Fungal photosensors

The rapidly developing research field of organic analogue sensors aims to replace traditional semiconductors with naturally occurring materials. Photosensors, or photodetectors, change their electrical properties in response to the light levels they are exposed to. Organic photosensors can be functionalised to respond to specific wavelengths, from ultra-violet to red light. Performing cyclic voltammetry on fungal mycelium and fruiting bodies under different lighting conditions shows no appreciable response to changes in lighting condition. However, functionalising the specimen using PEDOT:PSS yields in a photosensor that produces large, instantaneous current spikes when the light conditions change. Future works would look at interfacing this organic photosensor with an appropriate digital back-end for interpreting and processing the response.Comment: 15 figures, 8 page

On resistive spiking of fungi

We study long-term electrical resistance dynamics in mycelium and fruit bodies of oyster fungi P. ostreatus. A nearly homogeneous sheet of mycelium on the surface of a growth substrate exhibits trains of resistance spikes. The average width of spikes is c.~23~min and the average amplitude is c.~1~kOhm. The distance between neighbouring spikes in a train of spikes is c.~30~min. Typically there are 4-6 spikes in a train of spikes. Two types of resistance spikes trains are found in fruit bodies: low frequency and high amplitude (28~min spike width, 1.6~kOhm amplitude, 57~min distance between spikes) and high frequency and low amplitude (10~min width, 0.6~kOhm amplitude, 44~min distance between spikes). The findings could be applied in monitoring of physiological states of fungi and future development of living electronic devices and sensors