Aggregation of Aluminum Phthalocyanine Hydroxide in Water/Ethanol Mixtures

Tsubone, Tayana Mazin; Braga, Gustavo; Vilsinski, Bruno H.; Gerola, Adriana P.; Hioka, Noboru; Tessaro, André Luiz; Caetano, Wilker

doi:10.5935/0103-5053.20140058

Cited by 8 publications

(11 citation statements)

References 1 publication

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“…The 10 nm shift is due to the electronic effects brought about by the gold and PEG environment, which is also an indication that the Pc4 molecules are actually trapped inside the polymeric shell. Reports have also shown that phthalocyanines have the tendency to aggregate at high concentrations and in poor-solvent environments, resulting in a red-shift in its absorption spectra. , These conditions are possible in these AuNP-Pc4 conjugates in aqueous solution. However, the Pc4 molecules are unlikely to aggregate in the polymer shell, since no spectroscopic signatures of H- and J-aggregates were identified.…”

Section: Resultsmentioning

confidence: 99%

Prostate-Specific Membrane Antigen Targeted Gold Nanoparticles for Theranostics of Prostate Cancer

et al. 2018

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Prostate cancer is one of the most common cancers and among the leading causes of cancer deaths in the United States. Men diagnosed with the disease typically undergo radical prostatectomy, which often results in incontinence and impotence. Recurrence of the disease is often experienced by most patients with incomplete prostatectomy during surgery. Hence, the development of a technique that will enable surgeons to achieve a more precise prostatectomy remains an open challenge. In this contribution, we report a theranostic agent (AuNP-5kPEG-PSMA-1-Pc4) based on prostate-specific membrane antigen (PSMA-1)-targeted gold nanoparticles (AuNPs) loaded with a fluorescent photodynamic therapy (PDT) drug, Pc4. The fabricated nanoparticles are well-characterized by spectroscopic and imaging techniques and are found to be stable over a wide range of solvents, buffers, and media. In vitro cellular uptake experiments demonstrated significantly higher nanoparticle uptake in PSMA-positive PC3pip cells than in PSMA-negative PC3flu cells. Further, more complete cell killing was observed in Pc3pip than in PC3flu cells upon exposure to light at different doses, demonstrating active targeting followed by Pc4 delivery. Likewise, in vivo studies showed remission on PSMA-expressing tumors 14 days post-PDT. Atomic absorption spectroscopy revealed that targeted AuNPs accumulate 4-fold higher in PC3pip than in PC3flu tumors. The nanoparticle system described herein is envisioned to provide surgical guidance for prostate tumor resection and therapeutic intervention when surgery is insufficient.

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Section: Resultsmentioning

confidence: 99%

Prostate-Specific Membrane Antigen Targeted Gold Nanoparticles for Theranostics of Prostate Cancer

et al. 2018

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“…It is known that poorly water-soluble molecules tend to form aggregates and/or precipitates depending on various factors including physicochemical properties, concentration, pH, salt, and ionic strength [ 39 , 40 ]. This phenomenon may be exemplified by phthalocyanines (hydrophobic photosensitizers used for medical applications) where the increase of their concentration in aqueous media led to aggregate formation that impaired their effectiveness [ 41 ]. We suggest that EPIIS, also a hydrophobic molecule, had a similar dose-dependent behavior in the in vitro assays because significant cytotoxicity was observed with a 32 μg/mL EPIIS treatment while no cytotoxicity was shown with the dose of 512 μg/mL (16x higher).…”

Section: Discussionmentioning

confidence: 99%

Epiisopilosine alkaloid has activity against Schistosoma mansoni in mice without acute toxicity

et al. 2018

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Schistosomiasis is a disease caused by parasites of the genus Schistosoma, currently affecting more than 200 million people. Among the various species of this parasite that infect humans, S. mansoni is the most common. Pharmacological treatment is limited to the use of a single drug, praziquantel (PZQ), despite reports of parasite resistance and low efficacy. It is therefore necessary to investigate new potential schistosomicidal compounds. In this study, we tested the efficacy of epiisopilosine (EPIIS) in a murine model of schistosomiasis. A single dose of EPIIS (100 or 400 mg/kg) administered orally to mice infected with adult S. mansoni resulted in reduced worm burden and egg production. The treatment with the lower dose of EPIIS (100 mg/kg) significantly reduced total worm burden by 60.61% (P < 0.001), as well as decreasing hepatosplenomegaly and egg excretion. Scanning electron microscopy revealed morphological changes in the worm tegument after treatment. Despite good activity of EPIIS in adult S. mansoni, oral treatment with single dose of EPIIS 100 mg/kg had only moderate effects in mice infected with juvenile S. mansoni. In addition, we performed cytotoxicity and toxicological studies with EPIIS and found no in vitro cytotoxicity (in HaCaT, and NIH-3T3 cells) at a concentration of 512 μg/mL. We also performed in silico analysis of toxicological properties and showed that EPIIS had low predicted toxicity. To confirm this, we investigated systemic acute toxicity in vivo by orally administering a 2000 mg/kg dose to Swiss mice. Treated mice showed no significant changes in hematological, biochemical, or histological parameters compared to non-treated animals. Epiisopilosine showed potential as a schistosomicidal drug: it did not cause acute toxicity and it displayed an acceptable safety profile in the animal model.

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“…The role of PS aggregation on its photochemical and photophysical pathways is studied for several classes of PSes and in many different systems. Aggregation, which in most cases can be simply identified by changes in electronic spectra of the PS, can happen as a result of high PS concentration and also be affected by ionic strength, temperature and interaction with molecules that stabilize differently the monomeric or the aggregated form of the PS [ 141 , 142 , 145 , 146 , 147 , 148 , 149 , 150 ]. In some cases, aggregation just diminishes the activity of the PS, whereas in others it may change its mechanisms of action.…”

Section: Parameters Determining Photosensitizer (Ps) Efficiencymentioning

confidence: 99%

Photodynamic Efficiency: From Molecular Photochemistry to Cell Death

Bacellar

Tsubone

Pavani

et al. 2015

IJMS

326

267

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Photodynamic therapy (PDT) is a clinical modality used to treat cancer and infectious diseases. The main agent is the photosensitizer (PS), which is excited by light and converted to a triplet excited state. This latter species leads to the formation of singlet oxygen and radicals that oxidize biomolecules. The main motivation for this review is to suggest alternatives for achieving high-efficiency PDT protocols, by taking advantage of knowledge on the chemical and biological processes taking place during and after photosensitization. We defend that in order to obtain specific mechanisms of cell death and maximize PDT efficiency, PSes should oxidize specific molecular targets. We consider the role of subcellular localization, how PS photochemistry and photophysics can change according to its nanoenvironment, and how can all these trigger specific cell death mechanisms. We propose that in order to develop PSes that will cause a breakthrough enhancement in the efficiency of PDT, researchers should first consider tissue and intracellular localization, instead of trying to maximize singlet oxygen quantum yields in in vitro tests. In addition to this, we also indicate many open questions and challenges remaining in this field, hoping to encourage future research.

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Aggregation of Aluminum Phthalocyanine Hydroxide in Water/Ethanol Mixtures

Cited by 8 publications

References 1 publication

Prostate-Specific Membrane Antigen Targeted Gold Nanoparticles for Theranostics of Prostate Cancer

Prostate-Specific Membrane Antigen Targeted Gold Nanoparticles for Theranostics of Prostate Cancer

Epiisopilosine alkaloid has activity against Schistosoma mansoni in mice without acute toxicity

Photodynamic Efficiency: From Molecular Photochemistry to Cell Death

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