Transporting colloidal objects to specific locations within porous media is important for many applications, including drug or cargo delivery, material fabrication, oil recovery, chemical and biochemical sensing, and remediation of polluted soils and waters. Even the delivery of small particles into porous environments remains highly challenging, however, since the low permeability of pore structures heterogeneously slows or even stops the passage of the fluids that suspend these colloids. For example, it is often difficult or impossible to force a fluid to flow into some areas within porous media, such as dead-end pores or small pores that require extremely high pressure to force a fluid through them. While delivery of particles to these and other areas may proceed by diffusion, the timescale required for the particles to diffuse to the desired area may be prohibitively long. For example, suspended colloids may traverse porous media via Brownian motion, this mechanism is impossibly slow in that micron-diameter particles may take about a month to diffuse even 1 millimeter. Even more challenging is that, in most cases, the specific location of targets is generally not known, and often cannot be determined from outside.
According to one or more aspects of the invention, an object delivery system may include a solute selected to diffuse through at least a portion of a porous material to a target and to associate with the target to form a source beacon capable of generating a solute outflux; and an object to be delivered to the target, wherein the solute outflux causes the object to migrate towards the target.
According to one or more aspects of the invention, a method of using an object delivery system may include one or more of the following steps: loading a target with a solute to form a source beacon, wherein the target is located within a porous material; releasing the solute from the source beacon to produce a solute outflux, wherein the solute outflux causes an object to migrate towards the target; and reloading the target with solute one or more times to form one or more additional source beacons.
The present invention relates to object delivery systems and related methods that enable the delivery of objects (e.g., particles) to targets located within porous media. The delivery of objects to the target may occur autonomously and/or selectively (e.g., the objects may be directed along paths that lead specifically and/or directly to the target), without requiring any knowledge of the specific location of the targets within the porous media (e.g., the location of the targets within the porous media may be hidden, unknown, and/or inaccessible). In addition, the objects may be delivered to targets at a rate that is orders of magnitude faster than the rate of diffusion, which in many instances is prohibitively long. The object delivery systems and related methods are general and may be utilized in any application involving the delivery of objects to targets. For example, objects that may be delivered using the systems and methods disclosed herein include, without limitation, solids, particles, droplets, bubbles, proteins, enzymes, viruses, microcapsules, vesicles, and the like. These objects, among others, may be delivered to targets located in any porous media including, for example and without limitation, oil reservoirs, living tissue, brain, skin, polymeric materials, textiles, carpets, fabrics, construction materials (e.g., concrete, cement, grout, drywall, wood, etc.), paper, leaves, hair, and the like.
Embodiments of the present disclosure thus include object delivery systems and related methods, including methods of using object delivery systems. In some embodiments, an object delivery system may include a solute selected to diffuse through at least a portion of a porous material to a target and to associate with the target to form a source beacon capable of generating a solute outflux; and an object to be delivered to the target, wherein the solute outflux causes the object to migrate towards the target. In some embodiments, a method 100 of using an object delivery system may include one or more of the following steps: loading 102 a target with a solute to form a source beacon, wherein the target is located within a porous material; releasing 104 the solute from the source beacon to produce a solute outflux, wherein the solute outflux causes an object to migrate towards the target; and reloading 106 (not shown) the target with solute one or more times to form one or more additional source beacons. See, for example,
The object delivery systems and related methods may be based on a two-step strategy involving a solute loading step and an object delivery step. The solute loading step may include bringing a porous media and a first solution containing a solute into fluid communication with each other (e.g., sufficient for the solute to associate with the target). The solute may be selected to partition or associate strongly with the target such that the target becomes concentrated in solute, forming a source beacon. The manner in which the porous media and the first solution are brought into fluid communication is not particularly limited and may include any technique suitable for enabling the solute to be transported to the target via any transport mechanism, including, for example and without limitation, one or more of diffusion and fluid flow, among other transport mechanisms. For example, the solute loading step may include and/or proceed by one or more of flowing, contacting, immersing, dipping, applying, flooding, passing, injecting, feeding, attaching, connecting, and the like. In some embodiments, the solute loading step includes flowing the first solution through, proximal to, and/or adjacent to one or more of the porous media, the target, and the pores, and/or contacting (e.g., flooding) the porous media with the first solution. By bringing the first solution and the porous media include fluid communication, the solute may partition and/or associate with the target to form the source beacon.
The object delivery step (e.g., particle delivery step) may include bringing the porous media and a second solution containing an object (e.g., a suspension of particles), which is to be delivered to the target, into fluid communication with each other. The manner in which the porous media and the second solution are brought into fluid communication is not particularly limited and may include any technique suitable for enabling the object to be delivered to the target. For example, the object delivery step may include and/or proceed by one or more of flowing, contacting, immersing, dipping, applying, flooding, passing, injecting, feeding, attaching, connecting, and the like. In some embodiments, the object delivery step includes flowing the second solution through, proximal to, and/or adjacent to one or more of the porous media, the target, the source beacon, and the pores, and/or contacting (e.g., flooding) the porous media with the second solution. By bringing the second solution and the porous media into fluid communication, the second solution may replace (e.g., displace) the first solution, causing solute which permeated the porous media (e.g., but which does not associate with the target) to diffuse out of the area proximal to the target. The removal of said solute may generate an outward flowing solute outflux sustained by (e.g., emanating from) the source beacon and lasting longer than timescales for solute diffusion. The objects in the second solution may be selected to migrate up fluxes of the solute via, for example and without limitation, diffusiophoresis (DP) and/or soluto-capillary migration. The migration may proceed until the objects are delivered to the target.
The interactions on which the object delivery systems and related methods are based are not particularly limited. In some embodiments, the object delivery systems and related methods are based on a soluto-inertial (SI) interaction. In some embodiments, a soluto-inertial interaction includes structures and/or particles that slowly release a solute into solution to attract and/or repel other particles in suspension via diffusiophoresis. A soluto-inertial interaction may include one or more elements: a source beacon with a high solute capacity that is capable of establishing and maintaining a solute flux over sustained periods of time; a solute that mediates the interaction; and an object, such as particles or colloids, that is responsive to the solute flux and migrates via diffusiophoresis or another suitable mechanism up to solute flux to the target. For example, in a soluto-inertial interaction, a solute is concentrated at or near a target sufficient to form a source beacon. The source beacon may be designed to slowly release solute over relatively prolonged periods of time, thus establishing and maintaining a solute flux. The object, in response to the solute flux, may then migrate via, for example, diffusiophoresis (DP) up or down the solute flux (e.g., towards or away from the source beacon), depending on the specific solute-object surface interaction. Other mechanisms may be utilized herein besides DP including, for example and without limitation, soluto-capillary migration.
In some embodiments, the physico-chemical characteristics of one or more of the solute, the object, and the source beacon are considered when developing an object delivery system for delivering the object to a particular target. The physico-chemical attributes of the target, the mediating solute, and the object (e.g., particle) to be delivered may be chosen so as to work as a system. For a solute to load into a target — and therefore convert it to a source beacon (e.g., a SI beacon) — it should concentrate within the target. The basis for the selection of the solute may include a high partition coefficient, a strong adsorption constant, a strong absorption constant, a strong association constant, and/or some other basis. The object, which may include for example, suspended particles such as droplets, colloids, cells, proteins, and/or viruses, should migrate against these solute fluxes (e.g., a concentration gradient of the solute starting from the source beacon and emanating outwardly therefrom), e.g. via diffusiophoresis, soluto-capillary, or some other mechanism.
As mentioned above, the object delivery systems and related methods are general and may be utilized in any application involving the delivery of objects to targets. In other words, the solutes, the objects, and the porous media (e.g., porous material) are not particularly limited. The solutes, the objects, and the porous media may be characterized by any phase (e.g., solid, liquid, gas, vapor, and combinations thereof). Non-limiting examples of solutes include solvents (e.g., such as butanol), salts, surfactants, polymers, oligomers, monomers, enzyme substrates, dissolved gas, ionic liquids, small molecule solutes such as zwitterions, any chemical compound or molecule, whether organic, inorganic, or a combination thereof, and the like. Non-limiting examples of objects that may be delivered using the systems and methods disclosed herein include solids, particles, droplets, bubbles, proteins, enzymes, viruses, microcapsules, vesicles, and the like. Non-limiting examples of porous media include oil reservoirs, living tissue, brain, skin, polymeric materials, textiles, carpets, fabrics, construction materials (e.g., concrete, cement, grout, drywall, wood, etc.), paper, leaves, hair, and the like.
The behavior of the solute may involve the first step in which the target is loaded with solute and effectively converts it into a soluto-inertial beacon. During the particle delivery step, the solute-loaded target sustains a solute outflux, directed from the target towards the mouth of the pore. The delivery process may require that particles migrate up solute gradients (e.g., solute concentration gradients), against the solute outflux maintained by the target. Suspended particles, molecules, and droplets may migrate in response to solute gradients through various mechanisms, including without limitation diffusiophoresis, thermophoresis, thermocapillary, and soluto-capillary migration. The silicon oil drops may be delivered to targets using soluto-capillary migration: the solute is surface-active on the oil/water interface, so that solute gradients cause surface tension gradients along the droplet surface, driving a surface flow along the droplet that propels it up the surfactant gradient. Soluto-capillary migration may be characterized by a droplet migration speed that is proportional to the solute gradient.
Numerical computations of diffusive solute dynamics in an analogous branched network (
According to some embodiments, an object delivery system may include a solute selected to diffuse through at least a portion of a porous material to a target and to associate with the target to form a source beacon capable of generating a solute outflux; and an object to be delivered to the target, wherein the solute outflux causes the object to migrate towards the target.
In some embodiments, the solute and the target associate by one or more of partitioning, adsorption, and absorption. In some embodiments, partitioning may include a solute for which it is energetically more favorable for solute molecules to dissolve in, or be dissolved by, a target than by a solution phase. In some embodiments, a partition coefficient is a ratio of the concentration of solute in the target to the concentration of solute in the solution phase.
In some embodiments, the location of the target within the porous material is unknown, a dead-end pore, or a pore in which a fluid must be under pressure to flow through said pore.
In some embodiments, the solute is included in a first solution which is brought into fluid communication with the porous material for transport to the target. In some embodiments, the source beacon is formed when the association of the solute with the target equilibrates.
In some embodiments, the concentration of the solute within the source beacon is greater than the concentration of the solute in a neighboring solution.
In some embodiments, the object is included (e.g., suspended, emulsified, bubbled, or mixed) in a second solution which is brought into fluid communication with the porous material.
In some embodiments, the second solute removes permeated solute by convection from areas near the target to initiate the solute outflux.
In some embodiments, the object migrates up the solute outflux via one or more of diffusiophoresis and soluto-capillary migration.
In some embodiments, the solute outflux directs the object to the target to the substantially exclusion of areas not including the target.
In some embodiments, the object is delivered to the target at a rate that is greater than the rate of diffusion.
In some embodiments, the target and the object, before said object is delivered to the target, are greater than 100 nm apart.
In some embodiments, the object includes one or more of solids, droplets, bubbles, polymers, colloids, enzymes, cells, proteins, viruses, drugs, oil-liberating agents, microcapsules, and vesicles.
In some embodiments, the object includes suspended colloids (e.g., colloidal suspensions). In some embodiments, the object includes particles in a suspension.
In some embodiments, the porous material includes one or more of oil reservoirs, gas reservoirs, films, coatings, living tissues, brain, skin, polymeric materials, textiles, carpets, fabrics, concrete, cement, grout, drywall, wood, paper, leaves, and hair.
In some embodiments, the solute includes one or more of salts, surfactants, polymers, enzyme substrates, dissolved gas, solvents (e.g., butanol), small molecules (e.g., zwitterions), and combinations thereof.
According to some embodiments, a method of using an object delivery system may include one or more of the following steps: loading a target with a solute to form a source beacon, wherein the target is located within a porous material; releasing the solute from the source beacon to produce a solute outflux, wherein the solute outflux causes an object to migrate towards the target; and reloading the target with solute one or more times to form one or more additional source beacons.
In some embodiments, loading the target with the solute to form the source beacon includes bringing a first solution including the solute and the porous material into fluid communication (e.g., sufficient to associate the solute with the target).
In some embodiments, releasing the solute from the source beacon to produce the solute outflux includes bringing a second solution including the object and the porous material into fluid communication. In some embodiments, releasing the solute from the source beacon to produce the solute outflux includes removing solute at the pore mouth.
In some embodiments, the second solution removes permeated solute by convection from areas near the target to initiate the solute outflux.
In some embodiments, the objects are designed to migrate up concentrate gradients of the emitted solute, autonomously migrating against the solute fluxes emitted by the targets, thereby following chemical trails that lead to the target.
In some embodiments, the hidden targets are converted into source beacons, such as soluto-inertial beacons, that establish, maintain, and/or sustain a solute outflux for extended durations (e.g., durations longer than timescales for solute diffusion).
In some embodiments, the object includes one or more of a solid, droplet, bubble, polymer, colloid, enzyme, cell, protein, virus, drug, oil-liberating agent, microcapsule, and vesicle.
In some embodiments, the solute includes one or more of a salt, surfactant, polymer, enzyme substrate, dissolved gas, solvent (e.g., butanol), and small molecule (e.g., zwitterions).
In some embodiments, the porous material includes one or more of an oil reservoir, gas reservoir, film, coating, living tissue, brain, skin, polymeric material, textile, carpet, fabric, concrete, cement, grout, drywall, wood, paper, leaves, and hair.
According to some embodiments, a method of using an object delivery system may include flowing a first solution including a solute through a porous material sufficient to associate the solute with a target located within the porous material and form a source beacon which is capable of establishing and/or maintaining a solute outflux; and flowing a second solution including an object through the porous material, wherein the second solution initiates the solute outflux and wherein the solute outflux causes the object to migrate towards the target.
As mentioned above, the systems and methods disclosed herein may be utilized in any application requiring delivery of one or more objects to one or more targets within a porous material.
In some embodiments, for example, the systems and methods disclosed herein are used to deliver agents to oil trapped in reservoirs. For example, one or more agents may be included in flood water for various diagnostic purposes, liberating trapped oil, etc. The flood water including the one or more agents may be pumped through a reservoir to a target area. As the flood water is being pumped through the reservoir, it may optionally follow the lowest-resistance pathways through porous rock to the target area. The target area is generally not particularly limited and may include areas of interest for diagnostic purposes and areas within the reservoir in which oil is trapped, among other areas. For example, in some embodiments, the pumping of the flood water may be used to deliver the one or more agents to the target, wherein the target includes areas of the reservoir in which the oil is trapped. The one or more agents may be utilized to analyze the trapped oil for diagnostic purposes and/or liberate the trapped oil. In some embodiments, the pumping of the flood water is further used to displace the oil trapped therein and push it up through another well. In some embodiments, the flood water is flowed through macropores in a reservoir, wherein dead-end pores branch off of the macropores and include the target. In some embodiments, bringing the flood water into fluid communication with the dead-end pores is sufficient to associate the solute with a target located in the dead-end pores, even though the flood water is not able to flow through the dead-end pore (e.g., the solute diffuses to the target).
In some embodiments, the systems and methods disclosed herein are used for drug delivery. For example, a sustained-release reservoir may be embedded within the skin (e.g., subcutaneous). The sustained-release reservoir may be periodically recharged, or reloaded, using the systems and methods disclosed herein. This embodiment and various thereof may be useful in situations in which drugs or other objects cannot be delivered deep into some tissues and/or regions because said tissues and/or regions are inaccessible or difficult to access via blood flow (e.g., across a blood brain barrier, etc.).
In some embodiments, the systems and methods disclosed herein are used in rechargeable films and/or coatings. A functionality (e.g., a scent, a color, a biocide, etc.) may be desired within a film, coating, or other material. A reservoir may be embedded within, for example, a film and periodically reloaded using the systems and methods disclosed herein.
In some embodiments, the systems and methods disclosed herein are used in transdermal applications. For example, in some embodiments, the solute loading step includes applying a wet loading pad to skin sufficient to allow the solute (e.g., a solvent) to diffuse into the skin and load into a target. In some embodiments, the wet loading pad is replaced by a delivery pad containing objects (e.g., drugs, particles, etc.) for delivery to the target.
In some embodiments, the systems and methods disclosed herein include a solute loading step in which a porous material is immersed (e.g., dipped) into a loading solution for a select duration and removed therefrom. In some embodiments, the porous material is immersed (e.g., dipped) into a delivery solution containing an object to be delivered to the target.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/050457 | 9/15/2021 | WO |
Number | Date | Country | |
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63079208 | Sep 2020 | US |