Front Cover: Highly Sensitive Fluorescent Ph Microsensors Based On The Ratiometric Dye Pyranine Immobilized On Silica Microparticles (Chem. Eur. J. 53/2021)

Optical fluorescent pH sensors based on positively charged silica microparticles containing anionic pyranine molecules were developed by using a modified Stober method with a gradual immobilization of ratiometrically pH-sensing pyranine molecules during the growth of silica seed particles and an overall positive charge in a one-step reaction. The overly pH-sensitive nature of pyranine is preserved and long-term stability is ensured by silica shell coating. These cytocompatible ratiometric pH sensors can be used for pH sensing and pH tracking applications where each microparticle can be observed individually due to resolvable size. More information can be found in the Communication by A. Chandra, L. L. del Mercato et al. (DOI: 10.1002/chem.202101568).+