单重态氧化学VIII.类卟啉稀土配合物光敏化产生单重态氧的ESR研究

用电子自旋共振(ESR)方法研究类卟啉稀土配合物([CO2H-APPC)Gd]Cl2)光敏产生单重态氧的II型机制。利用2,2, 6, 6-四甲基哌啶(TEMP)对单重态氧的捕捉, 测定所生成的氮氧自由基的ESR信号, 经加NaN3和CD3OD的实验, 证实了([CO2H-APPC)Gd]Cl2)光敏作用可有效地产生单重态氧, 并观察到在实验所用的浓度范围内, 随着光敏剂浓度加大, 生成的单重态氧也增加, 同时比较了几种不同稀土离子配合物产生单重态氧的差别。结合氧的消耗和氮氧自由基的ESR线宽变化对氧浓度的依赖性, 证明了类卟啉稀土配合物光敏化生成单态氧的II型反应在光动力光疗中起关键作用。     

一种可生成单重态氧的新型光敏剂──类卟啉大环金属配合物

含丙基取代的不对称联三吡咯大环化合物及其金属配合物的合成已在前文报道,这些配合物在740～780nm光谱区域内具有强的光吸收。其单重态氧的生成可由它的光敏氧化蒈烯得到约68%高产率的“ene”型产物所证实,同时测定了它们的单重态氧量子产率(φ¹O₂)及荧光量子产率(φ₁)。     

2-(2-氨基苯基)苯并噻唑与四苯基卟啉及四苯基锌卟啉的荧光共振能量转移

采用紫外光谱和荧光光谱法研究了四氢呋喃溶液中2-(2-氨基苯基)苯并噻唑(APBT)与四苯基卟啉(TPP)、四苯基锌卟啉(ZnTPP)之间的相互作用.结果表明,APBT可作为能量供体分子分别与能量受体分子TPP或ZnTPP构成荧光共振能量转移(FRET)体系,APBT的作用将使TPP和ZnTPP的荧光增强.在此FRET...     

钴(Ⅱ,Ⅲ)与meso-四(4-苯基磺基)卟啉(TPPS)络合物的伏安行为研究

木文报道了钴(Ⅱ,Ⅲ)与meso-四(4-苯基磺基)卟啉(TPPS)络合物的形成条件和电还原行为.结果表明在醋酸缓冲溶液(pH3.5)中,Co²⁺-TPPS还原同时产生催化氢波.在氨性缓冲溶液(pH9.0)中,Co²⁺-TPPS产生络合吸附波,讨论了其伏安行为,认为络合物中Co²⁺和TPPS是一步同时还原.溶解氧可以把Co²⁺-TPPS氧化为Co³⁺-TPPS,对比Mn³⁺-TPPS讨论了络合物的形成和溶解氧的作用,认为氧对卟啉络合物中心离子价态变化和电子转移起着重要作用.     

葫芦[7]脲与紫精和香豆素修饰树枝形分子的分步结合及对体系发光性质的调控

合成了外围修饰香豆素PAMAM树枝形分子Gm-2(m+1)C, 外围和核心分别共价连接香豆素和紫精的树枝形分子EV-Gm-2(m+1)C (m=0, 1), 以及香豆素和紫精的模型化合物C-Model和EV, 化合物均通过了¹H NMR, IR和MALDI-TOF MS的鉴定. ¹H NMR和光物理研究结果表明, 在pH=4.5的醋酸-醋酸钠缓冲溶液中, CB[7]与紫精和树枝形分子外围的香豆素基团均可形成1:1的包结复合物, 结合常数分别为3.3×10⁶ mol^-1·L和1.4～1.6×10⁵ mol^-1·L. 香豆素基团中7位二乙氨基及取代侧部分香豆素环包裹在CB[7]刚性的疏水空腔内, 包结复合物的形成限制了香豆素7位N,N'-二乙氨基的扭转, 抑制了香豆素基团从发光的分子内电荷转移(ICT)态向不发光的扭曲的分子内电荷转移(TICT)态的转变, 而且CB[7]内腔的疏水环境有利于香豆素ICT态辐射跃迁, 使体系发光大大增强. EV-Gm-2(m+1)C与CB[7]的主客体作用为分步结合机制, 加入的CB[7]先与紫精基团作用形成包结复合物, 待体系中紫精基团与CB[7]结合后, 体系中香豆素基团再与CB[7]作用形成包结复合物. 无论是Gm-2(m+1)C还是EV-Gm-2(m+1)C体系, 均可以通过加入CB[7]的量调节体系中香豆素基团与CB[7]形成包结复合物的多少, 从而实现对Gm-2(m+1)C和EV-Gm-2(m+1)C体系发光的调控. 本工作为可调控发光树枝形聚合物的发展提供了一种新的策略.     

正离子Gemini表面活性剂/负离子聚电解质相互作用的研究

摘要 采用荧光探针法和电导法研究了正离子偶联表面活性剂(C₁₂H₂₅(CH₃)₂N-(CH₂)₆-N(CH₃)₂C₁₂H₂₅•2Br) (12-6-12• 2Br^－)和带相反电荷聚电解质聚丙烯酸钠(NaPA)的相互作用, 结果表明: 由于静电相互作用, 12-6-12•2Br^－和NaPA之间可以形成类胶束或复合物. 对比十二烷基三甲基溴化铵(DTMAB)与NaPA复配体系的荧光光谱, 发现偶联表面活性剂与NaPA的相互作用强于传统表面活性剂. 此外, 还研究了盐和醇对偶联表面活性剂/聚丙烯酸钠的复配体系微极性的影响, 发现盐和醇对表面活性剂在聚电解质上形成类胶束和复合物的溶解都有一定的促进作用.     

利用ESR技术研究二氢吡喃光敏氧化反应机理

利用自旋捕获 电子顺磁共振技术研究证实了二氢吡喃 (DHP)在乙腈、四氯化碳和正己烷溶剂中 9,10 二氰基蒽 (DCA)或四苯基卟啉 (TPP)敏化的光氧化反应机理 .实验证实 ,在四氯化碳中 ,DCA敏化光氧化反应中的单重态氧 ( 1O2 )反应来自DCA的激发三重态 ,而在乙腈中 ,所发生的单重态氧反应来自超氧负离子基 (O-·2 )与反应底物正离子自由基 (D ·)的电荷重组 (CR) ;TPP敏化光氧化反应 ,在乙腈中有O-·2 的反应 ,它来自单重态氧与底物 (D)的电子转移电荷分离 (CS) ;在反应过程中存在着CR与CS动态平衡     

多金属氧簇-聚合物复合物磁共振成像及光热-化学治疗性质

通过将阳离子型聚合物聚二烯丙基二甲基氯化铵、嵌段共聚物聚(甲基丙烯酸(聚乙二醇单甲醚)酯-b-甲基丙烯酸)和含Gd的多金属氧簇K7(Gd(H2O)3P2W17O61)以及部分还原的K₆(α-P₂W₁₈O₆₂)共混,构建了纳米尺寸的聚合物包埋多金属氧簇的多组分复合物PDDA-PPBM-rPOMs.实验表明,所制备的复合物在水溶液、磷酸盐缓冲液和细胞培养基溶液中都具有较好的结构稳定性,形成均一分散的直径约为67 nm的球形组装体.磁性金属氧簇的存在和较大的粒子半径使复合物在0.5 T磁场条件下的纵向弛豫效率达到51.32 L?mmol^-1?s^-1,并且在载药之后没有明显降低.复合物中部分还原的多金属氧簇中的不同价态金属离子之间存在的电荷转移使复合物在载药前后均表现出良好的光热转换能力,其中,载药后的复合物在808 nm激光(1.0 W?cm^-2)下持续照射10 min可以产生20℃的温度增量,为其用于肿瘤光热治疗提供了可能. PDDA-P...     

溶剂对四苯基卟啉氯化锰飞秒瞬态吸收光谱的影响

采用稳态和飞秒瞬态吸收光谱技术研究了四苯基卟啉氯化锰MnⅢ(TPP)Cl在甲苯(TOL)、二氯甲烷(DCM)、乙腈(ACN)和N,N-二甲基甲酰胺(DMF)四种溶剂中的光物理性质.结果表明随溶剂极性的增加,其紫外-可见吸收光谱的B带与Q带与飞秒瞬态对应的漂白信号均发生蓝移.随着MnⅢ(TPP)Cl二氯甲烷溶液浓度的增加, ⁵S₂态寿命无明显变化,⁵S₁态和⁵T₁态寿命依次变短.在四种溶剂中,非极性溶剂甲苯中的⁵S₂态寿命最长而⁵S₁和⁵T₁态寿命最短,这与⁵S₂→⁵S₁能差最大, ⁵S₁→5S0能差最小对应.从弱极性DCM到极性更大的DMF时, ⁵S₁和...     

单重态氧化学VIII.类卟啉稀土配合物光敏化产生单重态氧的ESR研究

用电子自旋共振(ESR)方法研究类卟啉稀土配合物([CO2H-APPC)Gd]Cl2)光敏产生单重态氧的II型机制。利用2,2, 6, 6-四甲基哌啶(TEMP)对单重态氧的捕捉, 测定所生成的氮氧自由基的ESR信号, 经加NaN3和CD3OD的实验, 证实了([CO2H-APPC)Gd]Cl2)光敏作用可有效地产生单重态氧, 并观察到在实验所用的浓度范围内, 随着光敏剂浓度加大, 生成的单重态氧也增加, 同时比较了几种不同稀土离子配合物产生单重态氧的差别。结合氧的消耗和氮氧自由基的ESR线宽变化对氧浓度的依赖性, 证明了类卟啉稀土配合物光敏化生成单态氧的II型反应在光动力光疗中起关键作用。     

Photoinduced Nitric Oxide and Singlet Oxygen Release from ZnPC Liposome Vehicle Associated with the Nitrosyl Ruthenium Complex: Synergistic Effects in Photodynamic Therapy Application

Under continuous photolysis at 675 nm, liposomal zinc phthalocyanine associated with nitrosyl ruthenium complex [Ru(NH.NHq)(tpy)NO]³⁺ showed the detection and quantification of nitric oxide (NO) and singlet oxygen (¹O₂) release. Photophysical and photochemical results demonstrated that the interaction between the nitrosyl ruthenium complex and the photosensitizer can enable an electron transfer process from the photosensitizer to the nitrosyl ruthenium complex which leads to NO release. Synergistic action of both photosensitizers and the nitrosyl ruthenium complex results in the production of reactive oxygen species and reactive nitrogen species, which is a potent oxidizing agent to many biological tissues, in particular neoplastic cells.     

Membrane Damage Efficiency of Phenothiazinium Photosensitizers

Structure–activity relationships have been widely reported for porphyrin and phthalocyanine photosensitizers, but not for phenothiazinium derivatives. Here, four phenothiazinium salts (methylene blue, toluidine blue O, 1,9‐dimethyl methylene blue and the pentacyclic derivative DO15) were used to investigate how the ability to damage membranes is affected by membrane/solution partition, photophysical properties and tendency to aggregation of the photosensitizer. These two latter aspects were studied both in isotropic solutions and in membranes. Membrane damage was assessed by leakage of a fluorescent probe entrapped in liposomes and by generation of thiobarbituric acid‐reactive species (TBARS), while structural changes at the lipid bilayer were detected by small‐angle X‐ray scattering. We observed that all compounds had similar singlet‐oxygen quantum yields in ethanol, but only the photosensitizers that had higher membrane/solution partition (1,9‐dimethyl methylene blue and DO15, the latter having the higher value) could permeabilize the lipid bilayer. Moreover, of these two photosensitizers, only DO15 altered membrane structure, a result that was attributed to its destabilization of higher order aggregates, generation of higher amounts of singlet oxygen within the membranes and effective electron‐transfer reaction within its dimers. We concluded that membrane‐based protocols can provide a better insight on the photodynamic efficiency of the photosensitizer.     

Highly Efficient,Conjugated‐Polymer‐Based Nano‐Photosensitizers for Selectively Targeted Two‐Photon Photodynamic Therapy and Imaging of Cancer Cells

Two‐photon photodynamic therapy (2P‐PDT) is a promising noninvasive treatment of cancers and other diseases with three‐dimensional selectivity and deep penetration. However, clinical applications of 2P‐PDT are limited by small two‐photon absorption (TPA) cross sections of traditional photosensitizers. The development of folate receptor targeted nano‐photosensitizers based on conjugated polymers is described. In these nano‐photosensitizers, poly{9,9‐bis[6′′‐(bromohexyl)fluorene‐2,7‐ylenevinylene]‐co‐alt‐1,4‐(2,5‐dicyanophenylene)}, which is a conjugated polymer with a large TPA cross section, acts as a two‐photon light‐harvesting material to significantly enhance the two‐photon properties of the doped photosensitizer tetraphenylporphyrin (TPP) through energy transfer. These nanoparticles displayed up to 1020‐fold enhancement in two‐photon excitation emission and about 870‐fold enhancement in the two‐photon‐induced singlet oxygen generation capability of TPP. Surface‐functionalized folic acid groups make these nanoparticles highly selective in targeting and killing KB cancer cells over NIH/3T3 normal cells. The 2P‐PDT activity of these nanoparticles was significantly improved, potentially up to about 1000 times, as implied by the enhancement factors of two‐photon excitation emission and singlet oxygen generation. These nanoparticles could act as novel two‐photon nano‐photosensitizers with combined advantages of low dark cytotoxicity, targeted 2P‐PDT with high selectivity, and simultaneous two‐photon fluorescence imaging capability; these are all required for ideal two‐photon photosensitizers.     

TEMPORAL and SPECTRAL SEPARATION OF SINGLET OXYGEN LUMINESCENCE FROM NEAR INFRARED EMITTING PHOTOSENSITIZERS

Abstract— The luminescence emission of singlet molecular oxygen (¹O₂) generated by bacteriopheophytin a, a near-infrared-emitting photosensitizer, was measured using a new high-sensitivity spectrometer system for time- and spectral-resolved near-infrared detection. The instrument uses a low energy pulsed nitrogen laser (40 μJ per pulse) to excite the photosensitizer optically and is capable of a time resolution of 40 ns per data point and an instrument response function of 350 ns FWHM (full width at half maximum). The use of a low-energy (and relatively low cost) source provides sufficient system sensitivity to measure time-resolved spectra in the near infrared with high spectral and temporal resolution. The simultaneous detection, with high accuracy and repeatability, of both the temporal and spectral dependence of the photoprocesses of ¹O₂ generation, especially with near-infrared-emitting photosensitizers, may further stimulate the current intensive investigations concerning the activity of ¹O₂ to biomolecules.     

The Effect of Biological Substrates on the Ultrafast Excited-state Dynamics of Zinc Phthalocyanine Tetrasulfonate in Solution

Zinc phthalocyanine tetrasulfonate (ZnPcS₄), a potential photosensitizer for photodynamic therapy (PDT), has been studied using femtosecond laser spectroscopy. The excited-state dynamics in water have been found to be fast (<80 ps) and dominated by intermolecular aggregation. Since the proposed mechanism for PDT is energy transfer from the triplet excited state of the photosensitizer to triplet O₂ creating singlet O₂, the short lifetime is expected to be unfavorable for producing singlet O₂. This leads to the suggestion that the presence of biological substrates may have an effect on the excited-state dynamics. To test this hypothesis, the lifetimes of the ex-cited states of ZnPcS₄ have been directly measured in the presence of a model membrane, n-hexadecyltrimethylammonium bromide (CTAB). The excited-state dynamics of ZnPcS₄ in buffer solutions and with human serum albumin (HSA) have also been measured. The presence of HSA and CTAB increases the excited-state lifetime significantly relative to that observed in water. The longer lifetime of ZnPcS4 in CTAB (>1 ns) indicates that the micellar surface favors monomer formation. By increasing the excited-state lifetime, the surface substantially in-creases the photosensitizing potential of ZnPcS₄.     

Semiconducting polymer dots with photosensitizer loading and peptide modification for enhanced cell penetration and photodynamic effect

We utilized semiconducting polymer do-PFDTBT, photosensitizer ZnPc and functional polymer PSMA to prepare carboxyl Pdots. The carboxyl Pdots were modified with cell penetrating peptides (R8) to prepare peptide coated-Pdots, which could enhance the cell penetration and photodynamic effect.     

POTENTIAL PHOTOSENSITIZERS FOR PHOTODYNAMIC THERAPY—II. PHOTOPHYSICAL PROPERTIES OF [26] PORPHYRIN

Abstract— –Photophysical properties of [26] porphyrin (26 P) were investigated in chloroform. The quantum yields of fluorescence, of S₁→ T₁ intersystem crossing and singlet oxygen formation were measured. The purity, stability, the strong absorption in the red (δ_max= 783 nm; ε_max= 28 000 M ¹ cm^-1) and the ability of singlet oxygen formation recommend 26 P as potential photosensitizer for tumor therapy.     

Unique behaviors of polymers having metalloporphyrin as their side chains

Several kinds of polymers having tetraphenylporphyrin (TPP) or some metallotetraphenylporphyrin (AgTPP, CuTPP, VOTPP or ZnTPP) moieties as their side chains have been prepared by the radical polymerization of the corresponding vinyl monomers. Visible spectra of these polymers show the clear hypochromism in the Soret bands of the tetraphenylporphyrin moieties as compared with those of the corresponding monomers. Polymer effects were clearly observed in the magnetic behaviors and the oxygen adsorption of paramagnetic metalloporphyrin moieties. In addition, polymer effects on photophysical and photochemical behaviors of ZnTPP were found in the amphiphilic polymers covalently tethered with small amounts of ZnTPP and hydrophobic substituents above a critical content, which form hydrophobic domains due to aggregation of the hydrophobic groups in aqueous solution.     

Aggregation and counter ion binding ability of sulfonatomethylcalix[4]resorcinarenes in aqueous solutions

¹H NMR spectroscopy, ¹H NMR spin-lattice relaxation, conductivity and pH-metric titration data have been used to study the aggregation and counter-ion binding of tetrasulfonatomethylcalix[4]resorcinarenes with methyl (H₈XNa₄) and amyl (H₈YNa₄) substituents. The data obtained reveal the self-aggregation of H₈YNa₄ driven by hydrophobic interactions. The NMR relaxation data indicate that Gd³⁺ is bound by both H₈XNa₄ and H₈YNa₄. The Gd³⁺ ions were found to induce the aggregation of H₈YNa₄ with critical association concentration (CAC) value less than in case of its self-aggregation. Using Gd³⁺ as a probe of counter-ion binding with the aggregate interface it was found out that binding of quaternary ammonium cations (QUATSs) with H₈YNa₄ aggregates and SDS aggregates is quite different, while binding of inorganic ions by both types of aggregates is similar. The most outstanding peculiarity of QUATSs binding with H₈YNa₄ aggregates is selective recognition of QUATSs, possessing trimethylammonium group, detected by NMR relaxation method.     

PHOTODYNAMIC EFFECTS OF NEW SILICON PHTHALOCYANINES: In vitro STUDIES UTILIZING RAT HEPATIC MICROSOMES AND HUMAN ERYTHROCYTE GHOSTS AS MODEL MEMBRANE SOURCES

Abstract— Photodynamic therapy (PDT) of cancer is a modality that relies upon the irradiation of tumors with visible light following selective uptake of a photosensitizer by the tumor tissue. There is considerable emphasis to define new photosensitizers suitable for PDT of cancer. In this study we evaluated six phthalocyanines (Pc) for their photodynamic effects utilizing rat hepatic microsomes and human erythrocyte ghosts as model membrane sources. Of the newly synthesized Pc, two showed significant destruction of cytochrome P-450 and monooxygenase activities, and enhancement of lipid peroxidation, when added to microsomal suspension followed by irradiation with ∼ 675 nm light. These two Pc named SiPc IV (HOSiPcOSi[CH₃]₂[CH₂]₃N[CH₃]₂) and SiPc V (HOSiPcOSi[CH₃]₂[CH₂]₃N[CH₃]₃¹ I) showed dose-dependent photodestruction of cytochrome P-450 and monooxygenase activities in liver microsomes, and photoenhancement of lipid peroxidation, lipid hydroperoxide formation and lipid fluorescence in rnicrosomes and erythrocyte ghosts. Compared to chloroaluminum phthalocyanine tetrasulfonate, SiPc IV and SiPc V produced far more pronounced photodynamic effects. Sodium azide, histidine, and 2,5-dimethylfuran, the quenchers of singlet oxygen, afforded highly significant protection against SiPc IV- and SiPc V-mediated photodynamic effects. However, to a lesser extent, the quenchers of superoxide anion, hydrogen peroxide and hydroxyl radical also showed some protective effects. These results suggest that SiPc IV and SiPc V may be promising photosensitizers for the PDT of cancer.