Real-time monitoring of DNAzyme cleavage process using fluorescent assay

Detection of deoxyribozyme （DNAzyme） cleavage process usually needs complex and time-consuming radial labeling, gel electrophoresis and autoradiography. This paper reported an approach to detect DNAzyme cleavage process in real time using a fluorescence probe. The probe was employed as DNAzyme substrate to convert directly the cleavage information into fluorescence signal in real time. Compared with traditional approach, this non-isotope method not only brought a convenient means to monitor the DNAzyme cleavage reaction, but also offered abundant dynamic data for choosing potential gene therapeutic agents. It provides a new tool for DNAzyme research, as well as a new insight into research on human disease diagnosis. Based on this method, 8- 17deoxyribozyme （8-17DNAzyme） against hepatitis C virus RNA （HCV-RNA） was designed and the cleavage process was studied in real time. ？2009 Ke Min Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.

Study on the specific interaction between angiogenin and aptamer by atomic force microscopy (AFM)

The specific interaction between angiogenin and aptamer has been investigated by using AFM. The specificity of the interaction is revealed by comparing the binding probability of aptamer to other ele- ments in a series of control experiments. The results have shown that there is specific interaction force between angiogenin and aptamer. Moreover, the single molecular pull-off force between angiogenin and aptamer has also been determined using the Poisson statistical method to be 133.7±11.7 pN. These findings obtained are helpful to the better revelation of recognition mechanism between angiogenin and aptamer, which provided basis for further understanding the inhibition of the aptamer to angio- genic activity.

Bioeffects of different functionalized silica nano-particles on HaCaT cell line

The bioeffects of silica nanoparticles (SiNP), phosphorylate-terminated nanoparticles (PO4- NP) and amino-terminated nanoparticles (NH2NP) on HaCaT cell line have been studied in this paper. The effects of the three kinds of functionalized silica nanoparticles on adherence, proliferation and cycle of HaCaT cells have been investigated. And the cel- lular uptake of the three kinds of functionalized silica nanoparticles by HaCaT cells has also been exam- ined. Results indicated that the bioeffects of the three kinds of functionalized nanoparticles on HaCaT cells were concentration-dependent. And the three kinds of functionalized nanoparticles all exhibited well bio- compatibility if the concentration was below 0.2 μg/μL. While the cytotoxicities of the three kinds of function- alized nanoparticles on HaCaT cells would increase with the increasing of nanoparticles concentration, and the following order was observed: NH2NP > SiNP > PO4NP. In addition, the quantity and rapidity of cellular uptake of nanoparticles by HaCaT cells were diverse due to the different functional groups. Under the same conditions, NH2NP was most and fast internalized by HaCaT cells, followed by SiNP, and PO4NP was the least and slowest. These results provided theoretical foundation for the safe applica- tion and further modification of silica nanoparticles, which could broaden the application of silica nano- particles in biomedicine.

Research of the relationship of intracellular acidification and apoptosis in Hela cells based on pH nanosensors

In this paper,the relationship of intracellular acidification and apoptosis in Hela cells induced by vin-cristine sulfate has been studied by use of the ratiometric pH nanosensors that have been developed by our group,employing fluorescein isothiocyanate(FITC) doped as the pH-sensitive dye and Tris(2,2'-bipyidyl) dichlororuthenium(II) hexahydrate(RuBpy) doped as reference dye. The pH change of the Hela cells induced by vincristine sulfate has been monitored in vivo,in situ and real time by use of the ratiometric pH nanosensors. The experimental results show that the pH of the apoptotic Hela cells induced by vincristine sulfate has been acidified from 7.11 to 6.51,and the percentage of intra-cellular acidification is correlated with the induced concentration and incubation time of the vincristine sulfate. The further study of the percentage of intracellular acidification and the percentage of apop-tosis of Hela cells at the same time reveals that apoptosis of Hela cells induced by vincristine sulfate is preceded by intracellular acidification. These results would provide theoretical foundation for the therapy of cancer through interfering the pH of cells by use of vincristine sulfate or other anti-cancer drugs.

Study on the effect of electrostatic interaction on core-shell nanoparticles preparation with microemulsion technique

The routine method for preparation of silica core-shell nanoparticles (NPs) is to carry out nucleation and shell coating through the hydrolysis of silane in water in oil (W/O) microemulsion to form three-dimensional netted silica shell. We found that electrostatic interaction of the core ma- terials with shell materials would determine whether the stable core-shell silica NPs formed or not. The traditional important factors such as molecular weight of core materials or the thickness of the shell have no obvious relationship with it. And the stability of the core-shell silica NPs can be im- proved after changing the electric charge polarity by regu- lating the experiment condition of relevant materials if some core materials cannot be doped inside to form the stable core-shell silica NPs based on the traditional method, which provided experimental and theoretic foundation for prepara- tion and application of the core-shell silica NPs.