Tailored Freestanding Multilayered Membranes based on chitosan and Alginate

Engineering metabolically demanding tissues requires the
supply of nutrients, oxygen, and removal of metabolic byproducts, as well
as adequate mechanical properties. In this work, we propose the
development of chitosan (CHIT)/alginate (ALG) freestanding membranes
fabricated by layer-by-layer (LbL) assembly. CHIT/ALG
membranes were cross-linked with genipin at a concentration of 1 mg·
mL−1 or 5 mg·mL−1. Mass transport properties of glucose and oxygen
were evaluated on the freestanding membranes. The diffusion of glucose
and oxygen decreases with increasing cross-linking concentration.
Mechanical properties were also evaluated in physiological-simulated
conditions. Increasing cross-linking density leads to an increase of storage
modulus, Young modulus, and ultimate tensile strength, but to a decrease in the maximum hydrostatic pressure. The in vitro
biological performance demonstrates that cross-linked films are more favorable for cell adhesion. This work demonstrates the
versatility and feasibility of LbL assembly to generate nanostructured constructs with tunable permeability, mechanical, and
biological properties.