Mechanically tunable pullulan-chitin nanocrystal scaffolds for biological applications

Abstract

The prepared pullulan-ChNC nanocomposite scaffolds offer a unique pathway towards controlling scaffold mechanical properties, morphology, and water retention while dis- playing promise for continued use for in vitro biological studies.

As disease modeling, tissue engineering, and lab on a chip systems advance, it is impera- tive that new scaffolding systems are developed to establish long term models. These scaffolds must be biocompatible, facilitate cell adhesion and mimic the mechanical prop- erties of native tissue.

We report a mechanically tunable scaffold made from pullulan covalently crosslinked by sodium trimetaphosphate. Chitin nanocrystals (ChNC) were added to the hydrogel in var- ious loading percentages. The viscoelastic properties of the crosslinked hydrogel nanocomposites were determined by linear rheology through frequency sweeps. The morphology of the freeze dried nanocomposite scaffolds were characterized by scanning electron microscopy. The rehydration abilities of the scaffolds were also characterized and found to be dependent on the ChNC concentration. The neutral scaffolds do not in- hibit mammalian cell growth, but do not facilitate cell adhesion. The use of the cationic polymer, chitosan, for improved cell adhesion and biocompatibility is explored.