Cytoskeletal networks are not only dynamic but also remarkably resilient: they can repair structural defects and restore function after damage. Yet the mechanisms of self-healing remain largely unknown. In this project, we used the light-activated microtubule–motor system to uncover how networks autonomously repair cracks and gaps. By projecting defined geometries of blue light, we generated O-shaped and V-shaped microtubule networks with controlled defects and observed their repair in real time.

Healing of a microtubule–motor network Figure 1: Self-healing behavior of O-shaped active networks is governed by a critical gap width.

Our experiments reveal that healing is governed by overlapping boundary layers of motors that crosslink and rejoin microtubules across a defect. This mechanism defines a critical geometrical threshold: narrow gaps heal, while wider ones rupture further. For V-shaped cracks, we discovered a striking bifurcation—networks zip closed below a critical angle but buckle open above it. Through continuum simulations and a minimal elastic-rod model, we showed that geometry and active stress together dictate the healing outcome.

This work establishes active healing as a distinct design principle in active matter: energy-consuming motors can encode mechanical logic, where structural fate depends on geometry and stress. By demonstrating how cytoskeletal networks can autonomously repair damage, this project provides insight into structural resilience in cells, and opens new avenues for engineering self-healing biomaterials that dynamically repair themselves.

Publication

  • 📄 F. Yang, S. Liu, H. Wang, H. J. Lee, R. Phillips, and M. Thomson. Geometry-dependent defect merging induces bifurcated dynamics in active networks. Physical Review Research (2025). HTML

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