Porous Biodegradable Scaffold: Predetermined Porosity by Dissolution of Poly(ester‐anhydride) Fibers from Polyester Matrix

Abstract

A novel selective leaching method for the porogenization of the biodegradable scaffolds was developed. Continuous, predetermined pore structure was prepared by dissolving fast eroding poly(epsilon-caprolactone)-based poly(ester-anhydride) fibers from the photo-crosslinked poly(epsilon-caprolactone) matrix. The porogen fibers dissolved in the phosphate buffer (pH 7.4, 37 degrees C) within a week, resulting in the porosity that replicated exactly the single fiber dimensions and the overall arrangement of the fibers. The amount of the porosity, estimated with micro-CT, corresponded with the initial amount of the fibers. The potential to include bioactive agents in the porogen fibers was demonstrated with the bioactive glass.

Two‐photon microfabrication of poly(ethylene glycol) diacrylate and a novel biodegradable photopolymer—comparison of processability for biomedical applications

“…Water‐soluble low‐viscosity PEGda with M n of 575 g/mol was purchased from Sigma‐Aldrich (Schnelldorf, Germany). The biodegradable, methacrylated PCL‐o was custom synthesized at the Laboratory of Polymer Technology in Aalto University School of Chemical Technology (Espoo, Finland) by the group of Professor Seppälä . The star‐shaped oligomer with four arms was purified by dissolution in dichloromethane and precipitation in hexane resulting in a product that was a water‐insoluble, highly viscous transparent liquid with a molecular weight of slightly over 1000 g/mol.…”

“…Similar results have been obtained with PCL‐o photocured with camphorquinone by incubating the samples in phosphate buffer solution (pH 7.4) at 37°C for 3 weeks. The pure PCL‐o matrix absorbed only 2.6% water in 3 weeks, and mass loss was 1% . The slow degradation behavior of PCL‐o originates from its partial crystallinity and high hydrophobicity …”

“…The biodegradable, methacrylated PCL-o was custom synthesized at the Laboratory of Polymer Technology in Aalto University School of Chemical Technology (Espoo, Finland) by the group of Professor Seppälä. [30] The star-shaped oligomer with four arms was purified by dissolution in dichloromethane and precipitation in hexane resulting in a product that was a water-insoluble, highly viscous transparent liquid with a molecular weight of slightly over 1000 g/mol. The biodegradation of thermally cured networks of PCL-o has been evaluated by Helminen and coworkers, and according to their studies, PCL-o with molecular weight of 11,550 g/mol crosslinked in the presence of dibenzoyl peroxide as radical initiator showed water absorption of under 2% and mass loss of 1% after immersion in phosphate buffer solution (pH 7.0) at 37°C for 12 weeks.…”

Photocrosslinkable Polyesters and Poly(ester anhydride)s for Biomedical Applications

“…There are significant differences in the degradation rates and mechanism of polyesters and polyanhydrides. For example, in our study PCL‐based poly(ester anhydride) eroded within one week, whereas the corresponding polyester did not show any mass loss at the same time 37, 38…”

“…Finally the poly(ester anhydride) fibers or meshes were hydrolytically degraded and leached out to form continuous pore structures into the scaffold. Bioactive glass was also introduced into the polymeric porogen 38…”