运用增强型荧光显微镜进行merocyanine540与骨髓白血病M1细胞结合的研究

通过增强型的荧光数字成像显微镜测量ｍｅｒｏｃｙａｎｉｎｅ ５４０（ＭＣ５４０）与鼠骨髓白血病（Ｍ１）细胞及正常红细胞的结合，研究发现，在相同面积的细胞膜上，与Ｍ１细胞结合的ＭＣ５４０平均比与红细胞珠ＭＣ５４０多３倍以上，这一结果与以前的研究结果相一致。但本次研究首次揭示了ＭＣ５４０与Ｍ１细胞间的结合是多样化的，约１５％的致敏Ｍ１细胞是ＭＣ５４０阴性的，运用白血病抑制因子作为分化诱导剂。

Merocyanine 540对亚线粒体能量化过程膜电位变化的荧光响应

研究了Ｍｅｒｏｃｙａｎｉｎｅ５４０对亚线粒体能量化过程膜电位变化的荧光响应的“ｏｎ－ｏｆｆ”机制，揭示了其快、慢双相反应的特征，探讨了该荧光响应的影响因素，如膜结合二聚体对膜上单体荧光的猝灭，探针与膜的相对浓度以及激发波长的影响。

Synthesis and Properties of Crown Ether Benzotellurazole Heterocyclic Styryl Cyanines and Merocyanines

Two Crown ether benzotellurastyryl cyanines and three crown ether benzotelluramerocyanines are synthesized via the key intermediate 3 methyl 5,6(15 crown 5) 2(β acetanilide)vinyl benzotellurazolium iodide.The reactive conditions are discussed.The influence of alkali( earth)metal ions on the visible absorption spectra of these two types of crown ether cyanines are also studied.

Excimer and Micellization of a Merocyanine

Excimers are molecular associates which exist only in excited electronic states so that they are detectable only in eemission spectra,especially in fluorescence spectra,This fluorescent phenomenon has also been observed for some stable aggregates in which molecules are arranged in a special form.Excimer fluorescence component should be affected by associate state in stable or metastable aggregates.It leads us to studying micellization by means of fluorescence spectroscopy.

A ratiometric merocyanine-based fluorescent probe for detecting hydrazine in living cells and zebra fish

We developed a merocyanine-based fluorescent probe,NEPB,for tracing hydrazine(N2 H4)in a ratiometric manner with large Stokes shifts and long emission wavelength.The fluorescence color of probe NEPB changed from green to yellow upon addition of hydrazine.Probe NEPB displayed high selectivity and sensitivity to hydrazine in solution,and could ratiometrically monitor N2 H4 in living cells and zebrafish with low cytotoxicity.

Events associated with apoptotic effect of p-Coumaric acid in HCT-15 colon cancer cells

AIM:To investigate the events associated with the apoptotic effect of p-Coumaric acid,one of the phenolic components of honey,in human colorectal carcinoma(HCT-15)cells.METHODS:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertazolium-bromide assay was performed to determine the antiproliferative effect of p-Coumaric acid against colon cancer cells.Colony forming assay was conducted to quantify the colony inhibition in HCT15 and HT 29 colon cancer cells after p-Coumaric acid treatment.Propidium Iodide staining of the HCT15 cells using flow cytometry was done to study the changes in the cell cycle of treated cells.Identification of apoptosis was done using scanning electron microscope and photomicrograph evaluation of HCT 15cells after exposing to p-Coumaric acid.Levels of reactive oxygen species(ROS)of HCT 15 cells exposed to p-Coumaric acid was evaluated using 2’,7’-dichlorfluorescein-diacetate.Mitochondrial membrane potential of HCT-15 was assessed using rhodamine-123 with the help of flow cytometry.Lipid layer breaks associated with p-Coumaric acid treatment was quantified using the dye merocyanine 540.Apoptosis was confirmed and quantified using flow cytometric analysis of HCT15 cells subjected to p-Coumaric acid treatment after staining with YO-PRO-1.RESULTS:Antiproliferative test showed p-Coumaric acid has an inhibitory effect on HCT 15 and HT 29 cells with an IC50(concentration for 50%inhibition)value of 1400 and 1600μmol/L respectively.Colony forming assay revealed the time-dependent inhibition of HCT 15 and HT 29 cells subjected to p-Coumaric acid treatment.Propidium iodide staining of treated HCT 15cells showed increasing accumulation of apoptotic cells(37.45±1.98 vs 1.07±1.01)at sub-G1phase of the cell cycle after p-Coumaric acid treatment.HCT-15 cells observed with photomicrograph and scanning electron microscope showed the signs of apoptosis like blebbing and shrinkage after p-Coumaric acid exposure.Evaluation of the lipid layer showed increasing lipid layer breaks was associated with the growth inhibition of p-Coumaric acid.A fall in mitochondrial membrane potential and increasing ROS generation was observed in the p-Coumaric acid treated cells.Further apoptosis evaluated by YO-PRO-1 staining also showed the timedependent increase of apoptotic cells after treatment.CONCLUSION:These results depicted that p-Coumaric acid inhibited the growth of colon cancer cells by inducing apoptosis through ROS-mitochondrial pathway.

Multi-dimensional, light-controlled switch of fluorescence resonance energy transfer based on orderly assembly of 0D dye@micro-micelles and 2D ultrathin-layered nanosheets

Fluorescence resonance energy transfer （FRET） systems have broad applications in visual detection, intelligent materials, and biological imaging, all of which favor the transmission of light through multiple dimensions and in diverse directions. Herein, we have demonstrated multi-dimensional （0D and 2D） FRET within a multi-layer ultrathin film （UTF） by employing a layer-by-layer （LBL） assembly technique. The anionic block copolymer micelle poly（tert-butyl acrylate- co-ethyl acrylate-co-methacrylic acid） （PTBEM） is chosen as a molecular carrier for the incorporation of bis（8-hydroxyquinolate） zinc （Znq2） and open-ring merocyanine （MC） （denoted as （Znq2/MC）@PTBEM）. Alternatively, electrostatic assembly is performed with cationic layered double hydroxide （LDH） nanosheets （denoted as [（Znq2/MC）@PTBEM/LDH]n）. This [（Znq2/MC）@PTBEM/ LDH]n system offers a multi-dimensional propagation medium and ensures that the FRET donor and acceptor are located within their F6rster radii in each direction. The system demonstrates a FRET process that can be switched via alternating ultraviolet/visible （UV/vis） irradiation, with tunable blue-green/red fluorescence, resulting in a FRET efficiency as high as 81.7%. It is expected that this assembly method, which uses 0D micelles on a 2D layered material, can be extended to other systems for further development of multi-dimensional FRET.

Developing a molecular platform for potential carbon dioxide fixing

This paper presents an attempt to develop a new system for fixing carbon dioxide from the atmosphere.The proposed molecular system has been designed to have the capacity to spontaneously bind CO_(2)from the atmosphere with high affinity.The molecular system is furthermore designed to have the ability to liberate CO_(2)at a later stage in the process,i.e.,in a separate compartment.The liberated CO_(2)presents a carbon neutral way of obtaining pure CO_(2).The proposed molecular system is based on a small stable organic molecule that potentially have two forms:one without bound CO_(2)and one with bound CO_(2).One class of molecules that undergo a reaction compatible with our purposal is the merocyanine dyes that exhibit photochromic properties.Based on this structural class of molecules,a system for the potential fixing of CO_(2)has been developed.