Mechanical properties of edible biofilm as a substrate for printed electronics

Edible electronics offers an alternative to invasive approaches in conventional medicine and provides novel ways of monitoring patient health and attaining point-of-care diagnostics. For further development of this emerging area, it is necessary to develop new biodegradable and eco-friendly materials as well as to determine their properties. This paper presents the process of biofilm preparation using pea protein isolate with the addition of apple pomace extract. Microstructural and morphological properties of this biofilm were determined. Additionally, mechanical characterization of the biofilm was conducted using nanoindentation at four different temperatures; 27 °C, 50 °C, 70 °C and 100 °C. The studied biofilm had lower mechanical flexibility with increasing temperature due to evaporation of liquids from the biofilm. The solubility of the biofilm at these four temperatures was also analysed. Exposing biofilms to higher temperatures reduced their solubility, as they formed strong, compact networks under these conditions. Mechanical characteristics such as hardness index and Young's module at elevated temperatures are very important parameters for determining the suitability of this edible biofilm as a substrate in bioresorbable and edible electronics.