Focused rotary jet spinning device and method of using the same

Abstract

Systems and methods for the focused directed deposition of micron or nanometer sized polymeric fibers and fiber materials are described. The systems and methods employ one or more gas streams to entrain and deflect fibers produced by a rotating jet spinning system to form a focused stream of fibers. Some embodiments are capable of controlling the arrangement and distribution of fibers at relatively high fiber fluxes.

Description

[0001] This application is a divisional application of the application filed on January 14, 2020, with application number 202080008998.3 and invention title "Focusing Rotary Jet Spinning Device and Method of Using Thereof".

[0002] Related applications

[0003] This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 792,036, filed January 14, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0004] Embodiments of this disclosure relate to a directional rotary jet spinning system that utilizes airflow convergence to manipulate fiber movement. Background Technology

[0005] Fiber structures are used by both nature and engineers for a variety of functions: fiber reinforcement, filtration, insulation, drive control, and more. The realization of these functions largely depends on the diameter of the fibers and their 3D organization. Many biological tissues are composed of small-diameter fibers (e.g., micrometer- or nanometer-diameter fibers) arranged in complex three-dimensional configurations. For example, muscle fibers that control human movement have diameters of approximately 10 μm to 100 μm and are bundled along the drive direction. As another example, collagen fibers, a major component of the extracellular matrix, have diameters of approximately 10 nm to 100 nm and are organized into various structures to achieve different mechanical properties in different tissues. Although humans have a rich history of designing thick fiber structures with diameters of approximately 100 μm and above, controlling the arrangement and organization of fibers using conventional techniques to design fine fiber structures with diameters of approximately 10 μm and below remains challenging. One challenge lies in simultaneously achieving fine fiber diameters, complex three-dimensional (3D) structures, and high throughput, which can be illustrated by comparing two major fiber manufacturing technologies, namely... Figure 1A-1CThe diagram illustrates random fiber deposition (random-FD) and extrusion 3D printing (extrusion-3DP). In random-FD technologies, such as meltblown and electrospinning, fibers approach the target as randomly arranged clouds, exhibiting poor control over fiber alignment and 3D geometry. Spatial distribution and fiber orientation within the cloud are uncontrolled. Poor control over the fiber cloud leads to poor control over deposition. In contrast, extrusion-3DP extrudes fibers by moving a nozzle that precisely controls the deposition location and the alignment of each section of the fiber. However, extrusion-3DP has lower throughput. While both technologies are capable of producing fibers with a wide range of diameters, only extrusion-3DP can produce complex 3D structures, while random-FD offers an order-of-magnitude advantage in throughput for fine fibers. The throughput limitation is inherent: to fill the same volume, the required fiber length increases rapidly as the fiber diameter decreases. Extrusion-3DP must track fiber lengths (e.g., for some applications, lengths >100 km), while fiber deposition does not.

[0006] Therefore, there is a need in the art for improved systems capable of producing complex 3D structures of small-diameter fibers (e.g., fibers with a diameter of less than 10 μm) in high throughput. Summary of the Invention

[0007] Some embodiments of the invention include a rotary jet spinning system configured to manipulate fiber movement by an externally applied gas (e.g., an airflow) to form a directional fiber flow. Some embodiments are capable of controlling fiber alignment and have relatively high throughput.

[0008] Some embodiments provide a system for focused directional deposition of one or more micron or nanometer-sized polymer fibers, the system including a reservoir configured to hold a polymer-component material and rotatable about a rotation axis. The reservoir includes a first end; a second end opposite the first end; an outer wall extending from the first end to the second end, the reservoir being shaped to include one or more holes radially inwardly disposed from the outer wall of the reservoir, the holes being configured to allow gas to move from the first end through the reservoir to the second end; and one or more orifices formed in the outer wall, each of the orifices being configured to eject material radially outwardly as a jet stream during rotation of the reservoir. The system also includes one or more airflow sources, each configured to guide airflow from upstream of a first end of the reservoir through one or more orifices of the reservoir to a second end and downstream of the second end of the reservoir during rotation of the reservoir. The one or more airflow sources together form a combined airflow in a first direction downstream of the second end of the reservoir. This combined airflow entrains and deflects one or more jet streams to form a focused flow of one or more micron or nanometer-sized polymer fibers in the first direction, which has an orientation within 5 degrees of the rotation axis of the reservoir.

[0009] In some embodiments, the one or more airflow sources include a plurality of airflow sources having a converging direction to form a combined airflow in a first direction. In some embodiments, the airflow velocity of at least some of the plurality of airflow sources is controllable relative to the airflow velocity of the other airflow sources to achieve a balanced combined airflow. In some embodiments, the number of the plurality of airflow sources and the arrangement of the plurality of airflow sources are configured such that at any single point in time during rotation of the reservoir, airflow from all of the plurality of airflow sources flows through the orifice of one or more orifices of the reservoir, or airflow from all of the plurality of airflow sources is blocked by the reservoir. In some embodiments, the plurality of airflow sources includes three airflow sources.

[0010] In some embodiments, the total airflow velocity from one or more airflow sources is controllable to vary the distance from the reservoir to the location where the micron or nano-sized polymer fiber flow has the tightest focus.

[0011] In some embodiments, the first direction is within 2 degrees of the axis of rotation. In some embodiments, the first direction is substantially parallel to the axis of rotation.

[0012] In some embodiments, the flow width of the focused flow of one or more micron or nanometer-sized polymer fibers is smaller than the diameter of the outer wall of the reservoir.

[0013] In some embodiments, the system further includes a flow-blocking structure disposed upstream of a plurality of airflow sources, the flow-blocking structure being configured to reduce the focusing effect of the airflow upstream of the plurality of airflow sources on the flow of micron- or nano-sized polymer fibers. In some embodiments, the flow-blocking structure is disposed upstream of a rotating reservoir and is configured to at least partially block the airflow from upstream of the rotating reservoir, thereby reducing the effect of the airflow from upstream of the rotating reservoir on the interaction between the airflow generated by the rotation of the reservoir and the airflow passing through one or more orifices. In some embodiments, the flow-blocking structure is stationary and does not rotate with the reservoir. In some embodiments, the flow-blocking structure can enhance control over the vortex structure generated by the airflow and the rotation of the reservoir, thereby improving control over the lateral deposition region of the micron- or nano-sized polymer fibers as the fibers travel toward the target.

[0014] In some embodiments, the one or more airflow sources are configured to control the flow rate of the gas to focus the lateral deposition region of the micron or nano-sized polymer fibers as the fibers travel toward the target.

[0015] In some embodiments, the system further includes a target rotation system configured to rotate a three-dimensional target during deposition to deposit fibers on more than one side of the target.

[0016] In some embodiments, the system is configured to be handheld.

[0017] In some embodiments, the system further includes a container for coagulation, precipitation, or crosslinking, the container being configured to contain a bath for coagulation, precipitation, or crosslinking of the polymer material to be sprayed.

[0018] In some embodiments, the system further includes a heat source for heating the polymer material before it is delivered to the storage container or while it is in the storage container.

[0019] In some embodiments, the system is configured for co-deposition of fibers, and the system further includes: a second reservoir configured to contain a second material comprising a second polymer and rotatable about a second axis of rotation, the second reservoir including: a first end; a second end opposite to the first end; an outer wall extending from the first end to the second end, the shape of the second reservoir including one or more holes radially inwardly disposed from the outer wall of the reservoir, the one or more holes being configured to allow gas to move from the first end through the reservoir to the second end; and one or more orifices formed in the outer wall, each of the one or more orifices being configured to radially outwardly eject the second polymer through the one or more orifices during rotation of the second reservoir. The material serves as a second jet stream; the system further includes a second plurality of airflow sources, each configured to guide airflow from upstream of a first end of the second reservoir through one or more orifices of the second reservoir to a second end and downstream of the second end of the second reservoir during rotation of the second reservoir. The plurality of airflow sources have a converging direction such that the airflows from the plurality of airflow sources collectively form a second combined airflow in a second direction downstream of the second end of the second reservoir. This second combined airflow entrains and deflects the second jet stream to form a second focused stream of one or more second micron or nanometer-sized polymer fibers in a second direction, the second direction having an orientation within 5 degrees of the axis of rotation of the second rotation axis. The first and second directions are oriented for deposition on the same collection surface. In some embodiments, the system is configured to simultaneously deposit one or more fibers of a first polymer and one or more fibers of a second polymer on the same collection surface.

[0020] Some embodiments provide a method for forming and depositing at least one micron or nanometer-sized polymer fiber. The method includes: rotating a reservoir holding a polymeric material about a rotation axis to eject at least one material jet from at least one orifice defined by an outer wall of the reservoir; guiding at least one airflow through a portion of the reservoir radially inward from the outer wall, the at least one airflow being guided from a first upstream end of the reservoir to a second downstream end of the reservoir during rotation of the reservoir and ejection of the at least one material jet, to form at least one micron or nanometer-sized polymer fiber, the at least one airflow entraining the at least one micron or nanometer-sized polymer fiber and forming a focused fiber deposition flow of the at least one micron or nanometer-sized polymer fiber in a first direction having a direction within 5 degrees of the rotation axis of the reservoir; and collecting the focused fiber deposition flow on a target surface.

[0021] In some embodiments, the first direction is substantially parallel to the rotation axis of the storage device.

[0022] In some embodiments, the at least one airflow comprises multiple airflows that converge in a first direction to form a combined airflow. In some embodiments, the airflow velocity of at least some of the converging multiple airflows is controllable relative to the velocity of other converging multiple airflows to achieve a balanced combined airflow. In some embodiments, the total airflow velocity of the converging multiple airflows is controllable to vary the distance from the reservoir to the location of the most tightly focused fiber deposition flow of at least one micron or nanometer-sized polymer fiber. In some embodiments, the multiple airflows comprise three airflows.

[0023] In some embodiments, during fiber collection, the focused fiber deposition stream has a direction substantially tangential to the target surface.

[0024] In some embodiments, the method further includes rotating the target surface during fiber collection.

[0025] In some embodiments, the method further includes at least partially blocking airflow from upstream of the storage device to reduce the focusing effect of airflow from multiple airflow sources on the fiber deposition flow of at least one micron or nanometer-sized polymer fiber.

[0026] In some embodiments, the target surface moves linearly during fiber flow deposition.

[0027] In some embodiments, the material in the reservoir includes a solvent.

[0028] In some embodiments, the material in the reservoir comprises a polymer melt. In some embodiments, the method further comprises heating the reservoir.

[0029] In some embodiments, the at least one jet stream contacts a bath before being collected onto the target surface. In some embodiments, the bath contains a crosslinking agent. In some embodiments, the at least one jet stream precipitates in the bath to form at least one micron or nanometer-sized polymer fiber. In some embodiments, the at least one jet stream solidifies in the bath to form at least one micron or nanometer-sized polymer fiber.

[0030] In some embodiments, at least one micron or nanometer-sized polymer fiber is deposited for reinforcement of the composite material.

[0031] In some embodiments, at least one micron or nanometer-sized polymer fiber is deposited on one or more foods.

[0032] In some embodiments, the method further includes: rotating a second reservoir containing a second material comprising a second polymer about a second axis of rotation to eject at least one jet of the second material from at least one orifice defined by an outer wall of the second reservoir. The method further includes guiding at least one second airflow through a portion of the second reservoir radially inward from the outer wall, the at least one second airflow being guided from an upstream first end of the second reservoir to a downstream second end of the second reservoir during rotation of the second reservoir and ejection of the at least one jet of the second material to form at least one micrometer or nanometer-sized polymer fiber of the second polymer, and the at least one second airflow entraining the at least one micrometer or nanometer-sized polymer fiber of the second polymer and forming a second focused fiber deposition stream. The method further includes collecting the second focused fiber deposition stream on a target surface. In some embodiments, the collection of the first focused fiber deposition stream and the collection of the second focused fiber deposition stream overlap in time.

[0033] Some embodiments provide a method for forming a three-dimensional tissue scaffold, including performing any of the methods described herein, wherein the target surface is a three-dimensional shape of the tissue scaffold. In some embodiments, the method further includes rotating the target to deposit on more than one side of the three-dimensional shape.

[0034] The embodiments disclosed in this invention meet these and other needs by providing systems and methods for fiber flow deposition.

[0035] Other features and advantages of the invention will become apparent from the following detailed description and claims. Brief description of the attached figures

[0036] Figure 1A These are fiber flux vs. diameter graphs for some conventional random fiber deposition techniques (circular) and some conventional extrusion 3D printing techniques (rhombus).

[0037] Figure 1B A schematic illustration of conventional random fiber deposition.

[0038] Figure 1C This schematically illustrates conventional extrusion 3D printing.

[0039] Figure 2A A rotary jet spinning system according to some embodiments is schematically illustrated, which utilizes an improved airflow for fiber flow deposition.

[0040] Figure 2B It is an image of fiber flow during deposition, generated by superimposing frames of video of fiber deposition and indicating the waist of the fiber flow, according to some embodiments.

[0041] Figure 3A This is a perspective view of a rotary jet spinning system for fiber flow deposition according to some embodiments, the system comprising multiple airflow sources that blow gas through orifices of a reservoir to form a combined airflow.

[0042] Figure 3B yes Figure 3A Image of the front view of the rotary jet spinning system shown.

[0043] Figure 3C According to some embodiments Figure 3A A perspective view of the storage container of a rotary jet spinning system.

[0044] Figure 3D According to some embodiments, it is used for Figure 3A A perspective view of the fixing device for multiple airflow sources in a rotary jet spinning system.

[0045] Figure 3E This is a perspective view of a flow choke according to some embodiments, the flow choke being coupled to a device for... Figure 3A A device for fixing multiple airflow sources in a rotary jet spinning system.

[0046] Figure 3F It is a front perspective view of a storage device, a supply line for polymer material to be conveyed to the storage device, a fixing device for multiple airflow sources, and a supply line for multiple airflow sources, according to some embodiments.

[0047] Figure 3G This is a rear perspective view of a storage device, a fixing device, and a supply line according to some embodiments.

[0048] Figure 4A This is an axial airflow velocity diagram based on a simulation of a rotary jet spinning system for fiber flow deposition according to some embodiments.

[0049] Figure 4B This is a radial airflow velocity diagram based on a simulation of a rotary jet spinning system for fiber flow deposition according to some embodiments.

[0050] Figure 5A The diagram schematically illustrates the airflow around a rotary jet spinning system for fiber flow deposition according to some embodiments, the rotary jet spinning system including a flow choke upstream of a reservoir.

[0051] Figure 5B The illustration schematically depicts a jet of polymer material cured into fibers according to some embodiments, and an airflow pulling the fibers into shape.

[0052] Figure 5C An axial view of a reservoir according to some embodiments is schematically shown, along with the forces acting on the polymer material jet after it is ejected from the reservoir.

[0053] Figure 6A This is a background subtraction image of a rotary jet spinning system for fiber flow deposition according to some embodiments, which does not have a flow choke to generate a focused fiber flow.

[0054] Figure 6B yes Figure 6A The average background subtraction image of a rotary jet spinning system during the generation of a focused fiber flow, without a flow choke, is shown in the figure, illustrating the average fiber flow distribution.

[0055] Figure 6C It is by Figure 6A The scanning electron microscope image of the fiber produced by the system, which does not have a flow choke.

[0056] Figure 7A This is a background subtraction image of a rotary jet spinning system for fiber flow deposition according to some embodiments, the system including a flow choke that generates a focused fiber flow.

[0057] Figure 7B yes Figure 7A The figure shows the average background subtraction image of a rotary jet spinning system during the generation of a focused fiber flow, which has a flow blocking device.

[0058] Figure 7C It is by Figure 7A The scanning electron microscope image of the fiber produced by the system, which has a flow choke.

[0059] Figure 8A According to some embodiments, this figure is a superposition of the maximum intensity of 3600 frames taken at a large field of view with an exposure of 1 / 800s and a tolerance of 1 / 60 during fiber generation and deposition, showing the fiber flow widening downstream of its waist.

[0060] Figure 8B According to some embodiments, fibers are collected on rotating target rods at different distances from the storage device to quantify the broadened thickness distribution map of the fiber flow.

[0061] Figure 9A The length dimensions of the fiber flow width w and the radius of curvature ρ of the target surface are schematically shown.

[0062] Figure 9B The illustration schematically shows a case where w << ρ, according to some embodiments, meaning that the target surface is actually flat for the fiber flow and the deposition conforms to the shape of the target.

[0063] Figure 9CThe illustration schematically depicts a situation where, according to some embodiments, w ~ ρ or w >> ρ, and the overhanging fibers prevent conformal deposition of the target feature.

[0064] Figure 9D It is a conformal deposition image formed on a female human body model when the radius of curvature of the target surface is greater than the fiber flow width.

[0065] Figure 9E It is a conformal deposition image on a Buddha face model with more refined features, where the radius of curvature of the target surface is smaller than the fiber flow width.

[0066] Figure 9F yes Figure 9E Conformal deposition is performed in embossing to shape the deposited material into an image that includes fine features.

[0067] Figure 10A This includes, according to some embodiments, a schematic diagram (top image) of fiber flow deposited onto a tangentially oriented target surface, an SEM image of the fibers deposited in a tangential deposition orientation (bottom left image), and a corresponding Fourier image of the fiber orientation (bottom right image).

[0068] Figure 10B Includes a schematic diagram (top) of depositing a fiber stream onto a target surface oriented at a 60° angle to the fiber stream, according to some embodiments; an SEM image of the fibers deposited at a 60° deposition orientation, showing partially aligned fibers (bottom left); and a corresponding Fourier image of the fiber orientation (bottom right).

[0069] Figure 10C This includes, according to some embodiments, a schematic diagram (top image) of fiber flow deposited onto a target surface oriented perpendicular to the fiber flow, an SEM image of the vertically oriented fibers (bottom left image), and a corresponding Fourier image of the fiber orientation (bottom right image).

[0070] Figure 10D The images include schematic diagrams of fiber structures deposited at a first depth (upper right figure) and a second depth of 360 μm (lower right figure) on a rotating tangentially oriented surface (left figure) according to some embodiments, and CT images of the resulting fiber structures, showing the rotation of fiber arrangement with depth.

[0071] Figure 10E The images include, according to some embodiments, a schematic diagram (top image) of deposition at a relatively low rotational speed onto the surface of a rotating cylinder oriented at an acute angle relative to the fiber flow, an optical profile measurement of the fiber orientation (bottom left image), and a Fourier transform image showing the helical arrangement of the fibers (bottom right image).

[0072] Figure 10FThe images include, according to some embodiments, a schematic diagram (top image) of deposition at a relatively fast rotational speed onto the surface of a rotating cylinder oriented at an acute angle relative to the fiber flow, an optical profile measurement of the fiber orientation (bottom left image), and a Fourier transform image showing the helical arrangement of the fibers (bottom right image).

[0073] Figure 11A A rotary jet spinning system for wet spinning applications, according to some embodiments, is schematically illustrated, including a water bath device for the precipitation, coagulation, or crosslinking of polymer materials.

[0074] Figure 11B A rotary jet spinning system for melt spinning according to some embodiments is schematically shown, which includes one or more heaters to heat a polymer material.

[0075] Figure 11C A handheld rotary jet spinning system according to some embodiments is illustrated schematically.

[0076] Figure 11D A system comprising multiple rotary jet spinning systems for fiber flow deposition during the production process is illustrated schematically according to some embodiments.

[0077] Figure 12A A method for forming a ventricular stent fibrous structure is illustrated schematically according to an example.

[0078] Figure 12B This is an image of a composite mandrel before deposition, based on an example.

[0079] Figure 12C This is an image of the combined heart axis after deposition on the combined heart axis used to form the resulting ventricular fiber scaffold structure.

[0080] Figure 12D It is a cross-section of a microscopic CT image of the ventricular structure obtained from an example.

[0081] Figure 12E This is a microscopic CT image of the diaphragm of the ventricular structure obtained from an example.

[0082] Figure 12F This is a detailed microscopic CT image of the diaphragm of the ventricular structure obtained according to one embodiment. Detailed Implementation

[0083] In the following description, it should be understood that terms such as “top,” “bottom,” “middle,” “outward,” and “inward” are used for convenience and should not be construed as limiting terms. Reference will now be made in detail to embodiments of the present disclosure illustrated in the accompanying drawings and examples. Generally, reference is made to the accompanying drawings, and it should be understood that these illustrations are intended to depict specific embodiments of the present disclosure and not to limit the scope of the disclosure.

[0084] Whenever a particular embodiment of this disclosure is referred to as comprising or consisting of at least one element from a group or a combination thereof, it should be understood that the embodiment may individually or in combination with any element from the group may include any element from the group or be constituted by any element from the group.

[0085] As used herein, the terms "polymer fiber" and "polymerized fiber" refer to fibers that contain polymers. The fiber may also include some non-polymer components.

[0086] As used in this article, micron or nano-sized fibers refer to fibers with a diameter of less than about 10 μm.

[0087] These and other aspects of the invention will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. While the following description points to various embodiments of the invention and many specific details thereof, it is given in an illustrative rather than limiting manner. Many substitutions, modifications, additions, or rearrangements can be made within the scope of the invention, and the invention includes all such substitutions, modifications, additions, or rearrangements.

[0088] Some embodiments described herein include methods and systems for forming polymer fibers with diameters ranging from micrometers to nanometers by jetting a fiber-forming liquid from a spinning reservoir that employs a gas (e.g., air) stream to focus and align the fibers generated in the fiber stream for controlled deposition. In some embodiments, the flux of microfiber production, measured in fiber length per unit time, is at least 80 km / min. In some embodiments, the flux of microfiber production is in the range of 1 m / min to 150 km / min. In some embodiments, the flux of microfiber production is in the range of 100 m / min to 150 km / min. In some embodiments, the flux of microfiber production is in the range of 1 km / min to 150 km / min. In some embodiments, the flux of microfiber production is in the range of 80 km / min to 150 km / min. In some embodiments, the flux of microfiber production is in the range of 80 km / min to 100 km / min. In some embodiments, the deposited fibers conform to various 3D geometries through controlled fiber alignment.

[0089] Some traditional high-throughput methods have attempted to deposit fibers onto 3D shaped targets to obtain 3D fibrous structures; however, the fibers often do not conform to the target shape, and overhanging fibers are common. Some traditional methods have employed target rotation to achieve circumferential fiber arrangement; however, this approach cannot handle the more complex arrangements observed in real tissues, such as the spiral arrangement in the ventricles, or the three-layered structure with circumferential and longitudinal arrangements in different layers of the heart valve.

[0090] In some embodiments, the systems and methods of the present invention offer improved structural controllability compared to conventional high-throughput fiber deposition techniques for fibers with diameters ranging from micrometers to nanometers. Some embodiments of the systems and methods described herein employ Fiber Stream Deposition (Stream-FD), in which fibers are constructed into a spatially confined and well-aligned fiber stream before being deposited onto a target. A well-structured fiber stream enables well-structured deposition. Stream-FD achieves precise control over consistency and deposition alignment without sacrificing throughput.

[0091] Fibers are formed using a rotary jet spinning process, under centrifugal force, by jetting one or more jets of fiber-forming liquid (e.g., a polymer-containing material, referred to herein as the polymer material) through one or more orifices of a rotating reservoir and subsequently solidifying it. The reservoir, including one or more orifices, may be referred to herein as a spinneret. In the embodiments described herein, specific aerodynamics of the airflow (e.g., airflow) are used to constrain the resulting fiber distribution and to align the fibers within the fiber flow. Constraining the fiber distribution requires a converging airflow that gathers the fibers together as they flow out of the reservoir. Aligning the fibers requires an accelerated airflow to straighten them. Furthermore, disturbances to the flow near the reservoir (e.g., the spinneret) should be minimized to avoid interfering with fiber formation. In some embodiments, these requirements can be achieved by blowing gas (e.g., air) from or near the axis of rotation of the reservoir.

[0092] Figure 2AAn exemplary rotary jet spinning system 10 according to some embodiments is schematically illustrated. The system includes a rotary motion generator (e.g., a motor) 11 that rotates a reservoir 12 including an orifice, referred to herein as a spinneret. The system employs an airflow (e.g., an air stream) 30 to converge and align a fiber stream 15 generated by jetting a polymer solution 17 from the spinneret 12 prior to fiber deposition onto a target 19. In some embodiments, the airflow may be a gas jet or air jet located at or near the axis of rotation 21 of the spinneret / reservoir 12 and may be directed to a direction parallel to or approximately parallel to the axis of rotation 21. The airflow is non-uniform over the rotor region. In some embodiments, the flow is concentrated in one or more central portions of the rotor, radially inwardly spaced from the sidewalls of the rotor. In some embodiments, downstream of the rotor, the airflow has a higher velocity at or near the axis of rotation of the rotor, which decreases at locations laterally displaced from the axis of rotation.

[0093] Rotary jet spinning generates one or more bundles of fibers through centrifugal force, creating a cloud of fibers that moves radially outward along an azimuth angle around the spinneret 12. When an airflow (e.g., an air jet) 30 is propelled from one or more central portions of the spinneret, the airflow 30 draws surrounding air into the jet in a phenomenon known as entrainment. The entrainment flow is several orders of magnitude slower than the flow within the jet, causing minimal disturbance to fiber formation. The entrainment flow converges and accelerates towards the jet, which confines and aligns the fibers into a flow, such as... Figure 2B The visualization of the fiber flow is shown, which is generated by overlaying different frames from the fiber deposition video.

[0094] Additional details of some embodiments of the rotary jet spinning system and method are referenced below. Figure 3A-3G Describe it. In Figure 3A-3G In the illustrated embodiment, the system employs multiple airflows that combine to form a combined airflow for converging and aligning the fiber streams. Furthermore, according to some embodiments, before forming the combined airflow, the multiple airflows flow radially inward through orifices in the reservoir along one or more openings.

[0095] refer to Figure 3A-3G Embodiments of the rotary jet spinning system 10 include at least one reservoir 12 configured to rotate about a rotation axis 21. Some systems may also include a rotary motion generator (e.g., a motor) 11 for rotating the reservoir.

[0096] In some embodiments, the reservoir 12 has a first end 14, a second end 16 opposite to the first end 14, and an outer sidewall 18 extending from the first end 14 to the second end 16. The reservoir 12 is configured and adapted to contain material for forming polymer fibers (e.g., polymer material). The reservoir 12 defines one or more orifices 22 in the outer sidewall 18. The reservoir 12 is configured and adapted to radially outward ejection of polymer material through the one or more orifices 22 formed in the outer sidewall 18 under pressure caused by rotation of the reservoir 12. Each of the one or more orifices 22 may be configured to radially outward eject polymer material as a jet 24 during rotation of the reservoir 12.

[0097] In some embodiments, the reservoir defines one or more holes 20a, 20b, 20c arranged radially inward from the outer wall 18, these holes being configured to allow gas to move from the first end 14 through or through the reservoir 12 to the second end 16. In some embodiments, the reservoir 12 may define three holes 20a, 20b, 20c arranged radially inward from the outer wall 18. In other embodiments, the reservoir 12 may define more than three holes arranged radially inward from the outer wall 18. In some embodiments, the reservoir may define 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 19 holes arranged radially inward from the outer wall 18. In view of this disclosure, those skilled in the art will understand that holes of different geometries and different numbers of holes fall within the scope of this invention.

[0098] According to some embodiments, the rotary jet spinning system 10 further includes one or more airflow sources 28a, 28b, 28c for forming an airflow, also referred to herein as a gas jet (e.g., an air jet), which are used to converge and align the fiber flow. In some embodiments, the rotary jet spinning system 10 includes a plurality of airflow sources 28a, 28b, 28c, each airflow source being configured to guide airflow from upstream of a first end 14 of the reservoir 12 through orifices 20a, 20b, 20c from the first end 14 of the reservoir 12 to a second end 16, and downstream of the second end 16. In some embodiments, the plurality of airflow sources 28a, 28b, 28c have a converging orientation, such that the airflows from the plurality of airflow sources collectively form a combined airflow or gas jet 30 in a first direction downstream of the second end 16 of the reservoir 12. In some embodiments, the first direction is substantially parallel to the axis of rotation 21. Figure 3F Includes arrows indicating airflows 30a, 30b, 30c from multiple airflow sources 28a, 28b, 28c and a combined airflow 30 aligned with the rotation axis 21. (Example) Figure 3FAs shown, airflows 30a, 30b, and 30c guided from airflow sources 28a, 28b, and 28c can converge at a location downstream of the second end 16 of the reservoir 12 to form a combined airflow 30. In some embodiments, airflow sources 28a, 28b, and 28c can converge to form a combined airflow within a range of 2 cm to 10 cm downstream of the second end 16 of the reservoir 12. In some embodiments, airflows from the airflow sources can converge at a location more than 10 cm from the second end 16 of the reservoir. The combined airflow 30 can entrain the jet 24 to form a focused flow of micron- or nano-sized polymer fibers 32 in a first direction. In a non-limiting example, multiple airflow sources can converge and homogenize at a distance of approximately 3 cm downstream of the second end 16 of the reservoir 12. At such a distance, in some embodiments, the airflow velocity can be between approximately 10 m / s and approximately 30 m / s.

[0099] In some embodiments, the first direction may form an angle relative to the rotation axis 21. In some embodiments, the first direction may be within a range of 5° of the longitudinal axis A1. In some embodiments, the first direction may be within a range of 3° of the longitudinal axis A1. In some embodiments, the first direction has an angle relative to the rotation axis 21 ranging from 0° to 5°.

[0100] As described above, in some embodiments, the rotary jet spinning system 10 may include an airflow system comprising one or more airflow sources (e.g., nozzles) 28a, 28b, 28c. The one or more airflow sources 28a, 28b, 28c may be supplied with airflow independently, or may share an airflow from a common source before the airflow is split into one or more airflow sources 28, 28b, 28c. In some embodiments, such as Figure 3A , 3D As shown in 3G, one or more airflow sources can be a single airflow unit or part of a fixture 26.

[0101] During operation, an airflow or gas jet 30 (which may be a combination of airflows) entrains and deflects the jet to form a focused flow of micron or nano-sized polymer fibers in a first direction. Airflow passing through the reservoir at or near the axis of rotation does not interfere with fiber formation. Figure 4A and Figure 4B A turbulence model simulation of the flow field around the spinneret 12 is shown, in which a central air jet 30 is applied from the central portion of the spinneret or reservoir. Even with a large volume of air jets, the presence of the central air jet in the axial direction of the flow field in the fiber forming region 41 is significant. Figure 4A ) or radial ( Figure 4BThis causes minimal disturbance in the direction of rotation, thus not interfering with fiber formation. Conversely, if the reservoir is subjected to a uniform external airflow parallel to the axis of rotation, rather than an external airflow passing through the central portion of the reservoir, the uniform external airflow will interfere with fiber formation in fiber formation region 41 and may lead to fiber entanglement.

[0102] In some embodiments, the reservoir 12 can begin to rotate without the application of an airflow (e.g., an air stream). The airflow (e.g., an air stream) can be gradually increased until a stream of micron or nano-sized polymer fibers (or fiber bundles) is focused. Figure 2B The focused fiber flow is shown, and the flow waist w at the narrowest point of the fiber flow is indicated. min In some embodiments, the waist of the fiber flow, measured along the axis of rotation, may be located at a distance of 3 cm to 7 cm from the orifice of the reservoir. If the flow rate is too low, the fibers will not align or will not align correctly. Higher flow rates will allow the fibers to align and be collected at a greater distance from the reservoir 12. Collecting the fibers at a greater distance from the reservoir 12 may be advantageous in ensuring the drying of the fibers and / or allowing the fibers to be distributed over a larger area / deposited on a larger target; however, at greater distances from the reservoir, the fiber flow widens, and the fibers may slow down and bend. In some embodiments, the fibers are deposited on the surface of the collector or target at a distance of 2 cm to 20 cm from the orifice measured along the axis of rotation. In some embodiments, the fibers are deposited on the surface of the collector or target at a distance of 3 cm to 20 cm from the orifice measured along the axis of rotation. In some embodiments, the fibers are deposited on the surface of the collector or target at a distance of 4 cm to 20 cm from the orifice measured along the axis of rotation. In some embodiments, the fibers are deposited on the surface of the collector or target at a distance of 3 cm to 50 cm from the orifice measured along the axis of rotation.

[0103] In some embodiments, the device with multiple airflow sources can be configured such that at any single point in time during reservoir rotation, airflow from all airflow sources flows through the orifice of the reservoir, or airflow from all airflow sources is blocked by the reservoir. In this way, the combined airflow does not deviate from its intended direction due to only some airflow being blocked at a given point in time, thus preventing an unbalanced combined airflow. For example, Figures 3A-3FThe airflow source devices and reservoirs in the illustrated system are configured such that at any given time, airflow from all three airflow sources 28a, 28b, 28c flows through the orifices 20a, 20b, 20c of the reservoir 12, or airflow from all three airflow sources 28a, 28b, 28c is substantially partially blocked by the reservoir 12 between the orifices 20a, 20b, 20c. In other embodiments, there may be a sufficient number of airflows such that the combined airflow can be balanced even when a portion of the airflow is blocked. For example, in an embodiment with six airflows symmetrically arranged about the axis of rotation and three orifices in the reservoir symmetrically arranged about the axis of rotation, at some point during the rotation of the reservoir, every other airflow will be blocked, but the combined airflow can still be balanced.

[0104] In some embodiments, the airflow sources 28a, 28b, 28c may be controllable to achieve a balanced combination of airflows. For example, the flow rate through the airflow sources may be adjustable, or the flow direction or orientation from the airflow sources may be adjustable. In some embodiments, the airflow sources 28a, 28b, 28c may be controllable to change the distance between the location where the fiber flow of the micron or nano-sized polymer fibers 32 has the tightest focusing and the reservoir 12 or orifice, which is also referred to herein as the flow waist (see [link to relevant documentation]). Figure 2B In some embodiments, the distance between the orifice and the flow waist along the first direction can be in the range of approximately 3 cm to approximately 7 cm. In other embodiments, this distance can be shorter than this range or greater than this range. In some embodiments, the gas flow rate can be adjustable. In some embodiments, the gas pressure can be in the range of approximately 0.1 MPa to approximately 0.5 MPa during fiber formation and deposition.

[0105] In some embodiments, the rotary jet spinning system 10 may include a flow restrictor 34 located upstream of the first end 12 of the reservoir 12 (see...). Figure 3A , 3B (and 3E). The flow deflector 34 can provide additional control over the vortices generated by the airflow and the rotation of the reservoir 12, thereby improving control over the lateral deposition region of the micron or nano-sized polymer fibers as the fibers travel toward the target.

[0106] In some embodiments, the flow deflector 34, also referred to herein as a flow regulator, is used to achieve a longer collection distance by preventing excessive disturbance of fiber formation near the reservoir 12 by a strong airflow. As described above, the flow deflector 34 may be located upstream of the first end 14 of the reservoir 12. In some embodiments, the flow deflector 34 may be located at a distance of approximately 2 cm to approximately 10 cm upstream of the first end 14 of the reservoir 12. In some embodiments, the flow deflector is located approximately 5 cm upstream of the first end 14 of the reservoir. In some embodiments, the flow deflector 34 is fixed and does not rotate. In other embodiments, the flow deflector 34 may be configured to rotate with the reservoir or be detached from the reservoir. According to some embodiments, the flow deflector 34 has a diameter equal to or greater than that of the reservoir 12. For example, in some embodiments, the diameter of the flow deflector 34 is in the range of approximately 1 to approximately 5 times the diameter of the reservoir 12; in other embodiments, the flow deflector may have a larger diameter. The diameter of the flow deflector 34 may be selected in part based on the position of the flow deflector 34 relative to the reservoir 12. For example, a larger obstruction 34 placed further away from the reservoir 12 can have a similar effect to a smaller obstruction 34 placed closer to the reservoir 12. In some embodiments, an obstruction may not be necessary when depositing onto a collector relatively close to the reservoir, but may be necessary when collecting at a greater distance from the reservoir (e.g., a distance greater than 20 cm, 30 cm, or 50 cm).

[0107] Figure 5A The airflow streamlines around the system and the effect of the flow deflector 34 on the airflow are schematically illustrated. The airflow is primarily dominated by radial and azimuthal airflow caused by the rotation of the reservoir and by externally applied airflow through the central portion of the reservoir. In the circulation region, vortices are formed due to the competition between the centripetal flow from the rapidly rotating reservoir and the entrainment flow of the air jet blown from the center of the reservoir. The external flow in the drive region also entrains airflow from outside the circulation region and from upstream of the reservoir and the flow deflector, flowing in subsequent regions. The flow deflector 34 can alter (e.g., block) at least some of the airflow from upstream of the reservoir and affect the size and shape of the vortices in the circulation region.

[0108] Figure 5B The diagram schematically illustrates the polymer jet 24 under the influence of flow in the centrifugal region and the resulting fiber 15 in the tension region. In the centrifugal region, the polymer jet 24 is subjected to centrifugal force due to being ejected from the reservoir in the absence of an external airflow. In the tension region, the fiber 15 is entrained by an external airflow 30 and subjected to tension. For simplicity, one or more airflow sources for generating the external airflow 30 are not shown in this schematic diagram.

[0109] Figure 5C An axial view of the reservoir is schematically shown, illustrating the various forces acting on the jet of polymer material ejected from the reservoir during fiber formation.

[0110] Figures 6A-6C Figures 7A-7C illustrate the effect of a flow choke according to some embodiments. In a non-limiting example, Figures 6A-6C This corresponds to the generation of fibers via a rotary jet spinning system 10 for fiber flow deposition, which does not include a flow deflector 34. In contrast, Figures 7A-7C Corresponding to the generation of fibers via a rotary jet spinning system 10 for fiber flow deposition, the rotary jet spinning system 10 includes a flow deflector 34. Figure 6A Compared to the background subtraction image shown without the use of a choke, Figure 7A Background subtraction images of the fiber deposition process show less turbulence downstream of reservoir 12 when using flow deflector 34. In some embodiments, flow deflector 34 provides additional control over eddies generated by gas flow and rotation of reservoir 12, thereby improving control over the lateral deposition region of the polymer fibers as they travel toward the target. Figure 7B When the flow deflector is shown, the fibers extend further before focusing into a flow. Flow deflector 34 suppresses the resistance region, resulting in better fiber morphology. Figure 6C and Figure 7C Scanning electron microscopy images were used to compare the morphology of the obtained fibers. These images show that the fibers produced using the choke have a more uniform fiber diameter and reduced fiber crimp. Samples were collected 20 cm downstream of the reservoir.

[0111] Although some embodiments of the system are described herein as including a flow choke, the systems and methods described herein do not require the inclusion, incorporation, or use of a flow choke or flow regulator upstream of the reservoir. In some embodiments, the fiber morphology, distribution, and fiber arrangement in the deposition may be acceptable even without the use of a flow choke. As mentioned above, in some embodiments, the need for or use of a flow choke can be determined at least in part based on the distance between the reservoir and the surface where the fibers are collected.

[0112] Although some embodiments are described herein as having multiple airflows converging into a single airflow that entrains and converges and focuses the airflow, in other embodiments a single airflow guided along the rotation axis of the reservoir may be employed.

[0113] For some of the systems and methods described herein, after the central airflow focuses the fiber stream to the waist, the fiber stream widens proportionally to the distance from the reservoir, just as the turbulent jet is predicted to widen. Figure 8AIt is a wide field-of-view image formed by multiple overlapping images of the fiber flow, and shows the fiber flow r stream It widens as the distance from the storage x increases. Figure 8B This is a thickness distribution map collected at different distances from the storage device. The thickness distribution map shows r stream A self-similar scaling factor of ~0.1x, similar to the self-similar scaling factor of the velocity distribution map of jet turbulence broadening. Therefore, downstream of the flow waist, the width of the fiber flow increases proportionally to the distance from the collection target surface to the reservoir.

[0114] In some embodiments, the system for rotary jet spinning with fiber flow deposition is configured for conformal deposition on 3D features. The constraint of the fiber flow is important for conformal deposition on three-dimensional features. In terms of length scale, such as... Figure 9A As schematically illustrated, this constraint is characterized by the fiber flow width *w*, and the 3D features of the target for deposition are characterized by the local radius of curvature *ρ*. Since the fiber flow is generated by a random cloud of fibers and is constantly perturbed by turbulent fluctuations, the fiber trajectory oscillates within the fiber flow. If the width of the fiber flow is much smaller than the curvature of the target surface, *w* << *ρ*, as... Figure 9B As illustrated in the diagram, for the fiber flow, the target surface is actually flat, and the deposition conforms to the target surface. If the fiber flow width is equal to or less than the curvature of the target surface, w ~ ρ or w >> ρ, then curvature has a significant effect on deposition. If the target surface is convex, the fibers wrapped around the target still produce conformal deposition. However, if the surface is concave, the fibers dangling across the concave portion will result in... Figure 9C The non-conformal deposition is shown. In practice, the width of the fiber stream is determined by the width of the central airflow, which varies with the spinneret diameter and increases linearly with the collection distance. The effect of contrasting the feature size of the target with the width of the fiber stream is illustrated by depositing a fiber stream of approximately 6 cm width on two targets: a 50 cm tall female anatomical model and a 15 cm tall Buddha face, a replica of a 5th-century statue from Qingzhou, China. For larger feature sizes, where the fiber stream width is approximately the same as the feature size on the target, the deposition conforms well to the body features of the female anatomical model (see [link to documentation]). Figure 9D For relatively small feature sizes, where the fiber flow width is larger than the feature size on the target, it is almost impossible to distinguish any facial features on the Buddha face on the deposition (see [link]). Figure 9E After embossing, the details of the Buddha's facial features become apparent (see...). Figure 9F ). Figure 9D-9F The scale on it is approximately 6cm.

[0115] Theoretically, a smaller rotation setting can be used to obtain a smaller fiber flow width, thus achieving finer feature resolution. In practice, a smaller fiber flow width typically requires a trade-off between flux and fiber quality. Because turbulent fluctuations constantly disturb the fibers in the fiber flow, the chances of fiber collisions and bundling increase with increasing fiber density in the fiber flow. Therefore, reducing the fiber flow width while maintaining the same flux results in poorer fiber quality, as it requires a higher fiber density. Alternatively, maintaining the same fiber density with a smaller fiber flow results in lower flux. For targets like Buddha faces, where fine features appear only as shallow fluctuations on coarse features, high-flux deposition capable of capturing large-scale features can be employed, followed by embossing (see...). Figure 9F ).

[0116] In some embodiments, the arrangement of fibers in the fiber stream allows the system and method to control the deposition arrangement by changing the deposition angle. If the fiber stream is at... Figure 10A The diagram above schematically shows that when the air jet impacts the target surface in a tangential direction, the flow field of the air jet is minimally disturbed by the target. The fibers fall onto the target surface as they oscillate in the airflow and maintain their alignment in the airflow. Figure 10A The scanning electron microscope (SEM) image (bottom left) and the corresponding Fourier transform image (bottom right) of the fibers deposited at this deposition angle confirm the fiber arrangement in the fiber flow. If the airflow is as... Figure 10C As shown in the diagram above, when an air jet impacts the target surface vertically, it creates a diverging, decelerating flow field, the opposite of the converging, accelerating field used to form the fiber flow. Therefore, as... Figure 10C The scanning electron microscope image (bottom left) and corresponding Fourier transform image (bottom right) of fibers deposited at this deposition angle show that the fibers bend and diffuse into random clouds, resulting in random depositions with almost no or even no arrangement. Using an intermediate incident angle produces... Figure 10B The image shows a partial arrangement of deposits. The scale bar in the scanning electron microscope image is 20 μm. According to some embodiments, various arrangement patterns are possible by moving the target relative to the fiber flow. For example, as... Figure 9D As shown, collection on a rotating disk produces fiber sheets arranged by rotation through thickness. Figure 10E and 10F As shown, collection on a rotating cylinder produces a spiral arrangement. In some embodiments, a combination of control over the deposition angle and target rotation can be used to create more complex fiber arrangement patterns.

[0117] In some embodiments, the rotary jet spinning system may further include a second reservoir configured to contain a second polymer material, which may be different from the first polymer material. In some embodiments, the rotary jet spinning system may further include a second or more configured airflow sources, and the second reservoir and the second or more airflow sources may be configured for airflow to pass through the reservoir, thereby forming an airflow downstream of the reservoir along a second direction, which may be substantially parallel to or at an angle to the axis of rotation of the second reservoir. The airflow may entrain and deflect fibers to form a second fiber flow in the second direction. In some embodiments, the first and second reservoirs are oriented such that they can simultaneously deposit fibers onto the same target surface. All features and aspects described herein with respect to reservoir 12 also apply to the second reservoir, and all features and aspects described herein with respect to one or more airflow sources also apply to the second or more airflow sources.

[0118] In some embodiments, the polymer material is a polymer solution, and the polymer fibers are formed by evaporation of the solvent from the polymer solution. In some embodiments, the polymer material is a polymer melt, and the polymer fibers are formed at least partially by cooling and solidification. Additional details regarding the rotary spinning system, such as the reservoir, spinning speed, orifice diameter, polymer, polymer solution, and other polymer materials, such as polymer melts, can be found in U.S. Patent No. 2013 / 0312638, which is incorporated herein by reference in its entirety.

[0119] In some embodiments, the rotary jet spinning system 10b for fiber flow deposition may employ a polymeric material that requires crosslinking, precipitation, or coagulation to form fibers. In some such embodiments, the rotating target 102, at least partially immersed in the precipitation, coagulation, or crosslinking bath 104, may be exposed to the polymeric material flow (see [link to relevant documentation]). Figure 11A Further details regarding precipitation, coagulation, or crosslinking baths, as well as wet rotary jet spinning systems and methods, can be found in U.S. Patent Publication No. 2015 / 0354094, the entire contents of which are incorporated herein by reference.

[0120] In some embodiments, the polymer material may include a polymer melt, and system 10b may include a heater 204 (e.g., a syringe heater) for heating the polymer material before delivery to a reservoir (see [link to relevant documentation]). Figure 11B System 10b may additionally or alternatively include a reservoir heater 204 for heating the polymer material while it is in the reservoir. Figure 11B As shown, in some embodiments, the storage heater may be an infrared point heater.

[0121] In some embodiments, the rotary jet spinning system for fiber flow deposition can be configured as follows: Figure 11C The handheld device shown.

[0122] In some embodiments, system 10d may include a plurality of rotary jet spinning systems for fiber deposition, which can deposit fibers onto a linearly transported target, such as in... Figure 11D On the conveyor belt 302 shown. In some embodiments, one or more rotary jet spinning systems may be used in the production line.

[0123] In some embodiments, the system is configured for depositing fibers with an average diameter of less than 10 μm. In some embodiments, the system is configured for depositing fibers with an average diameter of less than 5 μm. In some embodiments, the system is configured for depositing fibers with an average diameter of less than 3 μm. In some embodiments, the system is configured for depositing fibers with an average diameter of less than 2 μm.

[0124] Examples include methods for depositing micron- or nanometer-sized fibers onto a target surface. For illustrative purposes only, this document focuses on... Figure 3A-3G The system 10 shown illustrates some embodiments of the method; however, given this disclosure, those skilled in the art will understand that other systems can be used in conjunction with the method described herein. In some embodiments, a method includes rotating a reservoir 12 having an outer sidewall 18 and at least one orifice 22 about a rotation axis 21 to eject a jet 24 of polymer material from at least one orifice 22, the jet 24 solidifying to form polymer fibers 15. During the rotation of the reservoir 12 and the ejection of the polymer material jet 24 to form polymer fibers, at least one airflow, such as airflow 30a, airflow 30b, airflow 30c, or airflow 30, is guided radially inward from the outer sidewall 18 of the reservoir 12 from an upstream end 14 to a downstream end 16 of the reservoir through a portion of the reservoir, entraining the polymer fibers 24 with at least one airflow 30 and forming a focused fiber deposition stream. The focused fiber deposition stream is collected on a target surface to form polymer fiber material. In some embodiments, the focused fiber deposition stream flows in a first direction generally parallel to the rotation axis of the reservoir. In some embodiments, the orientation of the first direction is within 20 degrees, 10 degrees, or 5 degrees of the storage rotation axis. In some embodiments, at least one airflow is formed by the convergence and combination of multiple airflows 30a, 30b, and 30c to form a combined airflow 30 in the first direction (see...). Figure 3F In some embodiments, the reservoir includes at least one radially inwardly oriented hole 20a, 20b, 20c on the sidewall, which allows at least one stream of air to flow through the reservoir.

[0125] In some embodiments, the deposited fibers have an average diameter of less than 10 μm. In some embodiments, the deposited fibers have an average diameter of less than 5 μm. In some embodiments, the deposited fibers have an average diameter of less than 3 μm. In some embodiments, the deposited fibers have an average diameter of less than 2 μm.

[0126] The systems and methods described herein can be used for a wide variety of purposes. For example, as a non-limiting list, the systems and methods can be used to produce composite materials, for tissue engineering (e.g., for cell or tissue scaffolds), or for clothing design. In particular, some embodiments are suitable for forming structures with complex three-dimensional shapes and / or complex fiber arrangements. The ability to control the three-dimensional shape and arrangement of fiber deposition can impact various fields involving structured fibrous materials, such as fashion design, composite materials, and tissue engineering.

[0127] Example - Engineering Ventricle

[0128] This article provides tissue scaffolds for engineering ventricles to demonstrate the capabilities of some of the embodiments described herein. A ventricle is one of the two chambers of the heart responsible for pumping blood. It consists of a highly packed layer of cardiomyocytes coiled in a helical fashion. The helical angle rotates between 45° and -45° within the thickness of the ventricular wall. This complex helical arrangement of cardiomyocytes is supported by a fibrous extracellular matrix (ECM), which is primarily composed of layered collagen fibers ranging in diameter from tens of nanometers to several micrometers. Reconstructing this fibrous ECM is considered a key challenge in cardiac tissue engineering. Previous efforts to reconstruct the ventricular fibrous ECM have included various methods such as tissue decellularization, random fiber deposition, and 3D printing. However, these efforts remain limited by the trade-offs between fine fibers, complex structures, and high throughput.

[0129] Use a four-step rotation procedure to copy, such as Figure 12A The simplified three-layered helical biventricular model is shown. The fiber diameter is chosen to be a few micrometers, similar to the diameter of muscle surface fibers in the extracellular matrix of heart cells. In step one, the fiber stream is deposited onto a rotating axis shaped similar to the left ventricle, wherein the rotating axis is at a 45-degree angle relative to the deposited stream. In step two, the fiber stream is deposited onto a rotating left ventricular axis, which is perpendicular to the fiber stream. In step three, the fibers are deposited onto a rotating axis shaped similar to the right ventricle, wherein the right ventricular axis is at a 45-degree angle relative to the deposited stream. In step four, the left and right ventricular axes are positioned together to form a combined axis, and the fibers are deposited at an angle of -45 degrees to the fiber stream on the rotating combined axis and on the previously deposited fiber layer.

[0130] The implementation of these design features was verified through direct measurement and micro-CT imaging. Figure 12BIt is an image of a combined mandrel with previously deposited fibrous layers, and Figure 12C This is an image of a composite mandrel after the fiber layer has been deposited at an angle of -45 degrees to the fiber flow.

[0131] Figure 12C This is a microscopic CT image of the cross-section of the obtained deposited fiber structure. Figure 12D This is a microscopic CT image of the septum between the two ventricles, showing the changing helix angle. Figure 12E The image details of the septum also show the changing spiral angle.

[0132] The approximate language used throughout the specification and claims can be used to modify any quantitative or qualitative expression, allowing for variation without altering the essential function associated with it. Therefore, values ​​modified by terms such as "approximately" or numerical ranges are not limited to specific precise values ​​and can include values ​​other than specific ones. In at least some cases, approximate language can correspond to the precision of the instrument used to measure the value.

[0133] While this disclosure has been described in detail with reference to only a limited number of aspects and embodiments, it should be understood that this disclosure is not limited to these aspects. Rather, this disclosure can be modified to incorporate any number of variations, alterations, substitutions, or equivalents not previously described, but commensurate with the scope of the claims. Furthermore, although various embodiments of this disclosure have been described, it should be understood that aspects of this disclosure may include only some of the described embodiments. Therefore, this disclosure should not be considered as limited to the foregoing description, but only to the scope of the appended claims.

Claims

1. A system for focused directional deposition of one or more micron or nanometer-sized polymer fibers, the system comprising: A storage device configured to hold a material comprising a polymer and rotatable about a rotation axis, the storage device comprising: First end; The second end is opposite to the first end; An outer wall extending from the first end to the second end, the shape of the reservoir including one or more holes radially inwardly disposed from the outer wall of the reservoir, the one or more holes being configured to allow gas to move from the first end through the reservoir to the second end; and One or more orifices are formed in the outer sidewall, each of the one or more orifices being configured to radially outward eject the material as a jet stream during rotation of the reservoir; as well as One or more airflow sources, each of which is configured to guide airflow from upstream of the first end of the reservoir through the one or more orifices of the reservoir from the first end to the second end and downstream of the second end of the reservoir during rotation of the reservoir, the one or more airflow sources together forming a combined airflow in a first direction downstream of the second end of the reservoir, the combined airflow entraining and deflecting one or more jet streams to form a focused flow of the one or more micron or nano-sized polymer fibers in the first direction having an orientation within 5 degrees of the axis of rotation of the reservoir.

2. The system of claim 1, wherein the one or more airflow sources comprise a plurality of airflow sources having a converging orientation to form the combined airflow in the first direction.

3. The system of claim 2, wherein the airflow velocity of at least some of the plurality of airflow sources relative to the other airflow sources is controllable to achieve a balanced combined airflow.

4. The system of claim 1, wherein the total airflow velocity from the one or more airflow sources is controllable to change the distance from the reservoir where the flow of the micron or nano-sized polymer fibers has the most closely focused position.

5. The system of claim 2, wherein the number and arrangement of the plurality of airflow sources are configured such that, at any single point in time during rotation of the reservoir, airflow from all of the plurality of airflow sources flows through the holes in the one or more orifices of the reservoir, or airflow from all of the plurality of airflow sources is blocked by the reservoir.

6. A method for forming and depositing at least one micron or nanometer-sized polymer fiber, the method comprising: A reservoir containing a polymer material is rotated about a rotation axis to eject at least one jet of material from at least one orifice defined by an outer wall of the reservoir. At least one airflow is guided through a portion of the reservoir radially inward from the outer wall. The at least one airflow is guided from a first upstream end of the reservoir to a second downstream end of the reservoir during the rotation of the reservoir and the ejection of the at least one material jet to form at least one micron or nanometer-sized polymer fiber. The at least one airflow entrains and deflects the at least one micron or nanometer-sized polymer fiber to form a focused fiber deposition flow of the at least one micron or nanometer-sized polymer fiber in a first direction having an orientation within 5 degrees of the rotation axis of the reservoir. as well as The focused fiber deposition flow is collected on the target surface.

7. The method of claim 6, wherein the first direction is substantially parallel to the axis of rotation of the storage device.

8. The method according to claim 6 or claim 7, wherein the at least one airflow comprises multiple airflows that converge in the first direction to form a combined airflow.

9. The method of claim 8, wherein the velocity of at least some of the converging airflows is controllable relative to the velocity of the other converging airflows to achieve a balanced combined airflow.

10. A method for forming a three-dimensional tissue scaffold, the method comprising performing the method of any one of claims 6 to 9, wherein the target surface is a three-dimensional shape of the tissue scaffold.

Images