Nanocellulose Wound Dressings with Integrated Protease Sensors for Detection of Wound Pathogens

Wound infections result in delayed healing, morbidity, and increased risks of sepsis. Early detection of wound infections can facilitate treatment and reduce the need for the excessive use of antibiotics. Proteases are normally active during the healing process but are overexpressed during infection as part of the inflammatory response. Proteases are also produced by the bacteria infecting the wounds, making proteases a highly relevant biomarker for infection monitoring. Here, we show a fluorescence turn-on sensor for real-time monitoring of protease activity in advanced nanocellulose wound dressings for rapid detection of wound pathogens. Colloidal gold nanoparticles (AuNPs) were adsorbed on bacterial cellulose (BC) nanofibrils by using a carefully optimized self-assembly process. The AuNPs could either be homogeneously incorporated in BC dressings or 3D printed in wood-derived cellulose nanofiber (CNF) dressings using a BC-AuNP ink. The BC-adsorbed AuNPs were subsequently functionalized with fluorophore-labeled protease substrates. Cleavage of the substrates by proteases produced by the wound pathogens <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i> resulted in a significant increase in fluorescence that correlated with the growth phase of the bacteria. Wound dressing with integrated sensors for the detection of proteolytic activity can enable the sensitive and rapid detection of infections, allowing for optimization of treatment and reducing the risks of complications.