Separations of 15 pM rhodamine 6G and 30 pM rhodamine B performed in a micromachined electrophoresis channel were detected by counting fluorescence bursts from individual molecules. The migration times, peak widths, and analyte concentrations were estimated from the number and the migration time distribution of the detected molecules. Concentration detection limits estimated at >99% confidence ...

The study of mitochondria in situ has recently been facilitated through the use of rhodamine 123, a mitochondrial-specific fluorescent dye. It has been found to be nontoxic when applied for short periods to a variety of cell types and has thus become an invaluable tool for examining mitochondrial morphology and function in the intact living cell. In this report, however, we demonstrate that wit...

A new fluorogenic substrate for serine proteinases, bis(N-benzyloxycarbonyl-L-argininamido)Rhodamine [(Cbz-Arg-NH)2-Rhodamine], was synthesized, purified and chemically and enzymically characterized. This compound, which employs Rhodamine as a fluorophoric leaving group, is the first in a series of substrates designed to measure the amidase activity of proteinases. Cleavage of one of the amide ...

The expression of high levels of P-glycoprotein (Pgp) in circulating mononuclear cells allowed us to use an ex vivo assay as a surrogate measure of Pgp antagonism. Efflux of rhodamine from CD56(+) cells was measured before the start of PSC 833 and at varying times thereafter. Patients receiving PSC 833 had decreased rhodamine efflux from their circulating CD56(+) cells. Time course studies show...

Pgp is expressed on normal haemopoietic progenitor cells. The significance of the efflux pump in protecting normal progenitors for anthracycline toxicity is not defined and is the subject of this study. Pgp was measured in CD34+ progenitors with a rhodamine efflux assay. A high efflux, modulated by verapamil, was only found in a distinct subpopulation (20-30%). Pgp measured by the monoclonal an...

Mesoporous silica nanoparticles (MSN) have potential as drug delivery and controlled release devices due to their high surface area and absorption capabilities. The effect of surface charge and pH on the release of the fluorescent dye, rhodamine 6G, from MSN has been studied. Release profiles of rhodamine 6G from bare and amine-coated MSN at pH 5.0 and 7.4 are very different and demonstrate tha...

A novel method for the separation/analysis rhodamine B has been described. The ionic liquid (1-tetradecyl-3-methylimidazolium bromide)/anion surfactant (sodium dodecyl sulfate)/NaCl two-phase systems (ATPSs) is presented as a simple, rapid and effective sample pretreatment technique coupled with ultraviolet spectrometry for analysis rhodamine B in soft drink. The effects of parameters on the AT...

The rhodamine system is a flexible framework for building small-molecule fluorescent probes. Changing N-substitution patterns and replacing the xanthene oxygen with a dimethylsilicon moiety can shift the absorption and fluorescence emission maxima of rhodamine dyes to longer wavelengths. Acylation of the rhodamine nitrogen atoms forces the molecule to adopt a nonfluorescent lactone form, provid...

We demonstrate the enhancement of fluorescence emitted from dye molecules coupled with two surface plasmons, i.e., silver nanoparticles (AgNPs)-induced localized plasmons (LSP) and thin (Ag) film supported plasmons. Excitation light is illuminated to a SiO2 layer that contains both rhodamine 110 AgNPs. AgNPs enhances excitation rates in their close proximity due LSP-induced local electromagneti...

The effects of Klebsiella pneumoniae endotoxin on the biliary excretion and renal handling of rhodamine-123 were investigated in rats at different times after intraperitoneal injection (1 mg/kg of body weight). The typical substrates for P glycoprotein, i.e., cyclosporine, colchicine, and erythromycin, inhibited the biliary clearance of rhodamine-123, whereas a substrate for organic cation tran...