Super-helix in L-phenylalanine based supramolecular self-assembly with dynamic morphology transitions

Dynamic transitions of supramolecular assemblies between lower-order structures and higher-order super-helical structures (e.g. double helical DNA, helical biopolymers) are of vital importance in many physiological processes, but still remains a great challenge to be realized in artificial assembled systems. Herein, a novel biphenyl central core symmetrically coupled with phenylalanine groups drives the construction of dynamic super-helix. The rotary packing of biphenyl central units allows π-π stacking under molecular aggregation state, which combines with hydrogen bonding between phenylalanine moieties to contribute the formation of super-helix. Notably, the coordination between carboxyl moieties and metal ions enables the in situ morphological transition between super-helix and nanospheres, which is regulated by redox reaction. The super-helical fibers mimicking extracellular matrix (ECM) exhibit stronger stereospecific interactions to proteins than primary fibers, facilitating the cell adhesion and proliferation. Moreover, the dynamic super-helical fibers as cell culture scaffolds can induce cell release via change of morphology from super-helix to nanospheres. This study provides an innovative approach to explore the supramolecular assembly related biological processes by the dynamic variation of super-structured helix in artificial systems.