AsianScientist (Oct. 23, 2017) – A research group at the University of Tokyo have created amoeba-like fluids that oscillate spontaneously between liquid ‘sol’ and semisolid ‘gel’ states. Their results, published in Nature Communications, provide clues for studying the movements of amoeba and facilitate the creation of so-called soft machines.
The diverse range of biological phenomena observed in living organisms is achieved through a complex interaction of various substances. For example, the self-assembly and disassembly of a biopolymer called actin enables amoeba to move by changing their viscosity.
This sol-gel oscillation derived from actin is not only important for amoeba motility, but also plays a crucial role in the movement of cancer cells from one part of the body to another, the development of immune cells, cell division, wound healing and other mechanisms. However, reproducing these autonomous dynamic behaviors has been difficult.
In the current study, the research group led by Professor Ryo Yoshida and graduate student Mr. Michika Onoda of the Graduate School of Engineering at the University of Tokyo created fluids that exhibit amoeba-like spontaneous sol-gel oscillation without the need for external stimuli.
The researchers used a polymer with a special molecular arrangement and modified it by introducing a metal complex such that the polymer would be a sol in the oxidized state and a gel in the reduced state. When they initiated an oscillating chemical reaction called the Belousov-Zhabotinsky (BZ) reaction, the modified polymer spontaneously went through sol-gel oscillations.
The period or amplitude of the sol-gel oscillation was easily controlled by changing the temperature or the concentration of the polymer or BZ substrates. The authors say that their result is the first report of a successful attempt to artificially reproduce autonomous behavior observed in living organisms.
“The creation of the amoeba-like fluids exhibiting spontaneous sol-gel oscillation was one of our major goals,” said Yoshida. “We proved that autonomous bioinspired materials can be produced by extracting the essence of biological phenomena and using it deftly.”
“I will not forget the excitement I felt when I observed the first-ever spontaneous sol-gel oscillation in the lab,” said Onoda. “Based on this achievement, we will ramp up research on bioinspired materials with autonomous dynamic function.”
The article can be found at: Onoda et al. (2017) Amoeba-like Self-oscillating Polymeric Fluids with Autonomous Sol-gel Transition.
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Source: University of Tokyo; Photo: Pixabay.
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