Cytocompatibility / Antibacterial Activity Trade-off for Knittable Wet-Spun Chitosan Monofilaments Functionalized by the In Situ Incorporation of Cu 2+ and Zn 2 .

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 Cu 2+ or Zn 2+ 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 Cu 2+ or Zn 2+ 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.