Navegando por Palavras-chave "Metal Nanoparticles"
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- ItemSomente MetadadadosAplicações de nanopartículas de ouro em doenças de crescimento não controlável(Universidade Federal de São Paulo (UNIFESP), 2020-06-26) Goncalves, Karina De Oliveira [UNIFESP]; Courrol, Lilia Coronato [UNIFESP]; Universidade Federal de São PauloCancer and atherosclerosis are among the leading causes of death in Brazil and worldwide. Despite all the resources available for the treatment of these diseases, a variety of problems are observed, both about the effectiveness of the drugs and the range of effects that can be induced by them. In this context, metallic nanoparticles appear like an alternative, for the diagnosis and therapy of these diseases. Thus, visa work produces metallic nanoparticles (silver and gold) and heterodimer nanoparticles (silver/iron, silver/gold and gold/iron) and tests them as possible drug transport agents and as sensitizers for therapies against cancer and atherosclerosis. In the first step, describing the process of demonstrating 7 nanoparticles, using the photoreduction method, none of which nanoparticles are functional with aminolevulinic acid (5-ALA) or its methyl ester (MALA). Characterization techniques employed were: UV/Vis Spectroscopy, Zeta Potential, Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD). The potential for single oxygen generation by nanoparticles was also evaluated, using a DPBF (1,3-diphenyl isobenzofuran) probe or reagent, which combined a nanoparticle solution, was exposed to the LED at 590 nm or Ultrasound with pulses of 1 MHZ and 1W/cm2. DPBF decay measurements were not performed on the UV/Vis spectrophotometer. In the second stage, cytotoxicity tests were performed with murine melanoma cell lines (B16F-10), human monocytes (THP-1 - differentiated into macrophages) and breast tumor (MCF-7) to evaluate how they were less tested in nanoparticles. Cytotoxic effects after photodynamic therapies (PDT) with 590 nm LED (~ 100 mW) and sonodynamics (SDT) with ultrasound with pulses of 1 MHZ and 1W/cm2 were also analyzed, with a price assessment test 5-ALA/MALA by nanoparticles and consequent increase in the production of single oxygen. The results obtained indicate that nanoparticles can deliver 5-ALA / MALA to cells. Among the therapies, an SDT produces better results in conjunction with nanoparticles, applies the potential application of produced nanoparticles, in diseases of uncontrollable growth.
- ItemSomente MetadadadosFuncionalização De Nanopartículas Metálicas Com Diferentes Combinações De Peptídeos Para Aplicações Como Agentes Antimicrobianos E Antitumorais(Universidade Federal de São Paulo (UNIFESP), 2017-11-27) Formaggio, Daniela Maria Ducatti [UNIFESP]; Tada, Dayane Batista [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Metal nanoparticles (NPs) have showing promising applications in the biomedical field. These NPs have unique physicochemical properties, as well as great chemical versatility on their surface, which allows new modifications and incorporations of different molecules. In addition, they have the advantage of accumulating preferentially in tumor tissues due to the enhanced permeability and retention effect, known as EPR. The incorporation of therapeutic peptides to the surface of metallic NPs could be a promising strategy to improve their applications as therapeutic molecules. Peptides are highly selective molecules. However, they are also vulnerable to some in vivo pharmacologic barriers limiting their effective action, including low bioavailability or deactivation by enzymes. In this work, three types of metal NPs were prepared: gold NPs (AuNPs), silver NPs (AgNPs) and bimetallic NPs composed by gold and platinum (AuPtNPs). NPs were characterized by ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray diffraction (XRD). Aiming at biomedical applications, NPs were firstly evaluated regarding their toxicity by cell viability assays using human fibroblast cells (HS68 cell line) and embryonic toxicity test in zebrafish (Danio rerio). The assays showed better biocompatibility of AuNPs compared to AgNPs and AuPtNPs. Thus, AuNPs were studied as carriers of antitumor and antimicrobial peptides as an alternative approach of overcoming the pharmacokinetic limitations inherent in these molecules. Two peptides derived from complementary monoclonal antibodies (CDRs) with amino acid sequences YISCYNGATSYNQKFK (C7H2) and RASQSVSSYLA (HuAL1) were previously identified by collaborators of this project demonstrating excellent toxicity against tumor cells, antimetastatic activity as well as a potent antimicrobial activity. The peptides were individually conjugated to the AuNPs surface, forming the AuNPsC7H2 and AuNPsHuAL1 NPs. The peptides were also linked together forming the AuNPsC7H2HuAL1. The in vitro results suggested an improved antitumor activity for AuNPsHuAL1 and AuNPsC7H2HuAL1 against metastatic melanoma tumor cell line (B16F10-Nex2) compared to the peptides in solution. In vivo, the peptide combination of HuAL1 and C7H2 was even more efficient when linked to AuNPs. The antimicrobial activity of the three NPs separately as well as the peptide functionalized AuNPs were also evaluated employing microdilution test against strains of Candida Albicans, Pseudomonas aeruginosa and Staphylococcus aureus. The results confirm an intrinsic antimicrobial action of the three metal NPs and an optimal antibiotic action for AuNPsHuAL1.
- ItemSomente MetadadadosSíntese, Caracterização E Determinação Do Potencial Antimicrobiano De Nanopartículas Superparamagnéticas De Óxido De Ferro Funcionalizadas Com O Peptídeo Antimicrobiano Ocelatina Pt7 Dissertação(Universidade Federal de São Paulo (UNIFESP), 2018-08-30) Oyadomari, William Yoshio Agliardi [UNIFESP]; Daghastanli, Katia Regina Perez [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Recently, Many Studies Have Focused On The Development Of Drug Carriers To Bring A Bioactive Molecule To Target Tissue Using Lower Doses Of The Drug And Thus Reducing Its Toxicity. In This Work We Develop And Characterize Nanoparticles Of Superparamagnetic Iron Oxide (Spion) Bound To Ocelatina Pt7, An Antimicrobial Peptide. The Nanoparticles Were Synthesized Using The Co-Precipitation Method Of Iron (Iii) And Iron (Ii) (2: 1 Mol / Mol) With Nh4oh In The Presence Of Oleic Acid Under A Nitrogen Atmosphere And Under Stirring. The Final Suspension Of Nanoparticles Responded To The Magnetic Field Generated By A Magnet And Was Characterized By Dynamic Light Scattering (Dls), Zeta Potential (Zp), Fourier Transform Infrared Spectroscopy (Ftir), Scanning Electron Microscopy (Sem), Crystallography Of X-Ray And Optical Microscopy. Nanoparticles Not Coated With Oleic Acid Have A Hydrodynamic Diameter Of 1400 Nm, A Zp Of -23 Mv And Coalesce Rapidly. The Coating With Oleic Acid Decreased The Hydrodynamic Diameter Of The Na
- ItemSomente MetadadadosUsing femtosecond lasers to modify sizes of gold nanoparticles(Spie-int soc optical engineering, 2016) Cordeiro, Thiago da Silva; de Matos, Ricardo Almeida [UNIFESP]; de Oliveira Silva, Flavia Rodrigues; Vieira, Nilson Dias, Jr.; Courrol, Lilia Coronato [UNIFESP]; Samad, Ricardo ElgulMetallic nanoparticles are important on several scientific, medical and industrial areas. The control of nanoparticles characteristics has fundamental importance to increase the efficiency on the processes and applications in which they are employed. The metallic nanoparticles present specific surface plasmon resonances (SPR). These resonances are related with the collective oscillations of the electrons presents on the metallic nanoparticle. The SPR is determined by the potential defined by the nanoparticle size and geometry. There are several methods of producing gold nanoparticles, including the use of toxic chemical polymers. We already reported the use of natural polymers, as for example, the agar-agar, to produce metallic nanoparticles under xenon lamp irradiation. This technique is characterized as a "green" synthesis because the natural polymers are inoffensive to the environment. We report a technique to produce metallic nanoparticles and change its geometrical and dimensional characteristics using a femtosecond laser. The 1 ml initial solution was irradiate using a laser beam with 380 mW, 1 kHz and 40 nm of bandwidth centered at 800 nm. The setup uses an Acousto-optic modulator, Dazzler, to change the pulses spectral profiles by introduction of several orders of phase, resulting in different temporal energy distributions. The use of Dazzler has the objective of change the gold nanoparticles average size by the changing of temporal energy distributions of the laser pulses incident in the sample. After the laser irradiation, the gold nanoparticles average diameter were less than 15 nm.