Tailored Supramolecular Soft Robotics by Intermolecular Interactions Defined Aspect-Ratio of Nanoassemblies for Photocontrolled Cell-Material Interfaces

As inspired by nature, our supramolecular assemblies approach harnesses the extended π-conjugation and hydrogen bonding of DASA amphiphiles to pre-determined supramolecular dimers as basic units to improve structural precision. Through introductions of the subtle difference of amino acid side-chains, the formation of narrow aspect-ratio nanoribbons or high aspect-ratio helical nanofibres can be tailored by without altering the core molecular building block. Spectroscopic and microscopic analyses suggest that the supramolecular assemblies are governed by the interplay of intermolecular interactions and counterion selection. Excellent photoswitchability of DASA amphiphiles was displayed in organic media, while aqueous environments stabilize the cyclised isomer of DASA amphiphiles. At the macroscopic length-scale, the pre-defined supramolecular assemblies can be fabricated int macroscopic soft scaffolds, which mechanical properties and photoactuation speeds are dictated by the underlying nanostructure aspect-ratio. Remarkably, macroscopic soft scaffolds of phenylalanine-derived DASA amphiphile maintain integrity and photoactuation functions even after prolonged physiological incubation, enabling photocontrolled cell-material interfaces and mechanotransduction in stem cells. This work establishes a versatile platform for engineering photoresponsive supramolecular soft robotics, with promising applications in dynamic biomaterials and photocontrolled cell-material interfacial systems.