biostudies-literatureUmehara YUniversität WienJapan Society for the Promotion of Science5865-5873https://www.ebi.ac.uk/biostudies/studies/S-EPMC8694775biostudies-literatureUnknown11(10)Molecular oxygen plays an important role in living organisms. Its concentration and fluctuation in cells or tissues are related to many diseases. Therefore, there is a need for molecular systems that can be used to detect and quantify oxygen levels in vitro and in vivo. In this study, we synthesized phosphonated mesoporous silica nanoparticles bearing ruthenium complexes in their pores (pM-Rus) and evaluated their photophysical and biological properties. The pM-Rus were highly soluble in water and showed robust phosphorescence under hypoxic conditions, while the addition of oxygen suppressed this emission. Cellular experiments revealed that pM-Rus with a size of 100 nm showed efficient cellular uptake to emit phosphorescence in hypoxic cells. In addition, pM-Rus have negligibRSC advancesPhosphonated mesoporous silica nanoparticles bearing ruthenium complexes used as molecular probes for tracking oxygen levels in cells and tissues.PMC869477517J03866Kleitz FKimura YKondo TTanabe KUmehara YNishihara TfalsePhosphonated mesoporous silica nanoparticles bearing ruthenium complexes used as molecular probes for tracking oxygen levels in cells and tissues.Molecular oxygen plays an important role in living organisms. Its concentration and fluctuation in cells or tissues are related to many diseases. Therefore, there is a need for molecular systems that can be used to detect and quantify oxygen levels in vitro and in vivo. In this study, we synthesized phosphonated mesoporous silica nanoparticles bearing ruthenium complexes in their pores (pM-Rus) and evaluated their photophysical and biological properties. The pM-Rus were highly soluble in water and showed robust phosphorescence under hypoxic conditions, while the addition of oxygen suppressed this emission. Cellular experiments revealed that pM-Rus with a size of 100 nm showed efficient cellular uptake to emit phosphorescence in hypoxic cells. In addition, pM-Rus have negligib2021-01-01T00:00:00Z2021 Jan2025-05-31T23:34:40.569Z2025-05-31T23:34:40.569ZS-EPMC86947753542307810.1039/d0ra08771h