RESUMEN

Supramolecular chemistry currently faces the challenge of controlling nonequilibrium dynamics such as the dynamic instability of microtubules. In this study, we explored the emergence of dynamic instability through the hybridization of peptide-type supramolecular nanofibers with surfactant micelles. Using real-time confocal imaging, we discovered that the addition of micelles to nanofibers induced the simultaneous but asynchronous growth and shrinkage of nanofibers during which the total number of fibers decreased monotonically. This dynamic phenomenon unexpectedly persisted for 6 days and was driven not by chemical reactions but by noncovalent supramolecular interactions between peptide-type nanofibers and surfactant micelles. This study demonstrates a strategy for inducing autonomous supramolecular dynamics, which will open up possibilities for developing soft materials applicable to biomedicine and soft robotics.

RESUMEN

The fate of living cells often depends on their processing of temporally modulated information, such as the frequency and duration of various signals. Synthetic stimulus-responsive systems have been intensely studied for >50 years, but it is still challenging for chemists to create artificial systems that can decode dynamically oscillating stimuli and alter the systems' properties/functions because of the lack of sophisticated reaction networks that are comparable with biological signal transduction. Here, we report morphological differentiation of synthetic dipeptide-based coacervates in response to temporally distinct patterns of the light pulse. We designed a simple cationic diphenylalanine peptide derivative to enable the formation of coacervates. The coacervates concentrated an anionic methacrylate monomer and a photoinitiator, which provided a unique reaction environment and facilitated light-triggered radical polymerization─even in air. Pulsed light irradiation at 9.0 Hz (but not at 0.5 Hz) afforded anionic polymers. This dependence on the light pulse patterns is attributable to the competition of reactive radical intermediates between the methacrylate monomer and molecular oxygen. The temporal pulse pattern-dependent polymer formation enabled the coacervates to differentiate in terms of morphology and internal viscosity, with an ultrasensitive switch-like mode. Our achievements will facilitate the rational design of smart supramolecular soft materials and are insightful regarding the synthesis of sophisticated chemical cells.

Asunto(s)

Dipéptidos , Polímeros , Aniones , Cationes , Metacrilatos , Polímeros/química

RESUMEN

Multicomponent supramolecular hydrogels are promising scaffolds for applications in biosensors and controlled drug release due to their designer stimulus responsiveness. To achieve rational construction of multicomponent supramolecular hydrogel systems, their in-depth structural analysis is essential but still challenging. Confocal laser scanning microscopy (CLSM) has emerged as a powerful tool for structural analysis of multicomponent supramolecular hydrogels. CLSM imaging enables real-time observation of the hydrogels without the need of drying and/or freezing to elucidate their static and dynamic properties. Through multiple, selective fluorescent staining of materials of interest, multiple domains formed in supramolecular hydrogels (e. g. inorganic materials and self-sorting nanofibers) can also be visualized. CLSM and the related microscopic techniques will be indispensable to investigate complex life-inspired supramolecular chemical systems.

RESUMEN

Stochastic resonance is numerically and analytically studied using a model wherein two coupled particles are exposed to noise of heterogeneous (i.e., particle-dependent) amplitude. In a certain range of coupling constant and under noise of heterogeneous amplitude, a particle is observed to resonate intensively to the external field. In other words, one particle under noise of very small or zero amplitude exhibits intensive resonance with the assistance of a highly fluctuating second particle under noise of large amplitude. This intensive resonance is interpreted as a product of the unique combinatory dynamics between one particle that stochastically fluctuates and another particle that classically resonates to the external field.