Development of an amphiphilic PLA Sponge by Solvent-Induced Phase Inversion: Effect of a bacterial Cellulose-g-Poly(methylmethacrylate) additive

Surface-modified bacterial cellulose, namely, BC-g-PMMA fiber, was synthesized by graft polymerization. The BC-g-PMMA fiber was employed as a surface modifying agent for a porous polylactic acid (PLA) scaffold, which was prepared through phase inversion. In this study, BC-g-PMMA 1:1 (BC: MMA mole ratio of 1:1), BC-g-PMMA 1:3 (BC: MMA mole ratio of 1:3), and BC-g-PMMA 1:6 (BC: MMA mole ratio of 1:6) were prepared using methyl methacrylate (MMA) as a grafting monomer under sonication-assisted reactions. Various characterization methods, including FTIR, DSC, and TGA, were employed to confirm that BC-g-PMMA exhibited an amphiphilic structure. Next, the PLA/BC-g-PMMA composite scaffold was successfully prepared using a solvent-induced phase inversion technique involving a solvent exchange step (dioxane diffused out while water diffused in); due to this process, the honeycomb structure of the PLA/BC-g-PMMA composite contained amphiphilic surfaces, and the wettability and cell adhesion behavior of the porous material were manipulated. In the absence of BC-g-PMMA, porous PLA exhibited a hydrophobic surface and no wicking properties. In contrast, the PLA/BC-g-PMMA composites showed an ability to wick, which was related to the grafted PMMA moiety; the higher the grafted PMMA ratio was, the slower the wicking ability due to the decrease in the surface energy of the composites. Due to their tailored surface chemistry, these materials played a role in the adherence of the composites to proteins and human gingival fibroblasts. Therefore, amphiphilic spongy PLA/BC-g-PMMA composites are promising materials for tissue engineering and spheroid (3D cell structure) scaffolds.