Harmonic resonance and entrainment of propagating chemical waves by external mechanical stimulation in BZ self-oscillating hydrogels

Geher-Herczegh, T., Wang, Z., Masuda, T., Vasudevan, N. ORCID: https://orcid.org/0000-0003-4326-3938, Yoshida, R. and Hayashi, Y. ORCID: https://orcid.org/0000-0002-9207-6322 (2024) Harmonic resonance and entrainment of propagating chemical waves by external mechanical stimulation in BZ self-oscillating hydrogels. Proceedings of the National Academy of Sciences, 121 (16). e2320331121. ISSN 1091-6490 doi: 10.1073/pnas.232033112

Abstract/Summary

Smart polymer materials that are non-living yet exhibit complex “life-like” or biomimetic behaviours have been the focus of intensive research over the past decades, in the quest to broaden our understanding of how living systems function under nonequilibirum conditions. Discovery of how chemical and mechanical coupling can generate resonance and entrainment with other cells or external environment is an important research question. We prepared Belousov-Zhabotinsky (BZ) self-oscillating hydrogels which convert chemical energy to mechanical oscillation. By cyclically applying external mechanical stimulation to the BZ hydrogels, we found that when the oscillation of a gel sample entered into harmonic resonance with the applied oscillation during stimulation, the system kept a "memory" of the resonant oscillation period and maintained it post stimulation, demonstrating an entrainment effect. More surprisingly, by systematically varying the cycle length of the external stimulation, we revealed the discrete nature of the stimulation-induced resonance and entrainment behaviours in chemical oscillations of BZ hydrogels, i.e., the hydrogels slow down their oscillation periods to the harmonics of the cycle length of the external mechanical stimulation. Our theoretical model calculations suggest the important roles of the delayed mechanical response caused by reactant diffusion and solvent migration in affecting the chemomechanical coupling in active hydrogels and consequently synchronising their chemical oscillations with external mechanical oscillations.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/115608
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Biological Sciences > Department of Bio-Engineering
Publisher	National Academy of Sciences
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