Creation of Pressure-Responsive Chemosensors

Organic synthetic molecules and supramolecular assemblies that respond to a large variety of external stimuli, such as solvent, temperature, photoirradiation, pH, and mechanical forces (pressure, stress, strain, and tension), have attracted considerable attention in current chemistry. Such smart soft materials, or chemosensors, have potential applications in interfacial imaging, probing, and cancer detection, which necessitate stimuli-responsive structural/optical/functional changes. In recent years, there has been significant progress in the synthesis of dynamically controllable chemosensors in response to external stimuli. In particular, hydrostatic pressure, one of the mechanical isotropic forces, has gained attention in the field of “mechano” science (mechanochemistry and mechanobiology), where pressure-responsive chemosensors are strongly desired for detecting minute pressures in cancer cells. Indeed, based on the hydrostatic pressure-control concept, we have successively developed pressure-responsive functional soft materials that show (chir) optical changes. For example, notable examples include the flapping porphyrin tweezers with S2 fluorescence, the dynamic polymers with aggregation-induced emission, the biocompatible polymers with excimer fluorescence, and other various systems, all of which exhibit spectral responses under the influence of hydrostatic pressure. These discoveries have motivated us to develop a further practical chemosensor that can be controlled by hydrostatic pressure. In this review, we summarized our recent achievements on the pressure-responsive chemosensors.