In-situ crosslinked wet spun collagen triple helices with nanoscale-regulated ciprofloxacin release capability

The design of antibacterial-releasing coatings or wrapping materials with controlled drug release capability is a promising strategy to minimise risks of infection and medical device failure in vivo. Collagen fibres have been employed as medical device building block, although they still fail to display controlled release capability, competitive wet-state mechanical properties, and retained triple helix organisation. We investigated this challenge by pursuing a multiscale design approach integrating drug encapsulation, in-situ covalent crosslinking and fibre spinning. By selecting ciprofloxacin (Cip) as a typical antibacterial drug, wet spinning was selected as a triple helix-friendly route towards Cip-encapsulated collagen fibres; whilst in situ crosslinking of fibre-forming triple helices with 1,3 phenylenediacetic acid (Ph) was hypothesised to yield Ph-Cip {\pi}-{\pi} stacking aromatic interactions and enable controlled drug release. Higher tensile modulus and strength were measured in Ph crosslinked fibres compared to state-of-the-art carbodiimide crosslinked controls. Cip-encapsulated Ph-crosslinked fibres revealed decreased elongation at break and significantly-enhanced drug retention in vitro with respect to Cip-free variants and carbodiimide-crosslinked controls, respectively. This multiscale manufacturing strategy provides new insight aiming at wet spun collagen triple helices with nanoscale-regulated tensile properties and drug release capability.