Two-Photon Fluorescence Probe for Selective Monitoring of Superoxide in Live Cells and Tissues.

The abnormal location or generation of superoxide radical anion (O2•-) are implicated in many diseases, including cancers; thus, development of an efficient method to detect O2•- is of great importance. Inspired by the fluorophore-governed selective manner to O2•- and peroxynitrite (ONOO-) of previously reported phosphinate-based fluorescence probes, in this contribution, a phosphinothioate-containing probe, TPP, was designed. The probe exhibited easy accessibility through a one-step sequence and good photostability and biocompatibility. Interestingly, TPP showed high specificity and sensitivity to O2•- over other reactive oxygen species/nitrogen species including ONOO-. Furthermore, with the assistance of two-photon microscopy, TPP was successfully applied for imaging endogenous O2•- in live cells and tissues.

Controlled microwave derivatization reaction for reproducible trace analysis of budesonide in human plasma.

Microwave reactors with on-line controlled reaction conditions have been recently innovated to improve reaction kinetics and reproducibility. Herein, a modern microwave reactor was dedicated to develop a new, sensitive and reproducible approach for trace analysis of budesonide (BUD) in human plasma. The method was based on fast microwave reaction of BUD with dansyl hydrazine (DNS-HZ) reagent under controlled conditions coupled with high-performance liquid chromatography (HPLC)-fluorescence detection. The microwave irradiation and dansylation conditions were optimized for the best sensitivity and selectivity. The controlled microwave derivatization reaction (CMDR) decreased the reaction time, amplified the reaction yield and enhanced product purities by reducing the unwanted side reactions. The chromatographic separation was attained by isocratic elution on reversed phase column via a mobile phase consisted of methanol and phosphate buffer (10 mM, pH 7.0) at ratio 80:20 (v/v). The fluorescence detector was set at 500 nm after excitation at 330 nm. Betamethasone dipropionate (BDP) was used as an internal standard. CMDR-HPLC method validation was performed in agreement with bioanalytical method validation guidelines by the US food and drug administration (US-FDA). The obtained linearity range was 0.2-100 ng mL-1 with correlation coefficient 0.9991 and the lower limit of quantitation (LLOQ) in human plasma was 0.21 ng mL-1. The developed CMDR -HPLC method was applied successfully for assessment of plasma levels of BUD in allergic rhinitis patients after intranasal administration of the micronized BUD.

Internalization of cycloheptaamylose-dansyl chloride complex during labelling of surface membrane in living Paramecium aurelia cells.

Internalization of cycloheptaamylose-dansyl chloride complex during surface labelling of living long-term starved Paramecium aurelia cells has been observed. This process may be inhibited by pretreatment of the ciliates with dichloroisoproterenol. Uptake of cycloheptaamylose-dansyl chloride may be visualized only after UV preirradiation: the appearance of orange-fluorescing vacuoles of diameter 2.3-4.5 micron may then be observed. Microspectrographic analysis performed on the cells and dansyl derivatives indicates that this fluorescence is produced by a photochemical reaction of dansyl chloride - released from CDC complex inside the digestive vacuoles-under the influence of UV irradiation.