Preparation of three dimensional structures of polysaccharide derivatives for application in regenerative medicine : doctoral disertation

english

doktorska dela

2022

3D printing   carboxymethyl cellulose   chitosan   citric acid   collagen   dehydrothermal treatment   freeze drying   nanofibrillated cellulose

Univerza v Mariboru, Fakulteta za strojništvo

Biocompatible polysaccharide scaffolds with controllable pore size, good mechanical properties, and no hazardous chemical crosslinkers are desirable for long-term tissue engineering applications. Despite decades of development of novel scaffolds, there are still many challenges to be solved regarding their production and optimization for specifically engineered tissues. Herein, we have fabricated several three-dimensional (3D) scaffolds using polysaccharide or polysaccharide-protein composite hydrogels or inks for 3D printing, featuring strong shear thinning behavior and adequate printability. The inks, composed of various combinations of chitosan, nanofibrillated cellulose, carboxymethyl cellulose, collagen, and citric acid, were 3D printed, freeze-dried, and dehydrothermally heat-treated to obtain dimensionally and mechanically stable scaffolds. The heat-assisted step induced the formation of covalent amide and ester bonds between the functional groups of chosen polysaccharides and protein collagen. Citric acid was chosen as a non-hazardous and „green” crosslinker to further tailor the mechanical properties and long-term stability of the scaffolds. We have investigated how the complexation conditions, charge ratio, dehydrothermal treatment, and degree of crosslinking influence the scaffolds' chemical, surface, swelling, and degradation properties in the dry and hydrated states. The compressive strength, elastic modulus, dimensional stability and shape recovery of the (crosslinked) scaffolds increased significantly with balanced charge ratio, dehydrothermal treatment, and increased concentrations of citric acid crosslinker and collagen concentrations. The prepared crosslinked scaffolds promoted (clustered) cell adhesion and showed no cytotoxic effects, as determined by cell viability assays and live/dead staining with human bone tissue-derived osteoblasts and human adipose tissue-derived mesenchymal stem cells. The water-based and non-hazardous crosslinking methods presented here can be extended to all polysaccharide- or polysaccharide-protein-based materials to develop cell-friendly scaffolds with tailored properties suitable for various tissue engineering applications.

08.08.2023