Synthesis and characterisation of photocurable poly(glycerol sebacate)-co-poly(ethylene glycol) methacrylates

Poly (glycerol sebacate)-co-poly (ethylene glycol) (PGS-co-PEG) copolymers have multifunctional and tunable properties and great potential as high-performance biomaterials. However, the application of these materials is currently limited by harsh crosslinking conditions that include high temperatures and long reaction times. In this study, in order to overcome these limitations, the methacrylation process was conducted on PGS-co-PEG, resulting in photocurable (PGS-co-PEG)-M copolymers. Methacrylation of PGS-co-PEG, formulated respectively from polyethylene glycol (PEG2) or glycerol ethoxylate (PEG3), was investigated for the first time. (PGS-co-PEG2)-M and (PGS-co-PEG3)-M were found to be biodegradable, biocompatible, bioadhesive, pH-responsive and photocurable. Multifunctional characteristics remained after methacrylation, they were, however, drastically altered. Mechanical strength was enhanced significantly for (PGS-co-PEG)-M copolymers. Tensile Young's moduli of (PGS-co-PEG2)-M samples ranged from 0.08 to 0.48 MPa, while those of (PGS-co-PEG3)-M ranged from 2.67 to 35.47 MPa, indicating the mechanical properties of the materials can be tuned via crosslinking density. In contrast, bioadhesive properties, such as lap-shear and adhesion strengths, were almost halved due to methacrylation. The degradation and swelling rates were slightly reduced, but pH-responsive behaviours at pH = 5.0, 7.4 and 9.1 were still observed. Cell metabolic activity and double-stranded DNA content, investigated by resazurin and PicoGreen® assays, demonstrated that the (PGS-co-PEG)-M copolymers were biocompatible. Photocurable (PGS-co-PEG)-M copolymers facilitate a simple and user-friendly curing process (photocrosslinking) that could be used for biomedical applications. Moreover, these photocurable copolymers are beneficial for various biofabrication methods, including emulsion techniques and additive manufacturing, either directly or indirectly.