Optimization of cell growth on palmitoyl-hyaluronan knitted scaffolds developed for tissue engineering applications.

Polysaccharides meet several criteria for a suitable biomaterial for tissue engineering, which include biocompatibility and ability to support the delivery and growth of cells. Nevertheless, most of these polysaccharides, for example dextran, alginate, and glycosaminoglycans, are highly soluble in aqueous solutions. Hyaluronic acid hydrophobized by palmitic acid and processed to the form of wet-spun fibers and the warp-knitted textile scaffold is water non-soluble, but biodegradable material, which could be used for the tissue engineering purpose. However, its surface quality does not allow cell attachment. To enhance the biocompatibility the surface of palmitoyl-hyaluronan was roughened by freeze drying and treated by different cell adhesive proteins (fibronectin, fibrinogen, laminin, methacrylated gelatin and collagen IV). Except for collagen IV, these proteins covered the fibers uniformly for an extended period of time and supported the adhesion and cultivation of dermal fibroblasts and mesenchymal stem cells. Interestingly, adipose stem cells cultivated on the fibronectin-modified scaffold secreted increasing amount of HGF, SDF-1, and VEGF, three key growth factors involved in cardiac regeneration. These results suggested that palmitoyl-hyaluronan scaffold may be a promising material for various applications in tissue regeneration, including cardiac tissue repair. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1488-1499, 2018.

Fabrication of biodegradable textile scaffold based on hydrophobized hyaluronic acid.

In this work, we report on the preparation of a novel biodegradable textile scaffold made of palmitoyl-hyaluronan (palHA). Monofilament fibres of palHA with a diameter of 120µm were prepared by wet spinning. The wet-spun fibres were subsequently processed into a warp-knitted textile. To find a compromise between swelling in water and degradability of the final textile scaffold, a series of palHA derivatives with different degrees of substitution of the palmitoyl chain was synthesized. Freeze-drying not only provided shape fixation, but also speeded up scaffold degradation in vitro. Fibronectin, fibrinogen, laminin and collagen IV were physically adsorbed on the textile surface to enhance cell adhesion on the material. The highest amount of adsorbed cell-adhesive proteins was achieved with fibronectin (89%), followed by fibrinogen (81%). Finally, textiles modified with fibronectin or fibrinogen both supported the adhesion and proliferation of normal human fibroblasts in vitro, proving to be a useful cellular scaffold for tissue engineering.

Solid-state photocrosslinking of hyaluronan microfibres.

Hyaluronan (HA) was chemically modified to a photocurable derivative by the acylation with a mixed anhydride of trans-cinnamic acid and characterized by UV, IR and 2D NMR spectroscopy. Photocurable HA was processed to a microfibrous structure by wet-spinning technology. Water solubility of otherwise water-soluble HA microfibres was reduced significantly by the solid-state photocrosslinking. We also investigated that the nature of polymer structure had a great impact to a final crosslink ratio. The analysis of the mechanical properties showed higher ultimate tensile strength and increased rigidity of the photocrosslinked fibres in comparison to the untreated ones. Moreover all tested materials are regarded as biocompatible according to the tests of cell viability, phototoxicity and enzymatic degradability, which make them suitable candidates for numerous biomedical applications.

A novel DTPA cross-linking of hyaluronic acid and metal complexation thereof.

Macromolecular conjugates of a natural polysaccharide, hyaluronic acid, with diethylenetriaminepentaacetic acid (DTPA)-metal complexes were synthesized and characterized by FTIR, NMR, SEC-MALLS and ICP analysis. Several parameters of the cross-linking reaction as molecular weight of starting HA, temperature, equivalent of DTPA bis-anhydride, concentration of HA, presence of transacylation catalyst DMAP and reaction time were studied. The mechanism for the reaction was suggested and relationship between the molecular weight assigned by SEC-MALLS, reaction parameters and rheological properties of the final cross-linked products were investigated.