Biomimetic robotic Venus flytrap

Abstract
The work described in this paper is a novel design of a robotic Venus flytrap (VFT) (Dionaea
muscipula Ellis) by means of ionic polymeric metal composite (IPMC) artificial muscles as
distributed nanosensors and nanoactuators. Rapid muscular movements in carnivorous plants,
such as VFT, which are triggered by antenna-like sensors (trigger hair), present a golden key to
study distributed biomolecular motors. Carnivorous plants, such as VFT, possess built-in
intelligence (trigger hairs), as a strategy to capture prey, that can be turned on in a controlled
manner. In the case of the VFT, the prey that is lured by the sweet nectar in the VFT pair of
jaw-like lobes has to flip and move the trigger hairs, which are colorless, bristle-like and
pointed. The dynamically moved trigger hairs then electro-elastically send an electric signal to
the internal ions in the lobe to migrate outwardly for the jaw-like lobes to close rapidly to
capture the prey. The manner in which the VFT lobes bend inward to capture the prey shows a
remarkable similarity with typical IPMCs bending in an electric field. Furthermore, the
mechano-electrical sensing characteristics of IPMCs also show a remarkable resemblance to
mechano-electrical trigger hairs on the lobes of the VFT. The reader is referred to a number of
papers in connection with sensing and actuation of IPMCs in particular. Thus, one can
integrate IPMC lobes with a common electrode in the middle of one end of the lobes to act like
a spine and use IPMC bristles as trigger finger to sense the intrusion of a fly or insect to send a
sensing signal to a solid state relay which then triggers the actuation circuit of the IPMC lobes
to rapidly bend toward each other and close. The two lobes, which form the trap, are attached
to the midrib common electrode which is conveniently termed the spine. The upper surface of
each lobe is dished, and spaced along the free margins of the lobes with some 15–20
prong-like teeth . These are tough and pointed, and are inclined at an inward angle so that
when the trap is sprung shut they will interlock. We have been experimenting with the VFT
closing of its jaw-like lobes that close in about 0.3 s and have gained a lot of knowledge to
report on the ionic and electrical mechanisms involved in the operation of such intelligent
distributed biomolecular motors.

http://iopscience.iop.org/1748-3190/6/4/046004/pdf/1748-3190_6_4_046004.pdf