ROTARY ACTUATOR VALVE FOR A CELL CULTURE SYSTEM

BACKGROUND OF THE INVENTION

1. Field of the Invention:

[0001] The present invention relates to a sterilizable, disposable actuator driven rotary selection valve for a cell culture system, and more particularly to rotary selection valve having automated actuation to open and close various tubing lines in a cell culture application.

2. Description of the Related Art

[0002] The anticipated growth of personalized medicine will require new paradigms for the manufacture of therapies tailored to the needs of individual patients. The greatest challenge is expected to come in the area of cell based therapies, especially when such therapies are autologous in nature. In such cases each cell or cell based product will need to be manufactured from scratch for each patient. Manual methods for mammalian cell culture, by their nature, are prone to technician error or inconsistency leading to differences between supposed identical cultures. This becomes especially evident as more and more autologous cells are expanded for personalized therapies. Patient-specific cells, or proteins, are subject to variation, especially when scaled beyond levels that can be managed efficiently with manual methods.

[0003] In addition to being labor intensive, the stringent requirements for segregation of each patient's materials from that of every other patient wilFmean that manufacturing facilities will be large and complex, containing a multitude of isolation suites each with its own equipment (incubators, tissue culture hoods, centrifuges) that can be used for only one patient at a time. Because each patient's therapy is a new and unique product, patient specific manufacturing will also be labor intensive, requiring not just direct manufacturing personnel but also disproportionately increased manpower for quality assurance and quality control functions.

[0004] Moreover, conventional approaches and tools for manufacturing cells or cell based products typically involve numerous manual manipulations that are subject to variations even when conducted by skilled technicians. When used at the scale needed to manufacture hundreds or thousands of different cells, cell lines and patient specific cell based therapies, the variability, error or contamination rate may become unacceptable for a commercial processes.

[0005] Small quantities of secreted product are produced in a number of different ways. T-flasks, roller bottles, stirred bottles or cell bags are manual methods using incubators or warm-rooms to provide environments for cell growth and production. These methods are very labor intensive, subject to mistakes and difficult for large scale production.

[0006] Another method, ascites production, uses a host animal (usually a mouse) where the peritoneum is injected with the cells that express the product and are parasitically grown and maintained. The animals are sacrificed and the peritoneal fluid with the product is collected. This method is also very labor intensive, difficult for large scale production and objectionable because of the use of animals. Another method is to inoculate and grow the cells in a small stirred tank or bioreactor or bag-type chamber. The tank provides the environmental and metabolic needs and the cell secretions are allowed to accumulate. This method is costly in terms of facility support in order to do a large number of unique cells and produces product at low concentration.

[0007] Another method is to use a bioreactor (hollow fiber, ceramic matrix, fluidizer bed, etc) in lieu of the stirred tank. This can bring facilities costs down and increases product concentration. Biovest International of Coon Rapids, MN, has or had instruments using these technologies - hollow fiber, ceramic matrix, fluidized bed and stirred tanks.

[0008] Cell culturing devices or cultureware for culturing cells in vitro are known. As disclosed in U.S. Patent No. 4,804,628, the entirety of which is hereby incorporated by reference, a hollow fiber culture device includes a plurality of hollow fiber membranes. Medium containing oxygen, nutrients, and other chemical stimuli is transported through the lumen of the hollow fiber membranes or capillaries and diffuses through the walls thereof into an extracapillary (EC) space between the membranes and the shell of the cartridge containing the hollow fibers. The cells that are to be maintained collect in the extracapillary space. Metabolic wastes are removed from the bioreactor. The cells or cell products can be harvested from the device.

[0009] Preparing the system to start the cell culture is very labor intensive. The cultureware must be assembled and sterilized or probes must be prepared, sterilized and aseptically inserted into the pre-sterilized portion of the cultureware. The cultureware assembly is then loaded onto the instrument. A series of manual operations are needed to check the integrity of the assembly, introduce fluid into the cultureware flow path, flush the toxic residuals (e.g. surfactants) from the cultureware, start the cultureware in a pre- inoculation mode, introduce factors into the flow path getting it ready for the cells,

inoculating the cells into the bioreactor and starting the run (growth of the cell mass and eventual harvest of product).

[0010] Each unique cell or cell line must be cultured, cell products harvested and purified separately. In order to do a large number of unique cells or cell lines, a considerable number of instruments would be needed. If application of the cells or products for therapeutic purposes is contemplated strict segregation of each cell production process would be required. Consequently compactness of the design and the amount of ancillary support resources needed will become an important facilities issue. Moreover the systems currently available are general purpose in nature and require considerable time from trained operators to setup, load, flush, inoculate, run, harvest and unload. Each step usually requires manual documentation.

[0011] The necessity of sequentially controlling a series of flow conduits is necessary for such cell culture devices. The known selector valves are complex selector valves that are custom designed for use in particular products. These valves are not automated and must be actuated manually. Such valves are commercially available from vendors such as Upchurch Scientific of Oak Harbor, WA.

[0012] Another approach to actuator driven selector valves to control multiple fluid delivery utilize a solenoid driven pinch mechanism, such as those supplied by Aero Associates of Concord, CA. These devices utilize a piston plunger actuated by an electrical coil to provide linear motion to pinch the tubing. A manual pinch clamp is also available from Qosina Corporation of Edgewood, NY. In such a device the clamping position is manually activated by a mechanical bearing surface that compresses the tubing and then is held in position by a detent feature. Manual deactivation is required.

[0013] Another approach to selectively control flow via multiple ports is to use a membrane over a series of ports. The membrane is actuated against a port to seal it. Multiple ports are configured for use as a selector mechanism. Such a device is available from Baxter Healthcare of Deerfϊeld, IL.

[0014] In cell culture, the fluid path must be free of unwanted organisms, i.e., sterilizable. Commercially available selector valves are not gas sterilizable. Sealing surfaces of such devices may be unexposed to gas sterilant and hence may be non-sterile when the valve is repositioned.

[0015] Accordingly, there is a need for a disposable, actuator driven rotary selection valve for use in conjunction with a cell culture system that is a fully automated and sterilizable.

SUMMARY OF THE INVENTION

[0016] One aspect of the present invention is to provide a rotary selection valve for a cell culture system having automated actuation.

[0017] Another aspect of the present invention is to provide a rotary selection valve that can be sterilized.

[0018] Yet another aspect of the present invention is to provide a disposable rotary selection valve that simulates the function of an expensive switching valve.

[0019] An aspect of the invention is to also provide a rotary selection valve that does not require power to maintain any operating position.

[0020] Still another aspect of the present invention is to enable offset occluded/open cam positioning of two tubing lines to ensure a make-before-break switching of fluids.

[0021] According to these and other aspects of the present invention there is provided a cell culture system for the production of cells and cell derived products comprising a reusable instrumentation base device incorporating hardware to support cell culture growth. A cell cultureware module is removably attached to the instrumentation base device and includes a cell growth chamber. At least one rotary actuator valve is provided for controlling circulation of cell culture medium through at least one elastomer medium flow circuit in the cultureware module. The at least one rotary actuator valve includes a housing having an inner passage and at least one port for receiving the at least one elastomer medium flow circuit, and a valve body having first and second ends located within the inner passage of the valve housing and rotatable about a longitudinal axis within the valve housing. The valve body includes a plurality of cam surfaces and angular sections disposed along a length thereof to sequentially compress and open the elastomer medium flow circuit as the valve body rotates within the valve housing.

[0022] These and other features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment relative to the accompanied drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Fig. 1 is a perspective view of the system for producing cells and/or cell derived products according to the present invention.

[0024] Fig. 2 is a perspective view of the cultureware module of the present invention.

[0025] Fig. 3 is a perspective view of the instrumentation device of the present invention.

[0026] Fig. 4 a perspective view of a rotary selection valve of the present invention.

[0027] Fig. 5 is an exploded view of the rotary actuator valve of Fig. 4, wherein the valve housing is shown separate from the cultureware module for clarity.

[0028] Fig. 6 is another exploded view of the rotary selection valve of the present invention without the drive mechanism.

[0029] Fig. 7 is a front view of the valve housing shown separate from the cultureware module for clarity.

[0030] Fig. 8 is another perspective view of the rotary selection valve of the present invention.

[0031] Fig. 9 is a rear view of the instrumentation device.

[0032] Fig. 10 is a perspective view of the gas blending and fluid cycling control of the module of the present invention.

[0033] Fig. 11 is a perspective interior view of the back panel of the module of Fig. 2.

[0034] Fig. 12 is a flow diagram of the system of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Referring to Fig. 1 , the present invention provides a fully integrated system 10 for producing cells and cell derived products in a closed, self-sufficient environment. More specifically, the system allows for cell expansion and harvest of cells and their products with minimal need for technician interaction. As will be described further herein, the device incorporates cell culture technology, for example. hollow fiber or similar bioreactor perfusion technology, with all tubing components, media feed, harvest tubing and tubes threaded through the pump cassette, encased in a single-use, disposable incubator 12. Following bioreactor inoculation with cells, the system follows pre-programmed processes to deliver media, maintain pH, maintain lactate levels, control temperature and harvest cells or cell- secreted protein. Standard or unique cell culture growth parameters can be programmed, such that, various cell types can be expanded and such that cells or cell products can be harvested in an efficient, reproducible manner with minimal chance of human error.

[0036] The system is based on cell growth chamber technology. For example, bioreactors that have a plurality of semi-permeable hollow fibers or other type of semipermeable membrane or substrate potted in a housing to create a space inside the fiber or one

side of the membrane (referred to as intracapillary or IC space) separate from that outside the fibers or on the other side of the membrane (referred to as extracapillary or EC space). Fluid distribution between the IC and EC space occurs through the fiber pores which can range in size from IOMW (Kd) to 0.2μm. Cells are placed on one side of the fiber or membrane, usually in the EC space, in a complete cell culture medium, which is usually the same medium used to expand cells prior to bioreactor inoculation (serum containing, serum-free, or protein-free medium). Cells are usually placed in the EC space when secreted protein is the desired product. In some instances, when cells are the desired product, it may be beneficial to place cells in the IC space.

[0037] Medium is perfused through a bioreactor 20 by circulating through the IC space at a fast rate. This serves to deliver nutrients to the cell space and conversely, removes or prevents a toxic build-up of metabolic waste. During this circulation, medium is passed through a gas exchange cartridge 24 which serves to provide pH control and oxygen for the cells and conversely, remove carbon dioxide from the culture. When the bioreactor 20 contains a smaller number of cells, just after inoculation, gas exchange cartridge 24 is used to provide CO ₂ and subsequently control pH of the culture environment. As cell number increases, gas exchange cartridge 24 is used to remove CO2 which serves to enhance acid neutralization and control the pH of the culture. Other bioreactor configurations, in addition to hollow fibers, that are designed and optimized for the growth and production of cells and production of cell-derived products are also included.

[0038] As described above, integrated refrigerated storage area 18 maintains growth factors and harvested cells or cell products at a low temperature (approximately 4°C). Referring to Figs. 1, a plurality of bags 62, 64 are located within the refrigerated storage area 18. The bags are used to contain the smaller quantities of product or growth factors. It should be appreciated that other solutions can be disposed with the bags. For example, high molecular weight growth factor can be located with bag 62. This factor is connected via tubing to the bioreactor or cell growth chamber 20 and the flow controlled by pump 16. Harvested cells or cell products can be stored in bag 64. A cell filter can be provided to provide additional filtration. A filter bypass line is included if filtering of the harvest is not desired as in the case of cell collection. After the process is complete the cells can be removed from the cell culture chamber via the tubing and stored in bag 64 until use.

[0039] The system 10 provides significant efficiencies and cost reduction through its disposable component and enclosed operation. As such, cell lines are contained in a closed system and continuously cultured without the need for specialized, segregated clean rooms.

This fully integrated apparatus eliminates the need for cleaning and sterilization validations, as well as the need for hard plumbing associated with conventional cell culture facilities.

[0040] As shown in Figs 2 and 3, the system consists of two individual parts: an instrumentation base device 14 that is reusable and enclosed cultureware 12 that is used for a single production run and is disposable. The instrument base device 14 provides the hardware to support cell culture growth and production in a compact package. An easy-load multiple channel peristaltic pump drive 16 located in base device 14 having a pump cassette 70, removably located on module 12, moves the fresh basal media into the cultureware, removes spent media, adds growth factors or other supplements and removes product harvest. An integrated heating mechanism 22 (Fig. 9) maintains the cell environment to promote growth and production. The gas exchange cartridge 24 in conjunction with a cultureware pH sensor 26 controls the pH of the cell culture medium.

[0041] Referring to Figs 3-7, two automated rotary actuated tube valve drives 90 are used to control the cultureware flow path configuration to accomplish the fluidic switching functions needed to initiate arid do a successful run. It should be appreciated that although two valves are described the present invention contemplates the use of a single, as well as more than two valves 90. Valves 90 and sensors 32 (Figs. 8, 9) located in instrument device 14 control the fluid cycling in the cultureware module 12, as will be described further herein.

[0042] Sterilizable, disposable, actuator driven, rotary selection valves 90 of the present invention are shown in detail in Figs. 4-7. Valve 90 comprises a valve housing 92 and a valve body 94. Valve body 94 can be made from stainless steel or any other appropriate material. Valve housing 92 can be a molded plastic, such as Noryl ^® .

[0043] Referring to Figs. 5 and 6, valve body 94 is elongated and has a first end 95 and a second end 96. Valve body 94 rotates about a longitudinal axis of rotation 102. A drive shaft 106 is located at second end 96 and communicates with a servo 150 to rotate valve body 94 within housing 92.

[0044] Valve housing 92 has opposed ends 132, 134 and includes an inner passageway 130 extending therebetween. A plurality of ports 138 are formed in wall 136 of body 92. As shown in Fig. 7, a portion of elastomer tubing 100 that forms a flow circuit of one of the fluids of the system extends through each port 138.

[0045] The system of the present invention uses at least two rotary selection valves 90. A first valve 90 uses two tubing lines 100 each extending through an individual port 138. Referring to Fig. 12, the tubing lengths of valve V ₁ can direct growth factors to either the IC or the EC fluidic circuits. A second valve V ₂ can have three fluid circuits 100 that direct the

EC fluid to discrete flow directions. It should be appreciated however, that the use of additional valves is contemplated by the present invention.

[0046] Housing 92 can be a separate component integrated into module 12 or as shown in Fig. 11 molded integrally with a back panel 148 of module 12. For clarity, housing 92 is shown separately from back panel 148 in Figs. 4-7.

[0047] As shown in Fig. 6, valve body 94 includes a plurality of cylindrical cam portions 108, 110 and 112 that act as occluding cams to compress the tubing between these surfaces and inner wall 136 of housing 92 as the body is rotated. An upper portion 114 of valve body extends along the length of valve body 94 and when aligned with the ports and elastomer tubing acts to free the tubing lengths to allow the medium to flow therethrough. In addition to upper portion 114, valve body 94 includes a plurality of planar cam sections 116, 118 that are angularly offset from portion 114 and cylindrical cam surfaces 108, 110 and 112. Like upper portion 114, angular sections 116 and 118 when aligned with a respective elastomer tubing or conduit allows fluid to flow therethrough. Thus, rotation of valve body 94 allows cam surfaces 108, 110, 112 to sequentially compress adjacent conduits and/or upper portion 114 and angular sections 116, 118 to unobstruct the conduits.

[0048] Valves 90 are based on a cam shaft concept. The valve has a low position lobe, where portions 144, 116 and 118 are aligned with tubing 100, that allows for the tubing to be full open. When the valve body is rotated to a high position, where cam surfaces 108, 110 and 112 are aligned with the tubing, the tubing is occluded against the valve body or bearing surface. As will be described further herein, the valve requires power to rotate body 94 to move the cam surfaces to a specific location, but once it is there, it is a static condition and requires no additional power to retain an occluded or open state. The valve body of the present invention has multiple tubing sections on the same shaft. For one body, the cam surfaces may have multiple low and high positions. For another valve body, there may also have multiple low and high positions.

[0049] Thus, the elastomer tubing 100, only one length being shown in Fig. 7, of the conduits acts as a flow circuit for the various medium and is insertable through openings or portsl38 in valve housing 92 and is occluded by the cam surfaces 108, 110, 112 of the rotating valve body 94 that compresses the tubing against the inner wall 136 of valve housing 92. This is accomplished by using a controlled, incremental, servo drive 150 (actuator and position feed back loop) controlled by microprocessor 200 to move the cam surfaces that react against immobile valve housing 92, which holds the tubing in a constrained state. The cam design allows for a high area of the cam surfaces 108, 110 and 112 to occlude the tubing

and a smaller area of portions 114, 116, 118 of body 94 not to occlude, resulting in a closed and open condition respectively.

[0050] The valve body positioning is control by servo 150. As valve body 94 rotates an integral encoder disci 60 rotates with the valve body. Encoder disc 160 has rotary open slots 162 that allow for a light signal to pass through. The light signal is sent and received by an encoder sensor electronic assembly 163 that has multiple light sensors that trigger the electronics and control software to determine the angular position based on the receivers having or not having a light signal.

[0051] It should be appreciated that other configurations that allow multiple tubing segments in one device are contemplated by the present invention. The cam rotational positioning features may also be added to move valve body 94 to predetermined positions. Configurations can be structured to accommodate multiple tubing segments in one device.

[0052] As shown in Figs. 3 and 8, valve body 94 and servo 150 inserted from the back of instrument device 14 so that the servos 150 are located behind panel 36. Valve body 94 extends through panel 36 so that it is received within housing 92 that is integrally molded in back panel 148 of module 12 or separately disposed within the module.

[0053] The combined unit is to be automated, which required various tubing lines of the disposable to be occluded/open to provide automated process control. The selector valve is used to automatically open and close tubing lines to direct fluid or gas flow during process control. Minimizing operator set-up is also a requirement. The disposable cultureware must be inserted into the instrument in an operating position with no special operator procedures required for loading the tubing into the valves.

[0054] In the cell culture system of the present invention, the fluid path must be free of unwanted organisms, i.e., sterilized. Commercially available selector valves are not gas sterilizable. Sealing surfaces of the selected position may be unexposed to the gas sterilant and those surfaces may be "non-sterile" when the valve is repositioned. Valve 90 of the present invention provides automated actuation of the cam surfaces, compactness, use of multiple lines, maintains valve position even with loss of actuator power, the disposable valve body is less costly than an equivalent switching valve, and can be incorporated into the back panel of module 12. Offset occluded/open cam. positioning of two tubing lines can insure a make-before-break switching of fluids. Make-before-break is accomplished by radially offsetting these positions so that a high position for one tube is occluded before the low position of another tube as the cam is rotated. No power is required to maintain any

operating position, and the tubing segments used in the valve body can be sterilized when the valve body is in an open position.

[0055] The multiple piece design of valve 90 allows for the fluid contact portion of the valve (housing 92) to be molded into the back panel 148 (Fig. 11) and to be sterilized (either by EtO, chemical or radiation procedures) with the rest of the fluid circuit and eliminates the need to be added separately after sterilization.

[0056] Referring again to Figs. 1-3, the one-time use cultureware module 12 is provided pre-sterilized. It is designed for quick loading onto the instrument ("quick-load"), as will be described further herein. The loading of the cultureware body makes connections to the instrument. Pump cassette 70, which is physically attached to the tubing, allows the user to quickly load the pump segments. The design and layout minimizes loading errors. A fluid cycling unit 40 that maintains fluid volumes and cycling is included in cultureware 12. The blended gas from the instrument is routed to gas exchange cartridge 24 that provides oxygen and adds or removes carbon dioxide to the circulated fluid to support cell metabolism. A magnetically coupled pump drive 34 circulates fluid thru the bioreactor 20 and gas exchange cartridge 24. Disposable containers for harvest collection are provided. Prior to the beginning of the culture the operator attaches a media source, factor bag and spent media container to the cultureware before running. At the conclusion of the run the harvest containers are removed or drained, media and spent media container is disconnected, pump cassette is unloaded, harvest bag disconnected, cultureware body is unloaded and the used cultureware is placed in a biohazard container for disposal.

[0057] As described above, disposable cell culture module 12 is removably attachable to device 14. The module requires multiple mechanical and electrical interfaces to the control instrumentation of device 14. Module 12 has interface features integrated into the module that mate with instrument interface features in the device to allow for a single motion installation. As shown in Fig. 3, the interface features of device 14 include magnetically coupled circulation pump drive 34, rotary driven actuator valves 90 and a cycling sensor 32. In addition, a temperature probe 44 and a flow sensor 46 interface with the components of module 12. Device 14 also includes an electrical connection 48 forpH probe 26 disposed within module 12.

[0058] As described above, module 12 is heated to maintain cell fluid temperature. Heating mechanism 22 maintains the cell environment to promote growth and production. The cell culture, disposable modules 12 requiring elevated temperatures are warmed by fully encapsulating the module and attaching the module to the controlling instrument 14, such that

air ports are aligned and warmed air is forced into the module from the instrument at one location and allowed to escaped at another. Instrument device 14 has a heated air outlet 58 and a return heated air inlet 56.

[0059] During installation, module 12 is aligned with the connections of the device 14 and the module is placed into the operating position. All mating interface features are functional. Referring to Figs. 3 and 10, when installed, certain features of the module 12 interface with device 14. Module air outlet 86 aligns with device air inlet 56 and module air inlet 88 aligns with device air outlet 58 to circulate heated air through module 12 as described herein. Gas connectors 152 and 154 engage device gas ports 52 and 54, respectively, to allow gas to enter and exit module 12. Valve housings 92 receive actuator valves bodies 94 such that the free end 95 of the valve body 94 extends into housing 92 located in module 12. Hub 158 receives pH sensor probe 26 interface and aligns with electrical connector 48. Module 12 is connected to circulation pump drive 34 via module pump 164. Cycling unit 40 also communicates with cycling sensor 32 when the module is installed. The flow sensor 46 of device 12 mates with flow sensor connection 166. The temperature sensor 44 of device 14 mates with a non invasive receptacle 168 in module 12 that is in contact with the IC media to provide control feed back to the control mechanism to regulate the thermal output of heater 22. The above mating connections facilitate the one-motion installation of the module 12 on the device.

[0060] At present, the system of the present invention fully integrates the concept of disposable cultureware into automated process control for maintaining and expanding specialized (autologous or other) cell lines for a duration of any time needed. To accomplish this, the system of the present invention was designed for EC space fluid flow that enhances cell growth in high density perfusion culture, yet remains completely closed and disposable. The integrated pre-assembled cultureware, which consists of all tubing, bioreactor, oxygenator, pH probe, is enclosed in a single unit that easily snaps into the apparatus. In addition to this error-proof, quick-load design, the entire cultureware unit enclosed by the casing becomes the cell culture incubator with temperature control regulated through automated process control of the instrument.

[0061] Pumps and fluid control valves facilitate disposability and error-proof installation, eliminating the possibility of technician mistakes. The present invention provides automated actuation of the rotary selector valves in a compact, sterilizable unit. The position of the valves can be maintained even with the loss of actual power. The disposable valve

body is less costly than an equivalent switching valve and the tubing segments used in the system can also be sterilized.

[0062] Referring to the flow diagram of Fig. 12, pump 16 moves fresh basal media into the cultureware at media line 210. Media line 210 is connected to a user provided container of fresh media to provide the growth nutrients to the cell culture that are pumped into the disposable. Outflow line 214 is connected to a user provided container to collect the waste or spent media being pumped out of the disposable. Factor line 212 is connected to a user provided container of growth factors that are pumped into the disposable. EC inoculate can be added at 220 and IC sample at 216. Product harvest is removed at 126. The cells are harvested at 218. Harvest line 218 is a pre-attached container that is part of the disposable that is used to collect the product that is pumped out of the disposable. Pump 16 has multiple lines 210, 214, 212 and 126. Because the pump of the present invention has a common fixed axial shaft and individual servo driven rotors, the control of the flow of each can be independent, allowing one channel or flow to be increased while another decreased.

[0063] Each unique cell line must be cultured, cell secretions harvested and purified separately. In order to manage a large number of unique cell lines, as for example might be required for the production of large numbers of autologous cell therapeutic products or large numbers of unique monoclonal antibodies, a considerable number of instruments would be needed. Compactness of the design and the amount of ancillary support resources needed become an important facilities issue. Small stirred tank systems require a means of steam generation and distribution (for steam-in-place sterilization) or autoclaves to sterilize the vessels and supporting plumbing. To support a large number of units becomes a logistics problem for the facility. The system of the present invention has no such requirement. Larger scale cell culture is historically done in segregated steps that often require separate types of equipment. Manual handling, storage and tracking is needed for all these steps as the culture expands and product is harvested. The method of the present invention integrates these steps into a continuous, fully integrated sequential process. This eliminates the handling risk and facilitates the data gathering required for thorough documentation of the entire process.

[0064] Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.