Electrospray, also known as electro-hydrodynamic atomization, is a technique that consists in the injection of a liquid through capillary electrical field emitters, typically using metal needles. For a specific range of applied electric field and liquid injection flow rate, the electrified meniscus (i.e., the curve in the free surface of a liquid) forms a “Taylor cone”, i.e., a cone of liquid having a convex shape that is different from the shape caused by surface tension alone. When the Taylor cone is formed, a thin, electrically charged, steady jet of liquid breaks the surface tension and gives rise to fine droplets.
According to one aspect of the present application, a coaxial electrospray is provided. The coaxial electrospray device may comprise a substrate, an emitter having a proximal end and a distal end, the proximal end being connected to a surface of the substrate, wherein the emitter comprises therein a first channel and a second channel, and wherein the first and second channels extend to the distal end of the emitter, and first and second reservoirs formed in the substrate, the first reservoir being coupled to the first channel and the second reservoir being coupled to the second channel.
In some embodiments, the first channel encloses the second channel within at least a portion of the emitter.
In some embodiments, the emitter has a first width at the distal end of the emitter and a second width at the proximal end of the emitter, the second width being larger than the first width.
In some embodiments, the first and second channels have helical shapes.
In some embodiments, the coaxial electrospray device further comprises a spout connected to the distal end of the emitter, wherein the spout comprises an inner tank and an outer tank enclosing the inner tank, wherein the first channel is coupled to the outer tank and the second channel is coupled to the inner tank.
In some embodiments, at least one of the first and second reservoirs comprises one or more columns.
In some embodiments, the first and second channels have tapered shapes.
In some embodiments, each of the first and second channels has a first width at the distal end of the emitter and a second width at the proximal end of the emitter, the second width being larger than the first width.
In some embodiments, the first channel has a width that varies continuously between the first width and the second width.
In some embodiments, the emitter has a width at the distal end that is between 50 μm and 1 mm.
In some embodiments, the emitter has a truncated conical shape.
In some embodiments, the substrate is made of a material having a relative dielectric constant that is between 1.0 and 15.
In some embodiments, the substrate is made of a material selected from a group consisting of a polymer and a ceramic.
In some embodiments, the coaxial electrospray device further comprises a plurality of emitters, one of the plurality of emitters being the emitter, each of the plurality of emitters having a proximal end and a distal end, the proximal end being connected to the surface of the substrate, wherein each of the plurality of emitters comprises therein a first channel and a second channel extending to a respective distal end of the emitter, and wherein each of the first channels is coupled to the first reservoir and each of the second channels is coupled to the second reservoir.
In some embodiments, the plurality of emitters are arranged with a surface density that is between 1 emitter/cm2 and 1000 emitters/cm2.
In some embodiments, the plurality of emitters are arranged in a honeycomb configuration.
In some embodiments, the first channel has a length, measured between the distal end of the emitter and the proximal end of the emitter, that is between 10 and 1000 times larger than a maximum width of the first channel.
In some embodiments, at least one between the first and the second channel comprises a plurality of supporting beams.
According to another aspect of the present application, a method is provided. The method may comprise conveying a first liquid into a first inlet of a substrate and a second liquid into a second inlet of the substrate, the first and second liquids being immiscible; causing the first liquid to enter a first reservoir formed in the substrate and the second liquid to enter a second reservoir formed in the substrate; causing the first liquid to form a first plurality of menisci in respective emitters of a plurality of emitters, the plurality of emitters being connected to and protruding from the substrate, and causing the second liquid to form a second plurality of menisci in the respective emitters, wherein at least one meniscus of the second plurality of menisci encloses, in a plane, a respective meniscus of the second plurality of menisci; and causing the at least one meniscus of the first plurality of menisci and the at least one meniscus of the second plurality of menisci to form a Taylor cone.
In some embodiments, causing the at least one meniscus of the first plurality of menisci and the at least one meniscus of the second plurality of menisci to form a Taylor cone comprises exposing the plurality of emitters to an electric field.
In some embodiments, the electric field has a magnitude, in a region proximate the plurality of emitters, sufficiently large to generate an electric force larger than a maximum surface tension of the first and second plurality of menisci.
In some embodiments, each meniscus of the second plurality of menisci encloses a respective meniscus of the second plurality of menisci.
According to yet another aspect of the present application, a method for fabricating a coaxial electrospray device is provided. The method may comprise 3D printing a substrate; 3D printing an emitter with a proximal end and a distal end, the proximal end being connected to a surface of the substrate, wherein the emitter comprises therein a first channel and a second channel, and wherein the first and second channels extend to the distal end of the emitter; and wherein 3D printing the substrate comprises forming first and second reservoirs, the first reservoir being coupled to the first channel and the second reservoir being coupled to the second channel.
In some embodiments, the 3D printing of the substrate and the emitter is based on an output file defining a plurality of slices.
In some embodiments, the output file includes jagged edges.
In some embodiments, the method further comprises forming a spout such that the spout is connected to the distal end of the emitter, wherein the spout comprises an inner tank and an outer tank enclosing the inner tank, wherein the first channel is coupled to the outer tank and the second channel is coupled to the inner tank.
Various aspects and embodiments of the application will be described with reference to the following figures. It should be appreciated that the figures are not necessarily drawn to scale. Items appearing in multiple figures are indicated by the same reference number in all the figures in which they appear.
The inventors have recognized and appreciated a fundamental impediment in conventional coaxial electrospray devices that limits the ability to produce monodisperse core-shell particles in large volumes. Coaxial electrospray is a particular subset of electrospray, in which droplets are formed that have a core substance encapsulated within a shell substance. Coaxial electrospray is a technique that potentially finds application in several engineering and biomedical settings, including in the production of drug-loaded microcapsules with precise control of the core-shell geometry. However, this potential is still unmet due to the inability of current techniques to produce microcapsules in large quantities. In fact, in conventional techniques, any increase in throughput inevitably result in loss of uniformity; for example, this is achieved by different approaches including increasing the electric field acting on the emitter to the point to generate multiple cones per emitter. That is, when the rate at which microcapsules are generated is increased, the geometry of the fabricated microcapsules becomes unpredictable. Since in most application a precise control of the size and geometry of the microcapsules is a sine qua non, the applicability of these techniques is substantially decreased.
Accordingly, the inventors have developed systems and methods for coaxial electrospray that meet the throughput requirement in most applications. Unlike conventional techniques, the systems and methods developed by the inventors break the trade-off condition between throughput and accuracy control.
Some embodiments of the present application are directed to electrospray devices that include multiple emitters integrated into single substrates. In this way, multiple Taylor cones (and thus multiple jets) can be formed in parallel (e.g., one Taylor cone per emitter). Since the Taylor cones, in some embodiments, share the same liquids, the overall rate at which droplets are created can be substantially increased. Furthermore, since the emitters are fabricated as one piece using the same fabrication process, emitter array assembly is obviated; in addition, the emitters are subjected to the same fabrication tolerances, and therefore the likelihood of substantial variations in their geometries is limited.
The inventors have further developed processes for manufacturing coaxial electrospray devices that enable not only accurate control of the geometry of the emitters and ability to integrate large numbers of emitters, but also high manufacturing rates. Given the three-dimensional nature of the devices developed by the inventors, conventional techniques, which are essentially two-dimensional processes adapted to generate three-dimensional shapes, are found unsuitable. For example, microelectromechanical systems (MEMS) processes are configured to produce three-dimensional objects by selectively etching material in a layer-by-layer fashion, thus requiring the use of large numbers of photomasks, which renders the process cumbersome and expensive. In contrast, the processes developed by the inventors are innately three-dimensional. For example, in some embodiments, multi-emitter coaxial electrospray devices of the type described herein are fabricated using stereolithographic techniques. Accordingly, the devices are formed additively from the photopolymerization of resins using ultraviolet light, with the help of computer aided manufacturing (CAM) or computer aided design software (CAD). Compared to conventional techniques which have been traditionally used to fabricate single-emitter devices, this technique reduces fabrication time and costs.
As explained above, some embodiments of the present application relate to multi-emitter coaxial electrospray devices. These devices have geometries configured to inject two immiscible liquids at appropriate flow rates through a pair of capillary channels, where one capillary channel encloses the other, at least partially. When the liquids are exposed to an electric field having a suitable magnitude, the menisci of the liquids give rise to coaxial Taylor cones that result in the generation of a co-flowing jet. The jet breaks up into droplets wherein one liquid is contained within the other liquid. If the shell material is made of a photopolymerazible material, when exposed to light having a suitable intensity and wavelength (e.g., in the ultraviolet), the droplets can be transformed into capsules having a solid core and/or a solid shell.
As illustrated, substrate 101 and emitter 104 include a network of channels for conveying a pair of liquids to a suitable location for generating a co-flowing jet. As will be described further below, a co-flowing jet may break up into micro-droplets in which a core liquid is enclosed by a shell liquid. The network includes reservoirs 140 and 141, inlets 150 and 152, channels 120 and 122, and intermediate channels 130 and 132. In particular, a first network includes reservoir 140, inlet 150, channel 120, and intermediate channel 130, and a second network includes reservoir 142, inlet 152, channel 122, and intermediate channel 132. In some embodiments, the two networks are independent from one another, thereby preventing the liquids from mixing with one another. The liquids may be conveyed into device 100 through inlets 150 and 152. In the embodiment illustrated in
When the reservoirs are at least partially filled, the liquids are conveyed to channels 120 and 122, which are formed in the emitter 104, via intermediate channels 130 and 132, respectively. While
Emitter 104 has a proximate end 112 that is connected to the top surface 102 of substrate 101, and a distal end 110. In some embodiments, emitter 104 protrudes from top surface 102 along a direction that is perpendicular to top surface 102. Of course, emitter 104 may alternatively protrude at an angle with respect to the axis perpendicular to top surface 102. Channels 120 and 122 are arranged such that, at the distal end 110 of emitter 104, one liquid encloses the other liquid in the xy-plane. Two plane views of emitter 104, taken along lines AA′ and BB′ in the xy-plane, are illustrated in
In some embodiments, emitter 104 has a tapered shape, such that the width of the emitter decreases away from top surface 102. For example, the width of the emitter in the plane defined by line AA′ (see
In some embodiments, it may be desirable to slow down the rate at which liquid pressure builds up in channels 120 and 122. This may be the case, for example, when multiple emitters 104 are formed on substrate 101. In certain circumstances, the hydraulic impedance associated with the various emitters may be non-uniform, and as a result some emitters may be filled with liquid before others. To promote uniformity in the rate at which the emitters are filled, in some embodiments, channels 120 and 122 have a large aspect ratio (i.e., length-to-width ratio, where the length is measured along the axis of propagation of liquid in the channel), thereby increasing hydraulic impedance. For example, the channels may have an aspect ratio that is between 10 and 10000, between 10 and 1000, between 100 and 1000, between 10 and 100, or between any range within such ranges. In some embodiments, the minimum width of the channels is between 50 μm and 1 mm, between 50 μm and 800 μm, between 50 μm and 500 μm, between 50 μm and 250 μm, between 50 μm and 100 μm, between 200 μm and 800 μm, between 500 μm and 800 μm, or between any suitable range within such ranges.
In some embodiments, channels 120 and 122 (or at least one of them) have tapered shapes such that their widths decrease away from top surface 102. Having tapered shapes may be beneficial to decouple the pressure necessary to fill in the channels in the emitter from the pressure needed to create a meniscus at the tip of the emitter. This configuration may be used to promote pressure uniformity across multiple emitters. For example, the width of channel 120 in the plane defined by line AA′ (see
Intermediate channels 130 and 132 may have geometries configured to decouple the pressure necessary to fill in the channels in the emitter 104 from the pressure needed to set a desired flow rate. For example, in some embodiments, the intermediate channels may have tapered shapes, such that their widths are decreased closer to the emitter 104.
To prevent the channels from collapsing, in some embodiments, supporting beams are formed. Representative supporting beams are illustrated in
In the configurations illustrated in
To ensure that core-shell droplets are created wherein one liquid encloses the other liquid, a spout may be used. As illustrated in
As in device 100, channels 220 and 222 may have large aspect ratios (e.g., between 10 and 10000, between 10 and 1000, between 100 and 1000, between 10 and 100, or between any range within such ranges), so as to provide a large hydraulic impedance. In some embodiments, the width of the channels may be decreased along the length of a channel, thereby providing increasingly higher hydraulic impedance. For example, the width of channel 222 in the plane defined by line DD′ (see
As described above, substrate 101, whether in the configuration of
The emitters may be integrated with a density that is, for example, between 1/cm2 and 1000/cm2, between 1/cm2 and 50/cm2, between 25/cm2 and 100/cm2, between 25/cm2 and 100/cm2, or between any range within such ranges. In some embodiments, the emitters are arranged on the top surface 102 in a honeycomb configuration. Of course, other configurations are also possible.
As illustrated in
The columns may be sized and positioned to promote flow rate uniformity among the intermediate channels 1301 . . . 130N. The columns may have squared cross-section in some embodiments. In some embodiments, the square may have rounded corners, thereby limiting perturbations in the liquid near the corners. In some embodiments, the columns may be arranged in a honeycomb configuration, as illustrated in
In some embodiments, to improve space utilization within substrate 101, intermediate channels may be formed within the columns described above. One example of this configuration is illustrated in
The embodiments described herein may be used to generate co-flowing jets of immiscible liquids. Under certain circumstances, the jets may give rise to droplets having a core liquid enclosed within a shell liquid (referred to herein as core-shell droplets). This may be the case when the emitters 104 are exposed to an electric field having a magnitude sufficiently large to overcome the surface tension of the liquids menisci, thereby forming a Taylor cone. A representative configuration for generating core-shell droplets is illustrated in
An exemplary core-shell droplet is illustrated in
In one example, the device of
The representative device illustrated in
Two models, with different dimensions, were fabricated for testing different emitter density: one with a 500-μm spout diameter and one with a 450-μm spout diameter. The main dimensions for both models are listed in Table 1.
Each device was designed as a CAD and then 3D printed from an exported STL file with deviation tolerance of 2.5 μm and angle tolerance of 6°. Once the device was printed, remaining resin particles were removed by using an ultrasonic bath at 45° C. with a solution of deionized water mixed with isopropanol (1:1 v/v) for 10 minutes. The final appearance of the 3D printed devices with coaxial electrospray emitters is shown in the optical photograph of
Prior to the characterization process, a cleaning process was performed to remove solid residues inside the devices. A loaded 20 ml syringe with isopropyl alcohol was connected to the inlet port of the device; then the liquid was manually fed through the emitters with enough pressure to form continuous jets in all emitters. This process was repeated for both inner and outer liquids channels until homogenous jets among emitter were observed.
a. Characterization
Some of the material parameters contributing to the performance of a coaxial electrospray process include dielectric constant, electrical conductivity K, surface/interfacial tension, and viscosity. In some coaxial electrospray systems, it is desirable that the driving liquid (the one with the smaller electrical relaxation time) is the inner liquid. The electrical relaxation time, to =βε0/K is the time required to smooth a perturbation in the electrical charge; ε0 being the vacuum permittivity, β is the dielectric constant of the liquid.
Surface tension may play an important factor in maintaining an appropriate equilibrium between the multiple phases and in obtaining core-shell particles. In various examples, solutions of deionized water (DIW) mixed with isopropyl alcohol (ISP) or ethylene glycol (EG) were selected as the driving liquids and sesame oil (SO) was selected as the driven liquid.
The experimental apparatus shown in
First, the 500-μm model with 16 emitters was tested by feeding a solution of DIW:ISP (6:1 v/v) as the inner liquid. In uniaxial electrospray (i.e., with a single liquid) uniform operation among emitters was reached for flow rates per emitter higher than 2 ml/hr. In this case, steady cone-jets were observed simultaneously in all the emitters. Similarly, 3:1 and 1:1 solutions were used which resulted in minimum flow rates per emitter of 0.5 ml/hr and 0.1 ml/hr, respectively. This result indicates that the surface tension may play an important role in filling in all emitter and breaking up the meniscuses simultaneously. The same test was repeated with EG, resulting with a minimal per-emitter flow rate of 0.2 ml/hr. The properties of surface tension, the viscosity of the DIW:ISP (1:1 v/v) mixture were 25.8 dyn/cm, and 3.7 cP. In the case of EG were 47.7 dyn/cm and 21.0 cP. A DIW:ISP (1:1 v/v) solution was chosen with sesame oil to characterize the 500-μm models (1, 4 and 9-emitter versions). In addition, the pair ethylene glycol with sesame oil was used to characterize both 500-μm and 450-μm models in all 1, 4, 9, 16 and 25-emitters versions.
b. Operating Modes
Different spraying modes may arise according to the magnitude of the electrostatic field and the liquids' flow rates. In the dripping mode, the bias voltage may be such that the electrostatic force on the meniscus is lower than the hydrodynamic forces, the surface tension forces, and gravity. Therefore, the generation of droplets in this regime is set by the balance between gravity and surface tension (i.e., the droplets fall if gravity overcomes the surface tension) but no core-shell droplets are generated in this mode. In the cone-jet mode, the strength of the electric field may be sufficiently large to lead to the formation of a Taylor cone, which may produce core-shell particles through a jet emerging at the apex of the emitter. The cone-jet mode may be stable. However, further increases in the bias voltage may lead, in some circumstances, to emission instability; the multi-jet mode may appear when more than one jet is emitted from the surface of the meniscus.
The dripping mode may be identified by random fluctuations in the emitted current, which is in contrast with the steadiness of the emitted current in the cone-jet mode. The emitted current in the cone-jet mode is more constant, even after many minutes of continued emission.
In an another experiment, when the deionized water and sesame oil flow rates were set at 0.30 ml/hr and 0.10 ml/hr, respectively, and the extractor electrode was positioned 6.4 mm from the emitter spout(s), the cone-jet mode was achieved for extractor bias voltages between −5.4 and −6.3 kV. Similarly, when the extractor electrode was positioned 4.5 mm from the emitter spout(s), a stable Taylor cone was generated at bias voltage between −4.2 kV and −5.9 kV. However, when the extractor electrode was positioned 2.6 mm from the emitter spout(s), the range of bias voltages that generate a stable Taylor cone was −4.5 to −4.8 kV. Accordingly, the extractor voltage and position of the extractor electrode appear to have little effect on the per-emitter current. However, the electrical field acting on the Taylor cone may increase as the separation distance between the emitter spout and the extractor electrode decreases, which may significantly affect the formation of the Taylor cone. Based on this observation, the devices were characterized by placing the extractor electrode 4.75 mm from the emitter spout and with a bias voltage of −5 kV, varying the flow rates of the driven liquid between 0.25 ml/hr to 2.5 ml/hr for two values of sesame oil: 0.25 ml/hr and 0.50 ml/hr.
c. Results
An interesting electrospray behavior was detected when comparing single and coaxial electrospray of deionized water flowing at 1.0 ml/hr by using the 500-μm model, single emitter version. No stable uniaxial electrospray process was achieved. Instead, a spindle mode occurred which became stable once the outer liquid (sesame oil) was fed at 0.125 ml/hr. The per-emitter current in both circumstances was recorded and plotted in
For an extractor voltage of −5 kV, the effect of the concentration of DIW:ISP on the per-emitter current was investigated by using the single-emitter 500-μm device with solutions 1:1, 3:1 and 6:1. As a result, the per-emitter current reduced as the DIW-ISP proportion increased, since the conductivity of the solution is also decreased. Since in all cases, a stable jet was observed, a 1:1 solution was selected to test the coaxial electrospray of multiplexed devices with four and nine emitters per cm2. As can be seen in
d. Droplets Size Distribution
Droplets are generated when a coaxial jet arises. Examples of droplets having Ethylene Glycol encapsulated within sesame oil are illustrated in
Coaxial electrospray devices of the type described herein may be fabricated using 3D printing techniques, among other fabrication techniques. Representative processes for fabricating a coaxial electrospray device are depicted in
Representative process 1300 may then proceed to act 1304, wherein one or more smoothing techniques may be applied to the desired arrangement, for example to enhance 3D printing resolution. In one example anti-aliasing techniques may be used for producing a shape having smooth edges, where appropriate. Of course, other smoothing techniques may additionally or alternatively be used.
Representative process 1300 then proceeds to act 1306, wherein one or more output files are generated. The output file(s) may be output in a format which defines the designed arrangement in a plurality of slices. The slices may represent the 3D shape in a plurality of planes. One example of such a format is STL, which may be configured to use a series of linked triangles to recreate the surface geometry of the 3D model. In some embodiments, each triangle facet is described by a perpendicular direction and three points representing the corners of the triangle. An STL file may provide a complete listing of the x, y and z coordinates of these corners and perpendiculars.
Representative process 1300 then proceeds to act 1308, wherein a coaxial electrospray device is fabricated based on the output file(s) using 3D printing techniques. One example of a 3D printing technique is stereolithography, which creates models in a layer-by-layer fashion using photopolymerization, a process by which light causes chains of molecules to link, forming for example polymers. Accordingly, layers may be added by focusing an ultraviolet (UV) laser onto a vat of photopolymer resin. The UV laser may be driven to draw the desired arrangement onto the surface of the photopolymer vat. Because photopolymers are photosensitive under ultraviolet light, the resin may solidify and may form a layer of the desired coaxial electrospray device. This process may be repeated for each layer of the coaxial electrospray device. The layer thickness may be between 1 μm and 500 μm, between 1 μm and 40 μm, between 1 μm and 30 μm, between 20 μm and 40 μm, between 20 μm and 30 μm, between 24 μm and 26 μm, or between any suitable range within such ranges. Of course, other values can be used. In some embodiments, a 25 μm-resolution may be used. The fabrication tolerance in the xy-plane may be between 1 μm and 100 μm, between 20 μm and 80 μm, between 30 μm and 70 μm, between 40 μm and 60 μm, between 45 μm and 55 μm, or between any suitable range within such ranges. The fabrication tolerance in the z-axis may be between 1 μm and 200 μm, between 75 μm and 200 μm, between 100 μm and 150 μm, between 115 μm and 135 μm, between 120 μm and 130 μm, or between any suitable range within such ranges. Besides the height of the layers, other parameters may influence the print including but not limited to speed of relative movement between the vat and the platform (the surface on top of which the printed part is attached during printing), delay time between movements, separation between bottom of vat and free end of the printed part, and temperature.
Then, representative process 1300 ends.
An example of act 1308 is depicted in
The coaxial electrospray devices described herein may be used in a variety of settings, since they may be operated at room temperature. For instance, core-shell and hybrid core-shell droplets of the type described herein may be used, among other applications, in connection with drug delivery, tissue engineering, and plastic surgery.
In one example, microencapsulation may be provided that uses FDA-approved polymers as the shell material, in the context of mass production of drug-loaded microcapsules with precise control of the core-shell geometry. In another example, devices of the type described herein may be used in embedded microactuators, such as electrically sensitive hydrogel beads for regulating the release profile of encapsulated molecules. In yet another example, coaxial electrospray devices of the type described herein may be used for encapsulating ceramic with polymers, for example for use in dental biomaterials, and in bone grafts. In another example, encapsulation of active lipophilic compounds may be used in the food, pharmaceutical and/or flavoring industries for increasing the stability and protection of active compounds. In yet another example, coaxial electrospray devices of the type described herein may be used in the context of self-healing materials (e.g., by encapsulating liquid monomers inside polymer fibers).
While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art.
While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, system upgrade, and/or method described herein. In addition, any combination of two or more such features, systems, and/or methods, if such features, systems, system upgrade, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.
The terms “about,” “approximately,” and “substantially” may be used to refer to a value, and are intended to encompass the referenced value plus and minus variations that would be insubstantial. The amount of variation could be less than 5% in some embodiments, less than 10% in some embodiments, and yet less than 20% in some embodiments. In embodiments where an apparatus may function properly over a large range of values, e.g., one or more orders of magnitude, the amount of variation could be as much as a factor of two. For example, if an apparatus functions properly for a value ranging from 20 to 350, “approximately 80” may encompass values between 40 and 160.
The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”
The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.
As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.
In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.
The claims should not be read as limited to the described order or elements unless stated to that effect. It should be understood that various changes in form and detail may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims. All embodiments that come within the spirit and scope of the following claims and equivalents thereto are claimed.
This Application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 62/341,162, entitled “HIGH THROUGHPUT GENERATION OF CORE-SHELL PARTICLES USING MONOLITHIC ARRAYS OF COAXIAL ELECTROSPRAY EMITTERS MADE WITH 3D PRINTING” filed on May 25, 2016, which is herein incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2017/034287 | 5/24/2017 | WO | 00 |
Number | Date | Country | |
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62341162 | May 2016 | US |