Focused rotary jet spinning devices and methods of use thereof

Abstract

Systems and methods for focused direction deposition of a micron or nanometer dimension polymeric fiber and materials of such fibers are described herein. Systems and methods employ one or more gas flows to entrain and deflect fibers produced by a rotary jet spinning system forming a focused fiber stream. Some embodiments enable control of alignment and distribution of the fibers with a relatively high fiber throughput.

We claim: 
     
         1 . A system for focused directional deposition of one or more micron or nanometer dimension polymeric fibers, the system comprising:
 a reservoir configured to hold a material including a polymer and rotatable about a rotation axis, the reservoir including:
 a first end; 
 a second end opposite the first end; 
 an outer sidewall extending from the first end to the second end, a shape of the reservoir including one or more apertures disposed radially inward from the outer sidewall of the reservoir that are configured to enable a gas to move through the reservoir from the first end to the second end; and 
 one or more orifices formed in the outer sidewall, each of the one or more orifices configured for ejection of the material radially outward through the orifice as an ejected jet during rotation of the reservoir; and 
   one or more gas flow sources, each configured to direct a flow of gas from upstream of the first end of the reservoir through the one or more apertures of the reservoir from the first end to the second end of the reservoir and downstream of the second end of the reservoir during rotation of the reservoir the one or more gas flow sources collectively forming a combined gas flow in a first direction downstream of the second end of the reservoir that entrains and deflects the one or more ejected jets to form a focused stream of the one or more micron or nanometer dimension polymeric fibers in a first direction, the first direction having an orientation that is within 5 degrees of the rotation axis of the reservoir.   
     
     
         2 . The system of  claim 1 , wherein the one or more gas flow sources comprise a plurality of gas flow sources having a converging orientation to form the combined gas flow in the first direction. 
     
     
         3 . The system of  claim 2 , wherein a gas flow rate of at least some of the plurality of gas flow sources relative to others of the gas flow sources is controllable to achieve a balanced combined gas flow. 
     
     
         4 . The system of  claim 1 , wherein a total gas flow rate from the one or more gas flow sources is controllable to change a distance from the reservoir at which the stream of the micron or nanometer dimension polymeric fiber has the tightest focus. 
     
     
         5 . The system of  claim 2 , wherein a number of the plurality of gas flow sources and an arrangement of the plurality of gas flow sources are configured such that, at any single point in time during rotation of the reservoir, gas flow from all of the plurality of gas flow sources flows through an aperture of the one or more apertures of the reservoir or the gas flow from all of the plurality of gas flow sources is blocked by the reservoir. 
     
     
         6 . The system of any one of  claims 2-5 , wherein the plurality of gas flow sources comprises three gas flow sources. 
     
     
         7 . The system of any one of  claims 1-6 , wherein the first direction is within 2 degrees of the axis of rotation. 
     
     
         8 . The system of any one of  claims 1-6 , wherein the first direction is substantially parallel to the axis of rotation. 
     
     
         9 . The system of any one of  claims 1-8 , wherein the focused stream of the one or more micron or nanometer dimension polymeric fiber has a stream width smaller than a diameter of the outer sidewall of the reservoir. 
     
     
         10 . The system of any one of claims  1 - 10 , further comprising a flow blocking structure disposed upstream of the plurality of gas flow sources and configured to reduce an effect of airflow upstream of the plurality of gas flow sources on focusing of the stream of the micron or nanometer dimension polymeric fiber. 
     
     
         11 . The system of  claim 10 , wherein the flow blocking structure is disposed upstream of the rotating reservoir and configured to at least partially block airflow from upstream of the rotating reservoir reducing an effect of airflow from upstream of the rotating reservoir on an interaction between airflow due to rotation of the reservoir and the flow of gas through the one or more apertures. 
     
     
         12 . The system of  claim 10 or claim 11 , wherein the flow blocking structure is stationary and does not rotate with the reservoir. 
     
     
         13 . The system of any one of  claims 10-12 , wherein the flow blocking structure enables enhanced control of a structure of vortices generated by the flow of gas and the rotation of the reservoir thereby improving control of a lateral area of deposition of the micron or nanometer dimension polymeric fiber as the fiber travels toward a target. 
     
     
         14 . The system of any one of  claims 1-13 , wherein the one or more gas flow sources are configured to enable control of a rate of flow of the gas to focus a lateral area of deposition of the micron or nanometer dimension polymeric fiber as the fiber travels toward a target. 
     
     
         15 . The system of any one of  claims 1-14 , further comprising a target rotation system configured to rotate a three dimensional target during deposition to deposit the fiber on more than one side of the target. 
     
     
         16 . The system of any one of  claims 1-15 , wherein the system is configured to be hand held. 
     
     
         17 . The system of any one of  claims 1-15 , further comprising a coagulation, precipitation or cross-linking reservoir configured to hold a bath for coagulation, precipitation or cross-linking of the ejected polymer material. 
     
     
         18 . The system of any one of  claims 1-15 , further comprising a heat source for heating the polymer material prior to delivery to the reservoir or while in the reservoir. 
     
     
         19 . The system of any one of  claims 1-18 , wherein the system is configured for co-deposition of fibers and further comprises:
 a second reservoir configured to hold a second material including a second polymer and rotatable about a second rotation axis, the second reservoir including:
 a first end; 
 a second end opposite the first end; 
 an outer sidewall extending from the first end to the second end, a shape of the second reservoir including one or more apertures disposed radially inward from the outer sidewall of the reservoir that are configured to enable a gas to move through the reservoir from the first end to the second end; and 
 one or more orifices formed in the outer sidewall, each of the one or more orifices configured for ejection of the second polymer material radially outward through the orifice as a second ejected jet during rotation of the second reservoir; and 
   a second plurality of gas flow sources, each configured to direct a flow of gas from upstream of the first end of the second reservoir through the one or more apertures of the second reservoir from the first end to the second end of the second reservoir and downstream of the second end of the second reservoir during rotation of the second reservoir, the plurality of gas flow sources having a converging orientation such that the flows of from the plurality of gas flow sources collectively forming a second combined gas flow in a second direction downstream of the second end of the second reservoir that entrains and deflects the second ejected jet to form a second focused stream of one or more second micron or nanometer dimension polymeric fiber in a second direction, the second direction having an orientation that is within 5 degrees of the rotation axis of the second rotation axis,   wherein the first direction and the second direction are oriented for deposition on a same collection surface.   
     
     
         20 . The system of  claim 19 , wherein the system is configured for simultaneous deposition of one or more fibers of the first polymer and one or more fibers of the second polymer on the same collection surface. 
     
     
         21 . A method for formation and deposition of at least one micron or nanometer dimension polymeric fiber, the method comprising:
 rotating a reservoir holding a material comprising a polymer about a rotation axis to eject at least one jet of material from at least one orifice defined by an outer sidewall of the reservoir;   directing at least one flow of gas through a portion of the reservoir radially inward of the outer sidewall, the at least one flow of gas directed from an upstream first end of the reservoir to a downstream second end of the reservoir during rotation of the reservoir and ejection of the at least one jet of the material to form at least one micron or nanometer dimension polymeric fiber, the at least one flow of gas entraining the at least one micron or nanometer dimension polymeric fiber and forming a focused fiber deposition stream of the at least one micron or nanometer dimension polymeric fiber in a first direction, the first direction having an orientation of within 5 degrees of the rotation axis of the reservoir; and   collecting the focused fiber deposition stream on a target surface.   
     
     
         22 . The method of  claim 21 , wherein the first direction is substantially parallel to the rotation axis of the reservoir. 
     
     
         23 . The method of  claim 21 or claim 22 , wherein the at least one flow of gas comprises a plurality of flows of gas that converge and form a combined gas flow in the first direction. 
     
     
         24 . The method of  claim 23 , wherein a flow rate of at least some of the plurality of converging flows of gas relative to others of the plurality of converging flows of gas is controllable to achieve a balanced combined gas flow. 
     
     
         25 . The method of  claim 23 or claim 24 , wherein a total gas flow rate of the plurality of converging flows of gas is controllable to change a distance from the reservoir at which the focused fiber deposition stream of the at least one micron or nanometer dimension polymeric fiber has the tightest focus. 
     
     
         26 . The method of any one of  claims 23 to 25 , wherein the plurality of gas flows comprises three gas flows. 
     
     
         27 . The method of any one of  claims 21 to 26 , wherein the focused fiber deposition stream has a substantially tangential orientation to the target surface during fiber collection. 
     
     
         28 . The method of any one of  claims 21-26 , further comprising rotating the target surface during fiber collection. 
     
     
         29 . A method of forming a three dimensional tissue scaffold comprising performing the method of any one of  claims 21 to 28  where the target surface is a three dimensional shape for a tissue scaffold. 
     
     
         30 . The method for forming the three dimensional tissue scaffold of  claim 29 , further comprising rotating the target for deposition on more than one side of the three dimensional shape. 
     
     
         31 . The method of any one of  claims 21 to 30 , further comprising at least partially blocking flow of gas from upstream of the reservoir to reduce an effect of airflow upstream of the plurality of gas flow sources on focusing of the fiber deposition stream of the at least one micron or nanometer dimension polymeric fiber. 
     
     
         32 . The method of any one of  claims 21 to 31 , wherein the target surface is moved linearly during deposition of the fiber. 
     
     
         33 . The method of any one of  claims 21 to 32 , wherein material in the reservoir comprises a solvent. 
     
     
         34 . The method of any one of  claims 21-32 , wherein the material in the reservoir comprises a polymer melt. 
     
     
         35 . The method of  claim 34 , further comprising heating the reservoir. 
     
     
         36 . The method of any one of  claims 21-32 , wherein the at least one ejected jet contacts a bath prior to being collected on the target surface. 
     
     
         37 . The method of  claim 36 , wherein the bath comprises a cross-linking agent. 
     
     
         38 . The method of  claim 36 , wherein the at least one ejected jet precipitates in the bath forming the at least one micron or nanometer dimension polymeric fiber. 
     
     
         39 . The method of  claim 36 , wherein the at least one ejected jet coagulates in the bath forming the at least one micron or nanometer dimension polymeric fiber. 
     
     
         40 . The method of any one of  claims 21 to 31 , wherein the at least one micron or nanometer dimension polymeric fiber is deposited for reinforcement of a composite material. 
     
     
         41 . The method of any one of  claims 21 to 31 , wherein the at least one micron or nanometer dimension polymeric fiber is deposited on one or more items of food. 
     
     
         42 . The method of  claim 21 , further comprising:
 rotating a second reservoir holding a second material comprising a second polymer about a second rotation axis to eject at least one jet of second material from at least one orifice defined by an outer sidewall of the second reservoir;   directing at least one second flow of gas through a portion of the second reservoir radially inward of the outer sidewall, the at least one second flow of gas directed 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 second material to form at least one micron or nanometer dimension polymeric fiber of the second polymer, and the at least one second flow of gas entraining the at least one micron or nanometer dimension polymeric fiber of the second polymer and forming a second focused fiber deposition stream; and   collecting the second focused fiber deposition stream on the target surface.   
     
     
         43 . The method of  claim 42 , wherein the collection of the first focused fiber deposition stream overlaps in time with the collection of the second focused fiber deposition stream