Composite Biomaterials Based on Poly(L-Lactic Acid) and Functionalized Cellulose Nanocrystals

The biocomposite films were prepared from poly(L-lactic acid) and cellulose nanocrystals. To improve interfacial compatibility of hydrophilic cellulose nanocrystals with hydrophobic matrix polymer as well as to provide the osteoconductive properties, cellulose was functionalized with poly(glutamic acid). The modified cellulose nanocrystals were better distributed and less aggregated within the matrix, which was testified by scanning electron, optical and polarized light microscopy. According to mechanical tests, composites filled with nanocrystals modified with PGlu demonstrated higher values of Young's modulus, elongation at break and tensile strength. Incubation of composite materials in model buffer solutions for 30 weeks followed with staining of Ca2+ deposits with Alizarin Red S assay testified better mineralization of materials containing PGlu-modified cellulose nanocrystals as filler. As the result of in vivo experiment, the developed composite materials showed less level of inflammation in comparison with pure polymer matrix and composites filled with non-functionalized cellulose nanocrystals.