Aluminum Phthalocyanine Nanoparticles Research Articles

Theranostic Properties of Crystalline Aluminum Phthalocyanine Nanoparticles as a Photosensitizer.

The study of phthalocyanines, known photosensitizers, for biomedical applications has been of high research interest for several decades. Of specific interest, nanophotosensitizers are crystalline aluminum phthalocyanine nanoparticles (AlPc NPs). In crystalline form, they are water-insoluble and atoxic, but upon contact with tumors, immune cells, or pathogenic microflora, they change their spectroscopic properties (acquire the ability to fluoresce and become phototoxic), which makes them upcoming agents for selective phototheranostics. Aqueous colloids of crystalline AlPc NPs with a hydrodynamic size of 104 ± 54 nm were obtained using ultrasonic dispersal and centrifugation. Intracellular accumulation and localization of AlPc were studied on HeLa and THP-1 cell cultures and macrophages (M0, M1, M2) by fluorescence microscopy. Crystallinity was assessed by XRD spectroscopy. Time-resolved spectroscopy was used to obtain characteristic fluorescence kinetics of AlPc NPs upon interaction with cell cultures. The photodynamic efficiency and fluorescence quantum yield of AlPc NPs in HeLa and THP-1 cells were evaluated. After entering the cells, AlPc NPs localized in lysosomes and fluorescence corresponding to individual AlPc molecules were observed, as well as destruction of lysosomes and a rapid decrease in fluorescence intensity during photodynamic action. The photodynamic efficiency of AlPc NPs in THP-1 cells was almost 1.8-fold that of the molecular form of AlPc (Photosens). A new mechanism for the occurrence of fluorescence and phototoxicity of AlPc NPs in interaction with cells is proposed.

Generation of phthalocyanine nanoparticles by laser fragmentation

The optical properties and morphology of laser generated aluminum and copper phthalocyanine nanoparticles (nAlPc and nCuPc) in water are experimentally studied. A near-infrared laser source of nanosecond pulse duration was used for the fragmentation of a Pc micro-powder suspended in H2O. The extinction spectra in the visible and near-IR range of nanoparticle colloidal solutions in milli-Q water were acquired by means of optical spectroscopy. The optical density of both nCuPc and nAlPc increases with the laser fragmentation time. Transmission electron microscopy shows that nCuPcs are made of short (100 nm) rectangular bars interconnected at various angles with other bars. A similar morphology is observed for nAlPc.

The engraftment dynamics evaluation of skin grafts via aluminium phthalocyanine nanoparticles using spectroscopic methods

The research and comparison of spectroscopic methods for assessment of skin grafts engraftment/rejection after the back cross skin transplantation of laboratory mice were carried out. The spectral analysis was performed via inflammatory reaction evaluation of the studied area. The inflammatory reaction intensity correlates with the fluorescence intensity of the aluminum phthalocyanine nanoparticles. The photodynamic therapy was carried out to improve the skin engraftment and reduce the inflammatory reaction.

A novel spheroid model for preclinical intercellular nanophotosensitizer-mediated tumor study

Aluminum phthalocyanine nanoparticles (NP AlPc) possess the features that make them a promising photosensitizer. In particular, AlPc NPs do not fluoresce in free nanoform, fluoresce weakly in normal tissue, strongly in tumors and very strongly in macrophages. Also, such particles fluoresce and become phototoxic when contacting certain biocomponents. The type of biocomponents that bind to AlPc NPS defines intensity, lifetime, and spectral distribution of the fluorescence. This study aimed to investigate the peculiarities of nanophotosensitizer capturing in 3D models of cell cultures. The data obtained demonstrate that AlPc NPs are captured by cells inside the spheroid in the course of the first hour, as the fluorescent signal's growth shows. Having analyzed the fluctuations of the fluorescence signal of AlPc NPs inside a spheroid, we have also discovered that the cellular 3D models are heterogeneous. Laser irradiation (two-photon excitation at λ = 780/390 nm) resulted in photobleaching of fluorescence, which is probably associated with AlPc NP deactivation. Thus, the created model comprised of a 3D cell culture and AlPc NPs provides a better insight into metabolic processes in cells than monolayer 2D cell cultures. Besides, the model allows to evaluate the photodynamic effect depending on phenotypic properties of various areas in the heterogeneous 3D-structure.

Fluorescent diagnostics using aluminum phthalocyanine nanoparticles as a detection method for enamel microcracks

Early diagnosis of caries and enamel microcracks is of great importance for the prevention of the destruction of healthy tooth enamel. It was reported that aluminum phthalocyanine in the form of nanoparticles (nAlPc) can be used for fluorescent diagnostics of tooth enamel microcracks.A model compound with the nAlPc colloid and Protelan MST-35 were prepared for the development of the method of laser-induced fluorescent diagnostics (FD). Two groups of human teeth were used to research the interaction between the nAlPc colloid and the model compound for the detection of microcracks and the areas of accumulation of pathogenic microflora on the enamel surface. A Student’s two-sample unequal variances t-test was used to check whether the means of the coefficient of diagnostics contrast (kdc) between two groups of samples was significantly different. Experimental studies were conducted using a laser electronic spectro-analyser and a fluorescence video imaging system.The results of the studies of the nAlPc colloid interaction with the surface enamel of the tooth enamel ex vivo in the first group showed that in 3 min a low-intensity nAlPc fluorescence was observed. This was due to a slight activation of the surface molecules of nAlPc by a pathogenic microflora. Measurements of the interaction of the model compound (nAlPc colloid with the Protelan MST-35 and supplementary components) with the tooth enamel has shown that the high-intensity AlPc molecule fluorescence appears in the enamel microcracks 3 min after application. The high intensity of the fluorescence is accounted for by a preliminary activation of nAlPc by the surfactant as they meet pathogenic microflora. Statistical analysis of the results revealed a statistically significant difference between the kdc of the studied groups (α = 0.05).It has been concluded that the developed method of laser-induced FD of tooth enamel makes it possible to detect the hidden microcracks on the enamel surface and the hidden accumulation areas of the pathogenic microflora using the model compound.

Application of nanophotosensitizers (aluminum phthalocyanine nanoparticles) for early diagnosis and prevention of inflammatory diseases

This paper deals with a possibility of new types of photosensitizers application - Aluminum Phthalocyanine nanoparticles (nAlPc) in clinical practice for diagnosis, prevention and therapy of inflammatory diseases in dentistry and traumatology. It was detected that the aluminum phthalocyanine (AlPc) fluoresces in the nanoparticle form in the presence of pathologic microflora or inflammation process. It will make possible to detect the local accumulation of pathological microflora on the enamel surface and also for diagnostics and treatment of inflammatory diseases. Experimental studies of interaction of NP-AlPc with tooth enamel and with biological joint tissue at arthrosis are presented.

The study of laser induced fluorescence of tooth hard tissues with aluminum phthalocyanine nanoparticles

This work is about the possibility of fluorescence diagnosis application with the use of aluminum phthalocyanine nanoparticles (nAlPc) in order to detect enamel microdamage. For the investigation, five human teeth samples of various age groups were removed for various reasons. The autofluorescence spectrums of these samples hard tissues and fluorescence spectrums of nAlPc mixed with enamel powder were obtained during the experiment. The research shows that sample pathogenic microflora causes nAlPc fluorescence. This fact will allow detecting enamel microdamage in future studies.

Investigation of the aluminum phthalocyanine nanoparticles colloidal solutions pH-dependent photoluminescence kinetics in pico- and nanosecond time range

In this study, the fluorescence intensity decay of aluminum phthalocyanine nanoparticles colloidal solutions at different pH was investigated. Hamamatsu Streak-Camera (C10627 - 13 Hamamatsu Photonics) with picosecond temporal resolution (15 ps) was used to carry out the measurements. For excitation we used Hamamatsu Picosecond Light Pulser PLP - 10 with 637 nm wavelength and 65 ps pulse duration. The changes in fluorescence decay kinetics were found during the experiment. The number of fluorescence lifetime components and duration of lifetimes depends on pH. At pH 2 the presence of two fluorescence lifetimes was recorded: the first one was 5 ns, which corresponded to the molecular form in solution, and 1.5 ns, which corresponded to bound state of phthalocyanine molecules. This work is a preparatory step towards a model which describes the interaction of aluminum phthalocyanine nanoparticles with environment in biological tissue.

Spectral luminescent properties of bacteriochlorin and aluminum phthalocyanine nanoparticles as hydroxyapatite implant surface coating

Spectral luminescent properties of bacteriochlorin and aluminum phthalocyanine nanoparticles as hydroxyapatite implant surface coating

Analysis of photoluminescence decay kinetics of aluminum phthalocyanine nanoparticles interacting with immune cells

This work is dedicated to the study of the photoluminescence kinetics of aluminum phthalocyanine nanoparticles in colloidal solutions at different pH and in the interaction with immune cells (macrophages). For measurements we used a registration system based on Hamamatsu streak camera (C10627-13 Hamamatsu Photonics) with picosecond temporal resolution (15 ps), conjugated with the fiberoptic spectrometer and picosecond laser pumping. The changes in fluorescence decay kinetics as additional lifetime components of fluorescence were found during the experiment. The number of components and duration of lifetimes changed while interacting with cells and depends on pH. At pH 2 the presence of two fluorescence lifetimes was recorded: the first one was 5 ns, which corresponded to the molecular form in solution, and 1.5 ns, which corresponded to bound state of phthalocyanine molecules. Due to the absence of other possible objects for bounding in the solution except of the nanoparticles we can suggest with a high degree of accuracy that the bounding occurs with the very these nanoparticles. Analysis of the fluorescence lifetimes of aluminum phthalocyanine nanoparticles in macrophages indicated the presence of two components: 9 ns and 4.5 ns. A model of surface molecules transitions from parallel to perpendicular position, regarding to the plane of the crystal nanoparticle was proposed.

Fluorescence investigation of the detachment of aluminum phthalocyanine molecules from aluminum phthalocyanine nanoparticles in monocytes/macrophages and skin cells and their localization in monocytes/macrophages

Nanoparticles made from aluminum phthalocyanine (AlPc) are non-fluorescent in the nanoparticle form. Once AlPc molecules become detached from the particle, fluorescence occurs. Preliminary work showed the benefit of using aluminum phthalocyanine nanoparticles (nAlPc) for the rating of the rejection risk of skin autografts in mice by measuring fluorescence intensities of detached AlPc. Skin autografts showing a high fluorescence intensity were finally rejected suggesting an inflammatory process. In contrast, autografts with normal autofluorescence were accepted. This work was focused on the mechanism of this finding. The aim is detecting inflammatory processes and the potential use of nAlPc for PDT as a new treatment modality. The effect of the lipopolysaccharide-stimulated monocyte/macrophage murine cell line J774A.1 on the monomerization of internalized nAlPc was tested. Further, we investigated the influence of J774A.1 cells and the normal skin cell lines L-929 or HaCaT on the dissolution of nAlPc by laser scanning microscopy and flow cytometry. Localization of AlPc molecules after uptake and dissolution of nanoparticles by the cells was surveyed. In co-culture models composed of J774A.1 and HaCaT/L-929 cells, the AlPc fluorescence intensity in J774A.1 cells is 1.38/1.89 fold higher, respectively. According to localization measurements in J774A.1 cells it can be assumed that nAlPc is taken up via endocytosis and remains in endosomes and/or lysosomes dissolving there. Detached molecules of AlPc cause rapture of the endosomal and/or lysosomal membrane after irradiation to become quite uniformly distributed in the cytoplasm. Evidence for monocytes/macrophages being the origin of the measured AlPc fluorescence in rejected skin autografts was confirmed.

Application of aluminum phthalocyanine nanoparticles for fluorescent diagnostics in dentistry and skin autotransplantology

This paper deals with the possibility of application of aluminum phthalocyanine (AlPc) nanoparticles in clinical practice. AlPc fluoresces in the molecular form but in the form of nanoparticles it does not. Separation of molecules from an AlPc nanoparticle and therefore the appearance of fluorescence occurs under the effect of a number of biochemo-physical factors. Owing to this feature the application of AlPc nanoparticles followed by the measurement of fluorescence spectra is proposed as a diagnostics method. It was shown that after AlPc nanoparticle application on a tooth surface the fluorescence intensity in the enamel microdamage area is 2-3 times higher than that in the normal enamel area. The appearance of fluorescence after application of AlPc nanoparticles on skin autografts testifies to the presence of inflammation.