Direct UV-Triggered Thiol–ene Cross-Linking of Electrospun Polyester Fibers from Unsaturated Poly(macrolactone)s and Their Drug Loading by Solvent Swelling

Fernando C. S. de Oliveira, Dinorath Olvera, Michael J. Sawkins, Sally-Ann Cryan, Scott D. Kimmins, Tatiane Eufrasio da Silva, Daniel J. Kelly, Garry P. Duffy, Cathal Kearney, Andreas Heise

Electrospinning is considered a relatively simple and versatile technique to form high porosity porous scaffolds with micron to nanoscale fibers for biomedical applications. Here, electrospinning of unsaturated aliphatic polyglobalide (PGl) into well-defined fibers with an average diameter of 9 μm is demonstrated. Addition of a dithiol cross-linker and a photoinitiator to the polymer solution enabled the UV-triggered intracross-linking of the fibers during the spinning process. The in situ cross-linking of the fibers resulted in amorphous material able to swell up to 14% in tetrahydrofurane (THF) without losing the fiber morphology. Seeding mesenchymal stem cells (MSCs) onto both cross-linked and non-cross-linked PGl fibers proved their compatibility with MSCs and suitability as scaffolds for cell growth and proliferation of MSCs. Moreover, the ability to directly load cross-linked PGl with hydrophobic molecules by soaking the fiber mesh in solution is shown with Rhodamine B and Indomethacin, a hydrophobic anti-inflammatory drug. This marks an advantage over conventional aliphatic polyesters and opens opportunities for the design of drug loaded polyester scaffolds for biomedical applications or tissue engineering.