A simple and specific colorimetric biosensor for early detection of Pseudomonas aeruginosa wound infections

Wound healing is a critical aspect of surgical care, often complicated by infections such as those caused by Pseudomonas aeruginosa (PA). In this study, we aim to develop a sensitive and specific colorimetric biosensor which allows early detection and naked-eye monitoring of PA wound infections. We used hydrogen cyanide (HCN) as a PA specific biomarker and aquacyanocobinamide (ACCbi), a vitamin B12 derivative, as the indicator which changes color from orange to violet upon interaction with HCN. We then encapsulated ACCbi with different electrospun fibers, including polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polycaprolactone (PCL), and polyurethane (PU), and evaluated them for suitability as ACCbi carriers. The morphology of the fabricated membranes was analyzed using scanning electron microscopy (SEM). The performance of the materials was assessed for their structural integrity, sensitivity and sensor function. PVAc based membranes demonstrated the best stability and sensitivity, maintaining structural integrity and showing a distinct color change in response to HCN. In a real-world setup of negative pressure wound therapy, the optimized PVAc membranes exhibited a clear color change within 10 h of exposure to PA biofilms formed in vitro and within 12 h to that on ex vivo human skin wounds. The biosensor retained its functionality after two years of storage, offering a promising tool for the early PA detection in clinical wound care.