Electrical frequency discrimination by fungi Pleurotus ostreatus

2025-05-03 0 0 1.11MB 7 页 10玖币

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Dawid Przyczynaa, Konrad Szacilowskia, Alessandro Chioleriob,c, Andrew Adamatzkyc,d

aAcademic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Krakow, Poland

bIstituto Italiano di Tecnologia, Center for Converging Technologies, Soft Bioinspired Robotics, Via Morego 30, 16165

Genova, Italy

cUnconventional Computing Lab, UWE, Bristol, UK

dDepartment of Electrical and Computer Engineering, Democritus University of Thrace, Xanthi, Greece

Abstract

We stimulate mycelian networks of oyster fungi Pleurotus ostreatus with low frequency sinusoidal electrical

signals. We demonstrate that the fungal networks can discriminate between frequencies in a fuzzy or thresh-

old based manner. Details about the mixing of frequencies by the mycelium networks are provided. The

results advance the novel ﬁeld of fungal electronics and pave ground for the design of living, fully recyclable,

electron devices.

Keywords: fungi, unconventional materials, electrical properties, frequency, living electronics

1. Introduction

Fungal electronics aims to design bio-electronic devices with living networks of fungal mycelium [1] and

proposes novel and original designs of information and signal processing systems. The reasons for developing

fungal electronic devices are following. Mycelium bound composites (grain or hemp substrates colonised

by fungi) are environmentally sustainable growing bio-materials [2, 3, 4]. They have been already used in

insulation panels [5, 6, 7, 8, 9], packaging materials [10, 11], building materials and architectures [12] and

wearables [13, 14, 2, 15, 16]. To make the fungal materials functional we need to embed ﬂexible electronic

devices into the materials. Hyphae of fungal mycelium spanning the mycelium bound composites can play a

role of unconventional electronic devices. interestingly, their topology is very similar to conducting polymer

dendrites [17, 18]. These properties originate not only from common topology [19] but also from complex

electron transport phenomena.Therefore, it is not surprising that electrical properties of mycelial hyphae

and conducting polymer ﬁlaments have similar electrical properties: proton hopping and ionic transport

in hyphae vs ionic and electronic transport in polymers. Such transport duality must result in highly

nonlinear voltage/current characteristics, which in turn, upon AC stimulation must result in generation of

complex Fourier patterns in resulting current, as well as other phenomena relevant from the point of view

of unconventional computing, e.g. stochastic resonance [20].

We have already demonstrated that we achieved in implementing memristors [21], oscillators [22], photo-

sensors [23], pressure sensors [24], chemical sensors [25] and Boolean logical circuits [26] with living mycelium

networks. Due to nonlinear electric response of fungal tissues, they are ideally suited for transformation of

low-frequency AC signals. This paper is devoted to frequency discriminators and transformers, which are a

signiﬁcant contribution to the ﬁeld of fungal electronics.

Electrical communication in mycelium networks is an almost unexplored topic. Fungi exhibit oscillations

of extracellular electrical potential, which can be recorded via diﬀerential electrodes inserted into a substrate

colonised by mycelium or directly into sporocarps [27, 28, 29]. In experiments with recording of electrical

potential of oyster fungi Pleurotus djamor we discovered two types of spiking activity: high-frequency 6 mHz

and low-freq 1 mHz [29] ones. While studying other species of fungi, Ganoderma resinaceum, we found

that the most common signature of an electrical potential spike is 2-3 mHz [22]. In both species of fungi

we observed bursts of spikes within trains of impulses similar to that observed in animal central nervous

system [30, 31]. In [32] we demonstrated that information-theoretical complexity of fungal electrical activity

exceeds the complexity of European languages. In [33] we analysed the electrical activity of Omphalotus

nidiformis,Flammulina velutipes,Schizophyllum commune and Cordyceps militaris. We assumed that the

Preprint submitted to Journal October 5, 2022

arXiv:2210.01775v1 [cs.ET] 4 Oct 2022

Figure 1: Diagram showing connecting points to the fungi sample. The blue circles represent two places for the input signal

injection whereas the red circle represents the ground.

spikes of electrical activity could be used by fungi to communicate and process information in mycelium

networks and demonstrated that distributions of fungal word lengths match that of human languages. Taking

all the above into account it would be valuable to analyse the electrical reactions of fungi to strings of

electrical oscillations, featuring frequencies matching those of the supposed fungal language. The present

paper advances our research and development in (1) fungal electronics and (2) communication in mycelium

networks by proposing novel and original designs of frequency discriminators based on living fungi.

2. Methods

A slab of substrate, 200 g, colonised by Pleurotus ostreatus (Ann Miller’s Speciality Mushrooms, UK,

https://www.annforfungi.co.uk/shop/oyster-grain-spawn/) was placed at the bottom of a 5 l plastic

container. Measurements were performed in a classic two electrode setup. Electric contacts to the fungi sam-

ple were made using iridium-coated stainless steel sub-dermal needle electrodes (purchased by Spes Medica

S.r.l., Italy), with twisted cables. Signal was applied with 4050B Series Dual Channel Function/Arbitrary

Waveform Generators (B&K Precision Corporation). Signals featuring a series of frequencies — 1-10 mHz

with a 1 mHz step and 10-100 mHz with a 10 mHz step — have been applied between two points of the

fungi and measured with two diﬀerential channels on ADC-24 (purchased by Pico Technology, UK) high-

resolution data logger with a 24-bit analog-to-digital converter. We have chosen these particular intervals

of frequencies because they well cover frequencies of action-potential spiking behaviour of a range of fungi

species [29, 22, 33].

For these frequencies, the sinusoidal signal was applied along two paths separately. Finally, mixing of

signals was performed for 1 mHz base frequency applied on Path 1 and a series of frequencies on the Path

2. Frequencies used on Path 2 are 2, 5 and 7 mHz). Fast Fourier transform (FFT) was calculated with

Origin Pro software. Blackman window function was used as it is best suitable for the representation of

amplitudes [34]. Fuzzy sets for inference of new input data were constructed using ”fuzzylogic 1.2.0” Python

package.

3. Results

A response of the fungi sample to electrical stimulation is shown in Fig 1a. In all measurements, electrical

activity with frequency 50-200 mHz was observed even when substrates were not stimulated. This activity

is attributed to endogenous oscillations of electrical potential of fungi [29, 22, 33].

Exemplary generations of higher harmonics are shown in Fig. 2b. In some cases presented on Fig 3,

2nd harmonic is more damped than the 3rd harmonic. Generally, for frequencies below 10 mHz, higher

amplitudes were observed for 3rd harmonic versus the 2nd.

The ratio of the 2nd to 3rd harmonic amplitudes was calculated to better illustrate the changes between

them (Fig 4a). The calculated ratios were then normalised to the ratio of harmonics at 10mHz. Points at 30

and 50 mHz in 1 path, and 2 channel were treated as outliers because the ratios at these frequencies were

disproportionally larger than those at other frequencies, which disturbed data visualisation. Besides, the

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摘要：

ElectricalfrequencydiscriminationbyfungiPleurotusostreatusDawidPrzyczynaa,KonradSzacilowskia,AlessandroChioleriob,c,AndrewAdamatzkyc,daAcademicCentreforMaterialsandNanotechnology,AGHUniversityofScienceandTechnology,Krakow,PolandbIstitutoItalianodiTecnologia,CenterforConvergingTechnologies,SoftBioins...

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Electrical frequency discrimination by fungi Pleurotus ostreatus

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