The effect of temperature and solvent on the morphology of microcapsules doped with a europium beta-diketonate complex.

Fluorescent microcapsules doped with a europium beta-diketonate complex were fabricated for the first time by stepwise adsorption of polyelectrolytes and europium complex using the layer-by-layer technique. The influence of temperature and solvent treatment on the morphology of the microcapsules was investigated. Intense red light emission of the microcapsules could be clearly observed by fluorescence microscopy before and after treatment. Remarkable shrinking, decrease of the inner volume and increase of the wall thickness were observed using atomic force microscopy (AFM) and transmission electron microscopy (TEM) after thermal treatment. The shrinkage induced by annealing could be recovered by dissolving in ethanol solution, which was confirmed by AFM and TEM. Morphology variation of the luminescent microcapsules induced by annealing or solvent are both attributed to the molecular rearrangement of polyelectrolytes. While the shrinkage by annealing is an entropy driven process with formation of more coiled conformations of polyelectrolytes the morphology variation by ethanol might be due to the effective screening of electrostatic interaction within the polyelectrolyte multilayers and the changed interaction between hydrophobic fragments present in the polyelectrolytes.

Reversion of P-glycoprotein-mediated multidrug resistance in human leukemic cell line by carnosic acid.

One of the common hindrances to successful chemotherapy is the development of multidrug resistance (MDR) by tumor cells to multiple chemotherapeutic agents. In this regard, P-glycoprotein (P-gp) acts as an energized drug pump that reduces the intracellular concentration of drugs, even of structurally unrelated ones. The modulators of P-gp function can restore the sensitivity of MDR cells to anticancer drugs. Therefore, to develop effective drug-resistance-reversing agents, we evaluated the P-gp modulating potential of carnosic acid (CA) in multidrug-resistant K562/AO2 cells in the present study. The reversing effect of CA was evaluated by determining the inhibition rates of cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assays. The intracellular adriamycin fluorescence intensity and the expression of P-gp were measured by flow cytometry (FCM). Meanwhile, the subcellular distribution of adriamycin was detected via Laser Scanning Confocal Microscopy (LSCM). The mRNA expression of mdrlwas then detected via semiquantitative reverse transcription polymerase chain reaction (RT-PCR). The findings showed that CA decreased apparently the Inhibition Concentration 50% (IC50) of adriamycin by increasing its intracellular concentration and thus enhancing the sensitivity of K562/AO2 cells. Adriamycin was distributed evenly in the cytoplasm when the cells were treated with CA. The expression of mdrl was decreased. Overall, the results indicated that CA can serve as a novel, non-toxic modulator of MDR, and it can reverse the MDR of K562/AO2 cells in vitro by increasing intracellular adriamycin concentration, down-regulating the expression of mdrl, and inhibiting the function of P-gp.

[Detection of IFN-gamma level in single CD8+ T cell].

AIM: To establish a new method capillary electrophoretic immunoassay laser-induced fluorescence (CEIA-LIF), to detect IFN-gamma level in single CD8(+) T cell. METHODS: CD8(+) T cells were isolated from peripheral blood of two patients with severe aplastic anemia(SAA) and one normal person by Ficoll-Hypaque gradient centrifugation and then were purified by immunomagnetic microbead separation. Then purified CD8(+) T cells were incubated with digitonin for 15 min followed by FITC-anti-IFN-gamma mAb for 20 min. The single cell was detected continuously by CEIA-LIF. The feasibility of the method was confirmed by inverted microscopy and laser scanning confocal fluorescence microscopy. RESULTS: The IFN-gamma content in purified CD8(+) T cells was detected under the condition of cell-membrane integrity. The IFN-gamma level in single CD8(+) T cell from 2 SAA patients was (151.53+/-28.92)zmol and (223.72+/-45.23)zmol, respectively, and much higher that from normal control (47.47+/-17.97)zmol ( P=0.001). CONCLUSION: It is feasible to quantitate IFN-gamma in single CD8(+) T cell by CEIA-LIF. CEIA-LIF might be useful in the clinical detection of intracellular cytokines.