Synthesis of bilayer films from regenerated cellulose nanofibers and poly(globalide) for skin tissue engineering applications.

Commercial cell-based skin regenerative products are highly expensive, carry the risk of rejection and require a long cell culture period to manufacture. This work describes the synthesis of bilayer films from poly(globalide) (PGl) and regenerated cellulose nanofibers (rCNFs) and their use as a cell-free scaffold to support keratinocyte attachment and proliferation. The method is simple, eco-friendly (as the cellulose precursor is obtained from agricultural waste) and of low cost. The rCNFs were produced by acid hydrolysis and PGl was obtained via enzymatic ring-opening polymerization. The bilayer films were synthesized by layer-by-layer casting at ambient temperature. All the films showed a well-defined interface between PGl and cellulose. The produced rCNF/PGl bilayer films showed cell metabolic activity far superior in comparison with pristine PGl regarding the keratinocyte growth, which illustrates the potential use of these materials in skin tissue engineering.

Production of high-purity cellulose, cellulose acetate and cellulose-silica composite from babassu coconut shells.

Lignocellulosic biomass has been widely studied as a source of cellulose- and related products, attracting the great interest of researchers dealing with renewable energy sources, vegetable waste recycling and biomaterials. In this work, the babassu coconut shells (epicarp and endocarp) were used for the achievement of products such as cellulose, cellulose acetate and cellulose-silica composite, which were chemically and structurally characterized by solid-state 13C nuclear magnetic resonance spectroscopy and scanning electron microscopy, among other techniques. As this precursor also naturally contains a significant amount of silica, a composite containing cellulose fibers mixed with amorphous silica particles (with rosette-like shape) was also produced. Finally, the possibility of synthesis of cellulose acetate was also demonstrated, illustrating the plethora of potential applications of this important lignocellulosic residue for the production of cellulose-based materials of high technological interest.