PRISCILA DE QUEIROZ SOUZA PASSOS
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Artigo IPEN-doc 28654 In vitro and in vivo response of PSMA-617 radiolabeled with CA and NCA lutetium-1772022 - BOAS, CRISTIAN A.W.V.; SILVA, JEFFERSON de J.; DIAS, LUIS A.P.; FREIRE, MARIA R.B.; BALIEIRO, LUIZA M.; SANTOS, CAROLINA S.F. dos; VIVALDINI, BIANCA F.; BENEDETTO, RAQUEL; VIEIRA, DANIEL P.; PASSOS, PRISCILA de Q.S.; MARUMO, MARIA H.; TEIXEIRA, LUIS F.S.; ARAUJO, ELAINE B. deThe PSMA-targeted radionuclide therapy has been explored since 2015 with radioisotope lutetium-177, whose β− emission range is adequate for micrometastases treatment. This radioisotope is obtained by two different production routes that directly affect the specific activity of lutetium-177 (non-carrier added and carrier added) and, consequently, the specific activity of radiopharmaceuticals, like 177Lu-PSMA-617. The influence of the specific activity of lutetium-177 on the properties of the radiopharmaceutical PSMA-617 was evaluated through pre-clinical studies. The in vitro study pointed to a lower constant of dissociation with non-carrier added lutetium-177 due to the difference in the specific activity. However, competition and internalization assays resulted in similar results for both lutetium-177. Based on these pre-clinical experiments, the total in vitro tumor cell binding and tumor uptake in vivo were similar, with no influence of the specific activity of the 177Lu-PSMA-617. Regardless the specific activity did not directly affect tumor uptake, the tumor/non-target organs ratios were higher for the radiopharmaceutical labeled with carrier added lutetium-177, which had the lowest specific activity.Artigo IPEN-doc 26645 Microwave-mediated synthesis of iron-oxide nanoparticles for use in magnetic levitation cell cultures2019 - BONFIM, LETICIA; PASSOS, PRISCILA de Q.S.; GONÇALVES, KARINA de O.; COURROL, LILIA C.; SILVA, FLAVIA R. de O.; VIEIRA, DANIEL P.The use of three-dimensional cell cultures has been widely used for efficacy and/or toxicity testing of compounds. One of the most promising systems, based on magnetic levitation, is dependent on proper cell magnetization, achieved through adsorption of iron-oxide nanoparticles on cell membranes. These particles must bare not only significant responses to magnetic fields, but also a stable mechanism to attachment to cells. This work proposes a simple, one-pot synthesis method to produce magnetite nanoparticles, using a Fe2+ precursor associated with amino acids under microwave heating, and successive steps to confer positive charges to particles. X-ray diffraction could confirm Fe3O4 composition, and TEM analysis showed cubic-like crystallites with less than 50 nm. Zeta-potential experiments showed that particles remained positively charged (20.98 ± 0.28 mV) in physiological pH, suggesting ability to attach to (negatively charged) cell membranes, observed through optical microscopy. Iron colloid was found to be non-cytotoxic in concentrations up to 8% in cell culture media. Finally, human prostate cancer cells were cultured in 96-well plates using magnetic levitation and could be kept 8 days in culture. The results showed a feasible way to produce spheroids relying on magnetic levitation, using a newly described method of magnetic and cell adherent nanoparticle production.