Photo-responsive supramolecular actuators addressable with visible and near-infrared light for potential bio-medical applications – SOFTACTION

Engineering self-assembled functional materials that can respond to external stimuli is a research topic of great current interest. In the recent past, enormous efforts have been devoted to the investigation of small molecule and polymeric responsive materials prepared by synthetic pathways implying purely covalent chemistry. More recently, supramolecular responsive materials have attracted an increased deal of attention enriching the available chemical toolbox. Self-assembled materials possess a series of added-value features that cannot be found in covalent compounds, exhibiting structural dynamicity, responsiveness, and complexity emerging from a hierarchical and controlled organization of the building blocks. Furthermore, the modular synthetic approaches, as typical of supramolecular chemistry and molecular recognition strategies, allow fine modulation of the abovementioned features, rendering supramolecular materials potentially tunable at will. Light is a unique stimulus since it can be resolved in space, time and energy, as well as being applied remotely with high precision and fidelity. In fact, one of the most effective ways to promote a material’s response is the introduction of photo-switchable moieties that can undergo light-triggered isomerization. In this regard, several supramolecular systems containing photo-isomerizable moieties have been reported to date. However, most of the reported examples make use of photo-switching molecules that need UV light to isomerize at least in one direction. Employment of excitation wavelengths to trigger a material response, which fall within the so-called transparent “therapeutic window”, is instead preferable for in vivo applications. Thus, the project aims at preparing novel classes of autonomously healable and photo-responsive soft materials that can be addressed under non-harmful light excitation. Such innovative “smart” materials will find interesting applications in biomedicine and biomedical devices.