Browsing by Author "Buzza, Hilde H."

Now showing 1 - 4 of 4
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    Carbon-Based Materials in Photodynamic and Photothermal Therapies Applied to Tumor Destruction
    (MDPI, 2022) Lagos, Karina J.; Buzza, Hilde H.; Bagnato, Vanderlei S.; Romero, Maria Paulina
    Within phototherapy, a grand challenge in clinical cancer treatments is to develop a simple, cost-effective, and biocompatible approach to treat this disease using ultra-low doses of light. Carbon-based materials (CBM), such as graphene oxide (GO), reduced GO (r-GO), graphene quantum dots (GQDs), and carbon dots (C-DOTs), are rapidly emerging as a new class of therapeutic materials against cancer. This review summarizes the progress made in recent years regarding the applications of CBM in photodynamic (PDT) and photothermal (PTT) therapies for tumor destruction. The current understanding of the performance of modified CBM, hybrids and composites, is also addressed. This approach seeks to achieve an enhanced antitumor action by improving and modulating the properties of CBM to treat various types of cancer. Metal oxides, organic molecules, biopolymers, therapeutic drugs, among others, have been combined with CBM to treat cancer by PDT, PTT, or synergistic therapies.
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    Nanostructure-Driven Indocyanine Green Dimerization Generates Ultra-Stable Phototheranostics Nanoparticles
    (2023) Kwon, Nahyun; Jasinevicius, Gabriel O.; Kassab, Giulia; Ding, Lili; Bu, Jiachuan; Martinelli, Leticia P.; Ferreira, Vinicius G.; Dhaliwal, Alexander; Chan, Harley H. L.; Mo, Yulin; Bagnato, Vanderlei S.; Kurachi, Cristina; Chen, Juan; Zheng, Gang; Buzza, Hilde H.
    Indocyanine green (ICG) is the only near-infrared (NIR) dye approved for clinical use. Despite its versatility in photonic applications and potential for photothermal therapy, its photobleaching hinders its application. Here we discovered a nanostructure of dimeric ICG (Nano-dICG) generated by using ICG to stabilize nanoemulsions, after which ICG enabled complete dimerization on the nanoemulsion shell, followed by J-aggregation of ICG-dimer, resulting in a narrow, red-shifted (780 nm -> 894 nm) and intense (approximate to 2-fold) absorbance. Compared to ICG, Nano-dICG demonstrated superior photothermal conversion (2-fold higher), significantly reduced photodegradation (-9.6 % vs. -46.3 %), and undiminished photothermal effect (7 vs. 2 cycles) under repeated irradiations, in addition to excellent colloidal and structural stabilities. Following intravenous injection, Nano-dICG enabled real-time tracking of its delivery to mouse tumors within 24 h by photoacoustic imaging at NIR wavelength (890 nm) distinct from the endogenous signal to guide effective photothermal therapy. The unprecedented finding of nanostructure-driven ICG dimerization leads to an ultra-stable phototheranostic platform.
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    Structural Effect of Rhenium- and Iridium-Complex Liposome Composition on Their Selectivity for Antimicrobial Photodynamic Therapy
    (2024) Kassab, Giulia; Manav, Neha; Pires, Layla; Cheng, Miffy H. Y.; Mo, Yulin; Buzza, Hilde H.; Gupta, Iti; Chen, Juan; Zheng, Gang
    Antimicrobial photodynamic therapy (aPDT) is an alternative to antibiotics that has potential for the treatment of chronic skin wounds, but requires improved, highly selective photosensitizer systems. Rhenium (Re)-complex- and iridium (Ir)-complex-based phospholipid conjugates, as PDT-functional building blocks for liposomes, are presented, and varying structural components and proportion of compounds are explored, including adjusting the cholesterol and polyethylene glycol (PEG)-lipid contents, incorporating ethylenediaminetetraacetic acid (EDTA)-lipid, and introducing the cationic lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) to enhance their efficacy and selectivity in aPDT. Ir/Re-liposomes have nanostructurally enhanced photoactivity compared to monomeric Ir/Re-lipids. Ir-liposomes exhibit stronger light absorption and higher emission generation (>threefold) than Re-liposomes, resulting in superior efficacy against Staphylococcus aureus while maintaining better tolerability toward host cells. Formulations with higher cholesterol (40 mol%) and PEG-lipid (5%) content demonstrate increased potency against S. aureus. The incorporation of EDTA-lipid significantly enhances aPDT efficacy but also increases toxicity toward host cells. Incorporation of DOTAP alters the nanoparticles' surface charge, potentially improving their interaction with bacterial walls, but negatively impacts their stability, leading to aggregation of the nanoparticles. Ir-HC demonstrates ideal characteristics (effectiveness, selectivity, and stability) for aPDT under the tested conditions, indicating the importance of the structural design of Re- and Ir-complex liposomes for their selectivity in aPDT.a
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    Synergic vascular photodynamic activity by methylene blue-curcumin supramolecular assembly
    (2023) Silva, Rodrigo C.; Buzza, Hilde H.; Ducas, Eli S. A.; Oliveira, Kleber T.; Bagnato, Vanderlei S.; Souza, Guilherme R. L.; Almeida, Luciane M.; Goncalves, Pablo J.
    A supramolecular assembly was obtained by combining methylene blue (MB) with a natural plant extract, curcumin (Curc), in a stoichiometric ratio of 1:4 in aqueous solution (90% PBS + 10% ethanol) at room temperature. The MB-Curc supramolecular assembly was evidenced by absorption and fluorescence spectroscopies, and the stoichiometry and bonding constant were obtained using Cielens model. Its stability and photostability were evaluated by chromatographic analysis and UV-Vis absorption. The MB-Curc avoids the aggregation of both isolated compounds and efficiently produces singlet oxygen (& phi;& UDelta;= 0.52 & PLUSMN; 0.03). Its potential for photodynamic antiangiogenic treatments was evaluated through the vascular effect observed in chicken chorioallantoic membrane (CAM) assay. The results showed intense damage in CAM vascular network by MB-Curc after irradiation, which is higher than the effect of isolated compounds, indicating a synergistic vascular effect. This combination can be essential to prevent cancer revascularization after photodynamic application and improve the efficacy of this approach. The characteristics exhibited by MB-Curc make it a potential candidate for use in cancer treatments through photodynamic antiangiogenic therapy.