The disclosure relates to reagent containment and delivery.
Many analytical techniques require the use of precise, and sometimes small, amounts of reagent. In molecular biology for example, reactions are often conducted in microfluidic environments and several reagents must be combined in precise amounts and ratios to ensure an acceptable result. Furthermore, many reactions are sensitive to contamination and reagents must therefore be stored and manipulated in a controlled environment. Various attempts to automate reagent delivery can remove some human error but come with their own shortcomings.
Existing methods of automated reagent delivery include robotic fluid handlers and microfluidic devices. Typically, fluid is distributed from a central reservoir into reaction wells. The hardware used in fluidic devices has many moving parts, is expensive, challenging to maintain, and large in size. Hardware that controls microfluidic chips is simpler, less expensive, and small but chips used for dispensing reagents and conducting reactions can be expensive. Hardware used with fluid handlers offers programmable flexibility but are expensive due in part to associated programming costs.
Microfluidic chips are less flexible, they can be difficult to customize, and costs can escalate with additional layers, precision requirements, and additional channels or reservoirs. Inkjets have been coupled to robotic platforms but they are typically dedicated to a particular reagent (not washed and refilled), have dead volumes, must be primed, and reagents must be kept cool prior to dispensing. Due to set-up time and reagent overfill (dead volumes) robotic platforms are most practical with large numbers of samples (e.g., greater than 96 samples to be run under identical conditions). For ease of design, microfluidic chips frequently process a single sample through multiple steps or multiple samples through a single step.
The invention provides reagent delivery systems for the precise delivery of defined reagent volumes. Delivery systems include a reservoir having a deformable portion that, when actuated, causes delivery of reagent contained therein through a nozzle integrated into a wall of the reservoir. Such reservoirs can have a dead space due to an imperfect compression of the deformable portion causing some portion of the reagent to remain trapped in the reservoir after expression. That inefficiency results in wasted reagent, added costs, and imprecise delivery that can negatively impact sensitive reactions. This disclosure addresses that issue by providing for the addition of an inert solution that occupies the dead space within the reservoir to insure that the entire contained reagent is expressed through the nozzle and only some portion of the inert solution remains. Accordingly, minimal reagent is wasted and the volume of reagent expressed into a reaction can be precisely controlled. Furthermore, because the filler solution is inert, it will not affect the reaction should any be expressed into a reaction along with the reagent.
In a preferred embodiment, the delivery system is a blister pack comprising first and second barriers forming a reservoir for containing reagent and inert solution immiscible with the reagent. A nozzle is integrated in at least one of the barriers and at least one of the barriers forming the reservoir is deformable so as to push reagent through the nozzle upon actuation of the deformable portion. The reservoir can be of any convenient shape and size. A preferred system comprises a first deformable barrier and a second barrier comprising an integrated nozzle to form the reservoir. The nozzle may be fabricated into the second barrier or may simply comprise an opening through which reagent does not flow absent actuation of the deformable first barrier. The nozzle allows precise delivery of reagent upon actuation and avoids a “bulk” reagent dump or spray as is typical in blister pack rupture in other contexts.
Preferably, the inert solution has a lower density than the reagent. This provides an arrangement in which the inert solution occupies a dead space between the reagent and deformable portion of a barrier. When the deformable portion of the barrier is pushed into the cavity containing reagent and inert solution, the inert solution facilitates delivery of reagent through the nozzle, thereby reducing a dead volume of reagent. For example, providing the inert solution may reduce the dead volume of reagent to less than 5% of the total volume of reagent. In certain embodiments, the reagent is oil.
A pre-determined volume of reagent is packaged into reservoirs to be stored or transported, ready for distribution into a reaction environment. Because the volumes of reagents are added to the reservoirs at a manufacturing or distribution point, in the precise amounts required for a given reaction, the potential for human errors at the bench top is avoided. Additionally, the reagents remain sealed in a controlled environment within the reservoir until immediately prior to use, minimizing the potential for contamination.
At the reaction site, reagents are distributed through the nozzle to direct evacuation of the reagent, manage reagent flow rates, or form droplets or otherwise manage delivery format of the reagent. Nozzles may be pre-formed in the reservoir or formed during an unsealing process (e.g., piercing the reservoir with an external nozzle).
At least one surface forming reagent-containing reservoirs is deformable, allowing the forcible evacuation of reagent. The rate of deformation and therefore the rate of reagent delivery can be controlled by varying the actuation force applied to the deformable portion of the reservoir. Reservoirs of the invention can be multiplexed. For instance, multiple reservoirs may be joined together on a sheet or plane and can be positioned to allow sequential addition of different reagents to a reaction at various times.
Reservoirs may be sealed by any of several methods after appropriate amounts of reagent have been added. A sealing film or foil may be applied to cover the nozzle opening and can be removed prior to evacuation of the reagent from the reservoir. The film or foil may be peeled away manually or by machine or may form a frangible seal and open in response to increased pressure within the reservoir (e.g., through deformation of the reservoir). The nozzle may comprise a valve that closes or opens to allow the contained reagent to be retained within or evacuated from the reservoir.
Sheets or planes may be optimized for machine manipulation and automated delivery of contained reagents. For example, a planar array of reservoirs may include through-holes or openings to allow for various additional reagents to be pipetted or otherwise added to a reaction chamber below the sheet to react with reagents expelled from the reservoirs. Sheets or planes may comprise indexing marks or notches to be read by a machine to indicate positioning of one or more of the reservoirs with relation to a reaction chamber or a manipulation tool (e.g., a plunger for deforming the reservoir and evacuating its contents). Accordingly, an automated reagent delivery apparatus of the invention may execute programmed instructions by identifying specific reagent-containing reservoirs and adding their contents to a reaction chamber in a certain sequence and at specific intervals.
Reagents may be stored in a central reservoir in a plane or sheet and distributed in designated portions to various other reservoirs through a manifold to be evacuated through nozzles into a reaction. For example, dry reagents may be stored in a series of reservoirs connected to a central, liquid-containing reservoir. The dry reagents may be more stable in that state, allowing for longer or easier storage. The liquid reagent may be distributed to the various reservoirs containing the dry reagents through a sealed manifold (maintaining a controlled environment and minimizing contamination) just prior to use.
Aspects of the invention may include a reagent delivery system comprising a reservoir defined by a first barrier and a second barrier wherein at least one of the first and second barriers comprises a deformable portion and at least one of the first and second barriers comprises a nozzle. The reservoir can be configured to discharge one or more reagents contained therein through the preformed nozzle upon actuation of the deformable portion.
The nozzle may be pre-formed and the reservoir can have an interior volume from about 5 μl to about 100 μl, inclusive. The nozzle may have a diameter from about 100 μm to about 600 μm inclusive. The nozzle may taper from a diameter of about 0.5 mm near an interior opening in the reservoir to a diameter of about 0.6 mm near an exterior opening outside the reservoir. Alternatively, the taper may be from about 1 mm near the interior to about 1.2 mm near the exterior or any combination in that range (e.g., 1/0.6 mm; 1.8 mm/1.2 mm).
The reservoir may be disposed in a plane or sheet comprising a plurality of reservoirs. The plane can include indexing marks for locating one or more of the plurality of reservoirs. The plane may include one or more openings.
The preformed nozzle may be configured to retain reagents in the reservoir until the deformable portion is actuated. The preformed nozzle can include a sealing member configured to seal the reagents in the reservoir until the deformable portion is actuated. The sealing member may be frangible. The sealing member may include a removable film. The sealing member can include a valve. The sealing member may also comprise a plug and the plug may be composed of either inert or active materials. Moreover, the plug may be ejected by the reagent contents when the reservoir is disrupted (i.e., when the frangible portion is actuated). Alternatively, the plug may be removed prior to actuation. It is also contemplated that the plug material is changed (thermally or otherwise) such that it no longer presents a barrier to ejection of reagents. The nozzle may also be separated from air in the reservoir by a hydrophobic mesh.
In certain aspects, the invention may include a reagent delivery system comprising a deformable reservoir comprising a preformed nozzle, an upper sealing layer coupled to a top of the deformable reservoir, and a removable lower sealing layer, releasably coupled to the preformed nozzle and, in combination with the upper sealing layer, sealing one or more reagents within the deformable reservoir. The system can be configured such that removal of the lower sealing layer allows for the one or more reagents to be dispensed through the preformed nozzle upon compression of the deformable reservoir.
The upper and/or lower sealing layer can include a polymer film. The upper and/or sealing layer may be coupled to the top of the deformable reservoir and/or the nozzle by a pressure sensitive adhesive. Reservoirs of the invention may comprise a plastic.
Aspects of the invention may include a reagent delivery system comprising a multilayered sheet comprising a blister layer comprising a plurality of sealed, deformable reservoirs with one or more reagents disposed therein, a piercing layer comprising a plurality of hollow piercing members, the piercing layer positioned proximate to the blister layer such that the plurality of hollow piercing members align with the plurality of sealed, deformable reservoirs, wherein each of the plurality of hollow piercing member comprises a nozzle opposite the blister layer. The multilayered sheet may be configured such that the blister layer does not normally contact the piercing layer but, upon application of a force compressing one of the plurality of sealed, deformable reservoirs toward a corresponding hollow piercing member, dispenses the one or more reagents through the nozzle of the corresponding hollow piercing member.
In some aspects, this disclosure provides a method for reducing a dead volume of reagent in a reagent delivery system. The method includes the steps of providing a reagent reservoir containing a reagent, and introducing an inert solution that is immiscible with the reagent. In particular, the reservoir has a first and second barrier defining a cavity for containing the reagent and inert solution, the first barrier including a deformable portion and the second barrier having a nozzle. The deformable portion is configured to push into the cavity and dispense reagent through the nozzle.
The step of introducing of inert solution improves delivery of the reagent by filling a dead space within the reservoir. Preferably, the inert solution has a lower density than the reagent, and occupies a dead space between the reagent and the deformable portion inside the cavity. Upon actuation of the deformable portion, the inert solution helps express reagent from the nozzle and prevents reagent from getting trapped in certain areas of the reservoir.
Systems and methods of the invention provide for affordable, automated distribution of accurate reagent volumes for use in reactions in fields such as molecular biology. Unit-fill reservoirs, or blisters, are used to store, transport, organize, and distribute specified reagent volumes for use in various reactions. The disclosed systems and methods allow for processing small numbers of samples through multiple steps with minimal set-up time and no dead volume or priming. Specific volumes of various reagents required for certain reactions are pre-packaged into reservoirs to be stored or transported, ready for distribution into a reaction environment. The reagents remain sealed in reservoirs until time for use, minimizing the potential for contamination. At the reaction site, reagents are distributed through a nozzle (preformed in the reservoir or as part of a piercing member) that directs evacuation of the reagent, manages reagent flow rates, or forms droplets or otherwise manages delivery format of the reagent.
Once filled at, for example, a kit manufacturer's site, reservoirs or blisters of the invention can be sealed with a membrane having a preformed nozzle for reagent delivery. A simple hardware device, manually or automatically operated, compresses these reagent filled blisters to dispense the contents of the blister into a reaction vessel situated below the nozzle. A preconfigured set of blisters and indexing marks allows for machine control of the distribution of multiple reagents and complex methods to be executed including processing of multiple samples simultaneously.
The inert solution 1605 provided by this disclosure is any suitable substance that is immiscible, and unreactive, with the reagent 1603. Preferably, the inert solution 1605 has a lower density than the reagent 1603, for example, an oil, to provide an arrangement in which the inert solution 1605 occupies a portion of the cavity 1615 between the reagent 1603 and the deformable portion 1609 of the first barrier 1607, also known as a dead space. By occupying dead space, the inert solution 1605 improves delivery of the reagent 1603 by helping push reagent 1603 through the nozzle 1613 upon actuation of the deformable portion 1609, thereby reducing an amount of reagent 1603 otherwise left behind in the reservoir 1601, which is known in the art as a dead volume. In some embodiments, the presence of inert solution may decrease the amount of dead volume to less than 5% of total reagent volume. Because the inert solution 1605 improves delivery of reagent 1603, providing inert solution 1605 to the reservoir 1601 provides a cost benefit to a researcher.
In some aspects, the inert solution 1605 improves delivery of reagent 1603 by filling dead space and increasing a total volume of solution within the reservoir 1601. For example, as the deformable portion 1609 is pressed into the cavity a small gap of dead space may exist between the deformable portion 1609 and solution of the reservoir 1601. This gap may be partially occupied by air molecules. Because air is more easily compressed than liquid, at least some of the air molecules occupying dead space escape before reagent 1603, leaving reagent 1603 trapped in the reservoir 1601. However, by providing inert solution 1605, the total volume of solution in the reservoir 1601 is increased and less dead space is occupied by air, thereby decreasing opportunities for air molecules to escape and increasing the volume of reagent 1603 that is expressed.
In various embodiments, an inert material may be substituted for the inert solution described above. That inert material may be solid or semisolid at room temperature such that, upon compression of the deformable portion of the reservoir, the inert material within the cavity can deform to occupy all remaining dead space therein to thereby force the entirety of the reagent through the nozzle.
The inert material may have a density less than or greater than that of the reagent depending on the intended use orientation of the delivery system. The density should be selected such that, when oriented for reagent expulsion, the reagent is positioned between the nozzle and the inert material. In various embodiments, the inert material may be added to the reservoir before or after the reagent and before attachment and sealing of the first or second barrier, completing the sealed reservoir. The inert material may be heated or otherwise fluidized to ease its addition to the reservoir and then thermally, chemically, or otherwise solidified or semisolidified after its addition. Semisolid inert materials include, for example, waxes, polymers, and gels of inert substances as well as additional materials that would be apparent to one of ordinary skill in the art.
In certain embodiments, as illustrated in
As shown in
Manifold 1003 runner length can be varied in a parallel system as shown in
In certain embodiments, reagents may be held in the reservoirs in a dry or inactive state, in component form, or in any state that may require activation, addition, or alteration before use in the intended reaction. For example, reagents may have a limited shelf life once prepared or may have specialized storage requirements (e.g., temperature or light requirements) to avoid degradation or adverse reactions. By storing reagents in a more stable form (e.g., component form, dry form, or inactive form) and reconstituting just prior to use, shelf life can be increased and better results can be obtained from subsequent reactions involving the reagents.
As noted, the reservoirs and reservoir planes discussed herein may be configured for automated use through an apparatus 1401 to further decrease opportunity for human error and ensure fidelity to reaction protocols. An example of such an apparatus 1401 is shown in
A plane may comprise a sequence of reagents in a series of rows such that an entire reaction can be carried out by sequentially compressing each row's reservoirs. Each row may contain a single reagent and correspond to a well in a multi-well plate or a row of reaction chambers. Accordingly, a number of similar experiments may be performed simultaneously corresponding to the number of reservoirs in each row. The number of reagents needed to be added and the sequence in which they need to be added will dictate the number and position of the rows. The number of columns will correspond to the number of experiments simultaneously being performed.
Another exemplary apparatus 1501 is shown in
Initial studies anticipated a blister/nozzle combination behaving similar to an inkjet where nozzle diameter would be small and blister compression critical to efficient droplet delivery. Surprisingly, a significantly larger diameter nozzle performed best and its efficiency was largely independent of blister compression characteristics (force or speed). A preferred nozzle diameter is from about 100 μm to about 600 μm, inclusive. Additionally there was concern that the presence of air in the blister would result in satellite formation (spray) as air was forced out with the liquid as is experienced with inkjets. The observation was that use of larger nozzles minimized this phenomenon. This resulted in an additional benefit that blisters did not need to be closely paired with reagent volumes. Additionally, standard size blisters could be filled with different volumes. The third unanticipated benefit to using the larger nozzles was that the dispensing efficiency was largely independent of the solution viscosity within the range of reagents investigated (aqueous solutions with and without salts, surfactants, and glycerol).
Results were obtained by producing prototypes of the blister packs. A circular cavity molded into a thin plastic carrier. On the ejection side, the polypropylene chassis contained a small aperture or nozzle. A temporary seal was applied to the nozzle through heat fusion (adhesives or other alternatives can be used). Next, the reagents to be ejected were pipetted onto the carrier followed by mineral oil. Finally, the blister was sealed by contacting the polypropylene chassis with a polypropylene film under pressure at an elevated temperature (while other methods such as adhesives are contemplated as well). Ejection of stored reagents was then actuated by means of a linear electromechanical motor which can be set to a target speed.
References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.
Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.
Number | Date | Country | |
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62969862 | Feb 2020 | US |