Impedimetric fiber-based sensors for wound monitoring

To cover the high demands for an integrated in vivo wound monitoring concept, reliable sensor solutions have been under investigation for the past ten years. In this approach a sensor solution produced by textile machines is presented. The textile fabrication offers a cost-efficient opportunity to produce yard goods of sensors. The fiber-sensor integrates biocompatible electrodes separated by the functional material chitosan. The biopolymer is pH-dependent and changes its swelling state with the pH. The analysis of a thin chitosan layer by impedance spectroscopy is presented. It reveals a pH-dependent increase of the impedance of 7% at 120 Hz. The reaction is relatively slow and lasts many hours. The fiber setup with thermally cross-linked chitosan achieves even more impedance changes with over 50% signal increase at 450 kHz. However, stability of the sensor is still limited and needs to be improved.