Crosslinking effects of branched PEG on decellularized lungs of rats for tissue engineering

Poly (ethylene glycol) (PEG) has been paid much attention to its applications in tissue engineering. However, the studies on poly (ethylene glycol) in tissue applications were currently far from enough. To investigate the crosslinking effects of poly (ethylene glycol) in mechanical properties, anti-enzymatic ability and cytocompatibility, in this study, the poly (ethylene glycol) was crosslinked to decellularized lung scaffolds from rats. In order to obtain the PEGylated decellularized lung scaffold, the N-succinimidyl S-acetylthioacetate was first used to modify the decellularized lung scaffold, and a four-arm- poly (ethylene glycol) containing four acrylate groups was then crosslinked to the decellularized lung scaffold by the Michael addition reaction between acrylate group and sulfhydryl group. The results showed that the optimal concentration of poly (ethylene glycol) and reaction time of PEGylation of decellularized lung scaffold was 40 mg/mL and 4 h, respectively. Histological examinations, SEM and quantification of tissue morphology by septal thickness consistently indicated no differences between PEGylated and normal decellularized lung scaffold in morphology. Compared with native lung and normal decellularized lung scaffold, the Young's modulus and stiffness of PEGylated decellularized lung scaffold increased significantly, whereas enzymatic degradation rate of PEGylated decellularized lung scaffold decreased significantly, suggesting that poly (ethylene glycol) significantly enhanced the biomechanical property and anti-enzymatic stability of decellularized lung scaffold. Further, no significant differences in cell viability were found between PEGylated and normal decellularized lung scaffold, suggesting no toxicity introduction of poly (ethylene glycol) into decellularized lung scaffold by the crosslinking. These findings may provide useful information for further applications of poly (ethylene glycol) in tissue engineering.