Glycidyl methacrylate and methacrylic anhydride characterization for silk fibroin methacrylation in tissue engineering

The field of tissue engineering has been an ever-evolving discipline with a principal direction of creating artificial constructs to improve biological tissue types. Constructs used in tissue engineering arise from natural compounds, synthetic polymers, or a combination of the two to generate a hybrid biomaterial with optimized characteristics. In recent years, researchers have turned to silk fibroin (SF) as a natural source for its attractive physical characteristics and tunability. Using this platform, researchers have attempted to chemically modify SF through methacrylation to further improve its mechanical properties, thus making it a more appealing candidate for bioengineering applications. To date, the two most common methacrylating agents for synthesizing methacrylated SF across literature have been glycidyl methacrylate (GMA) and methacrylic anhydride (MA), which produce SFGMA and SFMA, respectively. However, the side-by-side characterization of SFGMA and SFMA has not been well compared with respect to their synthesis reactions and resulting degrees of methacrylation (DoM). To address this, our study developed a standardized protocol for SFGMA and SFMA synthesis in an effort to systematically compare the two NMR spectra. From this protocol, our results demonstrate GMA to be the superior methacrylating agent for its reactional consistency and DoM validity.