Zinc Phthalocyanine Research Articles

Nucleophilic Substitution in 4-Bromo-5-nitrophthalodinitrile: XVIII. Synthesis and Spectral Properties of Octasubstituted Zinc Phthalocyanines with Cyclohexylphenol Moieties

Nucleophilic Substitution in 4-Bromo-5-nitrophthalodinitrile: XVIII. Synthesis and Spectral Properties of Octasubstituted Zinc Phthalocyanines with Cyclohexylphenol Moieties

The effect of ascorbic acid and cranberry on the bond strength, surface roughness, and surface hardness of bleached enamel with hydrogen peroxide and zinc phthalocyanine activated by photodynamic therapy

AimTo evaluate the effect of different bleaching methods 40% (hydrogen peroxide) HP and Zinc Phthalocyanine (ZP) activated by photodynamic therapy (PDT) with the utilization of diverse procedures of reversal (10% ascorbic acid and 6% cranberry solution) on bond values, surface microhardness and surface roughness of bleached enamel surface. Material and MethodsAn aggregate of 60 extracted human mandibular molars was gathered and the buccal surface of each specimen was exposed to 2 mm of enamel surface for bleaching with chemical and photoactivated agents with the use of reversal solutions. Specimens were divided into six groups (n = 10) at random- Group 1: samples bleached with 40% HP with 10% ascorbic acid (reversal agent), group 2: ZP activated by PDT with 10% ascorbic acid (reversal agent), group 3: 40% HP with 6% cranberry solution as a reversal agent, group 4: ZP activated by PDT with 6% cranberry solution, group 5: 40% HP and group 6: ZP activated by PDT with no reversal agents. Resin cement restoration was performed via etch and rinse technique and SBS was estimated by using the universal testing machine, SMH by using Vickers hardness tester, and Ra by stylus profilometer. Statistical analysis was executed using the ANOVA test and the Tukey multiple tests (p<0.05). ResultsEnamel surface bleached with 40% HP reversed with 10% ascorbic acid displayed the highest SBS while 40% HP with no reversal agent use showed the least SBS. For SMH, ZP activated by PDT when applied on the enamel surface and reversed with 10% ascorbic acid showed the highest SMH while when bleached with 40% HP and reversed with 6% cranberry solution showed the least SMH value. For Ra, Group 3: samples bleached with 40% HP with 6% cranberry solution as reversal agent showed the highest Ra value while bleaching of enamel surface with ZP activated by PDT with 6% cranberry displayed the least Ra value. ConclusionBleached enamel surface with Zinc Phthalocyanine activated by PDT with the application of 10% ascorbic acid as reversal solution has demonstrated the highest SBS and SMH with acceptable surface roughness for bonding adhesive resin to the enamel surface.

Novel Zinc(II) Phthalocyanine Dyes for Color Photoresists

AbstractColor photoresists are the key materials for the fabrication of color filters (CFs). Organic dyes offer a promising alternative to the conventional pigment-based system to make CFs with higher resolution. However, the stability of dye molecules is an urgent problem to be solved. Herein, we designed and synthesized a series of highly stable zinc phthalocyanine dyes containing polymerizable acrylamide groups. Upon light exposure, dense and insoluble network structures were formed in the prepared CFs, which increase the thermal stability and anti-migration capacity of these dyes.

Ultrasensitive recognition performance of a folded π-based 1,8-naphthalimide-phthalocyanine fluorescence sensor

Designing ultrasensitive and smart molecules as molecular switches is highly valued in molecular recognition. In this work, a folded π-based molecular switch (NAPC) containing 1,8-naphthalimide and zinc(II) phthalocyanine functional modules was synthesized via cyclo tetramerization of four synthesized 1,8-naphthalimide sensors (NA). The photophysical properties of the folded molecular switch were investigated. This peripherally 1,8-naphthalimide substituted zinc(II) phthalocyanine possessed superior sensitivity in near-infrared “off-on” detection of Al3+, Fe3+, and Cr3+ compared with NA, and the detection limits were calculated to be 0.077 μmol/L for Al3+, 0.073 μmol/L for Fe3+ and 0.067 μmol/L for Cr3+, which were far less than that of NA. Due to the sensitive detection of Fe3+, NAPC was also applied in detecting NO2−. The ultrasensitive recognition mechanism of NAPC was determined to be the level-by-level linkage in the molecule in which the photo-induced electron transfer process in 1,8-naphthalimide sensor module was inhibited by complexing with metal ions first and then caused the inhibition of π-π stacking between two modules. This new folded molecule with a cascade linkage effect has the potential as an excellent fluorescence switch that could be applied in molecular recognition and environmental management.

Synthesis, characterization and photodynamic antitumor activity of amine-modified zinc (II) phthalocyanines

In order to reduce the intramolecular charge-transfer (ICT) effect of amine groups on the photophysical properties of zinc (II) phthalocyanine (ZnPc), tertiary amines were covalently connected with ZnPc ring via ethyl p-hydroxybenzoate or diethyl 5-hydroxyisophthalate. Six new tertiary amine-modified ZnPcs were therefore synthesized and characterized. Meanwhile, the corresponding quaternary ammonium ZnPcs were also synthesized. The effects of different substitution ways (mono-substitutions, symmetrical tetra-substitutions, or asymmetric tetra-substitutions) and the numbers of different substitutions on the photophysical and physicochemical properties of these ZnPcs were studied. All twelve ZnPcs had relatively high singlet oxygen quantum yields (ΦΔ = 0.32–0.68) and fluorescence quantum yields (ΦF = 0.23–0.40), where the amine-containing substituents did not show obvious ICT effect. All ZnPcs showed effective phototoxicity towards breast cancer cells (IC50 = 63–366 nmol/L). Among them, three tetra-substituted ZnPcs containing quaternary ammonium groups (4aN, 4bN and 4cN) showed the best in vitro anticancer photodynamic activities with IC50 = 64–76 nmol/L, which owned to their relatively high cellular uptake. The tumor inhibition rate of 4aN on H22 tumor-bearing mice reached 87% (4aN dose: 3 nmol/g; light dose: 685 nm, 135 J/cm2).

Influence of spacer and donor groups as tetraphenylethylene or triphenylamine in asymmetric zinc phthalocyanine dyes for dye-sensitized solar cells

Based on the available literature, the carboxylic acid is a suitable electron-withdrawing group for the development of push–pull type AB3 phthalocyanines that can be used in dye-sensitized solar cell (DSSC). This study aims to assess the impact of carboxylic acid groups on solar cell energy conversion efficiency. Two types of carboxylic acid groups were selected as electron-withdrawing groups for this purpose. These groups were attached to the phthalocyanine (Pc) core either directly or via conjugated linker groups. Two novel push–pull zinc phthalocyanine dyes (GT-52 and GGC-22) containing tetraphenylethylene (TPE) or triphenylamine (TPA) substituents as electron donor groups and carboxylic acid or phenoxy carboxylic acid as anchoring groups, respectively, have been synthesized to construct DSSCs. The optical, electrochemical, and photovoltaic properties of the effect of the spacer and electron donor groups in these phthalocyanines are evaluated. Both dyes exhibit good anti-aggregation ability owing to the presence of the bulky donor groups. On the other hand, the DSSC based on GGC-22 showed a significantly higher power conversion efficiency (PCE) of 2.15% than that of GT-52 (0.26%) under AM 1.5G solar conditions. The superior performance of GGC-22 is attributed to the introduction of a phenoxy spacer, which results in a longer distance between the donor groups and the TiO2 surface compared to GT-52 without any spacer. This allows for higher dye loading, resulting in higher JSC, VOC, and PCE for GGC-22. As a result, the presence of a longer anchoring group for the donor groups is an important synthetic strategy for efficient phthalocyanine-based DSSCs.

Synthesis, photophysical, and photochemical properties of functional molecules based on a novel zinc(II) phthalocyanine-1,8-naphthalimide skeleton

Designing multifunctional photosensitizers with high efficiency has been significant in the molecular engineering field. In this work, we designed a novel molecular skeleton with a bi-chromophore, in which four 4-substituted-1,8-naphthalimide fluorophores were introduced as energy pumps to the zinc(II) phthalocyanine photosensitive group. Four peripherally symmetrical 4-NH-substituted-1,8-naphthalimide functionalized zinc(II) phthalocyanine molecules (NAZP1, NAZP2, NAZP3, NAZP4) were synthesized and characterized. The photophysical and photochemical properties of the molecules were investigated. The novel molecules showed dual-channel absorption and emission features of both chromophores. The fluorescence resonance energy transfer (FRET) process from 1,8-naphthalimide to zinc(II) phthalocyanine was verified by the spectral overlap and theoretical calculations. NAZP1 had higher FRET efficiency than the other three molecules. The singlet oxygen quantum yields of NAZP1, NAZP2, NAZP3, and NAZP4 in DMF were 0.84, 0.60, 0.68, and 0.73 respectively, being higher than the unsubstituted ZnPc. The introduction of four 1,8-naphthalimide energy pumps greatly improved the photophysical and photochemical properties of zinc(II) phthalocyanine, being hopeful in developing high-performance photosensitizers.

Monomer and Oligomer Transition of Zinc Phthalocyanine Is Key for Photobleaching in Photodynamic Therapy.

Photodynamic therapy (PDT) is recognized as a powerful method to inactivate cells. However, the photosensitizer (PS), a key component of PDT, has suffered from undesired photobleaching. Photobleaching reduces reactive oxygen species (ROS) yields, leading to the compromise of and even the loss of the photodynamic effect of the PS. Therefore, much effort has been devoted to minimizing photobleaching in order to ensure that there is no loss of photodynamic efficacy. Here, we report that a type of PS aggregate showed neither photobleaching nor photodynamic action. Upon direct contact with bacteria, the PS aggregate was found to fall apart into PS monomers and thus possessed photodynamic inactivation against bacteria. Interestingly, the disassembly of the bound PS aggregate in the presence of bacteria was intensified by illumination, generating more PS monomers and leading to an enhanced antibacterial photodynamic effect. This demonstrated that on a bacterial surface, the PS aggregate photo-inactivated bacteria via PS monomer during irradiation, where the photodynamic efficiency was retained without photobleaching. Further mechanistic studies showed that PS monomers disrupted bacterial membranes and affected the expression of genes related to cell wall synthesis, bacterial membrane integrity, and oxidative stress. The results obtained here are applicable to other types of PSs in PDT.

RAFT Synthesis and Characterization of Poly(Butyl-co-2-(N,N-Dimethylamino)Ethyl Acrylates)-block-Poly(Polyethylene Glycol Monomethyl Ether Acrylate) as a Photosensitizer Carrier for Photodynamic Therapy.

Polymer micelles are promising drug delivery systems for highly hydrophobic photosensitizers in photodynamic therapy (PDT) applications. We previously developed pH-responsive polymer micelles consisting of poly(styrene-co-2-(N,N-dimethylamino)ethyl acrylate)-block-poly(polyethylene glycol monomethyl ether acrylate) (P(St-co-DMAEA)-b-PPEGA) for zinc phthalocyanine (ZnPc) delivery. In this study, poly(butyl-co-2-(N,N-dimethylamino)ethyl acrylates)-block-poly(polyethylene glycol monomethyl ether acrylate) (P(BA-co-DMAEA)-b-PPEGA) was synthesized via reversible addition and fragmentation chain transfer (RAFT) polymerization to explore the role of neutral hydrophobic units in photosensitizer delivery. The composition of DMAEA units in P(BA-co-DMAEA) was adjusted to 0.46, which is comparable to that of P(St-co-DMAEA)-b-PPEGA. The size distribution of the P(BA-co-DMAEA)-b-PPEGA micelles changed when the pH decreased from 7.4 to 5.0, indicating their pH-responsive ability. The photosensitizers, 5,10,15,20-tetrakis(pentafluorophenyl)chlorin (TFPC), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), protoporphyrin IX (PPIX), and ZnPc were examined as payloads for the P(BA-co-DMAEA)-b-PPEGA micelles. The encapsulation efficiency depended on the nature of the photosensitizer. TFPC-loaded P(BA-co-DMAEA)-b-PPEGA micelles exhibited higher photocytotoxicity than free TFPC in the MNNG-induced mutant of the rat murine RGM-1 gastric epithelial cell line (RGK-1), indicating their superiority for photosensitizer delivery. ZnPc-loaded P(BA-co-DMAEA)-b-PPEGA micelles also exhibited superior photocytotoxicity compared to free ZnPc. However, their photocytotoxicity was lower than that of P(St-co-DMAEA)-b-PPEGA. Therefore, neutral hydrophobic units, as well as pH-responsive units, must be designed for the encapsulation of photosensitizers.

Innentitelbild: Photo‐RAFT Polymerization for Hydrogel Synthesis through Barriers and Development of Light‐Regulated Healable Hydrogels under NIR Irradiation (Angew. Chem. 25/2023)

Hydrogel preparation under NIR light via a photoinduced RAFT polymerization catalyzed by tetrasulfonated zinc phthalocyanine is reported by Cyrille Boyer et al. in their Research Article (e202302451). Exploiting enhanced penetration of NIR light, photoinduced gelation is effectively performed through barriers. Thiocarbonylthio groups embedded in hydrogel networks facilitate the reactivation of polymer chains under NIR wavelengths, enabling the photoinduced healing of hydrogels through non-transparent barriers.

Stable β-form zinc phthalocyanine cathodes for flexible Zn-ion hybrid supercapacitors with ultra-long cycling life

Metal phthalocyanine with a unique π-conjugated structure, has shown extraordinary promise for electrocatalysis, batteries and supercapacitors. High-performance Zn-ion hybrid supercapacitors make high demands on the energy storage mechanisms of metal phthalocyanine. We propose a β-form zinc phthalocyanine (ZnPc) molecular crystal as a cathode material for flexible Zn-ion hybrid supercapacitors. The β-ZnPc is facilely synthesized through the annealing treatment of the original ZnPc, which is previously fabricated through a ring-closure reaction assisted by catalysis of sodium methanol and ultrasonic treatment. The structural transformation of ZnPc from α-ZnPc to β-ZnPc is demonstrated at the annealing temperature from 200 °C to 300 °C, probably attributed to the short-range neighbor interaction between the adjacent ZnPc molecular layers. The β-ZnPc electrode exhibits the higher specific capacitance and the better rate capability than those of the α-ZnPc electrode, mainly due to its higher specific surface area and more abundant pore structure. The electron density and adsorption energy of ZnPc are theoretically calculated, revealing the active N sites for the reversible adsorption/desorption of Zn2+. The flexible Zn-ion hybrid supercapacitor provides the maximum energy density of 86.2 Wh kg−1 at 0.22 kW kg−1, and maintains the capacitance retention of 73.4% after 100,000 cycles, opening up a new avenue for developing high-energy and long-life Zn-ion hybrid supercapacitors.

Electrochemical and spectroelectrochemical behavior of methyl pheophorbide a - zinc phthalocyanine dyad

The electrochemical properties of a covalently linked conjugate (Dyad) composed of methyl pheophorbide a (Pheo a) and zinc(II) 2-(2-hydroxymethylbenzyloxy)-9(10),16(17),23(24)-tri-tert-butylphthalocyaninate (ZnPc) were studied. Cyclic voltammetry (CV) and square wave voltammetry (SWV) measurements revealed three reductions at -1.59, 1.78 and -2.03 V vs. [Formula: see text]/Fc and four oxidations at 0.06, 0.47, 0.57 and 0.87 V vs. [Formula: see text]/Fc in [Formula: see text]-DCB containing 0.05 M TBAPF6. The first reduction included two overlapped processes, the reduction of Pheo a followed by the reduction of ZnPc, separated byca. 0.08 V. Compared to individual components, the ZnPc subunit in Dyad undergoes the first oxidation more easily with a cathodic shift of potential by 0.08 V, while Pheo a subunit, on the contrary, is more difficult to oxidize showing an anodic potential shift of 0.14 V. This indicates a certain interaction between the two subunits in Dyad, which is additionally confirmed by a slight bathochromic shift of the Q band positions in the UV-vis spectra of Dyad relative to its components. Moreover, the cathodic shift of the second oxidation potential of the ZnPc subunit concerning individual ZnPc reaches 0.35 V, indicating an intensification of the electronic interaction between [Formula: see text] and Pheo a in Dyad. The spectroelectrochemical experiment showed that the reversible first oxidation of the ZnPc subunit is followed by its irreversible second oxidation, which proceeds slightly ahead of the first oxidation of the Pheo a fragment. Thus, both electrochemical and spectroelectrochemical studies support the conclusion on the enhanced interaction between [Formula: see text] and Pheo a in Dyad, which even leads to a change in the order of their further oxidations.

Photobiomodulation Improves Anti-Tumor Efficacy of Photodynamic Therapy against Resistant MCF-7 Cancer Cells.

Cancer resistance is a primary concern in cancer treatment, and developing an effective modality or strategy to improve therapeutic outcomes is imperative. Photodynamic therapy (PDT) is a treatment modality that targets the tumor with a photoactive molecule and light for the specific destruction of cancer cells. Photobiomodulation (PBM) is a light exposure of cells to energize their biomolecules to respond to therapy. In the present study, we used PBM to mediate and improve the anti-tumor efficacy of zinc phthalocyanine tetrasulfonic acid (ZnPcS4)-PDT on resistant MCF-7 breast cancer cells and explore molecular changes associated with cell death. Different laser irradiation models were used for PBM and PDT combination. The combined treatment demonstrated an additive effect on the viability and Annexin-V/PI-staining cell death assessed through MTT assay and mitochondrial release of cytochrome c. Rhodamine (Rh123) showed increased affinity to mitochondrial disruption of the strategic treatment with PBM and PDT. Results from the autophagy assay indicate an interplay between the mitochondrial and autophagic proteins. These findings were indicative that PBM might improve the anti-tumor of PDT by inducing autophagy in resistant MCF-7 breast cancer cells that evade apoptosis.

Synthesis and Characterization of New-Type Soluble β-Substituted Zinc Phthalocyanine Derivative of Clofoctol.

In this work, we have described the synthesis and characterization of novel zinc (II) phthalocyanine bearing four 2-(2,4-dichloro-benzyl)-4-(1,1,3,3-tetramethyl-butyl)-phenoxy substituents on the peripheral positions. The compound was characterized by elemental analysis and different spectroscopic techniques, such as FT-IR, 1H NMR, MALDI-TOF, and UV-Vis. The Zn (II) phthalocyanine shows excellent solubility in organic solvents such as dichloromethane (DCM), n-hexane, chloroform, tetrahydrofuran (THF), and toluene. Photochemical and electrochemical characterizations of the complex were performed by UV-Vis, fluorescence spectroscopy, and cyclic voltammetry. Its good solubility allows a direct deposition of this compound as film, which has been tested as a solid-state sensing material in gravimetric chemical sensors for gas detection, and the obtained results indicate its potential for qualitative discrimination and quantitative assessment of various volatile organic compounds, among them methanol, n-hexane, triethylamine (TEA), toluene and DCM, in a wide concentration range.

The synthesis of novel water-soluble zinc (II) phthalocyanine based photosensitizers and exploring of photodynamic therapy activities on the PC3 cancer cell line.

In this study, Schiff base substituted phthalocyanine complexes (Zn1c, Zn2c) and their quaternized derivatives (Q-Zn1c, Q-Zn2c) were synthesized for the first time. Their structures have been characterized by FT-IR, 1H-NMR, UV-Vis, mass spectrometry and elemental analysis as well as. The photophysicochemical properties (fluorescence, singlet oxygen and photodegradation quantum yield) of these novel complexes were investigated in dimethylsulfoxide (DMSO) for both non-ionic and quaternized cationic phthalocyanine complexes and in aqueous solution for quaternized cationic phthalocyanine complexes. Water soluble cationic phthalocyanine compounds gave good singlet oxygen quantum yield (0.65 for Q-Zn1c, 0.66 for Q-Zn2c in DMSO; 0.65 for Q-Zn2c in aqueous solution). The binding of Q-Zn1c and Q-Zn2c to BSA/DNA was studied by using UV-Vis and fluorescence spectroscopy and these. Studies indicate that the mechanism of BSA quenching by quaternized zinc(II) phthalocyanines was static quenching. Quaternized zinc(II) phthalocyanines interacted with ct-DNA by intercalation. Quaternized zinc(II) phthalocyanines caused a decrease in cell viability and triggered apoptotic cell death after PDT was applied at a concentration that did not have a toxic effect on their own. Q-Zn1c and Q-Zn2c mediated PDT reduced the activity of SOD, CAT, GSH while increased MDA level in the prostate cancer cells. Furthermore, expression of apoptotic proteins after PDT was examined. The results revealed that the synthesized water soluble quaternized zinc(II) phthalocyanine complexes (Q-Zn1c and Q-Zn2c) are promising potential photosensitizers for PDT.

Investigation of Biological Activities of Tetra‐substituted Phthalocyanines Bearing Tetraethyleneglycol Monomethyl Ether Chains at Peripheral and Non‐peripheral Positions

AbstractThis study describes the synthesis and characterization of peripherally and non‐peripherally substituted copper(II) and cobalt(II) phthalocyanines bearing tetraethyleneglycol monomethyl ether chains. In addition, the metal‐free and zinc(II) phthalocyanine derivatives were prepared according to the referred procedure. All newly synthesized phthalocyanines were characterized using some spectroscopic techniques such as elemental analysis and fourier transform infrared, ultraviolet‐visible, and mass spectroscopies. The effects of solvent type and concentration on aggregation properties of phthalocyanines were studied, as well. The biological activities of a series of these peripherally and non‐peripherally tetra‐substituted phthalocyanines were investigated. The effects of the central metal ion and the position of the substituent on biological activities of phthalocyanines were also compared. When the antioxidant activities of the synthesized molecules were evaluated by the 2,2‐diphenyl‐1‐picrylhydrazyl method, 1,8/11,15/18,22/25‐tetrakis[2‐(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)ethoxy]phthalocyaninatocobalt(II) (63.17±0.012 %) showed the highest activity. The highest reducing power activity was obtained with the 2,9/10,16/17,23/24‐tetrakis[2‐(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)ethoxy]phthalocyaninatozinc(II) molecule. In the antibacterial activity studies using the disc diffusion method, 2,9/10,16/17,23/24‐tetrakis[2‐(2‐(2‐(2‐methoxyethoxy) ethoxy)ethoxy)ethoxy]phthalocyaninatocopper(II) exhibited the highest inhibition activity on both gram negative (18±0.23 mm) and gram positive (23±0.07 mm) strains. On the other hand, 2,9/10,16/17,23/24‐tetrakis[2‐(2‐(2‐(2‐methoxyethoxy)ethoxy) ethoxy)ethoxy]phthalocyaninatozinc(II) and 1,8/11,15/18,22/25‐tetrakis[2‐(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)ethoxy]phthalo‐cyaninatozinc(II) compounds presented hemolytic activity against sheep blood in the hemolytic activity studies. The results confirmed that the synthesized molecules demonstrated average antioxidant activity compared to standard antioxidants. 2,9/10,16/17,23/24‐Tetrakis[2‐(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)ethoxy]phthalo‐cyaninatocopper(II), 2,9/10,16/17,23/24‐tetrakis[2‐(2‐(2‐(2‐methoxy ethoxy)ethoxy)ethoxy)ethoxy]phthalocyaninatozinc(II) and 1,8/11, 15/18,22/25‐tetrakis[2‐(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy) ethoxy]phthalocyaninatozinc(II) complexes could remarkably inhibit S. aureus and CuPc‐1 complex E. coli growth.

Assembling Artificial Photosynthetic Models in Water Using β-Cyclodextrin-Conjugated Phthalocyanines as Building Blocks.

Two water-soluble zinc(II) phthalocyanines substituted with two or four permethylated β-cyclodextrin (β-CD) moieties at the α positions have been utilized as building blocks for the construction of artificial photosynthetic models in water. The hydrophilic and bulky β-CD moieties not only can increase the water solubility of the phthalocyanine core and prevent its stacking in water but can also bind with a tetrasulfonated zinc(II) porphyrin (ZnTPPS) and/or sodium 2-anthraquinonesulfonate (AQ) in water through host-guest interactions. The binding interactions of these species have been studied spectroscopically, while the photoinduced processes of the resulting complexes have been investigated using steady-state and time-resolved spectroscopic methods. In the ternary complexes, the ZnTPPS units serve as light-harvesting antennas to capture the light energy and transfer it to the phthalocyanine core via efficient excitation energy transfer. The excited phthalocyanine is subsequently quenched by the electron-deficient AQ units through electron transfer. Femtosecond transient absorption spectroscopy provides clear evidence for the singlet-singlet energy transfer from the photo-excited ZnTPPS to the phthalocyanine core with a rate constant (kENT ) in the order of 109 s-1 . The population of phthalocyanine radical cations indicates the occurrence of electron transfer from the excited phthalocyanine to the AQ moieties, forming a charge-separated state.

Synthesis and biological evaluation of novel zinc (II) and nickel (II) phthalocyanines as cholinesterase inhibitors

Alzheimer's disease (AD) is one of the irreversible neurodegenerative disorders among older people and causes behavior, memory and thinking problems. In this study, peripheral tetra-[(6-(3-(diethylaminophenoxy)hexyl]oxy) substituted zinc (II) and nickel (II) phthalocyanines and their water soluble derivatives were prepared for the first time. To determine the potential of novel synthesized compounds to be used in Alzheimer's disease (AD), in vitro and in silico AChE/BuChE inhibitory and cytotoxic effects were investigated. The docking scores and ∆G values clearly indicated a stronger affinity between DE-C6-CN and AChE than BuChE. In addition, DE-C6-ZnQ and DE-C6-NiQ had higher inhibitory effects than galantamine and both compounds were competitive inhibitors on AChE and BuChE according to Lineweaver-Burk plots. DE-C6-NiQ had a more potent cytotoxicity effect than DE-C6-ZnQ in SH-SY5Y cells. All these results indicated that DE-C6-ZnQ had the potential to be used in the treatment of AD.

Preparation and characterization of pH-responsive Zein-ZnPc-PDA/HA nanoparticles intended for tumor therapy

Photodynamic therapy (PDT) has emerged as a non-invasive modality where photosensitizer (PS) plays an indispensable role for treating tumors. This study proposes a novel Zein nanoparticle (ZP) encapsulating Zinc phthalocyanine (ZnPc) that targets tumor through intravenous delivery. The ZPs were prepared by phase separation process. Modification of ZPs were realized through encapsulation of polydopamine (PDA) and hyaluronic acid (HA) in order to maintain photothermal, pH-responsive, and tumor-targeting properties. The physiochemical properties, in vitro release, and in vitro evaluation of photothermal and photodynamic effects were studied. The biosafety was analyzed through cytotoxicity assay using human lung cancer cell line A549 as model. The excellent biosafety and significant anti-tumor effect demonstrated that the novel ZPs can be potential candidates for the alternative treatment of cancer.

Cupric-ion-promoted fabrication of oxygen-replenishing nanotherapeutics for synergistic chemo and photodynamic therapy against tumor hypoxia.

Mixing a glutathione (GSH)-responsive carboxy zinc(II) phthalocyanine (ZnPc*) and CuSO4·5H2O in water with or without the presence of the anticancer drug SN38 resulted in the formation of self-assembled nanotherapeutics labeled as ZnPc*/Cu/SN38@NP and ZnPc*/Cu@NP, respectively. The Cu2+ ions not only promoted the self-assembly of the carboxy phthalocyanine through metal complexation, but also catalyzed the transformation of H2O2 to oxygen via a catalase-like reaction, rendering an oxygen-replenishing property to the nanosystems. Both nanosystems exhibited high stability in aqueous media, but the nanoparticles disassembled gradually in an acidic or GSH-enriched environment and inside human colorectal adenocarcinoma HT29 cells, releasing the encapsulated therapeutic components. The disassembly process together with the activation by the intracellular GSH led to relaxation of the intrinsic quenching of the nanophotosensitizers and restoration of the photoactivities of ZnPc*. Under a hypoxic condition, ZnPc*/Cu/SN38@NP could attenuate the intracellular hypoxia level and maintain the photodynamic activity due to its Cu2+-promoted oxygen-replenishing ability. The photodynamic effect of ZnPc* and the anticancer effect of SN38 worked cooperatively, causing substantial apoptotic cell death. The dual therapeutic actions could also effectively inhibit the tumor growth in HT29 tumor-bearing nude mice without initiating notable adverse effects to the mice. STATEMENT OF SIGNIFICANCE: The oxygen-dependent nature of photodynamic therapy generally reduces its efficacy against tumor hypoxia, which is a common characteristic of advanced solid tumors and usually leads to resistance toward various anticancer therapies. We report herein a facile approach to assemble a glutathione-responsive carboxy phthalocyanine-based photosensitizer and an anticancer drug in aqueous media, in which Cu(II) ions were used to promote the self-assembly through metal complexation and catalyze the conversion of H2O2 to oxygen through a catalase-like reaction, making the resulting nanoparticles possessing an oxygen-replenishing property that could promote the photodynamic effect against hypoxic cancer cells and tumors. The use of Cu(II) ions to achieve the aforementioned dual functions in the fabrication of advanced nano-photosensitizing systems has not been reported.