An infection-responsive collagen-based wet-spun textile fibre for wound monitoring

Wound infections are a significant clinical and socioeconomic challenge, contributing to delayed healing and increased wound chronicity. To enable early infection detection and inform therapeutic decisions, this study investigated the design of pH-responsive collagen fibres using a scalable wet spinning process, evaluating product suitability for textile dressings and resorbable sutures. Type I collagen was chemically functionalised with 4-vinylbenzyl chloride, enabling UV-induced crosslinking and yielding mechanically robust fibres. Bromothymol blue, a halochromic dye responsive to pH changes, was incorporated via drop-casting to impart visual infection-responsive colour change. Gravimetric analysis and Fourier Transform Infrared Spectroscopy confirmed high dye loading, whereby a Loading Efficiency of 99 ± 3 wt% was achieved. The fibres exhibited controlled swelling in aqueous environments (Swelling Ratio: 323 ± 79–492 ± 73 wt%) and remarkable wet-state Ultimate Tensile Strength (UTS: 12±3–15 ± 7 MPa), while up to ca. 30 wt% of their initial crosslinked mass was retained after 24 h in a collagenase-rich buffer (pH 7.4, 37 °C, 2 CDU) and ethanol series dehydration. Importantly, distinct and reversible colour transitions were observed between acidic (pH 5) and alkaline (pH 8) environments, with up to 88 wt% dye retention following 72-h incubation. The fibres were successfully processed into woven dressing prototypes and demonstrated knotting ability suitable for suture applications. Overall, these wet-spun collagen fibres integrate infection-responsive capability, biodegradability, and scalable fabrication, representing a promising platform for smart wound dressings and resorbable sutures.