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Method of producing structures using centrifugal forces

a technology of centrifugal force and manufacturing structure, which is applied in the field of manufacturing structure, can solve the problems of limited size and shape, limited application, and limited material requirements for building structures, and achieve the effect of reducing the surface friction of the structure and enhancing the design application of the structur

Inactive Publication Date: 2005-12-29
SHOICHET MOLLY S +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0026] The polymeric product may contain a predetermined structure, which was inserted into the mold before said product fabrication, such as a wire, stent or mesh. The polymeric product would coat the predetermined structure, and may enhance the designed application of the said structure by releasing therapeutic agents or reducing the surface friction of said structure.

Problems solved by technology

Tubular structures and coatings have been prepared by a number of techniques, each of which has limitations for each application.
For biomedical applications, a limitation is the abundant material required to prepare structures of limited size and shape, which can prove costly.
There is no suitable method to prepare concentric, long HFMs, with thin walls, whether by dip-coating, spinning, or centrifugal casting, among others.
While the spinning technique has a proven record commercially, it requires abundant material and requires a certain amount of art to prepare reproducible HFMs.
Since a gas is required in the mold to form a tube (compared to a rod), attaining small diameter tubes with a small inner diameter on the micron scale cannot be achieved.
By these methods, the uniformity of the tube wall along the length of the tube is not well controlled.
Current coatings technologies have limitations in terms of the uniformity of the coating, thickness of the coating and coating porous materials.

Method used

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  • Method of producing structures using centrifugal forces
  • Method of producing structures using centrifugal forces
  • Method of producing structures using centrifugal forces

Examples

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Effect test

example 1

[0134] 2-hydroxyethyl methacrylate (HEMA) was polymerized in the presence of excess water, with a crosslinking agent, preferably, but not limited to ethylene dimethacrylate (EDMA), using a free radical initiating system and preferably an ammonium persulfate (APS) / sodium metabisulfite (SMBS) redox initiating system. A homogeneous mixture, with components detailed in Table 1, was injected into a cylindrical glass mold as described for the process involving 2-hydroxyethyl methacrylate. The homogeneous mixture was made by adding the relevant quantities of HEMA, and water into a glass vial, and mixing in the glass vial. Mixing of the solution was repeated after the appropriate amount of 10% APS solution listed in Table 1 was added. The appropriate volume of 10% SMBS solution was added to this mixture, which was mixed for an additional 30 seconds. The homogeneous monomer mixture was then drawn into a Luer-lok syringe using a 20-gauge needle. The needle was removed from the syringe and, us...

example 2

[0136] A coating with both gel-like and porous morphologies was prepared with the same methodology as Example 1; the monomer mixture used also included poly(ethylene glycol) methacrylate as a comonomer. The monomer mixture and rotation conditions used in Example 2 are listed in Table 1. The resulting porous material / gel-like hybrid coating on the inner surface of the mold is shown in FIGS. 7a and 7b with the outer gel-like coating (the surface that is against the inside of the mold) facing forward in FIG. 7a and the inner porous structure (the one against the water) facing forward in FIG. 7b. The thickness of the coating is approximately 30±5 μm thick. The micrograph in FIGS. 7a and 7b were taken after removing the coating from the glass mold. More specifically, FIG. 7a shows a scanning electron microscope (SEM) micrograph of the outer surface of a porous coating applied to the inside of a glass mold, in which the mixture is 1.9% HEMA, 0.1% PEGMA, 98% water, 0.02% APS, 0.02% SMBS, 2...

example 3

[0137] A porous material can have an outer coating applied to it using this technology. The coating that can be either gel-like or have porous morphology or both was prepared with similar methodology as in Example 1. Prior to the injection of a homogeneous mixture into the mold, a plug of porous material is inserted into the mold (FIG. 8a). Porous PLGA is manufactured using techniques previously described (Holy et al, Biomaterials, 20, 1177-1185, 1999), however the porous material may be made of any material, including polymers, ceramics, metals, composites, or combinations thereof. After insertion of the porous structure into the mold, the homogeneous mixture listed in Table 1 as Example 3 is injected into the mold and the mold rotated at the speed listed in Table 1. The resulting coated porous material removed from the mold is shown in FIG. 8b. There was no coating or blocked pores on the inside of the porous material; the only coating visible was on the outside. This example demo...

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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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of United States utility patent application Ser. No. 10 / 169,948 filed on Jul. 11, 2002, which is a National Phase application claiming the benefit of PCT / CA01 / 00680 filed May 11, 2001 published in English, which further claims priority benefit from United States provisional patent application 60 / 203,910 filed May 12, 2000.FIELD OF INVENTION [0002] This invention relates to a method of manufacturing structures and particularly polymeric tubular structures and coatings with complex and unique morphologies in the walls, and on the inner and outer surfaces of the structures. BACKGROUND OF THE INVENTION [0003] Tubular structures and coatings have been prepared by a number of techniques, each of which has limitations for each application. For biomedical applications, a limitation is the abundant material required to prepare structures of limited size and shape, which can prove costly. For porous poly...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61B17/11A61K9/00A61K9/16A61K9/70B29C37/00B29C39/00B29C39/08B29C41/00B29C41/04B29C41/50B29C67/02B32B1/08
CPCA61B17/1128Y10T428/139A61K9/1647A61K9/70B29C37/006B29C39/006B29C39/08B29C41/003B29C41/042B29C41/50B29C67/02B29K2105/0014B29K2105/04B29L2023/00B29L2031/753Y10T428/13A61K9/0092
Inventor DALTON, PAUL D.SHOICHET, MOLLY S.LEVESQUE, STEPHANE G.
Owner SHOICHET MOLLY S
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