Rhodamine Red-X

Figure 6.26 (a) CdSe/ZnS QDs for the optical analysis of the protease-mediated hydrolysis of the rhodamine red-X-functionalized peptide 38 (b) Decrease in fluorescence of the dye and corresponding increase in fluorescence of the... 

Fig. 16 Addition of 0.017-nmol aliquots of a rhodamine B-labeled streptavidin and b Texas Red-X-labeled streptavidin to 1.51 nmol of 43. Energy transfer observed in both cases with amplified emission of the dyes to the light-harvesting conjugated polymers. Direct excitation of the dyes at 575 and 585 nm correspond to 0.100 nmol of streptavidin.

Figure 4.10 Summary of 457 individual particle fluorescence vs. LSPR peak position measurements with three different fluorescent dyes. The LSPR peak positions are binned in 20 nm intervals along the x-axis. The average fluorescence intensity observed from particles within each bin is then plotted as a function of the LSPR position for Ag nanoprisms functionalized with (A) Alexa Fluor 488, (B) Alexa Fluor 532 and (C) Rhodamine Red dyes. The absorption spectra (dotted lines) and emission spectra (dashed lines) are plotted for reference for each dye. The solid...

The red-emitting rhodamine derivatives are constructed around the same basic xanthene framework as is fluorescein (2). Tetramethylrhodamine isothiocyanate (TRITC) has been widely employed for immunofluorescence. Additional derivatives of rhodamine available for conjugation to antibodies include lissamine rhodamine sulfonyl chloride (RB-200-SC), rhodamine B isothiocyanate (RBITC), rhodamine X isothiocyanate (XRITC), and Texas... 

The most important xanthenes are the imino derivatives known as rhodamines, exemplified by rhodamine B (Cl Basic Violet 10) (3.23a), A. 543 nm and 552 nm and rhodamine 6G (Cl Basic Red 1) (3.23b), /L 530 and X 557 nm (Figure 3.11). These are intensively fluorescent dyes with quantum yields close to unity. Rhodamine 6G especially has found wide apphcation in dayhght fluorescent pigments (see section 3.5.2) and this ring structure has been much modified for use in many other outlets, especially as laser dyes (see section 3.5.3) and in biomedical applications (see section 3.5.6). 

Murakami and co-workers12) have carried out one of the most thorough investigations of multi-armed compounds with ion-terminated chains. In 1979 they reported the substrate-binding behavior of an azaparacyclophane (16) in which the hydro-phobic cavity was deepened by substitution of long ion-terminated chains on the macrocyclic skeleton. Salient properties of the cyclophane (16) include (1) The compound has a critical micelle concentration of 3.2 x 10 4 M. (2) (16) binds cationic and neutral dyes but not anionic ones. Thus, Rhodamine 6G and Quinaldine Red form 1 1 complexes with (16) having association constants of about 5 x 103 M 1. 

From the results of SHG spectroscopy, the rhodamine dyes adsorb and form the in-plane associates at the heptane/water interface, pointing the xanthane moiety towards the heptane phase with a tilt angle as shown schematically in Figure 11.7. The structure of the associates at the interface differs from that in a bulk aqueous phase. In an aqueous solution, RB makes a sandwich dimmer when the concentration is above 1.0 x 10 M [66], and the molar fraction of the dimmer is 0.56 at 1.0 x 10 M. The absorption spectra of the sandwich dimmer show blue-shifted peak around 525 nm. In contrast, red-shifted peaks found in SHG spectra indicate that the in-plane associates are predominantly formed at the interface despite the presence of the sandwich dimmer in the water phase. The hydrophobic property arising from heptane molecules at the h tane/water interface would be crucial for the predominant formation of in-plane associates. 

The red-emitting rhodamine derivatives are constructed around the same basic xanthene framework as is fluorescein (2). Tetramethyl-rhodamine isothiocyanate (TRITC) has been widely employed for immunofluorescence. Additional derivatives of rhodamine available for conjugation to antibodies include lissamine rhodamine sulfonyl chloride (RB-200-SC), rhodamine B isothiocyanate (RBITC), rhodamine X isothiocyanate (XRITC), and Texas Red (Molecular Probes, Inc.). The spectra of XRITC and Texas Red are shifted to longer wavelengths compared to those of other rhodamines, which makes them particularly useful for combination with fluorescein in dual-labeling procedures see Section 5, below). Of the two, Texas Red, which is more hydrophilic and less likely to precipitate proteins upon conjugation (12), is more commonly employed. 

Dimethylacetamide X 4 (5) 4 (2) X ElIV protease inhibitors, amiloride, atenolo, losartan, lucifer yellow, phenol red, rhodamine 123, theophylline, warfarin Aungst et al., 2000... 

Fig. 13 Fluorescent Images and the corresponding line profiles of the F-actin fibers red) of ADSCs seeded on (a) glass surface and (b) silk fibroin/chitosan (SFCS) scaffold. F-actin fiber density of ADSCs was quantified and confirmed by line-profile analysis of the fibers using Image software. The x-axis is the distance in microns, and the peaks correspond to the intensity of the rhodamine-phalloidin stain (red), whose peak maximum occurs at the location of the fibers along the line. Nuclei were stained with DAPI (blue) [162]...

It is important to note that the exact characteristics of a particular dye will be very dependant on the precise molecular environment/solvent, as such these values are given only as a guide. The list was compiled from manufacturers web sites and published work. Abbreviations TMR (tetramethylrho-damine), Cyxfcyanine dye x, Amersham Biosciences, UK), AFxxxfAlexa Fluor dye xxx Invitrogen Ltd., UK), R6G (rhodamine 6G),TR (texas red),... 

A method that has shown to be quite satisfactory and relatively straightforward is described in Protocol 2. In this method a diffuser plate or an MgO scatterer plate is placed in the sample holder and then both ExM and EmM are scanned synchronously from 250-600 mn. This will produce a spectrum of the xenon arc source that has been distorted by the sensitivity variation of the emission detection system. The reflector is replaced by a concentrated sample of rhodamine B in a triangular cuvette. The cuvette is oriented so that the hypotenuse is on the face opposite to EmM. This is a similar configuration to the cell in the reference channel of the instrument. A red cut-oflf filter is placed in front of the entrance slit to EmM and Xem is set to 620 ran. Then ExM is scanned from 250-600 nm and the spectrum is recorded. This spectrum is a close representation of the true xenon lamp intensity profile. Often neutral density filters will have to be placed in the emission beam in order to prevent signal saturation of the PMT. The two curves thus generated can be compared and the correction fector curve, C(X), calculated ... 

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