Aluminum Phthalocyanine Chloride Research Articles

Spectroscopic analysis of aluminum chloride phthalocyanine in binary water/ethanol systems for the design of a new drug delivery system for photodynamic therapy cancer treatment

This study evaluated the behavior of aluminum chloride phthalocyanine in a binary water/ethanol mixture using electronic absorption spectroscopy and static and time-resolved fluorescence spectroscopy. The electronic absorption spectra, resonance light scattering and fluorescence quenching of aluminum chloride phthalocyanine in water/ethanol mixtures were studied at several concentrations. The electronic absorption spectra and fluorescence quenching changed significantly at approximately 50% water (v/v). Below 50% water, the dimerization constant values were negative (−2609.2M−1 and −506.5M−1 at 30% and 40% of water, respectively), indicating that the formation of aggregates under these conditions is not favored. However, at 50% water, the dimerization constant value was estimated to be 559.7M−1, which indicates the presence of dimers. Above 60% water, the aggregation process was responsible for the balance between large complexes (such as trimers, tetramers or oligomers) formed in the medium under these conditions. The appearance of new absorption bands at 387nm and 802nm and their bathochromic shift relative to the monomer bands suggested that some J-type aggregates form. These results are relevant to understanding the behavior and use of aluminum chloride phthalocyanine in the design of new drug delivery systems for clinical application in photodynamic therapy as a new approach to treat skin cancer.

Small-molecule organic solar cells with multiple-layer donor

Small-molecule organic solar cells (OSCs) with a multifunction three-layer donor are experimentally investigated to achieve higher power conversion efficiency. The proposed OSC has an indium tin oxide (ITO, anode)/three-layer donor/fullerene (C60, acceptor, 40 nm)/bathocuproine (BCP, cathode buffer, 10 nm)/Ag (cathode, 100 nm) structure. The three-layer donor is composed of 3-nm-thick pentacene/20-nm-thick copper phthalocyanine (CuPc)/5-nm-thick aluminum phthalocyanine chloride (ClAlPc). The OSC achieves a power conversion efficiency of 1.79%, which is 1.7 times as large as that for an OSC with a single-layer donor of 20-nm-thick CuPc. Atomic force microscopy observation is carried out to clarify in detail the surface morphology at typical organic layers. The acceptor C60 is in contact not only with ClAlPc but also with CuPc due to the vertical and wall-like growth of the ClAlPc layer. The open-circuit voltage for the OSC with the ClAlPc/C60 contact is 0.56 V, compared with 0.47 V for the OSC with the CuPc/C60 contact. The thin pentacene layer is uniformly grown on the ITO and serves to achieve a high short-circuit current density Jsc by lowering the barrier height for hole transport between ITO and CuPc. Jsc for the OSC with the thin pentacene layer is 5.60 mA/cm2, compared with 4.32 mA/cm2 for the OSC without the thin pentacene layer.

Reactive oxygen and nitrogen species disturb Ca2+ oscillations in insulin-secreting MIN6 β-cells

Disturbances in pulsatile insulin secretion and Ca2+ oscillations in pancreatic β-cells are early markers of diabetes, but the underlying mechanisms are still incompletely understood. Reactive oxygen/nitrogen species (ROS/RNS) are implicated in reduced β-cell function, and ROS/RNS target several Ca2+ pumps and channels. Thus, we hypothesized that ROS/RNS could disturb Ca2+ oscillations and downstream insulin pulsatility. We show that ROS/RNS production by photoactivation of aluminum phthalocyanine chloride (AlClPc) abolish or accelerate Ca2+ oscillations in the MIN6 β-cell line, depending on the amount of ROS/RNS. Application of the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) inhibitor thapsigargin modifies the Ca2+ response to high concentrations of ROS/RNS. Further, thapsigargin produces effects that resemble those elicited by moderate ROS/RNS production. These results indicate that ROS/RNS interfere with endoplasmic reticulum Ca2+ handling. This idea is supported by theoretical studies using a mathematical model of Ca2+ handling adapted to MIN6 cells. Our results suggest a putative link between ROS/RNS and disturbed pulsatile insulin secretion.

Structural and optical properties of nanocrystalline aluminum phthalocyanine chloride thin films

Thin films of aluminum phthalocyanine chloride (AlPcCl) were fabricated, with different thicknesses (109–518nm) using thermal evaporation technique. Structural and optical properties of AlPcCl thin films were investigated. The material in powder form showed a polycrystalline nature with monoclinic structure. Miller indices, hkl, values for each diffraction line in X-ray diffraction (XRD) spectrum were calculated. The field emission scanning electron microscope (FESEM) showed the nanostructure property of the as-deposited thin films. The optical properties of the thin films were studied by the spectrophotometric measurements of the transmittance, T, and the reflectance, R, at the normal incidence of the light in the spectral range 200–2500nm. The refractive and absorption indices of the thin films were calculated and were found to be independent of film thickness of 109–518nm. The films exhibited indirect allowed inter-band transitions. The optical band gaps transitions were calculated as 1.42, 2.87 and 3.69eV, respectively. Also, different dispersion and absorption parameters were determined for thin films of AlPcCl.

Enhancement of the photokilling effect of aluminum phthalocyanine in photodynamic therapy by conjugating with nitrogen-doped TiO2 nanoparticles

As a second-generation photodynamic therapy (PDT) photosensitizer, aluminum phthalocyanine chloride tetrasulfonate (Pc) has gained great attention due to its high absorption at the red light region. Yet, its application in PDT is strongly limited by its low cellular uptake efficiency. In this report, nitrogen-doped TiO2 nanoparticles (N–TiO2) conjugated with Pc are synthesized by a two-step surface modification method. The N–TiO2–Pc products are characterized by Zeta potential, transmission electron microscopy and UV–vis absorption spectroscopy. The cellular uptake, intracellular distribution, cytotoxicity and the photokilling effect of the nanoparticles are studied on different cancer cell lines. Compared with Pc, the absorption spectrum of N–TiO2–Pc expands from red to UV region, resulting in a higher production of reactive oxygen species under visible light irradiation. In addition, the cellular uptake of Pc is largely improved by its carrier N–TiO2. The photokilling efficiency of N–TiO2–Pc is over ten times higher than that of Pc. The results suggest that N–TiO2–Pc is an excellent candidate as a photosensitizer in PDT.

Gamma radiation-induced changes on the structural and optical properties of aluminum phthalocyanine chloride thin films

Thin films of aluminum phthalocyanine chloride (AlPcCl) were prepared by thermal evaporation technique under high vacuum at room temperature. The prepared films were divided into two groups for study; the first was the as – deposited films, the second group was irradiated in gamma cell type 60Co source in air at room temperature with different absorbed doses (20–60kGy). The surface morphology of γ-irradiated film was observed with a higher aggregation compared with as-deposited film with an average particles size of (10–28nm). The optical parameters were obtained using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in wavelengths range of 200–2500nm. The type of optical transition was found to be an indirect allowed transition, the band gaps decrease with increasing γ-irradiation doses. The calculated dispersion parameters of AlPcCl films decreased with increasing the γ-irradiation dose. The disagreement between the obtained values of ε∞ and εL may be attributed to the lattice vibration and free carrier contribution.

Formulation of Aluminum Chloride Phthalocyanine in Pluronic(™) P-123 andF-127 Block Copolymer Micelles: Photophysical properties and Photodynamic Inactivation of Microorganisms.

Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic Inactivation of Microorganisms (PDI). The AlPcCl showed favorable characteristics for PDI due to high quantum yield of singlet oxygen (ΦΔ ) and photostability. Physicochemical properties and photodynamic inactivation of AlPcCl incorporated in polymeric micelles of tri-block copolymer (P-123 and F-127) against microorganisms Staphylococcus aureus, Escherichia coli and Candida albicans were investigated in this work. Previously, it was observed that the AlPcCl undergoes self-aggregation in F-127, while in P-123 the PS is in a monomeric form suitable for PDI. Due to the self-aggregation of AlPcCl in F-127, this formulation did not show any effect on these microorganisms. On the other hand, AlPcCl formulated in P-123 was effective against S.aureus and C.albicans and the death of microorganisms was dependent on the PS concentration and illumination time. Additionally, it was found that the values of PS concentration and illumination time to eradicate 90% of the initial population of microorganisms (IC90 and D90 , respectively) were small for the AlPcCl in P-123, showing the effectiveness of this formulation for PDI.

The photosensitized oxidation of mixture of parabens in aqueous solution.

The work presents results of studies on the photosensitized oxidation of mixture of five parabens (methyl-, ethyl-, propyl-, n-butyl-, and benzylparaben) in aqueous solution. Aluminum phthalocyanine chloride tetrasulfonic acid and xenon lamp simulating solar radiation were used as a photosensitizer and a light source, respectively. The purpose was to investigate the influence of inhibitory effect compounds present in the mixture on the reaction rate. The influence of the addition of second photosensitizer on the parabens degradation rate was investigated. The effect of additives: tert-butanol-hydroxyl radical scavenger and sodium azide-singlet oxygen scavenger on reaction course was also determined. The transformation products formed during the photosensitized oxidation process were analyzed by UPLC-MS/MS. The efficiency of photosensitized oxidation of parabens with natural sunlight irradiation in the central Poland was checked.

SPECTROSCOPIC STUDY OF ALUMINUM PHTHALOCYANINE CHLORIDE (AlPcCl) IN HOMOGENEOUS AND MICRO-HETEROGENEOUS MEDIA CONSISTING OF P-123 AND F-127 POLYMERIC MICELLES

Aluminum phthalocyanine chloride (AlPcCl) is a photoactive compound which has been used as a photosensitizer (PS) in photodynamic therapy (PDT). Its spectroscopic properties have been studied in solvents of different polarities (ethanol, acetone, dimethylsulfoxide and chloroform). Its solubility has been found to decrease with increasing solvent polarity, together with full self-aggregation in aqueous solution. The binding of AlPcCl to the copolymer PluronicTM micellar class P-123 and F-127 used as solubilizer/carriers was studied. Greater interaction between the more hydrophobic copolymer P-123 and AlPcCl was observed, besides a complex interaction profile involving different AlPcCl forms (self-aggregate/monomeric form) in the copolymers. Time- and temperature-dependent structural organization of AlPcCl in the copolymers was also observed. Thus, AlPcCl has a strong tendency to self-aggregate with increasing solvent polarity, an effect also observed in micellar media.

Aluminum–phthalocyanine chloride associated to poly(methyl vinyl ether-co-maleic anhydride) nanoparticles as a new third-generation photosensitizer for anticancer photodynamic therapy

Photodynamic therapy is generally considered to be safer than conventional anticancer therapies, and it is effective against different kinds of cancer. However, its clinical application has been significantly limited by the hydrophobicity of photosensitizers. In this work, a system composed of the hydrophobic photosensitizer aluminum–phthalocyanine chloride (AlPc) associated with water dispersible poly(methyl vinyl ether-co-maleic anhydride) nanoparticles is described. AlPc was associated with nanoparticles produced by a method of solvent displacement. This system was analyzed for its physicochemical characteristics, and for its photodynamic activity in vitro in cancerous (murine mammary carcinoma cell lineage 4T1, and human mammary adenocarcinoma cells MCF-7) and noncancerous (murine fibroblast cell lineage NIH/3T3, and human mammary epithelial cell lineage MCF-10A) cell lines. Cell viability and the elicited mechanisms of cell death were evaluated after the application of photodynamic therapy. This system showed improved photophysical and photochemical properties in aqueous media in comparison to the free photosensitizer, and it was effective against cancerous cells in vitro.

Investigation of optical properties of annealed aluminum phthalocyanine derivatives thin films

Semiconducting molecular materials based on aluminum phthalocyanine chloride (AlPcCl) and bidentate amines have been successfully used to prepare thin films by using a thermal evaporation technique. The morphology of the deposited films was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Studies of the optical properties were carried out on films deposited onto quartz and (100) monocrystalline silicon wafers and films annealed after deposition. The absorption spectra recorded in the UV–vis region for the as-deposited and annealed samples showed two absorption bands, namely the Q- and B-bands. In addition, an energy doublet in the absorption spectra of the monoclinic form at 1.81 and 1.99eV was observed. A band-model theory was employed in order to determine the optical parameters. The fundamental energy gap (direct transitions) was determined to be within the 2.47–2.59 and 2.24–2.44eV ranges, respectively, for the as-deposited and annealed thin films.

Aluminium phthalocyanine chloride thin films for temperature sensing

This study presents the fabrication and temperature sensing properties of sensors based on aluminium phthalocyanine chloride (AlPcCl) thin films. To fabricate the sensors, 50-nm-thick electrodes with 50-μm gaps between them are deposited on glass substrates. AlPcCl thin films with thickness of 50–100 nm are deposited in the gap between electrodes by thermal evaporation. The resistance of the sensors decreases with increasing thickness and the annealing at 100 °C results in an increase in the initial resistance of sensors up to 24%. The sensing mechanism is based on the change in resistance with temperature. For temperature varying from 25 °C to 80 °C, the change in resistance is up to 60%. Simulation is carried out and results obtained coincide with experimental data with an error of ±1%.

Aluminum phthalocyanine chloride as a hole injection enhancer in organic light-emitting diodes

The characteristics of organic light-emitting diodes (OLEDs) with aluminum phthalocyanine chloride (AlPcCl) as an anode buffer layer were investigated. The basic structure of OLED is indium-tin oxide (ITO)/N,N′-di(naphth-2-yl)-N,N′-diphenyl-benzidine (NPB)/tris(8-hydroxyquinoline) aluminum (Alq3)/lithium fluoride (LiF)/aluminum (Al). AlPcCl inserted at the ITO/NPB interface as an anode buffer layer can enhance hole injection, and thus current density, luminance as well as efficiency. Based on the energy level and Richardson–Schottky (R–S) thermionic emission theory, the enhanced performance can be explained. Additionally, the effect of the deposition rate of AlPcCl on the device performance was also examined. The results show that the optimal deposition rate of AlPcCl is 0.05nm/s.

Electrical and photosensing performance of heterojunction device based on organic thin film structure

In this work, the heterojunction thin films of aluminum phthalocyanine chloride on N,N′-dioctyl-3,4,9,10-perylenedicarboximide device was fabricated by using thermal evaporation technique under high vacuum (∼10−4Pa). The morphology of the device was characterized by scanning electron microscopy (SEM). The dark current density–voltage (J–V), capacitance–frequency (C–f) and conductance measurements at different temperatures in the range 300–425K were performed to determine the electrical properties of the device. The exponent of the light intensity dependence for the short-circuit photocurrent (Jsc) of the device indicates the presence of continuous distribution of traps. The device showed improvement in the open circuit voltage as compared to other organic compounds. The photosensitivity of the device was calculated and found to be 3.1 at ±1V under illumination intensity of 100mW/cm2. This suggested that the device shows a photodiode characteristic. The interface state density of the device was determined using the conductance technique and was found to be low which suggested that the interface states at this density range are not effective on the device characteristics which supports the efficient properties for the studied device.

EPR investigation of the origin of the magnetic field effect on the dimerization of aluminum(III) and gallium(III) phthalocyanine chlorides in film structures

The origin of the magnetic field effect on the dimerization of aluminum(III) and gallium(III) phthalocyanine chloride films is revealed. The EPR technique is employed to demonstrate that the dimerization of the above coordination compounds occurs via a free radical pathway with the formation of phthalocyanine and OH radicals, thus resulting in the appearance of the magnetic moment in the studied compounds.

Development of experimental protocol for photodynamic therapy on colorectal tumors: determination of irradiation by fluorescence spectroscopy

In the last decades, there was a significant improvement in traditional techniques such as surgery, chemotherapy and radiotherapy used to treat different types of neoplasias. Such therapies have intense side effects because they are not selective to the tumor tissue and these limitations and disadvantages have led to the search and development of new therapeutic alternatives to treat cancer, including photodynamic therapy (PDT) which, according to several studies conducted in the last two decades, have proved effective in malignant and pre‐malignant conditions, such as head and neck tumors, lung cancer, prostate cancer, brain tumors, duodenal and colorectal tumors. However, there is difficulty in determining the optimal protocol of PDT considering the main variables involved such as laser and photosensitive drugs. Kinects by fluorescence spectroscopy in tumors can be a useful tool to verify the ideal period of irradiation after photosensitive administration. This work developed a new protocol of kinects by fluorescence spectroscopy in colorectal tumor in Wistar rats to support the photodynamic therapy. For this protocol it was used chloroaluminum phthalocyanine tetrasulfonate and aluminum phthalocyanine chloride incorporated into liposomes as photosensitive drugs. The kinetics of both drugs was performed by means of fluorescence spectroscopy during 48h monitoring of chemically induced colorectal tumors in Wistar rats. The best irradiation period indicated by kinetics for both drugs was between 22 and 26 hours and the fluorescence spectroscopy has been showed useful to determine the PDT irradiation.

Actividad fotodinámica de ftalocianina de aluminio (iii) y zinc (ii) en promastigotes de Leishmania

Photodynamic therapy is a two-step procedure, involving the use of photosensitizing agents followed by selective illumination of the target lesion with visible light. It produces highly reactive oxygen species and subsequent cellular damage. This study was designed to determine whether Leishmania chagasi and L. panamensis promastigotes were sensitive to photodynamic therapy in vitro. Leishmania promastigotes were treated with aluminium phthalocyanine chloride and zinc phthalocyanine photosensitizers before illumination with visible light at 670 nm. The parasite photoactivity was calculated by sigmoidal regression analysis. Leishmania chagasi promastigotes were highly photosensitive to aluminium phthalocyanine chloride treatment with effective inhibitory dose50 (ED50) concentration values of 0.0033, 0.0083 and 0.0093 microM upon exposure to 10.0, 5.0, and 2.5 J/cm2 light intensities respectively. By contrast, the activity of aluminium phthalocyanine chloride on L. panamensis was significantly lower (P < 0.01) with ED50 values of 0.17, 0.25, 0.34 microM at the same light intensities. Zinc phthalocyanine activity was significantly (P < 0.01) less active than aluminium phthalocyanine chloride on both strains of these two species and no differences in zinc phthalocyanine activity were found between them. A dose-response phototoxic effect with both phthalocyanines was observed. Parasite inhibition was not observed after aluminium phthalocyanine chloride or zinc phthalocyanine treatment in the dark. The reference drugs hexadecylphosphocholine and amphotericin B were not photoactive. Treatment of Leishmania promastigotes with aluminium phthalocyanine chloride and zinc phthalocyanine followed by illumination with visible light at 670 nm inhibited in vitro growth of promastigotes of L. chagasi and L. panamensis. Photodynamic therapy against Leishmania could be a promising strategy for leishmaniasis treatment.

Photoelectrode Characteristics of Partially Hydrolyzed Aluminum Phthalocyanine Chloride/Fullerene C60 Composite Nanoparticles Working in a Water Phase

Photoelectrochemical measurements were used to study the photoelectrode characteristics of composite nanoparticles composed of fullerene C60 and partially hydrolyzed aluminum phthalocyanine chloride (AlPc). In cyclic voltammetry measurements, the electrodes coated with the composite nanoparticles were found to have photoanodic [electron donor: 2-mercaptoethanol (ME)] and photocathodic (electron acceptor: O2) characteristics similar to those of the vapor-deposited p/n junction electrode. Their photoanodic features were further investigated with respect to the transient photocurrent response to light irradiation and the dependence on ME concentration (under potentiostatic conditions), from which it was noted that there was a decrease in the initial spiky photocathodic current and saturation of the steady-state photoanodic current at a higher ME concentration. Thus, the reaction kinetics was probably dominated by charge transport process. Moreover, external and internal quantum efficiency spectrum measurements indicated that the composite nanoparticles responded to the full spectrum of visible light (<880 nm) for both the photoanodic and photocathodic current. The present research will assist comprehension of photocatalytic behavior of the composite nanoparticles.

Humidity sensors based on aluminum phthalocyanine chloride thin films

In present paper, the fabrication and humidity sensing properties of aluminum phthalocyanine chloride (AlPcCl) thin film based sensors have been presented. AlPcCl thin films with nominal thickness of 50–100nm are deposited on glass substrates between pre-deposited 50nm thick aluminum electrodes. The gap between the electrodes is 50μm. It is observed that the sensing mechanism is based on the variation of resistance with change in humidity. For change in relative humidity (RH) from 20% to 92%, the change in resistance is 22.2×102 and 13.3×102 times respectively for the sensors having 50nm and 100nm thick AlPcCl films, while the 1h annealing of these samples at 100°C results in increase in average sensitivity up to 30% and 40% respectively. The consequence of measuring frequency and absorption–desorption behavior of the humidity sensor are also discussed in detail. It is also observed that annealing results in minimization of hysteresis and reduction of recovery time (τrec) up to 63% and 70% in sensors with 50nm and 100nm thick organic film respectively, while the response (τres) time is 10s for both the sensors.

Photocatalytic decomposition of N-methyl-2-pyrrolidone, aldehydes, and thiol by biphase and p/n junction-like organic semiconductor composite nanoparticles responsive to nearly full spectrum of visible light

Organic semiconductor nanoparticles composed of fullerene C60 and/or partially hydrolyzed aluminum phthalocyanine chloride (AlPc) were synthesized using a reprecipitation method. The composite's biphase structure was confirmed using scanning electron microscopy, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, zeta potential, and dynamic light scattering, and a possible formation mechanism for the biphase structure was also proposed. In the photodegradation experiments, the composite showed enhanced photocatalytic activity for the oxidation of various organic compounds (e.g. N-methyl-2-pyrrolidone, methanal, ethanal, and 2-mercaptoethanol (ME)) to CO2 as compared to the C60 or AlPc nanoparticles. Moreover, its action spectrum for the photocatalytic decomposition of ME to CO2 also covered almost the full spectrum of visible light (<700 nm). The present research demonstrated a novel organic photocatalyst featuring a biphase structure and p/n junction-like characteristics.