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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.

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 y, but it is still challenging for chemists to create artificial systems that can decode dynamically oscillating stimuli and respond in 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 light pulse frequency. We designed a simple cationic diphenylalanine peptide derivative to enable formation of coacervates. The coacervates concentrated an anionic methacrylate monomer and a photo-initiator, which provided a unique reaction environment and facilitated light-triggered radical polymerisation—even in air. Pulsed light irradiation at 9.0 Hz (but not at 0.5 Hz) afforded anionic polymers. This frequency dependence is attributable to the competition of reactive radical intermediates between the methacrylate monomer and molecular oxygen. The frequency-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 rational design of smart supramolecular soft materials and are insightful regarding the origin of life.

Stimulus-responsive hydrogels are promising as a platform for controlled drug release and regenerative medicine. We describe a polymer grafted with self-assembling triphenylalanine (FFF) peptides t...

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., A powerful tool! Confocal laser scanning microscopy (CLSM) is powerful for structural analysis of supramolecular hydrogels. In situ imaging enables to evaluate not only static but dynamic properties of supramolecular nanofibers in real time. This minireview summarizes representative examples of CLSM imaging of multicomponent supramolecular hydrogel systems.

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.