An electric generator using living Torpedo electric organs controlled by fluid pressure-based alternative nervous systems

Yo Tanaka,Shun-Ichi Funano,Takehiko Kitamori,Norihiro Kamamichi,Yohei Nishizawa,Masahiro Nishinaka

doi:10.1038/srep25899

Yo Tanaka, Shun-Ichi Funano + Show 4 more

Open Access

https://doi.org/10.1038/srep25899

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Abstract

Direct electric power generation using biological functions have become a research focus due to their low cost and cleanliness. Unlike major approaches using glucose fuels or microbial fuel cells (MFCs), we present a generation method with intrinsically high energy conversion efficiency and generation with arbitrary timing using living electric organs of Torpedo (electric rays) which are serially integrated electrocytes converting ATP into electric energy. We developed alternative nervous systems using fluid pressure to stimulate electrocytes by a neurotransmitter, acetylcholine (Ach), and demonstrated electric generation. Maximum voltage and current were 1.5 V and 0.64 mA, respectively, with a duration time of a few seconds. We also demonstrated energy accumulation in a capacitor. The current was far larger than that using general cells other than electrocytes (~pA level). The generation ability was confirmed against repetitive cycles and also after preservation for 1 day. This is the first step toward ATP-based energy harvesting devices.

Highlights

Development of clean and safe electric power generation methods is a pressing issue
The N. japonica used in the experiments were considered to have sufficient electric power generation performance
We showed that electric organs have large power generation performance and the electric power generation is possible even using extracted electric organs

Summary

Introduction

Development of clean and safe electric power generation methods is a pressing issue. Renewable energy conversions including hydraulic, geothermal or solar generation methods generally depend on the environment. From the viewpoint of directly harvesting electricity, two major methods have been reported: glucose bio-fuel cells incorporating enzyme onto electrodes[2] and MFCs3,4 were reported Differing from these approaches, we have focused on the unique biological function of strongly electric fish. There have been reports on artificial microdevices incorporating biological functions by cell/tissue engineered approaches including cardiomyocyte actuators[7,8,9,10], other muscle cell actuators[11,12], vascular systems[13,14], hybrid devices using lung[15], kidney[16], and liver[17] Inspired by these technological developments, we formed the idea to combine electric organ tissue, preserving its structure, and fluidic control systems to create novel functional devices. The ATP-based high energy conversion efficiency from glucose to electricity is significant for large-scale power generation Another advantage of our concept is that power load following operation (generation with arbitrary timing) is easy by controlling chemical stimuli. Investigation of fundamental electrical properties of living electric organs is indispensable

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