D8.1 - Detection of Wound Inflammations with Impedimetric Sensors

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
D8 - Medical III
A. Schröter, G. Gerlach, A. Walther, D. Wersing - Technische Universität Dresden (Germany), K. Fritzsche, A. Rösen-Wolff - University Hospital Carl Gustav Carus, Dresden (Germany)
659 - 660


In clinical practice a common possibility to avoid infections of wounds is to change the wound coverage in certain time intervals of 24 to 48 hours. This changing of dressing means stress for the micro ambience of the wound. To support the wound healing it makes sense to integrate a sensor in the bandage that detects an infection and, consequently, avoids the stress factors given by frequent changes of bandages. The wound environment is changing during an inflammation process, e.g. temperature, pH-value, composition and viscosity of the exudate.
The challenge in designing a sensor for this application is to find the right parameter that definitely indicates an infection. For this purpose it also makes sense to think about a multi-parametric ascertainment.

To be independent from wound smears we use human granulocytes in cell medium as a model environment. Neutrophil granulocytes react on germ contact by spreading out a matrix of extracellular DNA (neutrophil extracellular traps). The surrounding medium is getting more viscous. Our research deals mostly with impedimetric methods to detect these changes in the exudate.

The cells are settled on the surface of impedance sensors with interdigitated electrode structures. The characterization of the inflammation process on granulocytes can be determined by electrical impedance spectroscopy. With the described setup, spectra of stimulated and unstimulated granulocytes have been recorded. From the measurement results conclusions were drawn about ideal excitation requencies for capacitive and conductive measurements. They can be used to design functional coated electrodes to enhance the measuring signal. These coatings can be biopolymers with different sensitivities which change their molecular structure in presence of special substances. To realize an ascertainment of several parameters the new concept contains a multi-area-sensor.