Method of producing structures using centrifugal forces

Abstract

A variety of hollow structures with unique morphologies were manufactured with a rotational spinning technique. Phase separation of soluble solutions or emulsions was induced within a filled mold as it was being rotated about one of its axis. The density difference between phases results in sediment at the inner lumen of the mold under centrifugal forces. After or during sedimentation, gelation of the phase-separated particles fixes the hollow structure morphology and the solvent remains in the center of the mold. The solvent is removed from the mold resulting in a coating or tube. By controlling the rotational speed and the formulation chemistry, the tube dimensions and wall morphology can be manipulated. This technique offers a new approach to the manufacture of polymeric tubes. It requires small quantities of starting material, permits multi-layering of tubes, is applicable to diverse polymers and can result in highly diffusive hollow structures while maintaining good mechanical strength.

1 - 30 . (canceled)  
   
   
       31 . A product produced by a method comprising the steps of: 
 filling an interior of a mold with a mixture so that substantially all gas bubbles are displaced therefrom, the mixture comprising at least two components which can be phase separated by a phase separation agent into at least two phases;    rotating said mold containing said mixture at an effective rotational velocity so that under rotation at least one of the phases deposits onto an inner surface of the mold; and    forming said product by stabilizing said at least one of the phases deposited onto the inner surface of the mold.    
   
   
       32 . The product according to  claim 31  including removing said product from said mold.  
   
   
       33 . The product according to  claim 31  wherein said hollow mold is a cylindrical tube so that said product is a tube.  
   
   
       34 . The product according to  claim 31  wherein of said at least two components at least one is selected from the group consisting of the group of monomers and macromers and the other is at least one solvent, wherein said at least one of the phases that deposits onto the inner surface includes at least one of the monomer and macromer, and wherein the step of stabilizing said deposited phase includes gelation of the at least one of the monomer and macromer by polymerization thereof.  
   
   
       35 . The product according to  claim 34  wherein said phase separation agent is selected from the group consisting of solution immiscibility, polymer immiscibility, light, pH, initiation agents, change in temperature, creation of a chemical product within the mold, changes in cationic and/or anionic concentrations, electric and magnetic fields.  
   
   
       36 . The product according to  claim 35  wherein said initiation agent is selected from the group consisting of free radical initiators, thermal and photo initiators, redox initiators, anionic, cationic or ring-opening initiators.  
   
   
       37 . The product according to  claim 34  wherein the product has a wall morphology that includes a porous structure, a gel structure or overlapping regions of porous/gel structure.  
   
   
       38 . The product according to  claim 34  wherein the product has a wall morphology that includes a predominantly gel morphology with porous channels running from a periphery to a lumenal side, resulting in spotting on an outer wall surface.  
   
   
       39 . The product according to  claim 31  wherein said at least two components includes at least one polymer dissolved in at least one solvent, and wherein said mixture is composed of at least two solutions, wherein said at least one of the phases that deposits on the inner surface includes at least the polymer, and wherein the step of stabilizing said deposited phase includes gelation thereof.  
   
   
       40 . The product according to  claim 39  wherein said phase separation agent is selected from the group consisting of solution immiscibility, light, change in pH, change in temperature, creation of a chemical product within the mold, changes in cationic and/or anionic concentrations, electric and magnetic fields.  
   
   
       41 . The product according to  claim 39  wherein gelation is achieved by exposure to an agent selected from the group consisting of light, change in pH, change in temperature, creation of a chemical product within the mold, changes in cationic and/or anionic concentrations, electric and magnetic fields.  
   
   
       42 . The product according to  claim 39  wherein the product has a wall morphology that includes a porous structure, a gel structure or overlapping regions of porous/gel structure.  
   
   
       43 . The product according to  claim 39  wherein the product has a wall morphology that includes a predominantly gel morphology with porous channels running from a periphery to a lumenal side, resulting in spotting on an outer wall surface.  
   
   
       44 . The product according to  claim 31  wherein said product is a multi-layered product produced by repeating steps a), b) and c), at least once to produce a multi-layered product.  
   
   
       45 . The product according to  claim 34  wherein the wall structure is used as a reservoir for the delivery of drugs, therapeutics, cells, cell products, genes, viral vectors, proteins, peptides, hormones, carbohydrates, growth factors, enzymes.  
   
   
       46 . The product according to  claim 39  wherein the wall structure is used as a reservoir for the delivery of drugs, therapeutics, cells, cell products, genes, viral vectors, proteins, peptides, hormones, carbohydrates, growth factors, enzymes.  
   
   
       47 . The product according to  claim 39  wherein the solution contains particles containing pre-selected constituents, and wherein the product includes said particles are distributed either uniformly or in a gradient within the wall structure of the product.  
   
   
       48 . The product according to  claim 39  wherein the particles are microspheres or nanospheres and said pre-selected constituents include enzymes, proteins, peptides, genes, vectors, growth factors, hormones, nucleotides, carbohydrates, drugs, therapeutics, or cells.  
   
   
       49 . The product according to  claim 39  wherein the cells include neurons, stem cells, stem cell derived cells, olfactory ensheathing cells, Schwann cells, astrocyte cells, microglia cells, or oligodendrocyte cells, endothelial cells, epithelial cells, fibroblasts, keratinocytes, smooth muscle cells, hepatocytes, bone marrow-derived cells, hematopoetic cells, glial cells, inflammatory cells, and immune system cells.  
   
   
       50 . The product according to  claim 39  wherein the particles are microspheres or nanospheres and said pre-selected constituents include enzymes, proteins, peptides, genes, vectors, growth factors, hormones, oligonucleotides, or cells.  
   
   
       51 . The product according to  claim 50  wherein the cells include neurons, stem cells, stem cell derived cells, olfactory ensheathing cells, Schwann cells, astrocyte cells, microglia cells, or oligodendrocyte cells, endothelial cells, epithelial cells, fibroblasts, keratinocytes, smooth muscle cells, hepatocytes, bone marrow-derived cells, hematopoetic cells, glial cells, inflammatory cells, and immune system cells.  
   
   
       52 . The product according to  claim 50  wherein the particles are degradable particles thereby releasing said constituents over time.  
   
   
       53 - 56 . (canceled)  
   
   
       57 . The product according to  claim 31  wherein the process includes a step of inserting an object into the mold to be coated with wherein said product includes said object being coated with said at least one of the phases and which is stabilized on said object.  
   
   
       58 - 59 . (canceled)  
   
   
       60 . The product produced in accordance with  claim 31  for use as a coronary artery bypass graft, vascular graft, artificial fallopian tubes, a drainage implant for glaucoma, a drainage implant for the lachrymal duct, artificial tissues such as intestines, ligaments, tendons, nerve guidance channels, ureter and urethra replacements, aural drainage tubes, abdominal/gastrointestinal structural replacements, stents for aortic aneurysms, esophageal scaffolds, composite catheters, shunts, delivery matrices, coatings applied to pacemaker leads, implantable sensor wire leads, wires for interventional cardiology, and biosensors.