  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.
