Smart Sensor for Monitoring Antimicrobial Interventions in Wound Infections

Abstract

Effective therapeutic monitoring of wound infections is crucial for wound care. In this study, we explore a novel approach using a previously described 3D-printed, colorimetric indicator to non-invasively monitor antimicrobial interventions in wound infection. The indicator contains a pH-sensitive dye, xylenol blue, which detects carbon dioxide production from rapidly growing wound pathogens by changing colour from blue to yellow.The indicator accurately reported the minimum inhibitory concentration of antibiotic against Pseudomonas aeruginosa in a sealed 96-well plate by monitoring the headspace of each well. Subinhibitory antibiotic concentrations resulted in the sensor changing colour from blue to yellow, whilst inhibitory concentrations remained blue.The sensor was then applied to an ex vivo porcine skin wound model with Pseudomonas aeruginosa biofilms, testing three different antimicrobial treatments: antibiotic monotherapy, phage monotherapy, and a combination of both approaches. After treatment, the sensor, sealed with the wound, enabled visual and quantitative monitoring of CO2 composition in the wound headspace.In parallel, the bioburden of the surrounding wound fluid was determined and compared with the sensor response. Greater log-fold reductions in P. aeruginosa following antimicrobial treatment correlated with longer sensor response times. Sensors monitoring biofilms exposed to sublethal antimicrobial concentrations changed colour, while those treated at or above the minimum biofilm eradication concentration elicited no colour change, indicating complete P. aeruginosa eradication.This innovative sensor holds promise for real-time monitoring of wound infection treatment efficacy, with potential for improving patient outcomes and supporting undisturbed wound healing as a non-invasive point-of-care tool.

Note:
Funding declaration: This research was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) under grant number EP/T007575/1.

Conflict of Interests: There are no conflicts of interest to declare.

Ethics approval: Stillborn piglets from organically grown animals were ethically sourced from Agri-Food and Biosciences Institute (AFBI) research facility (Hillsborough, Northern Ireland).

Keywords: wound infection, biofilm, smart sensor, point-of-care, carbon dioxide