部分还原氧化石墨烯的制备、 表征及对人宫颈癌HeLa细胞的体外杀伤作用

以氧化石墨烯(GO)为原料, 利用温和方法制备了3种不同还原程度的部分还原氧化石墨烯pRGO₁, pRGO₂和pRGO₃(pRGO_1—3)； 利用傅里叶变换红外光谱(FTIR)、 拉曼光谱(Raman)、 X 射线光电子能谱(XPS)、 紫外-可见光谱(UV-Vis)、 透射电子显微镜(TEM)和 EDS能谱对其结构和形貌进行了表征. 细胞实验结果表明, 无激光照射下pRGO_1—3本身的细胞毒性较低; 近红外(NIR)激光照射下pRGO_1—3通过光热和光毒性双重作用杀伤肿瘤细胞. 实验结果显示了pRGO 在肿瘤光热疗法和光动力疗法领域的应用潜力.     

Phototoxicity testing by online irradiation and HPLC

A high-performance liquid chromatography (HPLC) system was developed for the determination of drug photostability and phototoxicity based on an automated column-switching system with aqueous online UV-A irradiation and hyphenated organic separation of the drug and its photoproducts. The photoreactor is built with an poly(ethylene-co-tetrafluoroethylene) (ETFE) reaction coil knitted around a UV-A light source. The chromatographic separation was performed with two special C₁₈ columns, which are also suitable for using with pure water as eluent. Degradation of chlorpromazine (CPZ) by ultraviolet light was investigated at pH 7 and pH 3. Furthermore chlorpromazine was irradiated in the presence of guanosine-5-monophosphate (GMP) in pH 7 buffered solution, leading to a new photoproduct. In the pH 3 irradiation studies of CPZ and GMP, no reaction was detected between the molecules.     

Increased cytotoxicity and phototoxicity in the methylene blue series via chromophore methylation

The cytotoxic and photodynamic activities of the commercially-available biological stains methylene blue (MB), 1,9-dimethyl MB (Taylor's Blue) and a newly synthesised compound, 1-methyl MB, were measured against the murine mammary tumour cell line, EMT-6 Both 1-methyl MB and 1,9-dimethyl MB exhibited increased dark toxicity with concomitant higher phototoxicity compared to MB at a light dose of 7.2 J cm⁻². While increasing the light dose as a function of the fluence rate increased the photocytotoxicity of MB, this had little effect on the methylated derivatives. In vitro chemical testing proved that successive methylation rendered the phenothiazinium chromophore both more resistant to reduction to its inactive leuco form, and also led to increased levels of singlet-oxygen production, thus providing a possible explanation for the increased toxicities of the methylated derivatives. Comparisons are made with the benzo[a]phenothiazinium photosensitizer, EtNBS.     

Phototoxicity of some novel porphyrin hybrids against the human leukemic cell line TF-1

Photodynamic induced cytotoxicity by porphyrin-DNA cross linker/intercalator hybrid diads and triads has been studied on the human leukemic cell line TF-1. Cells were incubated for 1 to 4 h with these new photosensitizers and irradiated with white light. Cell survival was assessed by the propidium iodide staining, using flow cytometry analysis. A comparison of the dark and light cell survival factor values suggests that irradiation has a significant effect on the toxicity at low concentrations for the porphyrin-chlorambucil diad and to a lesser extent at high concentrations for the porphyrin-acridone diad, the porphyrin-acridine diad and the porphyrin-cholic acid-chlorambucil triad. While the intrinsic antileukemic (via DNA cross-linking) activity of the chlorambucil moiety and the structural details may be responsible for the photoenhancement of the toxicity, the presence of acridine or acridone which are avid intercalators of DNA, is responsible for a similar effect seen for diads.     

Microwave-mediated ‘click-chemistry’ synthesis of glycoporphyrin derivatives and in vitro photocytotoxicity for application in photodynamic therapy

In this paper, we report the synthesis of a series of porphyrins, designed as photodynamic therapy (PDT) agents, substituted by three glycosyl units linked by a triazole group to chromophore in the aim to target tumor cells overexpressing lectin-type membrane receptors, by ‘click-chemistry’ under microwave heating.     

光诱导富精氨酸多肽修饰的Fe2O3@Au纳米粒子的细胞毒性

以人宫颈癌细胞(HeLa细胞)为对象考察了富精氨酸多肽RRRRRRRR(R8)修饰的金-三氧化二铁壳核纳米粒子(R8-Fe2O3@Au NPs)对活细胞的光毒性. 研究结果表明, 内化后的R8-Fe2O3@Au NPs对活HeLa细胞无显著的细胞毒性, 但在激光照射下则可导致HeLa细胞的凋亡, 表现出很强的细胞光毒性. R8-Fe2O3@Au NPs的细胞光毒性与照射激光波长有关, 并随细胞吞噬的R8-Fe2O3@Au NPs的量、 光照强度和时间的增加而增强.     

The interference of HEPES buffer during amperometric detection of ATP in clinical applications

HEPES-based biological buffer is subject to photooxidation upon exposure to fluorescent illumination. Thereby hydrogen peroxide is generated, which interferes with amperometric oxidoreductase-based biosensors for glucose or adenosine triphosphate (ATP). These biosensors operate at an oxidation potential above 500 mV vs. the standard calomel electrode (SCE) and involve hydrogen peroxide as the electroactive molecule detected at the electrode surface. False-positive detection of ATP was observed in HEPES buffer utilizing an amperometric microbiosensor based on the co-immobilization of glucose oxidase and hexokinase for detection of ATP in biological specimens. Electrochemical, mass spectrometric, ³¹P NMR, and ¹H NMR studies indicate that complexation of ATP and HEPES induced by the presence of Ca²⁺ in HEPES buffer decreases the photooxidation of HEPES. Consequently, the hydrogen peroxide background concentration is reduced, thereby leading to erroneous ATP detection at the dual-enzyme microbiosensor, which determines an increase in ATP via a reduced hydrogen peroxide signal.     

Photocytotoxicity of platinum(IV)-chloride surface modified TiO2 irradiated with visible light against murine macrophages

Phototoxicity of titanium dioxide modified with platinum(IV)-chloride complexes, [TiO2/PtCl4], irradiated with visible light was tested on murine macrophage cell line (RAW 264.7) in vitro. Presence of antioxidants such as alpha-tocopherol or beta-carotene during photodynamic treatment significantly increased cells viability. Our results indicate that observed cell death induced by [TiO2/PtCl4] was due to photogeneration of reactive species.