MAYELLE MARIA PAZ LIMA

MAYELLE MARIA PAZ LIMA

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A simple and quick method to generate in vitro tridimensional tumor bodies from a human breast adenocarcinoma (MCF7) using magnetic aggregation technique
2021 - 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.
Comparações estruturais e funcionais entre nanopartículas superparamagnéticas de óxido de ferro sintetizadas a partir de duas fontes diferentes de ferro divalente
2019 - LIMA, MAYELLE M.P.; VIEIRA, DANIEL P.
Synthesis of paramagnetic iron oxide nanoparticles for application in in vitro three-dimensional biological models through electron beam irradiation and microwave reduction of iron ions
2019 - PASSOS, PRISCILA de Q.S.; CORAZZA, FULVIO G.; LIMA, MAYELLE M.P.; TOMINAGA, FLAVIO K.; SAKATA, SOLANGE K.; GONÇALVES, KARINA O.; COURROL, LILIA C.; VIEIRA, DANIEL P.
Three-dimensional (3D) cell culture is increasingly being used in assays to assess the safety and efficacy of new drug candidates. Tumor cell spheroids can mimic with high precision the biological complexity of cellular interactions with their tumor microenvironment. Currently, several techniques can be used to construct 3D spheroids. Among them, magnetic levitation is one of the most used in biomedical research. This technique consists in the magnetization of cells through the adsorption of magnetic nanoparticles of iron oxide (Fe3O4) that are produced by the reaction of Fe2+ and Fe3+ ions in alkaline medium. In this work, nanoparticles of paramagnetic iron oxide (PIONS) were synthesized by coprecipitation through electron beam irradiation at 15 and 30 kGy doses. After functionalization with polar amino acids, nanoparticle suspensions were characterized by physical-chemical assays that showed the successful attachment of the carboxylate groups to the iron, explaining the ability of the particles to adsorb the membranes. Cytotoxicity assay showed that the nanoparticles synthesized by microwave (MW) and electron beam had no toxicity. Others biological assays have also shown efficient adsorption of the particles by human prostate tumor cells, allowing the in vitro application of a biomimetic 3D biological model with potential utilization regarding the development and evaluation of antitumor drugs and radiopharmaceuticals for the treatment of prostate cancer.
Synthesis of paramagnetic iron oxide nanoparticles for application in in vitro three-dimensional biological models through gamma radiation and microwave reduction of iron ions
2019 - CORAZZA, FULVIO G.; PASSOS, PRISCILA de Q.S.; LIMA, MAYELLE M.P.; TOMINAGA, FLAVIO K.; SAKATA, SOLANGE K.; GONÇALVES, KARINA O.; COURROL, LILIA C.; VIEIRA, DANIEL P.
Two-dimensional (2D) cell models are extensively used in biomedical research to evaluate the efficacy and safety of new drugs. However, these conventional approaches do not precisely mimic the complexity of the organ microenvironment. To overcome this obstacle, three-dimensional (3D) spheroid cell structures usually referred to as spheroids are being developed to better represent the morphological and functional similarity to the tissues. Among several techniques currently employed to produce three-dimensional cell cultures, one of the most promising is the magnetic levitation, which consists of the magnetization of the cells through adsorption of magnetic nanoparticles of iron oxide (Fe3O4), which are produced by the reaction of Fe2+ and Fe3+ ions in alkaline medium. This work produced paramagnetic iron oxide nanoparticles (PIONs) by coprecipitation from an Fe2+ source. The reduction to Fe3+ was obtained by the ionization caused by gamma radiation (60Co) at 15 or 30 kGy radiation absorbed doses. After functionalization with poly-lysine, the nanoparticle suspensions were characterized by XRD, FTIR, zeta potential analysis, DLS and TEM which showed the successful attachment of the carboxylate groups to iron, explaining the ability of the particles to be adsorbed by the membranes. Biological assays showed that these PIONs were biocompatible and efficiently could be applied to develop prostate 3D tumor spheroids model for drug screening.