Investigation of Detergent-Modified Enzymomimetic Activities of TEMED-Templated Nanoceria Towards Fluorescent Detection of Their Cellular Uptake

Ceria nanoparticles can catalyze many redox reactions that resemble reactions catalyzed by naturally occurring enzymes, such as peroxidase, catalase, haloperoxidase or phosphatase. This makes nanoceria an attractive material for biomedical and sensing applications. Presence of detergents dramatically affects the catalytic activity of nanoceria. The catalytic activity is also strongly influenced by biogenic compounds present in the sample. Furthermore, biomedical applications are hindered by the difficulties to detect nanoceria uptake by cells. Therefore, we have developed a new fast and sensitive fluorescent haloperoxidase assay based on fluorescein bromination in presence of CTAB to detect uptake of CeO2 nanoparticles by cells invitro. Moreover, catalytic activities of standard nanoceria (CeO2) were compared to nanoceria hydrates (CeO2 center dot xH(2)O) that are easier for preparation and might be stabilized by biologically relevant molecules allowing for a specific targeting to cells or tissues. We have developed a new approach to produce CeO2 center dot xH(2)O in presence of TEMED and analyzed whether the presence of H2O2 during the synthesis influences the catalytic activity of produced particles.