Long-Term Effect of Gamma Irradiation on the Functional Properties and Cytocompatibility of Multiblock Co-Polymer Films

Abstract

The purpose of this work was to investigate the long-term effect of gamma-irradiation treatment on the functional properties of PEG-PDLLA and PEG-PLGA films and to evaluate the cytocompatibility of sterilized samples. Chemical and thermal properties, and cytocompatibility of sterilized films were detected for samples at time zero and after storage at 5 ± 3°C for 60 days. An in vitro degradation study was carried out on polymer samples to examine the effect of sterilization on the degradation performances of co-polymer films. Incubated samples were characterized in terms of film surface structure (SEM), chemical (GPC) and thermal (DSC) properties. The study performed on films upon gamma sterilization showed no significant changes of the PEG-PDLLA and PEG-PLGA film structure, while GPC analysis highlighted that the effect of gamma irradiation was dependent on the M_w and composition of polymers. DSC traces suggested more pronounced gamma-ray effects on the PEG-PLGA multiblock co-polymer. During the stability study important changes in terms of structure surface, thermal properties and cytocompatibility were observed and investigated. Data collected during the in vitro degradation study emphasized the need to know and investigate the degradation performances and behaviour of polymer or polymer systems (as DDS, scaffolds and bandage) treated with gamma rays.

Keywords:

• Multiblock co-polymers
• gamma irradiation
• degradation behaviour
• cytocompatibility

Acknowledgements

This research has been supported by SAL-45 program financed by Regione Lom- bardia and by the project Nanomedicine in ageing-associated prototypic diseases: activation of a scientific and technological platform challenging seminal aspects of pathogenesis, diagnosis and therapy, financed by the Alma Mater Ticinensis foundation.