ADRIANA NAPOLEAO GERALDES
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Artigo IPEN-doc 30371 Calculation of the budget of uncertainty on measurements size nanoparticles using dynamic light scattering2024 - GERALDES, ADRIANA N.; ROSERO, WILMMER A.A.; ROSTELATO, MARIA E.C.M.; SARKIS, JORGE E.S.Accurate nanoparticle characterization is essential since it can significantly affect its physicochemical and biological properties. Among physicochemical properties used to characterize nanomaterials, size and size distribution are essential and should be assessed before surveying poisonousness or biocompatibility. Several methods are suitable to evaluate these characteristics including the dynamic light scattering. The aims of the present paper were to propose a methodology to measure nanoparticle size and present the estimation of the particle size uncertainty using the dynamic light scattering technique. The reliability of measurements was ensured by a series of handling precautions and quality criteria for good measurements to be applied for methodology validation using reference material polyvinylpyrrolidone coated silver nanoparticles. The identification and quantification of input quantities to the measurement uncertainties were estimated. The uncertainty concerning the equipment was 1.2% while the repeatability obtained was 1.4%, within the range of values stipulated in the reference standard (less than 5%). The relative standard uncertainties of trueness and repeatability were below the thresholds defined by the International Organization for Standardization. The result of the expanded uncertainty was 3.9% with 95% coverage probability for the reference material.Resumo IPEN-doc 23767 Synthesis of radioactive gold 198 nanoparticle encapsulated by albumin as cancer theranostics agent2016 - LUGAO, A.B.; GERALDES, A.N.; LEAL, J.; VARCA, G.H.C.; BATISTA, J.G.S.; GRASSELLI, M.; KATTI, K.; BARROS, J.Albumin is a natural drug nanocarrier as it has equivalent diameter of about 5 nm and has natural affinity for hydrophobic and hydrophilic drugs. They can be bound in a reversible way and the delivery controlled by endogenous mechanism. Albumin can be crosslinked by radiation alternatively to conventional systems, in such way that dialdehydes or toxic chemicals are avoided. On the theranostic side, radioactive ions are commonly employed for diagnostic and therapeutic applications. As an example, radioactive gold nanoparticles are currently employed in radiotherapy whether to increase local dose deposition in tissue during radiotherapy or as a local emitter of gamma and beta rays. The radioactive properties of gold include: 198Au (?max=0.96 MeV; t1/2 = 2.7 days) and 199Au (?max =0.46 MeV; t1/2 = 3.14 days), making it a strong candidate for theranostics . Conjugation of such materials with sugars, peptides, antibodies, proteins among others is routinely used nowadays for targeting. While radioactive nanoparticles can offer a much higher dose payload than ions for therapy and diagnostic, in addition to the the huge surface to bind targeting species presented by the nanoparticles, functionalization with proteins may potentially increases the particle uptake by tumors or tissues. The main purpose of this work was the development of one pot in situ synthesis of radioactive gold 198 nanoparticle encapsulated by albumin for application in cancer Theranostics. While crosslinked albumin may provide a nontoxic coating on AuNPs with a controllable hydrodynamic diameter, conventional AuNP can be activated by nuclear reactor to produce 198AuNP. The gamma or beta radiation originated from the gold nanoparticle was used to crosslink the Albumin layer. The use of a radioactive particle able to emit radiation for crosslinking of the Albumin layer and simultaneous theranostic application was tried for the first time. The elegant procedure and ease of produc¬tion combined with the properties of 198Au and the safety of HSA-198AuNP make this new particle an exciting advancement in cancer therapy and diagnosis. For such purpose, radioactive tetrachloroauric acid H198AuCl4 was produced from gold foils of high purity by neutron irradiation in IPEN research nuclear reactor. 198AuNP/BSA were synthesized by stirring aqueous solutions of BSA and radioactive tetrachloroauric acid H198AuCl4. The reaction mixtures were stirred continuously at 25 °C. The color of the mixture become purple-red from pale yellow within 15 minutes indicating the formation of gold nanoparticles. The reaction mixture was stirred for an additional 20 minutes. The 198AuNP/BSA formed were characterized by UV-Vis spectrophotometry, DLS and TEM analysis. The spectra were recorded at first day of preparation and after 1 month. Radioactive gold nanoparticle encapsulated by crosslinked Albumin was prepared in reproducible way. The gold nanoparticle core size measured by TEM was about 20 nm and about 60 to 70 nm with the albumin layer as measured by DLS. Bityrosine formation was measured by fluorescence and it was an evidence of intramolecular and intermolecular crosslinking. In conclusion the technique was suitable for the in situ production of the crosslinked albumin functionalized radioactive gold nanoparticles. Acknowledgements The authors would like to thank Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq) project number 402887/2013-1 and 401438/2014-7 and International Atomic Energy Agency (IAEA) (CRP code F22064 ) for financial support.Artigo IPEN-doc 21227 Binary and ternary palladium based electrocatalysts for alkaline direct glycerol fuel cell2015 - GERALDES, ADRIANA N.; SILVA, DIONISIO F. da; ANDRADE e SILVA, LEONARDO G. de; SPINACE, ESTEVAM V.; OLIVEIRA NETO, ALMIR; SANTOS, MAURO C. dosPd/C, PdAu/C 50:50, PdSn/C 50:50, PdAuSn/C 50:40:10 and PdAuSn/C 50:10:40 electrocatalysts are prepared using an electron beam irradiation reduction method and tested for glycerol electro-oxidation in alkaline medium. X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Transmission electron Microscopy (TEM) and Cyclic Voltammetry (CV) are used to characterize the resulting materials. The activity for glycerol electro-oxidation is tested in alkaline medium at room temperature using Cyclic Voltammetry and Chronoamperometry (CA) and in a single alkaline direct glycerol fuel cell (ADGFC) at temperature range of 60e90 C. EDX analysis demonstrate that Pd:Au:Sn atomic ratios are very similar to the nominal ones. X-ray diffractograms of PdAuSn/C electrocatalysts evidence the presence of Pd (fcc), Au (fcc) and SnO2 phases. TEM analysis demonstrates a good dispersion of the nanoparticles on the carbon support with some agglomerates. Cyclic Voltammetry experiments suggest that PdAuSn/C electrocatalysts demonstrate better results. In single fuel cell tests, at 85 C, using 2.0 mol L 1 glycerol in 2.0 mol L 1 KOH solutions, the electrocatalyst PdAuSn/C 50:40:10 demonstrate highest power density (51 mW cm 2 ) and the 120 h durability tests demonstrate a 210 mV h 1 degradation rate.Artigo IPEN-doc 21177 Síntese de nanoparticulas de ouro estabilizadas por quitosana2015 - GERALDES, ADRIANA N.; OLIVEIRA, MARIA J.A.; SILVA, ANDRESSA A. da; LEAL, JESSICA; BATISTA, JORGE G.S.; LUGAO, ADEMAR B.Artigo IPEN-doc 21135 Comparative study of gun arabic and PVP as stabilizing agents for sinthesys of gold nanoparticles2015 - SILVA, ANDRESSA A.; LEAL, JESSICA; GERALDES, ADRIANA N.; LUGAO, ADEMAR B.Artigo IPEN-doc 21104 Gold nanoparticles synthetized by gamma radiation and stabilized by bovine serum albumin2015 - LEAL, JESSICA; SILVA, ANDRESSA A.; GERALDES, ADRIANA N.; GRASSELLI, MARIANO; LUGAO, ADEMAR B.Artigo IPEN-doc 21067 Ethanol electro-oxidation in alkaline medium using Pd/MWCNT and PdAuSn/MWCNT electrocatalysts prepared by electron beam irradiation2015 - GERALDES, ADRIANA N.; SILVA, DIONISIO F. da; ANDRADE e SILVA, LEONARDO G. de; SPINACE, ESTEVAM V.; OLIVEIRA NETO, ALMIR; SANTOS, MAURO C. dosArtigo IPEN-doc 20451 Palladium and palladium-tin supported on multi wall carbon nanotubes or carbon for alkaline direct ethanol fuel cell2015 - GERALDES, ADRIANA N.; SILVA, DIONISIO F. da; SILVA, JULIO C.M. da; SA, OSVALDO A. de; SPINACE, ESTEVAM V.; OLIVEIRA NETO, ALMIRPd and PdSn (Pd:Sn atomic ratios of 90:10), supported on Multi Wall Carbon Nanotubes (MWCNT) or Carbon (C), are prepared by an electron beam irradiation reduction method. The obtained materials are characterized by X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Transmission electron Microscopy (TEM) and Cyclic Voltammetry (CV). The activity for ethanol electro-oxidation is tested in alkaline medium, at room temperature, using Cyclic Voltammetry and Chronoamperometry (CA) and in a single alkaline direct ethanol fuel cell (ADEFC), in the temperature range of 60e90 C. CV analysis finds that Pd/MWCNT and PdSn/MWCNT presents onset potentials changing to negative values and high current values, compared to Pd/C and PdSn/C electrocatalysts. ATR-FTIR analysis, performed during the CV, identifies acetate and acetaldehyde as principal products formed during the ethanol electrooxidation, with low conversion to CO2. In single fuel cell tests, at 85 C, using 2.0 mol L 1 ethanol in 2.0 mol L 1 KOH solutions, the electrocatalysts supported on MWCNT, also, show higher power densities, compared to the materials supported on carbon: PdSn/MWCNT, presents the best result (36 mW cm 2 ). The results show that the use of MWCNT, instead of carbon, as support, plus the addition of small amounts of Sn to Pd, improves the electrocatalytic activity for Ethanol Oxidation Reaction (EOR).Resumo IPEN-doc 20358 Estudo de eletrocatalisadores Pd/C e PdBi/C com diferentes razões atômicas para uso em uma célula a combustível alcalina alimentada diretamente por etanol2014 - SA, OSVALDO A. de; GERALDES, ADRIANA N.; NETO, A.O.; SANTOS, MAURO C.Resumo IPEN-doc 20359 Desenvolvimento de materiais eletrocatalíticos para uso em uma célula a combustível alcalina alimentada diretamente por glicerol2014 - GERALDES, ADRIANA N.; SILVA, DIONISIO F.; OLIVEIRA NETO, ALMIR; SPINACE, ESTEVAM V.; SANTOS, MAURO C.