Entwicklung eines Sensors zur frühzeitigen Detektion von Wundinfektionen

Wound infections are the main cause for delayed or not occurred wound healing and therefore poses a big issue for the health care system. In the worst case they can even lead to death and furthermore cause tremendous costs. At the moment a wound infection is diagnosed by typical signs of inflammation, but not until the infection already exists. The aim of this master thesis is the development of a sensor for the early detection of wound infections. This would allow interventions in time, with a reduction of the patient’s load, the applications of antibiotic agents and the financial burden of the health care system as a result.

To meet these requirements, the activity of the enzyme myeloperoxidase can be determined directly in wound fluid. This enzyme is released into the wound fluid in high quantities at the onset of an infection and therefore could be used as a marker of infection. Hydrogen peroxide represents a substrate of this enzyme and can be measured by amperometric sensors. Compounding a buffer solution (including this substrate) with wound fluid (including the enzyme) leads to a loss of hydrogen peroxide and therefore to a signal loss, that is proportional to the enzyme activity in the wound fluid. The enzyme activity can be determined by the measured signal loss, enabling the detection of a wound infection.

Twelve real samples of wound fluid were available for testing the system. Out of these samples, six were classified by the attending physicians as “good healing” and the other six as “critical”, regarding wound infection. The results showed a clear difference between these 2 groups, whereas the “critical” wound samples indicated a more than fourfold higher enzyme activity compared with the samples of the “good healing” wounds.

The obtained results demonstrate the applicability of this system to quantitatively assess the status of a wound infection and therefore could represent the basis for the development of a device for the early detection of wound infection.