title: Creating porous tubes by centrifugal forces for soft tissue application.
abstract: Chemically crosslinked poly(2-hydroxyethyl methacrylate) (PHEMA) tubes were synthesized by applying centrifugal forces to propagating polymer chains in solution. Initiated monomer solutions, with a composition typical for PHEMA sponges, were placed into a cylindrical mold that was rotated about its long axis. As polymerization proceeded, phase separated PHEMA formed a sediment at the periphery under centrifugal action. The solvent remained in the center of the mold while the PHEMA phase gelled, resulting in a tube. By controlling the rotational speed and the formulation chemistry (i.e., monomer, initiator and crosslinking agent concentrations), the tube dimensions and wall morphology were manipulated. Tube manufacture was limited by a critical casting concentration [M]c, above which only rods formed. All tubes had an outer diameter of 2.4 mm, reflecting the internal diameter of the mold and a wall thickness of approximately 40-400 microm. Wall morphologies varied from interconnecting polymer and water phases to a closed cell, gel-like, structure. Concentric tubes were successfully prepared by using formulations that enhanced phase separation over gelation/network formation. This was achieved by using formulations with lower concentrations of monomer and crosslinking agent and higher concentrations of initiator. This technique offers a new approach to the synthesis of polymeric tubes for use in soft tissue applications, such as nerve guidance channels.
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Ontario, Canada.
authors.forename: P D
authors.initials: PD
authors.lastname: Dalto
authors.forename: M S
authors.initials: MS
authors.lastname: Shoichet
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011102:Polyhydroxyethyl Methacrylate / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D001672:Biocompatible Materials; D011102:Polyhydroxyethyl Methacrylate