Cytocompatibility / Antibacterial Activity Trade-off for Knittable Wet-Spun Chitosan Monofilaments Functionalized by...

The wet spinning of cytocompatible, bioresorbable, and knittable chitosan (CTS) monofilaments would be advantageous for a variety of surgical applications. The complexation capacity of chitosan with Cu²⁺ or Zn²⁺ can be leveraged to enhance its antibacterial activity, but not at the expense of cytocompatibility. In this work, a wet-spinning process was adapted for the in situ incorporation of Cu²⁺ or Zn²⁺ with chitosan dopes to produce monofilaments at different drawing ratios (τ_tot) with various cation/glucosamine molar ratios, evaluated in the fibers (r_Cu,f and r_Zn,f). Cytocompatibility and antibacterial activity of wet-spun monofilaments were, respectively, quantified by in vitro live-dead assays on balb 3T3 and by different evaluations of the proliferation inhibition of Staphylococcus epidermidis (Gram+) and Escherichia coli (Gram-). Knittability was tested by a specific tensile test using a knitting needle and evaluated with an industrial knitting machine. It was found that r_Cu,f = 0.01 and r_Zn,f = 0.03 significantly increase the antibacterial activity without compromising cytocompatibility. Wet spinning with τ_tot = 1.6 allowed the production of knittable CTS-Cu monofilaments, as confirmed by knitting assays under industrial conditions.