Rhodamine cellular uptake

In a screening on the effects of poria on chemotherapy drug uptake in human cervical carcinoma cells, an aqueous extract of poria enhanced the target cell sensitivity to the p-glycoprotein (P-gp) substrate paclitaxel, with no changes in sensitivity to 5-fluorouracil, which is not a substrate for P-gp. Poria increased cellular uptake of rhodamine 123 (Takara et al. 2005). 

Fig. 3 Micelle formation by the amphiphilic DNA-polymer conjugate resulting from the coupling of nucleotide sequences and poly(DjL-lactic-co-glycolic acid) in aqueous medium. Confocal image shows cellular uptake of rhodamine-labeled micelles transported within NIH3T3 mouse fibroblast cells [77] (figure adapted with permission of American Chemical Society)...

Function of mitochondria is also commonly monitored as an indicator of cellular toxicity. Mitochondrial uptake and retention of the fluorescent dye, rhodamine 123, can be visualized microscopically. Biochemical measurements of mitochondrial function include the ATP-ADP ratio and dehydrogenase activity with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), which yields a colored formazan product upon reduction. The dye, neutral red (3-amino-7-dimethyl-amino-2-methylphenazine hydrochloride), targets lysosomes, and its retention is inversely related to cytotoxicity. Commercially available versions of the MTT and neutral red assays have been adapted to microtiter plate formats to provide highly efficient screening assays. Examples of how cell-type-specific functions can be followed as indicators of cell toxicity are included in Table 8.1. 

Polyplex uptake is typically assessed by transfecting cells with polyplexes formed with nucleic acids labeled with a fluorescent tag (such as rhodamine, fluorescein, and the alexa fluor dasses of dyes). " In some cases, the polymer or dendrimer can also be labeled with a fluorophore and cellular internalization of both the polymer and the nudeic acid is monitored. The assessment is then typically made by one or more of the following techniques measurement of the cell lysate fluorescence, fluorescence microscopy (wide-field or confocal miaoscopy)... 

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