Engineering tubular structures based on Chitosan

The creation of versatile tubular structures is a subject of broad interest in tissue engineering applications due to the wide variety of tissues with a tubular geometry, such as the trachea, intestines, ureters, blood and lymph vessels.  The currently available options for repair such tissues are autologous grafts, xenografts, artificial prostheses or synthetic grafts. However, it is well-known the lack of tissue donors, anatomical variability, shorter life span and rejection by the immune system.

Herein, we demonstrate the production of tubular-like structures based on chitosan through a simple combination of a dipping approach and supercritical technology. Combining both techniques, it was possible to obtain flexible and versatile tubes with a perfect defined hollow imprint. The ability to tailor the properties of tubes combined with a time efficient and relative ease fabrication suggest the potential of this approach. The tubular structures were chemically cross-linked using genipin at a different concentration, with that the cross-linking degree was tailored between 0% to 65%. As expected, upon chemical cross-linking of these structures with genipin, the chemistry of the surface change and  the mechanical properties are favored (i.e., increase on Young Modulus (E) ). In addition, the increase in cross-linker concentration also increases the stability of the structures in wet conditions, by reducing the water uptake.

The biological performance of the tubular structures was also evaluated, and the results reveal that L929 fibroblast-like cells remain attached, well-spread and viable on the surface of cross-linked tubes. We envisage that our approach may open up new avenues on the production of tubular tissue engineering approaches, specially in cardiovascular field, where the design of tubular structures with tuned length, diameter and elasticity is required.