Effect of electron beam irradiation on the mechanical and solubility properties of nanofibrous electrospun polyurethane composite biomaterials

This study investigated how electron-beam irradiation used for biomaterial sterilization affects the mechanical performance and solvent stability of electrospun polyurethane-based tissue-engineering scaffolds. Two nanofibrous scaffold formulations were evaluated: a synthetic degradable polar/hydrophobic/ionic polyurethane and polycarbonate urethane composite (D-PHI/PCNU), and a GelMA-containing faster-degrading D-PHI/PCNU composite referred to as LGD. Samples were exposed to a target electron-beam dose of 30 kGy and compared with non-irradiated controls. Scanning electron microscopy showed that irradiation did not significantly alter scaffold fiber morphology. Mechanical testing of PBS-conditioned scaffolds showed that e-beam exposure significantly increased ultimate tensile strength in both material formulations. Elastic modulus also increased significantly in D-PHI/PCNU scaffolds, while LGD showed a similar increase that did not reach statistical significance. Elongation at break was not significantly changed by irradiation, indicating that the increase in strength did not produce a corresponding loss of extensibility. Acetone-solubility testing showed no statistically significant change in mass loss following irradiation, although both formulations exhibited a trend toward reduced solubility. The authors conclude that 30 kGy e-beam irradiation can preserve or enhance important mechanical properties of electrospun polyurethane composite scaffolds without significantly changing their solvent stability. The findings support electron-beam treatment as both a viable sterilization approach and a potential post-fabrication method for mechanically tuning polymeric tissue-engineering materials, while emphasizing that irradiation effects depend on material composition and should be characterized for each scaffold formulation.