Superior photo-induced antibacterial/antibiofilm activities of ZnPcs/TiO2 and computational simulation studies.

Bacteria can form biofilms on any surface, which causes biofilm-associated infections and bacterial resistance to antibiotics. Thus, it is important to design new-generation non-chemotherapeutic nanoagents for effective antibacterial and antibiofilm strategies. Herein, the effects of the anchoring groups, which are imidazole and carboxylic acid, of zinc phthalocyanines (ZnPcs) sensitized TiO2 on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated under light-emitting diode (LED) irradiation. The photocatalytic antibacterial activities of ZnPc-1/TiO2 and ZnPc-2/TiO2 on the bacterial strains were examined by monitoring the optical density value at 600 nm (OD600 nm). Glutathione (GSH) oxidation assay was used to measure the reactive oxygen species (ROS) generation activity of the compounds. Bacterial damages were imaged by scanning electron microscopy (SEM). According to our photocatalytic antibacterial mechanism, photogenerated electrons are transferred from Pcs to TiO2 and then react with O2, thus creating ROS, which causes damage to bacterial membrane, protein and biofilm destruction as well. Further, computational simulation analysis was used to show the interaction patterns of ZnPc-1 and ZnPc-2 with penicillin binding protein 2a (PBP2a) of S. aureus and FimH lectin protein (PDB:4XO8) of E. coli to elucidate the dark molecular antibacterial mechanism of the compounds. The obtained results from computational studies showed that ZnPc-2 binds firmly through bonds with the 1MWT protein from S. aureus. On the other hand, ZnPc-1 binds firmly through bonds with the 4XO8 protein from E. coli. From combining experimental and computational results, we can conclude that this strategy can be applied to different types of bacterial infections.

Non-canonical anti-cancer, anti-metastatic, anti-angiogenic and immunomodulatory PDT potentials of water soluble phthalocyanine derivatives with imidazole groups and their intracellular mechanism of action.

Cancer is currently a leading health issue globally. Chemotherapy is a prominent treatment method but due to undesired side effects t, there has been a need for novel less toxic approaches. Photodynamic therapy may be listed among the alternatives for efficient and potentially less detrimental applications of cancer therapy. Canonical photodynamic therapy (PDT) approach requires a light source with a specific wavelength of light, a non-toxic photosensitizer and molecular oxygen. PDT creates the desired effect by the photochemical reaction created through interaction of these components to create reactive oxygen species that will act on the cancer cells to enable anti-cancer activities. In our study we focus on non-canonical PDT application. In this approach we are not only aiming to eliminate cancer cells in the environment but also test the anti-metastatic, anti-angiogenic and possible immunomodulatory activities of the novel photosensitizers. Moreover, in our approach, we studied the intracellular pathways that are crucial for carcinogenesis, cell cycle, apoptosis, angiogenesis, metastasis and immune function to decipher the mechanism of the action for each compound. Reactive oxygen species based explanation was not valid in our study, hence it brings out a non canonical approach to PDT applications. Our results suggests that Phthalocyanine derivatives with imidazole groups can be effectively used against lung, colon, breast and prostate cancer while differentially effecting metastasis, angiogenesis, cell cycle, apoptosis and immune system cells' activities. Based on the results, PDT application of these phthalocyanine derivatives can be an effective treatment option to replace chemotherapy to minimize the potential side effects.

Porphyrins and phthalocyanines as biomimetic tools for photocatalytic H2 production and CO2 reduction.

The increasing energy demand and environmental issues caused by the over-exploitation of fossil fuels render the need for renewable, clean, and environmentally benign energy sources unquestionably urgent. The zero-emission energy carrier, H2 is an ideal alternative to carbon-based fuels especially when it is generated photocatalytically from water. Additionally, the photocatalytic conversion of CO2 into chemical fuels can reduce the CO2 emissions and have a positive environmental and economic impact. Inspired by natural photosynthesis, plenty of artificial photocatalytic schemes based on porphyrinoids have been investigated. This review covers the recent advances in photocatalytic H2 production and CO2 reduction systems containing porphyrin or phthalocyanine derivatives. The unique properties of porphyrinoids enable their utilization both as chromophores and as catalysts. The homogeneous photocatalytic systems are initially described, presenting the various approaches for the improvement of photosensitizing activity and the enhancement of catalytic performance at the molecular level. On the other hand, for the development of the heterogeneous systems, numerous methods were employed such as self-assembled supramolecular porphyrinoid nanostructures, construction of organic frameworks, combination with 2D materials and adsorption onto semiconductors. The dye sensitization on semiconductors opened the way for molecular-based dye-sensitized photoelectrochemical cells (DSPECs) devices based on porphyrins and phthalocyanines. The research in photocatalytic systems as discussed herein remains challenging since there are still many limitations making them unfeasible to be used at a large scale application before finding a large-scale application.

Imidazole substituted Zinc(II) phthalocyanines for co-catalyst-free photoelectrochemical and photocatalytic hydrogen evolution: influence of the anchoring group.

Novel zinc phthalocyanine derivatives, ZnPc-1 and ZnPc-2, consisting of one and four imidazole units, respectively, have been synthesized and utilized as panchromatic photosensitizers for photocatalytic and photoelectrochemical H2 evolution. The effect of the imidazole-anchoring group on the photocatalytic H2 production has been compared with ZnPc-3, which possesses a carboxylic acid unit as the anchoring group. ZnPc-1/TiO2 shows the best photoactivity with the highest H2 evolution rate of 0.4006 mmol g-1 h-1, which is much higher than that of ZnPc-2/TiO2 and ZnPc-3/TiO2 (0.3319 mmol g-1 h-1 and 0.3555 mmol g-1 h-1, respectively). After 20 h of irradiation, ZnPc-1 produces an H2 production rate of 3.4187 mmol g-1 with a turnover number (TON) of 14863 and a solar-to-hydrogen energy (STH) conversion efficiency of 1.03%, without using a co-catalyst.

Detection of Kallikrein-Related Peptidase 4 with a Label-free Electrochemical Impedance Biosensor Based on a Zinc(II) Phthalocyanine Tetracarboxylic Acid-Functionalized Disposable Indium Tin Oxide Electrode.

A new impedimetric biosensing system based on kallikrein-related peptidase 4 (KLK 4) antigen-specific antibodies and a zinc(II) phthalocyanine tetracarboxylic acid (Zn-PcTCa) matrix material was developed for the first time in this study. First, a Zn-PcTCa-coated indium tin oxide surface was used as an interface matrix material for the immobilization of anti-KLK 4 antibodies, and they bound to the platform via amide bonds. In the presence of KLK 4 antigens, the anti-KLK 4 antibodies specifically captured these antigens and caused changes in the electrochemical properties of the system. Randles equivalent circuit was utilized to evaluate the impedimetric signal, which was measured with the help of an electrochemical impedance spectroscopy method. After the specific interaction, the electron transfer resistance (Rct) was remarkably increased and displayed a linear relationship with the level of the KLK 4 antigen in the range of 0.02-15 pg/mL, with a a detection limit of 6.8 fg/mL. The designed biosensor was able to detect a KLK 4 antigen with good sensitivity, excellent specificity, and high stability. In addition, because of having a low-cost and robust procedure for fabrication, it could be repeatedly used in several areas including clinical diagnosis.

Subphthalocyanine-sensitized TiO2 photocatalyst for photoelectrochemical and photocatalytic hydrogen evolution.

A series of SubPcs comprising a carboxylic acid anchoring group at the peripheral (SubPcs 1, 2) or axial position (SubPc 3) were synthesized and used as sensitizers for photocatalytic H2 production, for the first time. SubPc 3/TiO2 shows the best photocatalytic activity with a hydrogen evolution rate of 1396 µmol h-1, which is much higher than that of SubPcs 1 and 2 (771 and 658 µmol g-1, respectively). This work clearly shows that considering their optical and redox properties, SubPcs are promising candidates for light-driven water splitting systems.

Radiolabeling, In Vitro Cell Uptake, and In Vivo Photodynamic Therapy Potential of Targeted Mesoporous Silica Nanoparticles Containing Zinc Phthalocyanine.

Photodynamic therapy (PDT) is a noninvasive therapy based on the photodynamic effect. In this study, we sought to determine intracellular uptake and in vivo photodynamic therapy potential of Zn phthalocyanine-loaded mesoporous silica nanoparticles (MSNP5) against pancreatic cancer cells. MSNP5 were labeled with 131I; the radiolabeling efficiency was found to 95.5 ± 1.2% in pH 9 and 60 min reaction time. Besides, the highest intracellular uptake yields of 131I-MSNP5 nanoparticles in MIA PaCa-2, AsPC-1, and PANC-1 cells were determined as 43.9 ± 3.8%, 41.8 ± 0.2%, and 37.9 ± 1.3%, respectively, at 24 h incubation time. In vivo PDT studies were performed with subcutaneous xenograft cancer model nude mice with AsPC-1 pancreatic cancer cells. For photodynamic therapy, 685 nm red laser light 100 J/cm2 light dose using and 5-20 µM ZnPc containing MSNP5 concentrations were applied. Histopathological studies revealed that the ratio of necrosis in tumor tissue was higher in the treatment group than the control groups.

Photo induced anti-inflammatory activities of a Thiophene substituted subphthalocyanine derivative.

Materials that possess photo induced biological activities present opportunities for more localized, targeted and efficient treatment options that may also reduce side effects. There have been studies supporting photo induced effects of photosensitizers as anti-cancer, anti-inflammatory and anti-microbial agents. In this study, we tested photo activated anti-inflammatory effects of a Thiophene substituted subphthalocyanine (SubPc) derivative. Thiophene and its derivatives are well known for their anti-inflammatory and anti-microbial effects. There are unwanted side effects associated with Thiophene derivatives. By substituting this biologically active molecule to SubPc structure we acquired control over its activation. Upon light treatment this derivative exerted anti-inflammatory activity on the mammalian macrophages in vitro based on the substantial decrease in extracellular inflammatory cytokine levels. Our results suggest that Thiophene substituted SubPc derivative has photo induced anti-inflammatory activities. This material can be used for the treatment of patients suffering from chronic inflammation that are not associated with a bacterial burden such as autoimmune diseases and inflammatory or allergic reactions.

Antifungal photodynamic activities of phthalocyanine derivatives on Candida albicans.

Antimicrobial resistance is one of the most important causes of morbidity and mortality in the treatment of infectious diseases worldwide. Candida albicans is one of the most virulent and common species of fungi to cause invasive fungal infections on humans. Alternative treatment strategies, including photodynamic therapy, are needed for controlling these infectious diseases. The aim of this study was to investigate the antifungal photodynamic activities of phthalocyanine derivatives on C. albicans. The minimum inhibitory concentration (MIC) values of compounds were determined by the broth microdilution method. Uptake of the compounds in C. albicans and dark toxicity of the compounds were also investigated. Photodynamic inhibition of growth experiments was performed by measuring the colony-forming unit/mL (CFU/mL) of the strain. Maximum uptake into the cells was observed in the presence of 64 µg/mL concentration for each compound except for ZnPc. Compounds did not show dark toxicity/inhibitory effects at sub-MIC concentrations on C. albicans when compared to the negative control groups. Zn(II)Pc, ZnPc, and ZnPc-TiO2 showed fungicidal effect after irradiation with the light dose of 90 J/cm2 in the presence of the compounds. In addition to the fungicidal effects, SubPc, SubPc-TiO2, Es-SiPc, and Es-SubPc compounds were also found to have inhibitory effects on the growth of yeast cells after irradiation.

Anti-Cancer and Anti-Inflammatory Activities of Bromo- and Cyano-Substituted Azulene Derivatives.

Natural products and their synthetic derivatives gathered attention due to their pharmaceutical capacities. They have been in use against different types of diseases ranging from cancer to inflammatory disorders. In order to increase their efficacy and prevent the possible side effects, these natural compounds are manipulated at the laboratory conditions and modified according to our needs. Azulene is one of these compounds whose anti-inflammatory potential have been shown by the previous studies, but a detailed analysis of its effect at the cellular level in terms of pro-inflammatory cytokine production has not been studied yet. Moreover, its derivative potential has not been characterized extensively. In our study, we examined the cytotoxic, immunomodulatory and immunostimulatory potential of bromo- and cyano-substituted azulenes on the mammalian macrophages. These unique compounds had differential effects on the production of pro-inflammatory cytokines and they were anti-inflammatory immunomodulators. Furthermore, they exerted anti-proliferative effect on breast and prostate cancer cells which supports their anti-cancer potential as well.

Immunomodulatory activities of zinc(II)phthalocyanine on the mammalian macrophages through p38 pathway: Potential ex vivo immunomodulatory PDT reagents.

A series of zinc phthalocyanine having imidazolyl moieties was synthesized. These compounds' immunostimulatory and immunomodulatory activities were tested on the mammalian macrophages in vitro. In the absence of photo induction neither dmso soluble nor the water soluble imidazole Pc had any immunostimulatory or immunomodulatory effect on the macrophage activity based on the differences in the pro-inflammatory cytokine secretion levels compared to the control groups. Upon photo induction, especially, at 5 min exposure time both derivatives lead to an increased pro-inflammatory cytokine secretion level by LPS activated macrophages. Whereas, this effect was completely reversed after 10 min of light treatment and both derivatives gained stark anti-inflammatory potential. Our molecules were cell penetrating and exerted their effects by regulating the phosphorylation levels of p38. This study is one of its first examples suggesting differential immunomodulatory photo dynamic therapy applications of phthalocyanine derivatives depending on light exposure time as well as their possible route of modulating the intracellular signaling pathways.

Azulenocyanines immobilized on graphene; on the way to panchromatic absorption and efficient DSSC blocking layers.

Herein, a novel electron donor-acceptor hybrid consisting of a NIR absorbing azulenocyanine as an electron donor and few-layer graphene as an electron acceptor was prepared. The extended aromatic core of azulenocyanine (1) assists in the exfoliation of graphite and allows the formation of a very high-quality few-layer graphene azulenocyanine hybrid system (2). The formation of a stable azulenocyanine/graphene hybrid was verified by means of an arsenal of spectroscopic and microscopic techniques. Notable is the fact that the absorption spectrum recorded for 1 and likewise that for 2 covers large portions of the solar spectrum, that is, from the UV through the visible to the NIR region. In light of the latter, we incorporated 1 as well as 2 as a photosensitizer in dye sensitized solar cells (DSSCs) and probed their light harvesting. Besides an increase in the photovoltaic conversion efficiency we focused on the stability of DSSCs by preventing charge recombination between FTO and the liquid electrolyte. We used 2 as a blocking layer and in comparison with a TiCl4 pretreated blocking layer a superior conversion efficiency was realized.

Subphthalocyanine as a fluorescence imaging agent for breast tumor.

Tri-tert-butyl-carboxyl subphthalocyanine (SubPc) was synthesized and evaluated as a fluorescence agent. Fluorescence imaging for breast tumor in vivo was performed using nude mice as models. Results indicate high uptake in tumor at 20 h. Tumor-non tumor ratio was determined as 2.25. The imaging results demonstrate the potential of this fluorescence-imaging agent in the diagnosis of breast tumor. In the future, subphthalocyanine is also developing as a dual functional, which is fluorescence imaging and as a photodynamic therapeutic agent for the treatment and diagnosis of cancer.

Photo-induced anti-inflammatory activities of chloro substituted subphthalocyanines on the mammalian macrophage in vitro.

In this study, a series of subphthalocyanines (SubPcs) derivatives were synthesized to generate unique immunomodulatory molecules that can be activated through photo-induction. Immunomodulatory agents have a great potential in medicine to manipulate the immune system according to our needs and prevent disease symptoms. Inflammation is one of these symptoms and macrophages play a crucial role in the generation of inflammatory responses. Being able to control the activity of these agents through photo-induction enables the fine tuning on their activities in a location specific and non-invasive manner with possibly minor side effects. Mammalian macrophages' pro-inflammatory activity was examined in the presence of our compounds as well as LPS as a danger mimic. These compounds exerted photo-induced anti-inflammatory activities on the macrophages. Number of Cl atoms was a defining factor in their photo-induced anti-inflammatory immunomodulatory efficiencies.

Selective Photokilling of Human Pancreatic Cancer Cells Using Cetuximab-Targeted Mesoporous Silica Nanoparticles for Delivery of Zinc Phthalocyanine.

BACKGROUND: Photodynamic therapy (PDT) is a non-invasive and innovative cancer therapy based on the photodynamic effect. In this study, we sought to determine the singlet oxygen production, intracellular uptake, and in vitro photodynamic therapy potential of Cetixumab-targeted, zinc(II) 2,3,9,10,16,17,23,24-octa(tert-butylphenoxy))phthalocyaninato(2-)-N29,N30,N31,N32 (ZnPcOBP)-loaded mesoporous silica nanoparticles against pancreatic cancer cells. RESULTS: The quantum yield (ΦΔ) value of ZnPcOBP was found to be 0.60 in toluene. In vitro cellular studies were performed to determine the dark- and phototoxicity of samples with various concentrations of ZnPcOBP by using pancreatic cells (AsPC-1, PANC-1 and MIA PaCa-2) and 20, 30, and 40 J/cm² light fluences. No dark toxicity was observed for any sample in any cell line. ZnPcOBP alone showed a modest photodynamic activity. However, when incorporated in silica nanoparticles, it showed a relatively high phototoxic effect, which was further enhanced by Cetuximab, a monoclonal antibody that targets the Epidermal Growth Factor Receptor (EGFR). The cell-line dependent photokilling observed correlates well with EGFR expression levels in these cells. CONCLUSIONS: Imidazole-capped Cetuximab-targeted mesoporous silica nanoparticles are excellent vehicles for the selective delivery of ZnPcOBP to pancreatic cancer cells expressing the EGFR receptor. The novel nanosystem appears to be a suitable agent for photodynamic therapy of pancreatic tumors.

Immunostimulatory effect of Zinc Phthalocyanine derivatives on macrophages based on the pro-inflammatory TNFα and IL1ß cytokine production levels.

In this study, we examined the effect of halogen substitution on the ability of ZnPcs to stimulate or regulate the immune system cells. There have been studies focusing on the usage of Pcs as treatment option against different cancer types. More attention should be paid on their possible positive or negative effects on the immune system for better prognosis rates. We designed and synthesized unique ZnPcs with iodine substitution and further tested their effect on mammalian macrophage cell line. Macrophages are crucial cell types that can define the immune response by cytokine production as well as by antigen presentation to the other immune system cells after phagocytosis of the danger associated molecules. Our results suggest an immunostimulatory role for the iodine substituted ZnPc on macrophages based on the changes in pro-inflammatory cytokine production levels (TNFα, IL1ß and IL6). This effect dependent on the presence of iodine; since non-substituted ZnPc did not exert such a stimulatory activity on the macrophages. These results support a possible use of the reagents against the tumor types that would get affected detrimentally by the pro-inflammatory environment.

Photophysicochemical properties and photodynamic therapy activity of highly water-soluble Zn(II) phthalocyanines.

The syntheses of two zinc(II) phthalocyanines (ZnPcs) having either imidazole (ZnPc 1) or pyridiloxy (ZnPc 2) moieties as their macrocycle substituents are reported. Quaternization of the ZnPcs with methyl iodide afforded water soluble cationic phthalocyanines. The photophysical, photochemical properties and photodynamic therapy (PDT) activity of the ZnPcs were studied in solution. The fluorescence quantum yield and lifetime of ZnPc 1 were higher as compared to ZnPc 2. ZnPc 2 afforded higher triplet state (ΦT) and singlet oxygen quantum yields (ΦΔ) in comparison to ZnPc 1. The PDT activity of ZnPcs was investigated against human breast adenocarcinoma cells (MCF-7). The two compounds afforded a very minimal in vitro dark cytotoxicity with 85% viable cells at concentration ≤80 µM. On irradiation of the cells having the ZnPcs, ≥50% cell death was recorded for ZnPc 1 which was also evidenced by the cells photo-micrograph.

Photoinduced Energy Transfer in ZnCdSeS Quantum Dot-Phthalocyanines Hybrids.

In this article, interaction between ZnCdSeS quantum dot (QD) and phthalocyanines with variable linker has been reported. Steady-state and time-resolved spectroscopic investigation reveals that only photoinduced energy transfer occurs from QD to phthalocyanines. To evaluate quantitatively the energy transfer, the Poisson statistics of QD-dye complex formation was used in the analysis of steady-state and time-resolved emission quenching, which allows to estimate the energy transfer rate constant for an ideal one-to-one complex. The measured rate constants are compared to the rates evaluated based on the classic Förster theory, which shows roughly 1 nm discrepancy in the energy transfer distance estimation, or one order in magnitude discrepancy in the transfer rate constants.

Photodynamic therapy and nuclear imaging activities of zinc phthalocyanine-integrated TiO2 nanoparticles in breast and cervical tumors.

In recent years, phthalocyanines (Pcs) have been widely used as photosensitizer in photodynamic therapy applications. Because of their strong absorptions in the near-infrared region (640-700 nm). The integration of phthalocyanine derivatives to a nanoparticle is expected to be efficient way to improve the activity of the photosensitizer on the targeted tissue. It is known that the integrated molecules not only show better accumulation on tumor tissue but also reduce toxicity in healthy tissues. In this study, the ZnPc molecule was synthesized and integrated to the TiO2 nanoparticle, to investigate the potential of PDT and its cytotoxicity. Additionally, ZnPc and ZnPc-TiO2 molecules were labeled with 131 I and it was aimed to put forth the nuclear imaging/therapy potentials of 131 I labeled ZnPc/ZnPc-TiO2 by determining in vitro uptakes in mouse mammary carcinoma (EMT6), human cervical adenocarcinoma (HeLa). In result of our study, it was observed that the radiolabeling yields of the synthesized ZnPc and ZnPc-TiO2 with 131 I were quite high. In vitro uptake studies shown that 131 I-ZnPc-TiO2 could be a potential agent for nuclear imaging/treatment of breast and cervical cancers. According to PDT results, ZnPc-TiO2 might have as to be a potential PDT agent in the treatment of cervical tumor. ZnPc and ZnPc-TiO2 might be used as theranostic agents.

Investigation of in vitro PDT activities of zinc phthalocyanine immobilised TiO2 nanoparticles.

Phthalocyanines (Pcs) are commonly used as Photosensors (PSs) in Photodynamic Therapy (PDT) applications due to their intense absorption in the far red-near IR spectral region with a high extinction coefficient and high ability for generating singlet oxygen. Pcs targetspecifically tumors, and do not show any considerable toxic effects under the absence of light. In particular, their chemical versatility has allowed the introducion a number of substituent at the periferal or axial positions which provide modulating photophysical properties, increases the solubility of these compounds in organic solvents. Nanoparticles increase the bioavailability, stability, and transport of PSs to target tissue. TiO2 nanoparticles are prefered in these applications because of their non toxic, low cost and high chemical stability properties. In our study, a Zinc Phthalocyanine (ZnPc) was used as a photosensor. The design of ZnPc integrated TiO2 nanoparticles is intended to make PSs a more effective PDT agent. With the aim to examine the nuclear imaging/treatment potentials of ZnPc and ZnPc-TiO2 in hepatocellular carcinoma (HepG2), colorectal adenocarcinoma (HT29) tumor and human healthy lung (WI38) cell lines in vitro study ZnPc and TiO2-ZnPc were also labeled with 131I. It is determined that 131I-ZnPc-TiO2 nanoparticle show a potential as an agent for the imaging/treatment of hepatocellular cancer by in vitro. The toxicity studies revealed that TiO2 nanoparticle decreases the toxicity of ZnPc. In vitro PDT results show that TiO2-ZnPc has a potential as a PDT agent in colon tumor treatment. Consequently, synthesized ZnPc and ZnPc-TiO2 could be promising candidates as theranostic agents.