新型激光光敏根管消毒剂在牙本质中渗透性的研究

目的:观察新型激光光敏根管消毒剂、甲苯胺蓝和亚甲基蓝在牙本质中的渗透效果,评价三种光敏剂在牙本质中的渗透性。方法:收集新鲜拔除的离体单根管牙90颗,根管预备后随机分为三组。每组30颗。A组为新型激光光敏根管消毒剂组;B组为甲苯胺蓝组;C组为亚甲基蓝组。A、B、C三组实验根管内分别用浸有饱和的新型激光光敏根管消毒剂、甲苯胺蓝和亚甲基蓝的棉捻在根管内停留60秒。沿牙体长轴颊舌纵向劈开,倒置荧光显微镜下观察并拍照,用Photoshop8.01软件测量三种光敏剂渗透入牙本质的平均深度。结果:新型激光光敏根管消毒剂在牙本质内的渗透平均深度为553.25μm,甲苯胺蓝在牙本质内的渗透平均深度为350.75μm,亚甲基蓝在牙本质内的渗透平均深度为168.25μm。结论:新型激光光敏根管消毒剂在牙本质渗透性明显优于甲苯胺蓝和亚甲基蓝,具有良好的牙本质渗透性。     

A naphthalocyanine based near-infrared photosensitizer: Synthesis and in vitro photodynamic activities

A hydrophilic near-infrared (NIR) photosensitizer featuring a naphthalocyanine core and peripheral carboxylate acid groups was synthesized and characterized. Its photophysical and photochemical properties were studied and compared with phthalocyanine. Due to the extended π-conjugation, both the Q band and fluorescence emit of this naphthalocyanine bathochromically shift to NIR region. It also exhibits superior NIR photodynamic efficiency to phthalocyanine as evidenced by high efficiency in generating singlet oxygen (Φ_Δ = 0.66) and in vitro phototoxicity toward Hela human cervical cancer cells. Therefore, this novel naphthalocyanine could potentially be a NIR photosensitizer for photodynamic therapy.     

Synthesis of β-functionalized temoporfin derivatives for an application in photodynamic therapy

The synthesis of novel β-functionalized derivatives of the clinically used photosensitizer Temoporfin has been achieved by nucleophilic addition reactions to a corresponding diketo chlorin. The β-substituted dihydroxychlorin products exhibit a strong absorption in the red spectral region, a high singlet oxygen quantum yield, and were found to be highly effective in in vitro assays against HT-29 tumor cells.     

Theoretical studies on the absorption spectra of heteroleptic ruthenium polypyridyl dyes for nanocrystalline TiO2 solar cells: Revisited with transition-component analysis

The absorption spectra of Ru complexes of the type cis-[Ru(H₂dcbpy)(L)(NCS)₂], where H₂dcbpy = 4,4′-dicarboxy-2,2′-bipyridine and L = 1,10-phenanthroline (phen) (1) or dipyrido[3,2-a:2′,3′-c]phenazine (dppz) (2), in water were calculated by means of the time-dependent density functional theory, and the calculated spectra were subjected to transition-component analysis. Comparison of the calculated spectra of protonated, partially and fully deprotonated, and electrostatically non-compensated and fully compensated forms of 1 and 2 in water with the corresponding experimental absorption spectra in 0.01 M aqueous NaOH indicated that the predominant molecular structures are fully deprotonated anionic structures that are fully compensated with counter cations. The shapes of the calculated absorption spectra well reproduce the shapes of the corresponding experimental spectra in detail over the entire visible region. The calculated results indicated that the difference between the performances of 1- and 2-sensitized solar cells is due to differences in the contributions of the various electronic excitations that make up the absorption spectra. Transition-component analysis provided a detailed, quantitative explanation of the components of the absorption spectra of 1 and 2 and may be useful for the design and synthesis of improved sensitizers for high-performance dye-sensitized solar cells.     

Photodynamic effect of meso-(aryl)porphyrins and meso-(1-methyl-4-pyridinium)porphyrins on HaCaT keratinocytes

Sixteen porphyrins, including neutral, anionic and cationic meso-(aryl)porphyrins and meso-(1-methyl-4-pyridinium)porphyrins were herein evaluated in terms of their photosensitizing properties against HaCaT keratinocytes. After an initial screening, the cationic porphyrins were studied in more details, by both determining their log P_OW and performing PDT assays in lower porphyrin concentrations. Porphyrins presenting two or more adjacent positively charged groups, directly linked to the macrocycle meso positions, appeared to be the most effective photosensitizers. The present study also included the dicationic 5,10-diphenyl-15,20-di(1-methylpyridinium-4-yl)porphyrin (14b), which has previously shown promising results on a psoriasis-like in vivo model. Overall results indicated that the beneficial effect related to porphyrins on psoriasis can be related to the decreasing of keratinocyte viability. Furthermore, some of the cationic porphyrins studied appeared as candidates to be utilized as photosensitizers for psoriasis treatment.     

Water-soluble cationic gallium(III) and indium(III) phthalocyanines for photodynamic therapy

The new tetra-non-peripheral and peripheral 2-mercaptopyridine substituted gallium(III) and indium(III) phthalocyanine complexes (np-GaPc, p-GaPc, np-InPc and p-InPc) and their quaternized derivatives (Qnp-GaPc, Qp-GaPc, Qnp-InPc and Qp-InPc) have been synthesized and characterized. The quaternized complexes show excellent solubility in water, which makes them potential photosensitizer for use in photodynamic therapy (PDT) of cancer. Photophysical and photochemical properties of these phthalocyanines were investigated. General trends are described for quantum yields of photodegradation, fluorescence and fluorescence lifetimes as well as singlet oxygen quantum yields of these compounds. In this study, the effects of the position of the substituents, the nature of the metal ion and quaternization of the substituents on the photophysical and photochemical parameters of the gallium(III) and indium(III) phthalocyanines are also reported. This study also presented the ionic gallium(III) and indium(III) phthalocyanines strongly bind to bovine serum albumin (BSA).     

Cytochrome c decelerates channel kinetics of negatively charged gramicidin due to electrostatic interaction

The effect of cytochrome c on the kinetic properties of ion channels formed by O-pyromellitylgramicidin (OPg), the negatively charged analogue of gramicidin A (gA), in bilayer lipid membranes was studied by the method of sensitized photoinactivation. The addition of cytochrome c to both sides of the membrane caused substantial deceleration of the photoinactivation kinetics of OPg channels which expose three negative charges to the aqueous phase at both sides of the membrane. By contrast, the gA photoinactivation kinetics was unaltered by the addition of cytochrome c. Based on the sensitivity of the observed effect to the ionic strength of the bathing solution, the cytochrome c-induced deceleration of the OPg photoinactivation kinetics reflecting the increase in the OPg channel lifetime was ascribed to electrostatic interaction of positive charges of cytochrome c with negative charges of OPg that resulted in channel clustering. Formation of clusters of OPg channels was previously inferred to explain the polylysine effect on the OPg channel kinetics. The decelerating effect of cytochrome c on OPg channels was observed only at a high number of OPg channels in the membrane, thus suggesting that the interaction between cytochrome c and the charged transmembrane protein requires sufficiently high negative charge density on the surface of the membrane.     

竹红菌甲素光敏作用所致的HeLa细胞DNA单链断裂重接的研究

本文采用羟基磷灰石离心法对竹红菌甲素光敏作用所致的HeLa细胞DNA的单链断裂进行荧光定量测定。以单链DNA的含量变化衡量DNA链断裂程度及其修复活性,并与γ射线的作用进行了比较。细胞经γ射线和甲素的光敏作用后,DNA产生单链断裂,当细胞存活率为0.1时,前者是6.0×10~(-10)断裂/道尔顿,后者是2.3×10~(-10)断裂/道尔顿,两者之比为2.8。细胞本身具有修复能力,当最初的单链断裂频率相等时,γ射线处理的细胞其DNA单链断裂重接能力高于光敏作用的细胞。后者的修复能力能被羟基脲、放线菌素D及丁酸钠等所抑制。细胞修复能力的差别指出两种作用产生的单链断裂的化学性质有重要差别。     

A Ru(II) polypyridyl complex bearing aldehyde functions as a versatile synthetic precursor for long-wavelength absorbing photodynamic therapy photosensitizers

The use of Photodynamic Therapy (PDT) for the treatment of several kinds of cancer as well as bacterial, fungal or viral infections has received increasing attention during the last decade. However, the currently clinically approved photosensitizers (PSs) have several drawbacks, including photobleaching, slow clearance from the organism and poor water solubility. To overcome these shortcomings, many efforts have been made in the development of new types of PSs, such as Ru(II) polypyridyl complexes. Nevertheless, most studied Ru(II) polypyridyl complexes have a low absorbance in the spectral therapeutic window. In this work, we show that, by carefully selecting substituents on the polypyridyl complex, it is possible to prepare a complex absorbing at a much higher wavelength. Specifically, we report on the synthesis as well as in-depth experimental and theoretical characterisation of a Ru(II) polypyridyl complex (complex 3) combining a shift in absorbance towards the spectral therapeutic window with a high ¹O₂ production. To overcome the absence or poor selectivity of most approved PSs into targeted cells/bacteria, they can be linked to targeting moieties. In this line, compound 3 was designed with reactive aldehyde groups, which can be used as a highly versatile synthetic precursor for further conjugation. As a proof of concept, 3 was reacted with benzylamine and the stability of the resulting conjugate 4 was investigated in DMSO, PBS and cell media. 4 showed an impressive ability to act as a PDT PS with no measurable dark cytotoxicity and photocytotoxicity in the low micromolar range against cancerous HeLa cells from 450 nm up to 540 nm.     

Production of cis-syn thymine-thymine cyclobutane dimer oligonucleotide in the presence of acetone photosensitizer

cis-syn Cyclobutane pyrimidine dimer (CPD) oligonucleotide was produced by UV irradiation in the presence of acetone photosensitizer. Acetone could enhance the productivity but evidently induced the photocleavage of oligonucleotide under a long time irradiation. A statistical approach of orthogonal design was applied to optimize the preparation condition for the production of the modified oligonucleotide. Optimal conditions for maximal cis-syn CPD oligonucleotide productivity were determined based on three factors: acetone concentration, initial oligonucleotide concentration, and irradiation time at several different levels. The optimal modified oligonucleotide that this optimization could produce was 32.7%. Through analysis of 20% polyacrylamide gel electrophoresis, it was found that modified oligonucleotide migrated slightly more slowly than the parent oligonucleotide. The photoreactivation of cis-syn thymine-thymine dimer oligonucleotide displayed the selectivity of the substrate specificity of DNA photolyase with high-performance liquid chromatography (HPLC) analysis.