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Cell-inspired synthetic fibers reveal a reversible route to self-protecting smart materials
Researchers at the University of Bayreuth, together with colleagues from Freie Universität Berlin and the Leibniz Institute of Polymer Research Dresden, have developed a synthetic fiber system inspired by the cellular cytoskeleton that protects itself through controlled bundling. The findings open up new avenues for smart, switchable materials whose properties can be deliberately altered in response to a specific stimulus. The research is published in the journal Advanced Materials.
Living cells accomplish a remarkable feat: They maintain delicate structures, such as the cytoskeleton, that are held together only by weak intermolecular interactions, even under adverse conditions. They achieve this through hierarchical organization and targeted bundling.
Individual protein molecules form the smallest building blocks, which assemble into filaments. Multiple filaments are then bundled together and joined by crosslinking proteins, creating more stable structures. Reproducing this principle in synthetic polymers could lead to new resource-efficient materials for applications such as 3D printing, sensing and optoelectronics, as well as biotechnology.
From nanofibers to protective bundles
For the first time, a research team led by Dr. Alex Plajer at the University of Bayreuth has recreated a fiber system with hierarchical order and controlled bundling in a fully synthetic aqueous system. The starting point is a zinc-containing planar molecule linked to a temperature-responsive polymer. In dilute aqueous solution, these building blocks spontaneously assemble into nanofibers. Remarkably, water molecules themselves become incorporated as structural components of the nanofibers instead of merely acting as a solvent.
When the temperature is raised above 32°C, the initially independent nanofibers bundle together into micrometer-sized structures. The same bundling process can also be triggered by changes in salt concentration or solvent composition. Reversing the respective stimulus, for example by lowering the temperature or adjusting the salt concentration or solvent composition, causes the bundles to dissociate again. The process is therefore fully reversible.
Crucially, this higher-order organization protects the otherwise fragile building blocks, just as in the cytoskeleton. While individual nanofibers rapidly disassemble under dilution, acidic conditions or chemical attack, bundled fibers remain stable.
"We were even able to demonstrate selective protection of the fibers. In a mixture containing bundled and unprotected fibers, only the bundle-forming fibers survive, while the others disintegrate. This behavior resembles the selective compartmentalization observed in cells, where distinct regions or organelles are formed within the cellular environment," explains Merlin Stühler, first author of the study and a doctoral researcher in Plajer's group.
Survival tied to energy input
This principle became particularly evident in an unusual experiment. Upon irradiation with UV light, the zinc complex heats itself photothermally and maintains the fibers in their protected, bundled state for as long as energy is supplied by the light source. Once irradiation ceases, the bundles dissociate and the building blocks disintegrate under acidic conditions.
"In this way, we have created an analogy to mechanisms used by acid-resistant bacteria, which actively expend energy to maintain their internal balance under hostile conditions," Stühler says. "Our system literally survives only while energy is being supplied. It therefore exists in a state far from thermodynamic equilibrium, a defining feature of biological systems."
Low-concentration gelation with applications
The hierarchical bundling not only enhances fiber stability but can also be observed with the naked eye. Upon heating, the fibers form a hydrogel at concentrations about 200 times lower than those required in comparable polymer systems. Cooling reverses the process, returning the gel to a liquid state. Gelation can be triggered by light irradiation, while the gelation temperature can simultaneously be controlled through salt concentration or solvent composition. Even in the hydrogel state, the building blocks remain protected against acid and chemical attack.
"Beyond the fundamental insight that biological organizational principles can be transferred to synthetic systems, we see clear application potential for our material. Its reversible, repeatedly stimulus-responsive gelation at comparatively low material concentrations makes the system attractive for 3D printing, where it could serve as a recyclable, 'switchable' printing resin," Plajer concludes.
The work also provides a novel design strategy for sensing and optoelectronics, due to the light-responsive photophysical properties of the zinc-containing building block, as well as for the development of more robust and intelligent materials in nanotechnology and biotechnology.
Publication details
Merlin R. Stühler et al, Stimuli‐Responsive Hierarchical Structuring Controls Survival and Programs Hydrogelation of Supramolecular Metallofibers, Advanced Materials (2026). DOI: 10.1002/adma.74151
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Citation: Cell-inspired synthetic fibers reveal a reversible route to self-protecting smart materials (2026, August 5) retrieved 5 August 2026 from https://phys.org/news/2026-08-cell-synthetic-fibers-reveal-reversible.html
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