MAYELLE MARIA PAZ LIMA
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Resumo IPEN-doc 28615 A simple and quick method to generate in vitro tridimensional tumor bodies from a human breast adenocarcinoma (MCF7) using magnetic aggregation technique2021 - LIMA, MAYELLE M.P.; NASCIMENTO, PAMELA F. do; NASCIMENTO, ANA C.G.; VIEIRA, DANIEL P.INTRODUCTION Tumor physiology studies have to rely on efficient and representative models, as animal-based or in vitro tridimensional cell constructs. The work used magnetite (Fe3O4) nanoparticles produced by electron-beam induced chemical reduction to give cells the ability to form aggregates when submitted to a magnetic field, and thus to produce micro tumors in vitro. OBJECTIVES The work aimed to produce human breast adenocarcinoma mini tumors (BAMT's) in vitro. MATERIALS AND METHODS Paramagnetic iron oxide nanoparticles (PION’s) were synthesized through electron-beam induced Fe3+ reduction and subsequent coprecipitation. Due to its poly-L-lysine coating, PION’s were adsorbed on cell membranes ofMCF7 (human breast adenocarcinoma). Cells were seeded in 24-well cell culture plates pre-treated overnight with Pluronic® F-127 to prevent cell adhesion and kept in culture conditions under magnetic fields for at least 6 days. BAMT's were differentially stained with Hoescht 33342 and ethidium bromide and imaged by wide-field fluorescence microscopy. DISCUSSION AND RESULTS BAMT's appeared as integer and well-defined cellular aggregates, with sparse dead cells stained by ethidium bromide. These structures can be further used for in vitro tumor studies, as BAMT’s are supposed to be more reliable models than monolayer cultures. Treatment of wells with poloxamer caused a mild to moderated cell-repellent effect, similar to those found in commercially available products, only by a fraction of the cost. CONCLUSION The experiments succesfully produced mini tumors prone to be used in in vitro studies.Resumo IPEN-doc 28598 A simple and quick method to generate in vitro tridimensional tumor bodies from a human breast adenocarcinoma (MCF7) using magnetic aggregation technique2021 - LIMA, MAYELLE M.P.; NASCIMENTO, PAMELA F. do; NASCIMENTO, ANA C.G.; VIEIRA, DANIEL P.Tumor physiology studies have to rely on efficient and representative models, as animal-based or in vitro tridimensional cell constructs. The work used magnetite (Fe3O4) nanoparticles produced by electron-beam induced chemical reduction to give cells the ability to form aggregates when submitted to a magnetic field, and thus to produce micro tumors in vitro. The work aimed to produce human breast adenocarcinoma mini tumors (BAMT's) in vitro. Paramagnetic iron oxide nanoparticles (PION’s) were synthesized through electron-beam induced Fe3+ reduction and subsequent coprecipitation. Due to its poly-L-lysine coating, PION’s were adsorbed on cell membranes of MCF7 (human breast adenocarcinoma). Cells were seeded in 24-well cell culture plates pre-treated overnight with Pluronic® F-127 to prevent cell adhesion and kept in culture conditions under magnetic fields for at least 6 days. BAMT's were differentially stained with Hoescht 33342 and ethidium bromide and imaged by wide-field fluorescence microscopy. BAMT's appeared as integer and well-defined cellular aggregates, with sparse dead cells stained by ethidium bromide. These structures can be further used for in vitro tumor studies, as BAMT’s are supposed to be more reliable models than monolayer cultures. Treatment of wells with poloxamer caused a mild to moderated cell-repellent effect, similar to those found in commercially available products, only by a fraction of the cost. The experiments succesfully produced mini tumors prone to be used in in vitro studies.Resumo IPEN-doc 27653 Mouse mioblast (C2C12) spheroids structured using paramagnetic iron nanoparticles as an in vitro culture system of Toxoplasma gondii tachyzoites2020 - NASCIMENTO, A.C.; PASSOS, P.d.; LIMA, M.M.; GALISTEO JUNIOR, A.J.; VIEIRA, D.P.Tridimensional cell culture techniques became essential for understanding physiological processes that are obliterated or fainted in conventional bi-dimensional cultures. These techniques are prone to produce more realistic modeling of the complex environment of living tissues, leading to much better understanding of mammalian tissue organization. This work used magnetic levitation of cell aggregates (spheroids) by adsorbing iron nanoparticles to C2C12 mouse (Mus musculus) mouse line cells (ATCC # CRL-1772), which are suspended with magnetic fields. The cells formed three-dimensional bodies that were cultivated suspended in the air-liquid interface. Magnetite (Fe3O4) nanoparticles with mean diameter of approximately 50 nm were produced by an alkaline coprecipitation methodology under reduction by microwave energy. Composition and size of crystallites were determined by DRX analysis. Adsorption on cell membranes occurred after functionalization with poly-L-lysine. Work concentrations of nanoparticles did no induce cytotoxicity in C2C12 monolayer cultures. Transmission electron microscopy of spheroid sections showed some findings morphologically compatible to the shape of reproductive intracellular vacuoli of T.gondii after cell invasion, demonstrating an interaction of cells with parasites in three-dimensional models.