Collective chemomechanical oscillations in active hydrogels

Area of Science:

• Chemical Engineering
• Materials Science
• Soft Matter Physics

Background:

• Single Belousov-Zhabotinsky (BZ) hydrogel beads below a critical size do not oscillate.
• Collective behavior in chemical systems can lead to emergent properties not observed in isolated components.

Purpose of the Study:

• To investigate the collective response of chemomechanical BZ hydrogel beads.
• To understand the transition from non-oscillating to oscillating states in BZ hydrogel assemblies.
• To explore the potential of collective effects for enhancing hydrogel oscillation and motility.

Main Methods:

• Experimental observation of BZ hydrogel bead assemblies.
• Development of a BZ chemical model incorporating chemical flux.
• Analysis of quorum sensing behavior to trigger chemomechanical oscillations.

Main Results:

• Assemblies of BZ hydrogel beads exhibit chemical oscillations, unlike isolated beads.
• A chemical model confirmed that inhibitor flux out of the hydrogels drives oscillations.
• Neighboring beads reduce the critical size required for oscillation in assemblies.
• Quorum sensing was successfully leveraged to trigger chemomechanical oscillations.

Conclusions:

• Collective behavior is crucial for initiating oscillations in BZ hydrogel beads.
• The findings provide a foundation for designing autonomous, communicating, and motile hydrogel swarms.
• This work enhances the understanding of coupled chemical and mechanical oscillations in soft materials.