Recent advances and perspectives on natural latex serum and its fractions for biomedical applications.

Advances and the discovery of new biomaterials have opened new frontiers in regenerative medicine. These biomaterials play a key role in current medicine by improving the life quality or even saving the lives of millions of people. Since the 2000s, Natural Rubber Latex (NRL) has been employed as wound dressings, mechanical barrier for Guided Bone Regeneration (GBR), matrix for drug delivery, and grafting. NRL is a natural polymer that can stimulate cell proliferation, neoangiogenesis, and extracellular matrix (ECM) formation. Furthermore, it is well established that proteins and other biologically active molecules present in the Natural Latex Serum (NLS) are responsible for the biological properties of NRL. NLS can be obtained from NRL by three main methods, namely (i) Centrifugation (fractionation of NRL in distinct fractions), (ii) Coagulation and sedimentation (coagulating NRL to separate the NLS from rubber particles), and (iii) Alternative extraction process (elution from NRL membrane). In this review, the chemical composition, physicochemical properties, toxicity, and other biological information such as osteogenesis, vasculogenesis, adhesion, proliferation, antimicrobial behavior, and antitumoral activity of NLS, as well as some of its medical instruments and devices are discussed. The progress in NLS applications in the biomedical field, more specifically in cell cultures, alternative animals, regular animals, and clinical trials are also discussed. An overview of the challenges and future directions of the applications of NLS and its derivatives in tissue engineering for hard and soft tissue regeneration is also given.

Development of Biotechnological Photosensitizers for Photodynamic Therapy: Cancer Research and Treatment-From Benchtop to Clinical Practice.

Photodynamic therapy (PDT) is a noninvasive therapeutic approach that has been applied in studies for the treatment of various diseases. In this context, PDT has been suggested as a new therapy or adjuvant therapy to traditional cancer therapy. The mode of action of PDT consists of the generation of singlet oxygen (¹O2) and reactive oxygen species (ROS) through the administration of a compound called photosensitizer (PS), a light source, and molecular oxygen (3O2). This combination generates controlled photochemical reactions (photodynamic mechanisms) that produce ROS, such as singlet oxygen (¹O2), which can induce apoptosis and/or cell death induced by necrosis, degeneration of the tumor vasculature, stimulation of the antitumor immune response, and induction of inflammatory reactions in the illuminated region. However, the traditional compounds used in PDT limit its application. In this context, compounds of biotechnological origin with photosensitizing activity in association with nanotechnology are being used in PDT, aiming at its application in several types of cancer but with less toxicity toward neighboring tissues and better absorption of light for more aggressive types of cancer. In this review, we present studies involving innovatively developed PS that aimed to improve the efficiency of PDT in cancer treatment. Specifically, we focused on the clinical translation and application of PS of natural origin on cancer.

Photodynamic inactivation of Candida albicans and Candida tropicalis with aluminum phthalocyanine chloride nanoemulsion.

The in vitro susceptibilities of Candida albicans and Candida tropicalis to Antimicrobial Photodynamic Treatment with aluminum phthalocyanine chloride in nanoemulsion (ClAlPc/NE) were investigated. PS concentration- and fluence-dependent cell survival after APDT were compared before and after unbound extracellular PS had been washed out. The PS uptake and its subcellular localization were also determined. Exposure to light in the absence of the PS and treatment with the PS in the absence of light did not kill the fungi. APDT with ClAlPc/NE resulted in a reduction of five orders of magnitude in viability for C. albicans and between four and five orders of magnitude for C. tropicalis. Washing the cells to remove unbound PS before light exposure did not impair fungal inactivation, suggesting that cell photosensitization was mainly carried out by cell bound ClAlPc. The degree of ClAlPc uptake was dependent on its concentration. Internalization of ClAlPc by C. albicans and C. tropicalis was confirmed by confocal fluorescence microscopy that showed the PS does not penetrate the nucleus and instead accumulates in specific regions of the cytoplasm. Our results show that incorporating the water-insoluble ClAlPc into a nanoemulsion leads to an efficient formulation capable of photoinactivating both Candida species.

Antiviral activity of curcumin-nanoemulsion associated with photodynamic therapy in vulvar cell lines transducing different variants of HPV-16.

Vulvar intraepithelial neoplasia (VIN) is associated with human papillomavirus (HPV) infection. Curcumin is a natural bioactive compound with antineoplastic properties. The use of nanoparticles containing curcumin could allow a better performance of this compound in therapies. So, VIN biopsies were collected and HPV DNA detection was performed by PCR, positive samples were genotyped by Restriction Fragment Length Polymorphism (RFLP) and HPV-16 variants were determined by sequencing. HPV-16 positive vulva carcinoma cells (A431) were transduced with E-P and E-350G HPV-16 E6 variants. The viability of the transduced cells treated with nanoemulsions was determined by MTT assay. Besides, apoptosis was evaluated by enzymatic activity of Caspase-3/7. The cell viability assay showed that both the empty nanoemulsion (NE-V) and the nanoemulsion of curcumin (NE-CUR) had little effect on cell viability as compared to control cells. Additionally, we observed that cells irradiated in the presence of NE-CUR presented 90% of cell death. The apoptosis assay further revealed a significant increase in the activity of caspases 3 and 7 in A431 cells expressing both HPV-16 E6 variants after treatment with NE-CUR. Finally, we submitted the HPV transduced A431 cells to organotypic cultures and observed that the combination of treatments affected tissue architecture with evident signals of tissue damage. We concluded that nanoemulsions attain good biocompatibility, since no cytotoxicity was observed and NE-CUR associated with photoactivation showed promising results, leading to death only in cells subjected to irradiation. This drug delivery system associated with photodynamic therapy may become promising in the treatment of vulva lesions.

Copper-Doped Carbon Dots for Optical Bioimaging and Photodynamic Therapy.

Carbon dots (CDs), as an effective bioimaging agent, have aroused widespread interest. With the increasing number of CDs used in photodynamic therapy (PDT), developing efficient CDs with multiple functions such as imaging and phototherapy has become a new challenge. Herein, a new type of copper-doped CDs (Cu-CDs) with a high fluorescence quantum yield of 24.4% was synthesized from a copper complex of poly(acrylic acid) through coordination between the carboxyl group and copper ions. Owing to their good solubility, bright fluorescence, and low cytotoxicity, the Cu-CDs can be used for fluorescence imaging in both the HeLa (human cervical cancer) cell line and SH-SY5Y (human neuroblastoma cells) multicellular spheroids (3D MCs). More importantly, the Cu-CDs show a high quantum yield of singlet oxygen (1O2; 36%), good photoinduced cytotoxicity, and effective inhibition of 3D MC growth. Therefore, the Cu-CDs can be used as a promising imaging-guided PDT agent. This study provides a new carbon-based nanomaterial for multifunctional photodiagnostic and therapeutic agents for biological applications.

Experimental study of the neurotoxic effects of photodynamic therapy on the spinal cord / Estudo experimental dos efeitos neurotóxicos da terapia fotodinâmica na medula espinhal / Estudio experimental de los efectos neurotóxicos de la terapia fotodinámica en la médula espinal

ABSTRACT Objective To evaluate the effects of photodynamic therapy (PDT) on the dura mater using the photosensitizers aluminum chloride phthalocyanine and methylene blue in in vivo assays. Methods Fifty-six male Wistar rats were divided into two groups; one submitted to PDT and the other submitted to the photosensitizers without their photoactivation (control). The photosensitizers were applied to the dura mater after laminectomy at the T10 level. The methods used for assessment were the Basso, Beattie and Bresnahan (BBB) functional evaluation scale and study of the dura mater by light microscopy. Results No changes in motor activity were observed in the animals submitted to PDT compared to control. Histological and pathological evaluation did not show any differences between the group exposed to activated photosensitizers and the control group with regard to the inflammatory process and tissue necrosis. Conclusion The joint use of PDT with the photosensitizing pharmaceuticals aluminum chloride phthalocyanine and methylene blue did not induce any clinical neurotoxic effects or histological changes in the dura mater of the animals studied. Level de evidence V; Expert Opnion.

RESUMO Objetivo Avaliar os efeitos da terapia fotodinâmica (PDT) na dura-máter usando os fotossensibilizadores cloreto de alumínio ftalocianina e azul de metileno em ensaios in vivo. Métodos Cinquenta e seis ratos Wistar machos divididos em dois grupos; um submetido à PDT e o outro submetido aos fotossensibilizadores sem a fotoativação (controle). Os fotossensibilizadores foram aplicados sobre a dura-máter depois de laminectomia no nível T10. Os métodos de avaliação usados foram a escala de avaliação funcional de Basso, Beattie e Bresnahan (BBB) e o estudo da dura-máter por microscopia óptica. Resultados Não foram observadas alterações da atividade motora dos animais submetidos à PDT com relação ao grupo controle. A avaliação histológica e histopatológica não mostrou diferenças entre o grupo exposto aos fotossensibilizadores ativados e o grupo controle, com relação ao processo inflamatório e à necrose tecidual. Conclusões O uso conjunto de PDT e os fármacos fotossensibilizantes cloreto de alumínio ftalocianina e azul de metileno não induziu efeitos neurotóxicos clínicos e/ou alterações histológicas sobre a dura-máter dos animais estudados. Nível de evidência V; Opinião de Especialista.

RESUMEN Objetivo Evaluar los efectos de la terapia fotodinámica (PDT) en la duramadre utilizando los fotosensibilizadores de ftalocianina de aluminio clorada y azul de metileno en ensayos in vivo. Métodos Cincuenta y seis ratas Wistar machos se dividieron en 2 grupos; uno fue sometido a PDT y el otro sometido a fotosensibilizadores sin fotoactivación (control). Los fotosensibilizadores se aplicaron a la duramadre después de la laminectomía en el nivel T10. Los métodos de evaluación utilizados fueron la escala de evaluación funcional de Basso, Beattie y Bresnahan (BBB) y el estudio de la duramadre mediante microscopía óptica. Resultados No hubo cambios en la actividad motora de los animales sometidos a PDT en relación con el grupo de control. La evaluación histológica e histopatológica no mostró diferencias entre el grupo expuesto a fotosensibilizadores activados y el grupo de control con respecto al proceso inflamatorio y la necrosis tisular. Conclusiones El uso conjunto de PDT con las sustancias fotosensibilizadores ftalocianina de aluminio clorada y azul de metileno no indujo efectos neurotóxicos clínicos o cambios histológicos en la duramadre de los animales estudiados. Nivel de evidencia V; Opinión del Especialista.

Effect of curcumin-nanoemulsion associated with photodynamic therapy in breast adenocarcinoma cell line.

Curcumin, a natural compound has several antineoplastic activities and is a promising natural photosensitizer used in photodynamic therapy. However, its low solubility in physiological medium limit the clinical use of curcumin. This study aimed to analyze the action of curcumin-nanoemulsion, a new and well-designed Drug Delivery System (DDS+) molecule, used as a photosensitizing agent in photodynamic therapy in an in vitro breast cancer model, MCF-7 cells. The empty nanoemulsion fulfils all necessary requirements to be an excellent DDS. Furthermore, the use of curcumin-nanoemulsion in photodynamic therapy resulted in a high phototoxic effect after activation at 440 nm, decreasing to <10% viable tumor cells after two irradiations and increasing the reactive oxygen species (ROS) production. The use of curcumin-nanoemulsion associated with photodynamic therapy resulted in an increase in the levels of caspase 3/7 activity for the studied MCF-7 cell model, indicating that this therapy triggers a cascade of events that lead to cell death, such as cellular apoptosis. In conclusion, curcumin-nanoemulsion proved to be efficient as a photosensitizing agent, had phototoxic effects, significantly decreased the proliferation of MCF-7 cells and stimulating the ROS production in combination with photodynamic therapy, so, this formulation has a great potential for use in treatment of breast cancer.

Synthesis and colloidal characterization of folic acid-modified PEG-b-PCL Micelles for methotrexate delivery.

Hydrophobic drugs, such as methotrexate, are not easily delivered into the human body. Therefore, the use of amphiphilic nanoplatforms to the transport of these drugs through the bloodstream is a challenge. While the hydrophobic region interacts with the drug, the hydrophilic outer layer enhances its bioavailability and circulation time. Poly (ethylene glycol)-block-poly(ε-caprolactone) PEG-b-PCL micelles are biodegradable and biocompatible, allowing its use as a nanocarrier for drug delivery systems. The stealth property of PEG that composes the outer layer of nanoplatforms, makes the micelle unperceivable to phagocytic cells, increasing the circulation time in the human body. In addition, folic acid functionalization enables micelle selectively targeting to cancer cells, improving treatment efficiency and reducing side effects. In this work, PEG-b-PCL copolymer was synthesized by ring opening polymerization (ROP) of the ε-caprolactone with Poly(ethylene glycol) as a macroinitiator and tin(II) 2-ethyl hexanoate as a catalyst. Functionalization of such micelles with folic acid occurred through the modification of the PEG terminal group. The surface modification of the copolymer micelles resulted in higher critical micellar concentration (CMC), increasing approximately 100 times. The synthesis of the copolymers resulted in molecular weight around 3000 g mol-1 with low polydispersity. The polymer micelles have a hydrodynamic diameter in the range of 100-200 nm and the functionalized sample doesn't show aggregation in the considered pH range. High incorporation efficiency was obtained with a minimum percentage of 85%. The drug release profile and linearization from the Peppas model confirmed the interaction of methotrexate with the hydrophobic segment of the copolymer and its release mechanism by relaxation and/or degradation of the chains, making PEG-b-PCL micelles suitable candidates for hydrophobic drug delivery systems.

Combining Photodynamic Therapy and Chemotherapy: Improving Breast Cancer Treatment with Nanotechnology.

Nanomedical approaches are the major transforming factor in cancer therapies. Based on important previous works in the field of drug delivery nanomaterials, recent years have brought a broad array of new and improved intelligent nanoscale platforms that are suited to deliver drugs. In this context, the purpose of this study was to investigate the action of different nanoemulsions designed to encapsulate chloroaluminum phthalocyanine, a hydrophobic photosensitizer used in photodynamic therapy, and doxorubicin, a well-known chemotherapeutic agent used to treat aggressive breast cancer cells. The mean nanostructured system size ranged from 170.8 to 181.0 nm, and the nanoemulsions presented spherical morphology. All formulations exhibited negative zeta potential values (-68.7 to -75.0 mV) and suitable polydispersity values (0.20 to 0.28), explaining their colloidal stability up to three months. Murine breast cancer cells (4T1) were incubated with nanoemulsions for three hours at various concentrations and were subjected to cell viability tests to find the concentration dependence profile. Thereafter, the in vitro phototoxic effect was evaluated in the presence of the visible laser light irradiation. Less than 10% of 4T1 viable cells were observed when photodynamic therapy and chemotherapy were combined at a 1.0 J · cm-2 laser light dose with 1.0 µM phthalocyanine and 0.5 µM doxorubicin. The cell death assay and cell cycle arrest analysis confirmed the therapy efficiency demonstrating an increase in the apoptosis rate and in the cell cycle arrest on G2. Additionally, 15 genes related to apoptosis and 25 target genes of anti-cancer drugs were overexpressed. Four genes related to apoptosis and four target genes of anti-cancer drugs were downregulated in 4T1 cells after treatment with nanoemulsion with phthalocyanine and doxorubicin associated with photodynamic therapy. Thus, the nanoemulsions loaded with phthalocyanine and doxorubicin presented appropriate physical stability, improved photophysical properties, and remarkable activity in vitro to be considered as promising formulations for photodynamic therapy and chemotherapeutic use in breast cancer treatment.

Effect of Curcumin-Nanoemulsion Associated with Photodynamic Therapy in Cervical Carcinoma Cell Lines.

Cervical cancer is the fourth cause of cancer death in women. Curcumin has antineoplastic properties. Furthermore, curcumin may be used as a photosensitizing agent in Photodynamic Therapy. This study aimed to investigate the effects of Photodynamic Therapy in cellular viability using curcumin-nanoemulsion as a photosensitizing drug in cervical carcinoma cell lines. The empty nanoemulsion presented very low cytotoxicity in all cell lines analyzed. Additionally, the incubation with curcumin-nanoemulsion at 20 µM of curcumin showed more than 80% of cell viability for cell lines. Nanoemulsions were shown to be internalized inside cells by fluorescence microscopy and were observed in the intracellular environment for up to 36 hours after incubation with cell lines. In addition, after the Photodynamic Therapy we observed a high phototoxic effect of the curcumin-nanoemulsion with less than 5% of viable cells after irradiation. This was accompanied by an increase in caspase-3/caspase-7 activities after cell treatment with curcumin-nanoemulsion and Photodynamic Therapy, suggesting cell death by apoptosis. We conclude that the curcumin-nanoemulsion formulation behaves as a photosensitizing drug in Photodynamic Therapy and shows potential as an alternative treatment to cervical lesions using an endoscopic diode fiber laser setup for in situ activation or cavity activation using a diffuse fiber delivery system.

In vitro assessment of anti-tumorigenic mechanisms and efficacy of NanoALA, a nanoformulation of aminolevulic acid designed for photodynamic therapy of cancer.

BACKGROUND: The development of nanocarriers is an important approach to increase the bioavailability of hydrophilic drugs in target cells. In this work, we evaluated the anti-tumorigenic mechanisms and efficacy of NanoALA, a novel nanoformulation of aminolevulic acid (ALA) based on poly(lactide-co-glycolide) (PLGA) nanocapsules designed for anticancer photodynamic therapy (PDT). METHODS: For this purpose, physicochemical characterization, prodrug incorporation kinetics, biocompatibility and photocytotoxicity tests, analysis of the cell death type and mitochondrial function, measurement of the intracellular reactive oxygen species production and DNA fragmentation were performed in murine mammary carcinoma (4T1) cells. RESULTS: NanoALA formulation, stable over a period of 90days following synthesis, presented hydrodynamic diameter of 220±8.7nm, zeta potential of -30.6mV and low value of polydispersity index (0.28). The biological assays indicated that the nanostructured product promotes greater ALA uptake by 4T1 cells and consequently more cytotoxicity in the PDT process. For the first time in the scientific literature, there is a therapeutic efficacy report of approximately 80%, after only 1h of incubation with 100µgmL-1 prodrug (0.6mM ALA equivalent). The mitochondria are probably the initial target of treatment, culminating in energy metabolism disorders and cell death by apoptosis. CONCLUSIONS: NanoALA emerges as a promising strategy for anticancer PDT. Besides being effective against a highly aggressive tumor cell line, the treatment may be economically advantageous because it allows a reduction in the dose and frequency of application compared to free ALA.

Collagen-based silver nanoparticles: Study on cell viability, skin permeation, and swelling inhibition.

Collagen is considered the most abundant protein in the animal kingdom, comprising 30% of the total amount of proteins and 6% of the human body by weight. Studies that examine the interaction between silver nanoparticles and proteins have been highlighted in the literature in order to understand the stability of the nanoparticle system, the effects observed in biological systems, and the appearance of new chemical pharmaceutical products. The objective of this study was to analyze the behavior of silver nanoparticles stabilized with collagen (AgNPcol) and to check the skin permeation capacity and action in paw edema induced by carrageenan. AgNPcol synthesis was carried out using solutions of reducing agent sodium borohydride (NaBH4), silver nitrate (AgNO3) and collagen. Characterization was done by using dynamic light scattering (DLS) and X-ray diffraction (XRD) and AFM. Cellular viability testing was performed by using flow cytometry in human melanoma cancer (MV3) and murine fibroblast (L929) cells. The skin permeation study was conducted using a Franz diffusion cell, and the efficiency of AgNPcol against the formation of paw edema in mice was evaluated. The hydrodynamic diameter and zeta potential of AgNPcol were 140.7±7.8nm and 20.1±0.7mV, respectively. AgNPcol failed to induce early apoptosis, late apoptosis, and necrosis in L929 cells; however, it exhibited enhanced toxicity in cancer cells (MV3) compared to normal cells (L929). AgNPcol demonstrated increased toxicological effects in cancer MV3 cells, promoting skin permeation, and preventing paw edema.

Genotoxicity assessment of reactive and disperse textile dyes using human dermal equivalent (3D cell culture system).

Thousands of dyes are marketed daily for different purposes, including textile dyeing. However, there are several studies reporting attributing to dyes deleterious human effects such as DNA damage. Humans may be exposed to toxic dyes through either ingestion of contaminated waters or dermal contact with colored garments. With respect to dermal exposure, human skin equivalents are promising tools to assess in vitro genotoxicity of dermally applied chemicals using a three-dimensional (3D) model to mimic tissue behavior. This study investigated the sensitivity of an in-house human dermal equivalent (DE) for detecting genotoxicity of textile dyes. Two azo (reactive green 19 [RG19] and disperse red 1[DR1]) dyes and one anthraquinone (reactive blue 2 [RB2]) dye were analyzed. RG19 was genotoxic for DE in a dose-responsive manner, whereas RB2 and DR1 were nongenotoxic under the conditions tested. These findings are not in agreement with previous genotoxicological assessment of these dyes carried out using two-dimensional (2D) cell cultures, which showed that DR1 was genotoxic in human hepatoma cells (HepG2) and RG19 was nongenotoxic for normal human dermal fibroblasts (NHDF). These discrepant results probably may be due to differences between metabolic activities of each cell type (organ-specific genotoxicity, HepG2 and fibroblasts) and the test setup systems used in each study (fibroblasts cultured at 2D and three-dimensional [3D] culture systems). Genotoxicological assessment of textile dyes in context of organ-specific genotoxicity and using in vitro models that more closely resemble in vivo tissue architecture and physiology may provide more reliable estimates of genotoxic potential of these chemicals.

Antimicrobial photodynamic therapy against pathogenic bacterial suspensions and biofilms using chloro-aluminum phthalocyanine encapsulated in nanoemulsions.

Antimicrobial photodynamic therapy represents an alternative method of killing resistant pathogens. Efforts have been made to develop delivery systems for hydrophobic drugs to improve the photokilling. This study evaluated the photodynamic effect of chloro-aluminum phthalocyanine (ClAlPc) encapsulated in nanoemulsions (NE) on methicillin-susceptible and methicillin-resistant Staphylococcus aureus suspensions and biofilms. Suspensions and biofilms were treated with different delivery systems containing ClAlPc. After the pre-incubation period, the drug was washed-out and irradiation was performed with LED source (660 ± 3 nm). Negative control samples were not exposed to ClAlPc or light. For the suspensions, colonies were counted (colony-forming units per milliliter (CFU/mL)). The metabolic activity of S. aureus suspensions and biofilms were evaluated by the XTT assay. The efficiency was dependent on the delivery system, superficial load and light dose. Cationic NE-ClAlPc and free-ClAlPc caused photokilling of the both strains of S. aureus. For biofilms, cationic NE-ClAlPc reduced cell metabolism by 80 and 73% of susceptible and resistant strains, respectively. Although anionic NE-ClAlPc caused a significant CFU/ml reduction for MSSA and MRSA, it was not capable of reducing MRSA biofilm metabolism. This therapy may represent an alternative treatment for eradicating resistant strains.

Effects of Photodynamic Process (PDP) in Implant Osseointegration: A Histologic and Histometric Study in Dogs.

BACKGROUND: The combination between photosensitivity substances with laser or light-emitting diode (LED) form the photodynamic therapy basis that consists of photosensitivity drug activated by low-frequency light. This mechanism is used in soft tissue healing process to improve the oxygen tension leading to a fast revascularization. PURPOSE: The objective of this study was to evaluate the effects of photosensitivity drugs activated through LED on osseointegration process. MATERIALS AND METHODS: Eight mongrel dogs underwent implant therapy in four mandibular bone defects using 5.0 mm trephine drill on each side of the mandible. The defects were randomly filled up with (1) Nano emulsion, (2) liposome, (3) blood clot, and (4) autogenous bone. LED with visible and infrared light were applied after 48/72 postoperative hours on four dogs and after 96/120 postoperative hours in the other four dogs. All the animals were euthanized at 15 days after surgery. Ground sections slides were prepared from the experimental site for histomorphometry and histological analysis. RESULTS: No difference was detected in the following parameters: bone-implant contact, bone inside the defect and crest level on LED 48/72. Significant difference was detected inside the defect when filled with autogenous bone (p = .0238) on LED 96/120. When LED 48/72 and LED 96/120 were compared, significant higher bone formation was detected when autogenous bone on bone-implant contact (p = .0043) and bone inside the defect (p = .0008) was used. CONCLUSION: The use of photosensitivity drugs activated by LED demonstrated a tendency to stimulate bone formation, similar to autogenous bone graft on later time point.

Photodynamic inactivation of planktonic cultures and biofilms of Candida albicans mediated by aluminum-chloride-phthalocyanine entrapped in nanoemulsions.

New drug delivery systems, such as nanoemulsions (NE), have been developed to allow the use of hydrophobic drugs on the antimicrobial photodynamic therapy. This study evaluated the photodynamic potential of aluminum-chloride-phthalocyanine (ClAlPc) entrapped in cationic and anionic NE to inactivate Candida albicans planktonic cultures and biofilm compared with free ClAlPc. Fungal suspensions were treated with different delivery systems containing ClAlPc and light emitting diode. For planktonic suspensions, colonies were counted and cell metabolism was evaluated by XTT assay. Flow cytometry evaluated cell membrane damage. For biofilms, the metabolic activity was evaluated by XTT and ClAlPc distribution through biofilms was analyzed by confocal laser scanning microscopy (CLSM). Fungal viability was dependent on the delivery system, superficial charge and light dose. Free ClAlPc caused photokilling of the yeast when combined with 100 J cm(-2). Cationic NE-ClAlPc reduced significantly both colony counts and cell metabolism (P < 0.05). In addition, cationic NE-ClAlPc and free ClAlPc caused significant damage to the cell membrane (P < 0.05). For the biofilms, cationic NE-ClAlPc reduced cell metabolism by 70%. Anionic NE-ClAlPc did not present antifungal activity. CLSM showed different accumulation on biofilms between the delivery systems. Although NE system showed a lower activity for planktonic culture, cationic NE-ClAlPc showed better results for Candida biofilms.

The effect of photosensitizer drugs and light stimulation on osteoblast growth.

OBJECTIVE: A promising new treatment in dentistry involves the photodynamic process, which utilizes a combination of two therapeutic agents, namely a photosensitizer drug and a low dose of visible light. We investigated the in vitro effect of low intensity laser irradiation (visible light irradiation at 670 nm) using doses ranging between 0.5 and 3 J/cm(2), combined with nanoemulsion (NE) of the photosensitizer drug aluminum phthalocyanine chloride (AlClPc), ranging from 0.5 to 5 µmol/L, on the growth and differentiation of osteoblastic cells isolated from rat bone marrow. BACKGROUND DATA: Treatments using laser radiation of low intensity in dentistry are of great interest, especially in bucco-maxillofacial surgery and dental implantology, where this approach is currently employed to stimulate osteogenesis. In the presence of oxygen, the combination of these agents could induce cellular biostimulation, via an efficient noninvasive method. METHODS: We have done the colorimetric MTT assay, collagen content, total protein content, ALP activity and bone-like nodule formation. RESULTS: We observed that an increased number of viable cells was evident upon application of a laser dosage equal to 0.5 J/cm(2) when combined with 0.5 µmol/L of AlClPc/NE, suggesting cellular biostimulation. CONCLUSIONS: It was possible to demonstrate that low intensity laser irradiation can play an important role in promoting biostimulation of osteoblast cell cultures. Therefore, whether biostimulation of osteoblastic cell cultures by photodynamic therapy or the cytotoxic effect of this therapy occurs only depends upon the light dose, and the results can be completely reversed.

Photoinduced nitric oxide and singlet oxygen release from ZnPC liposome vehicle associated with the nitrosyl ruthenium complex: synergistic effects in photodynamic therapy application.

Under continuous photolysis at 675 nm, liposomal zinc phthalocyanine associated with nitrosyl ruthenium complex [Ru(NH.NHq)(tpy)NO](3+) showed the detection and quantification of nitric oxide (NO) and singlet oxygen ((1)O(2)) release. Photophysical and photochemical results demonstrated that the interaction between the nitrosyl ruthenium complex and the photosensitizer can enable an electron transfer process from the photosensitizer to the nitrosyl ruthenium complex which leads to NO release. Synergistic action of both photosensitizers and the nitrosyl ruthenium complex results in the production of reactive oxygen species and reactive nitrogen species, which is a potent oxidizing agent to many biological tissues, in particular neoplastic cells.