Sensor materials for the detection of human neutrophil elastase and cathepsin G activity in wound fluid

Human neutrophil elastase (HNE) and cathepsin G (CatG) are involved in the pathogenesis of a number of inflammatory disorders. These serine proteinases are released by neutrophils and monocytes in case of infection. Wound infection is a severe complication regarding wound healing causing diagnostic and therapeutic problems. In this study we have shown the potential of HNE and CatG to be used as markers for early detection of infection. Significant differences in HNE and CatG levels in infected and non-infected wound fluids were observed. Peptide substrates for these two enzymes were successfully immobilised on different surfaces, including collagen, modified collagen, polyamide polyesters and silica gel. HNE and CatG activities were monitored directly in wound fluid via hydrolysis of the chromogenic substrates. Infected wound fluids led to significant higher substrate hydrolysis compared with non-infected ones. These different approaches could be used for the development of devices which are able to detect elevated enzyme activities before manifestation of infection directly on bandages. This would allow a timely intervention by medical doctors thus preventing severe infections.