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Sun Z Zheng X Hoshi T Kashiwagi Y Anzai J Li G 《Analytical and bioanalytical chemistry》2004,380(3):545-550
Ligustrazine is one of the active ingredients contained in Ligusticum chuanxiong Hort. (Umbelliferae), which is widely used in traditional Chinese medicine for the treatment of cardiovascular problems. In this work, the electrochemistry of Ligustrazine hydrochloride (LZC) and its determination are investigated. The detection limit is estimated to be 8.0×10–8 M, with three linear ranges from 1.0×10–6 to 1.0×10–4 M, 1.0×10–4 to 5.0×10–4 M, and 6.5×10–4 to 1.6×10–3 M. The method has been proved to be highly sensitive, selective, and stable, and has been successfully applied to determining LZC in LZC injections. 相似文献
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Liu X Huang Y Zhang W Fan G Fan C Li G 《Langmuir : the ACS journal of surfaces and colloids》2005,21(1):375-378
In this study, we investigated redox thermodynamics of myoglobin as well as the ionic (phosphate ions) and ligation (imidazole) effects via a dynamic electrochemical approach. We employed a previously established system that features nonmediated, direct electrochemistry of myoglobin and myoglobin in an immobilized state (i.e., diffusionless electrochemistry). Thermodynamics parameters were obtained by measuring redox potential (E degrees ') of myoglobin at varied temperature (T), in the presence and in the absence of specific ions or axial ligands. As a step further, we evaluated contributions from allosteric effect and axial iron ligation by partitioning E degrees ' changes into entropic and enthalpic terms. Compensation phenomena between the entropic and enthalpic changes were observed in all these cases. On the basis of these studies, we also correlated these phenomena to possible structural variations. 相似文献
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Sensitive detection of human breast cancer cells based on aptamer–cell–aptamer sandwich architecture
Breast cancer is one of the most critical threats to the health of women, and the development of new methods for early diagnosis is urgently required, so this paper reports a method to detect Michigan cancer foundation-7 (MCF-7) human breast cancer cells with considerable sensitivity and selectivity by using electrochemical technique. In this method, a mucin 1 (MUC1)-binding aptamer is adopted to recognize MCF-7 human breast cancer cells, while enzyme labeling is employed to produce amplified catalytic signals. The molecular recognition and the signal amplification are elaborately integrated by fabricating an aptamer–cell–aptamer sandwich architecture on an electrode surface, thus a biosensor for the detection of MCF-7 is fabricated based on the architecture. The detection range can be from 100 to 1 × 107 cells, and the detection limit can be as low as 100 cells. The method is also cost-effective and conveniently operated, implying potential help for the development of early diagnosis of breast cancer. 相似文献
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Baicalin is an anti-HIV drug purified from the traditional Chinese medicinal plant Scutellaria Baicalensis Georgi. Baicalin has proven to be electroactive at pyrolytic graphite (PG) electrodes. We thus studied its interaction with DNA via the electrochemical approach. We observed that the peak currents corresponding to the baicalin reduction–oxidation (redox) reaction significantly decrease upon the addition of DNA. With complementary ultraviolet/visible (UV/Vis) spectroscopic evidence, we suggest that baicalin binds to DNA through intercalation. This feature has enabled baicalin to discriminate between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA).Electronic Supplementary Material Supplementary material is available in the online version of this article at . A link in the frame on the left on that page takes you directly to the supplementary material. 相似文献
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In this article, electrochemistry of mitochondria is achieved. Cyclic voltammograms of freshly prepared mitochondria were obtained by immobilizing mitochondria together with glutaraldehyde and bovine serum albumin on the surface of a pyrolytic graphite electrode. Two pairs of redox peaks could be observed which were ascribed to the electron transfer reactions of cytochrome c and FAD/FADH2. Study of submitochondrial particles was also conducted, which could confirm the results of the study of the entire mitochondria. The redox wave of NADH could be obtained due to the destruction of the membrane of mitochondria. We have also checked the function of succinate in mitochondria by employing the electrochemical method. This work is not only the first to be able to obtain the direct electrochemistry of mitochondria, but is also beneficial to the further understanding of the structure and function of mitochondria in vitro. 相似文献
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Lei Liu Peng Miao Yuanyuan Xu Zhipeng Tian Zhigang Zou Genxi Li 《Journal of photochemistry and photobiology. B, Biology》2010,98(3):207-210
The increasing incidence of cancer all over the world demands new, effective and secure materials for treatment. In this paper, we propose Pt/TiO2 nanocomposite for cancer-cell treatment because noble metal nanoparticles are supposed to enhance the photocatalytic activity of TiO2 nanoparticles. To evaluate the cancer-cell killing effect of our Pt/TiO2 nanocomposite, TiO2 and Au/TiO2 nanoparticles are also introduced. The prepared Pt/TiO2 nanocomposite are characterized with transmission electron microscopy (TEM) and UV–vis adsorption spectra. Results of cell treatment indicate that Pt/TiO2 nanocomposite, as extremely stable metal–semiconductor nanomaterial, can exhibit a very high photodynamic efficiency under a mild ultraviolet radiation. And our Pt/TiO2 nanocomposite shows to be more effective in cancer-cell treatment than TiO2 and Au/TiO2 nanoparticles. As a result, Pt/TiO2 nanocomposite may be supposed to have a promising application for cancer-cell treatment. 相似文献
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Various strategies have been proposed for the detection of disease protein biomarkers; however, most methods are too expensive, cumbersome or limited in sensitivity for clinical use. Here, we report that a fabricated complex can be used as a powerful tool to detect trace proteins in complex samples. In this strategy, a DNA–protein complex that comprises of one target molecule and two or more deoxyribozyme-containing probes can exhibit autonomous cleavage behavior on the surface of the substrate DNA modified electrode. In the meantime, the complex can remove the cleaved DNA fragment from the electrode surface by taking advantage of the proximity effect. The proposed approach allows one-step and highly sensitive detection of a variety of targets based on the changes of the direct electrochemical readout. Moreover, this method may also have considerable advantages over the commonly reported DNA amplification-assisted immunoassays, particularly in terms of assay simplicity and cost, which may hold great potential for application in resource-constrained regions. 相似文献
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