrodes 95 that can have attracting or repulsing potentials that facilitate transmission of repulsion of sample ions . the combination of three electrode layers is designated as a laminated array . fig9 b shows the planar display of the individually addressable discrete electrodes 95 with associated conductance aperture 98 . the voltage applied to the discrete electrodes is controlled by control means 97 . the three electrode layers of the laminated array are separated by an insulating material that fully defines the conductance pathway through the apertures from upstream to downstream regions . the thickness of the insulating material can be quite substantial and in some device the insulators can be bundles of insulated tubes connecting the layer of the laminate . in the longer tube embodiments , electrophoretic processes can by used to select and separate sample components across the addressable arrays . the simplest addressable arrays lack discrete electrodes but have the ability to attract or repel uniformly across the entire laminate surface . mechanically controlled addressable aperture arrays may comprise additional components at each aperture that restrict of facilitate the selective transport of material across the discrete aperture . alternate modes of gating or valving the apertures will involve the use of micro - valves and piezoelectric materials to open or close apertures . we envision micro - fabrication processes associated with mems ( micro electrical and mechanical systems ) are required to meet the spatial requirements for selective sampling of output products from cell samples . samples interrogated with this invention include , but are not limited to cells , tissues , micro - organisms , cell cultures , tissue cultures , viruses , bacteria , collected samples from a biological ( e . g . bio - hazards or bio agents ), and cells supported upon a substrate material . we envision homogeneous biological samples to be evaluated by precise spatial and temporal monitoring under controlled input of input media , allowing both spatial and temporal information about the sample activity . it is important to note that one mode of operation of this invention with homogeneous samples will include differential input of input media across the sample volume in order to test differential response to said input media by the sample ; as measured by the differential spatial and temporal measurement of output products . applications to drug dosing studies or toxicity studies for a given cell line apply to this embodiment . in addition , interrogation of samples may also include heterogeneous composition of sample applied to the sample observation window in order to evaluate differential response from varied cell or tissue types to uniform input media application . this application would certainly have applications in tissue imaging studies , as well as interrogation of wild and variant cell lines . any combination of sample variability and input variability may be applied to application of this invention to solve problems in studying living cell behavior . other applications for samples that do not include living cells are envisioned for monitoring 2 - dimensional and 3 - dimensional samples for spatial and temporal imaging . an example of this would involve the inclusion of 2 - d gels containing separated components from a cell lysate in order to extract and characterize gel sample components by transferring then downstream ( z - dimension ) for further conditioning and analysis ( e . g . enzymatic digest and sequencing ). non - biological samples can also be evaluated for temporal and spatial composition . an example would be the evaluation and interrogation of catalytic surfaces under time and space varying conditions . the general concept of the current invention is to allow local and controlled input of various media to cell cultures and tissues while also maintaining precise local collection of output products from biological activity . the present preferred embodiments illustrate two approaches ; namely , laminar and tubular . it is the intent of this invention not to limit the geometries to the illustrated embodiments ; but to further disclose that combinations of sample geometries that incorporate both laminar and tubular input , sample , and output components will serve to address the sampling needs for some set of sampling applications . we envision , for example , incorporating tubular beds into the sampling region of a laminar device . this added input or output capability will have advantages for some cell types of sample geometries . we also envision geometries that may conform to sample characteristics that are neither laminar or tubular . 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