Nanofibrous scaffolds based on polyelectrolyte complexes of chitosan-alginate-COLLAGEN and chitosan-hyaluronic acid for tissue Engineering

Synthetic extracellular matrices have great potential for regenerative medicine. Among various scaffolding techniques, electrospinning has gained increasing interest in tissue engineering. Here, biomimetic nanofibrous scaffolds based on polyelectrolyte complexes consisting of chitosan (CS) and alginate (AL) or CS and hyaluronic acid (HA) at different concentrations were fabricated. Poly(vinyl alcohol) (PVA) was used as a fluid viscosity modulating agent. To improve the structural stability of the systems, the electrospun scaffolds were cross-linked using freeze-thaw processes and ethyl-dimethyl-aminopropyl carbodiimide (EDC) and N‑hydroxy-succinimide (NHS). Furthermore, the CS-AL scaffold was treated with different amounts of collagen to make it biomimetic. The collagen-containing matrices showed high thermal (T_D increase of >10 °C) and structural stability (swelling ratio 1.5–1.9). In contrast, HA-based matrices exhibited more homogeneous fibers (190–250 nm) and larger pore size (6–9 µm), but lower mechanical strength (0.5–1.1 GPa) and more swelling in water. Finally, it was verified that the electrospun scaffolds tested showed cell viability increased as the amount of collagen increased up to 85 %, whereas for scaffolds containing a high amount of HA, it decreased (71 %). However, the sample containing the lowest HA concentration exhibited a morphology more suitable for interaction with cells, demonstrating great potential in tissue engineering applications.