Synthesis and Supramolecular Functional Assemblies of Ratiometric pH Probes

Tracking the pH with spatiotemporal resolution is a critical challenge for synthetic chemistry, chemical biology and beyond. Over the last decade different small probes and supramolecular systems have emerged for in celluloor in vivo pH tracking. However, pH reporting still presents critical limitations such as background reduction, sensor improved stability, cell targeting, endosomal escape, near and far infrared ratiometric pH tracking, adaptation to the new imaging techniques (i.e. super-resolution), etc. These challenges will demand the combined efforts of synthetic and supramolecular chemistry working together to develop a next generation of smart materials that will resolve the current limitations. In this review we describe the recent advances in the synthesis of small fluorescent probes together with new supramolecular functional systems employed for pH tracking with emphasis in ratiometric probes. The combination of organic synthesis and stimuli-responsive supramolecular functional materials will be essential to solve future challenges of pH tracking such as the improved signal to noise ratio, on target activation and microenvironment reporting.