A few years ago, we published a study exploring the possibility of coating natural spider silk to create strain sensors and actuators. Although the results were highly promising, working with native silk proved challenging and, at times, frustrating due to its intrinsic variability, limited control over production conditions, and poor scalability.
To overcome these limitations, we decided to build on the recent advances in bio-inspired artificial spider silk spinning developed by the Rising Lab. Our goal was to reproduce the same concept in a far more controlled and reproducible system. The results were truly remarkable.
When our composite fibers were subjected to tensile strain, their magnetic signal changed accordingly, demonstrating that the interaction between the metallic coating and the silk substrate remained stable and functional. This behavior could therefore be exploited to monitor the tensional state of the material, even under demanding cyclic loading conditions.
We are grateful to the editorial team of Advanced Functional Materials and to the reviewers, whose insightful comments helped make this publication possible. Interestingly, our earlier work on natural spider silk sensors was also published in the same journal (a nice update on the story!).
This is yet another beautiful scientific story that originated during my EPASS project journey.
The Marie Skłodowska-Curie Actions continue to provide researchers with extraordinary opportunities to pursue ambitious and interdisciplinary projects.
Finally, sincere thanks to all the brilliant authors and co-authors who contributed to making this work possible.
Filippo Lanaro Federico Spizzo Benjamin Schmuck Anna Rising Lucia Del Bianco
The paper can be found here: https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.75699
Follow up EPASS project: https://gabriele-greco.com/epass/
ABSTRACT OF THE PAPER:
Combining spider silk and magnetic nanostructures is a key challenge for advancing technological fields such as soft robotics,magnetosurgery, and smart textiles. It is essential to devise approaches that also aim to expand fundamental knowledge on the feasibility of coupling the protein-based fiber with the inorganic magnetic phase. An original strategy is presented to create magneto-responsive artificial spider silk fibers by coating them with thin layers (nominal thickness 5nm, 10nm, and 100nm) of ferromagnetic and magnetostrictive FeCo alloy via sputtering deposition. The mechanical strength and elasticity of the produced fibers remain close to those of the uncoated material. A relationship is established between the magnetic properties of the FeCo coating and its structural characteristics, which are strongly influenced by the underlying fiber morphology. The magnetomechanical response of the FeCo coating of single fibers under strain is evaluated using magneto-optical Kerr effect magnetometry. Experimental data, interpreted through the shear-lag model, reveal excellent silk-metal coupling and highlight how the coating thickness governs stress transmission and the fragmentation process. The reversibility of the magnetomechanical response is investigated, providing further insights into the silk/metal coupling. These findings contribute to clarifying how the interplay between organic and inorganic components determines the composite’s overall properties.
