Fluorescence with polyethylene glycols

A EXPERIMENTAL FIGURE 12-22 The movement of human hnRNP Al protein between nuclei in a heterokaryon shows that it can cycle in and out of the cytoplasm, but human hnRNP C protein, which showed no such movement, cannot. Cultured HeLa cells and Xenopus cells were fused by treatment with polyethylene glycol, producing heterokaryons containing nuclei from each cell type. The hybrid cells were treated with cycloheximide Immediately after fusion to prevent protein synthesis. After 2 hours, the cells were fixed and stained with fluorescent-labeled antibodies specific for human hnRNP C and Al proteins. These antibodies do not bind to the homologous Xenopus proteins, (a) A fixed preparation viewed by phase-contrast microscopy Includes unfused HeLa cells (arrowhead) and Xenopus cells (dotted arrow), as well as fused heterokaryons... 

The following Tables 2.1 to 2.3 summarize some examples based exclusively on thermochemical reactions on the sorbent surface which lead to the formation of fluorescent reaction products. The derivatives formed frequently remain stable for weeks [6] and the fluorescence can frequently be intensified and/or be stabilized by treatment with viscous liquids (liquid paraffin, Triton X-100, polyethylene glycol etc.). 

Confocal laser scanning microscopy can be used in conjunction with microwave heating for examining the three-dimensional structure and cellular interrelationships in sections of paraffin-embedded tissues (Boon and Kok, 1994). Tissues are fixed with Kryofix, a coagulant fixative containing 50% ethyl alcohol and polyethylene glycol (PEG molecular weight 300) for 90 sec in a microwave oven. The use of thick paraffin sections (15 (xm) and fluorescently labeled antibodies is preferred. 

Another successful example is the separation of a series of steroids listed in Fig. 6.11 using a monolithic capillary column prepared by redox initiated polymerization of a solution of acrylamide 4, methylene bisacrylamide 5, vinylsulfonic acid 12, and dodecyl acrylate 18 in N-methylformamide/TRIS-boric acid buffer (pH 8.2) to which polyethylene glycol) (MW 10,000) was added (overall composition 5% T, 60% C, 10% vinylsulfonic acid, 15% lauryl acrylate, 3% polyethylene glycol)). The capillary tube was first vinylized and its part beyond the detection window was coated with linear polyacrylamide to avoid band broadening. Since laser induced fluorescence was used to decrease the detection limit of the method to about 100 attomoles for neutral steroids, all of the analytes were first tagged with dansylhydrazine. Fig. 6.12 shows an... 

Separations of complex steroid mixtures were achieved recently by Que et al. [76] using both isocratic and gradient elution. Mass spectrometric detection gave femto-mole detection limits while laser-induced fluorescence of dansylated ketosteroids ranged in attomole levels (Fig. 10.16). Monolithic column packings were used with a 35 cm (25 cm packed bed) x 100 pm i.d. capillary packed with a polymer prepared from 5% T (total monomer concentration), 60% C (total crosslinker concentration), 3% polyethylene glycol, 10% vinylsulfonic acid and 15% lauryl acrylate. Details of the monolithic column preparation can be found in refs. 36,76, and 193. Similar monolithic columns can be used for the separation of bile acids [194],... 

Nakayama-Ratchford N, Bangsaruntip S, Sun X et al (2007) Noncovalent functionalization of carbon nanotubes by fluorescein-polyethylene glycol supramolecular conjugates with pH-dependent absorbance fluorescence. J Am Chem Soc 129 2448-2449... 

With fluorescent substances, this is usually very satisfactorily achieved by the use of fluorescence intensifiers (FlTs). Vol. la of the reagent books of Jork et al. gives tables of lipophilic FITS (mainly mineral oils) and hydrophilic FlTs such as polyethylene glycols, triethylamine, triethanolamine and especially Triton X-100, including areas of use. Treatment by spraying and dipping in various solvents is recommended. In gen-... 

Fluorescence polarisation studies on acenaphthylene labelled polyacrylic acid has demonstrated complexation occurs with polyethylene oxide to give a tightly packed and sterically restricted conformation SS. Neutralisation of the acidic groups restored the polarisation of the fluorescence and together with time resolved fluorescence analysis indicated that the motion of the probe is anisotropic. Solvent partitioning has been observed between glycol methacrylate copolymers from the fluorescence anisotropy changes of... 

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