Nicolas Henriksson

The Chen Lab does bio-inspired nanoscience research focusing on identifying materials from biological systems that experience evaporation induced mechanical deformations for engineering applications

Abstract:

Water-responsive materials (WR) such as pine cones experience mechanical deformations in response to changes in relative humidity (RH). The Chen Lab focuses on finding powerful and efficient WR materials and utilizing their deformations for clean electricity generation and evaporation-powered locomotion. They discovered a powerful evaporation induced mechanical deformation in the endospores of Bacillus subtilis bacteria which is found in soil, plant roots, and animal digestive systems. These endospores represent an example for an extreme WR material. They found that the structural component of the B. subtilis endospores, peptidoglycan (PG), absorbed 90% of the water, which led to the bacteria's change in size. To determine whether PG would be a practical component in a mechanical actuator or energy generator they tested how effective and powerful it is. The Chen Lab Scientists used a Dynamic Vapor Sorption system (DVS), a box where they could control the humidity inside for their tests. Within the (DVS), an Atomic Force Microscope (AFM) was used to measure the effectiveness and power of PG's mechanical deformation. The scientists found that Cell Wall PG in B. subtilis had a higher power density and energy density than any other mammalian muscle or insect muscle. The scientists hypothesized that PG’s WR was incredibly effective and powerful due to its three-dimensional mesh-like structure, which contained nanoscale pores. The scientists demonstrated PG’s applications by mixing PG with adhesive and utilizing the bilayer to bend flexible materials. This method led the scientists to develop mechanical actuators that could pick up pencils and pull objects, even developing evaporation-powered electrical generators.

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