A broad range fluorescent pH sensor based on hollow mesoporous silica nanoparticles, utilising the surface curvature effect.

In this study, a broad range pH sensor was synthesized by loading the pH sensitive dye, fluorescein isothiocyanate (FITC), and a reference dye, rhodamine B isothiocyanate (RITC), into the mesostructure of hollow mesoporous silica nanoparticles (HMSNs) synthesized using a co-condensation method. Compared to a pH sensor based on the same pair of dyes on conventional mesoporous silica nanoparticles (MSNs), this dual-labeled pH sensor based on HMSNs shows a larger pH sensitive range, between 4.5 and 8.