1.
[Application of the Ca2+ indicator fluo-3 and fluo-4 in the process of H2O2 induced apoptosis of A549 cell].
Zhang, S, Li, C, Gao, J, Qiu, X, Cui, Z
Zhongguo fei ai za zhi = Chinese journal of lung cancer. 2014;(3):197-202
Abstract
BACKGROUND AND OBJECTIVE Lung cancer is a common malignant tumor all over the world, and Ca(2+) is a critical regulator for apoptosis of cancer cells. The monitoring of cytoplastic Ca(2+) level in real-time will contribute to further investigate the molecular mechanisms of apoptosis mediated by Ca2+ in lung cancer cells. To evaluate the Ca(2+) indicator fluo-3 and fluo-4 in the process of H2O2 induced the apoptosis of lung adenocarcinoma A549 cells. The cytoplastic Ca(2+) concentration ([Ca(2+)]i) was determined in real-time, and the correlations between [Ca(2+)]i and cell apoptosis were investigated. The differences in fluorescence intensity and measured value were compared between the two Ca(2+) indicators. METHODS Cells were loaded with the Ca(2+) indicator fluo-3 or fluo-4 for 1 h, and then stimulated with 50 mM H2O2. Laser scanning confocal microscope was applied to perform real-time monitoring on the variation of [Ca(2+)]i in selected cells. DAPI staining was used to observe apoptosis in H2O2 treated cells. RESULTS Our results showed that the fluorescence intensity of fluo-4 was stronger than that of fluo-3 in the same condition of dye concentration, loading time and image acquisition parameters before or after H2O2 stimulation. The cytoplastic [Ca(2+)]i was rapidly elevated in H2O2 stimulated A549 cells. The range of [Ca(2+)]i in selected cells loaded with fluo-3 was 112.2 nM-1,069.6 nM, and that in selected cells loaded with fluo-4 was 7.6 nM-505.4 nM. Moreover, the apoptotic rate was significantly increased in H2O2 treated cells, compared with untreated ones (P<0.01). CONCLUSION In summary, H2O2 promoted Ca(2+) release in A549 cells, and induced cell apoptosis. Ca(2+) indicator fluo-4 was probably more applicable to measure [Ca(2+)]i in cells with less content of Ca(2+).
2.
Biosensor based on the biocatalysis of microperoxidase-11 in nanocomposite material of multiwalled carbon nanotubes/room temperature ionic liquid for amperometric determination of hydrogen peroxide.
Wan, J, Bi, J, Du, P, Zhang, S
Analytical biochemistry. 2009;(2):256-61
Abstract
A novel nanocomposite material of multiwalled carbon nanotubes (MWCNTs) and room temperature ionic liquid (RTIL) N-butylpyridinium hexafluorophosphate (BPPF6) was explored and used to construct a novel microperoxidase-11 (MP-11) biosensor for the determination of hydrogen peroxide (H2O2). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to characterize the performance of the biosensor. Under the optimized experimental conditions, H2O2 could be detected in a linear calibration range of 0.5 to 7.0 x 10(-7)mol L(-1) with a correlation coefficient of 0.9949 (n=9) and a detection limit of 3.8 x 10(-9) mol L(-1) at 3 sigma. The modified electrodes displayed excellent electrochemical response, high sensitivity, long-term stability, and good bioactivity and selectivity.