Submissões Recentes
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Characterization of iron oxide nanoparticles for production of breast adenocarcinoma spheroids
2024 - LIMA, M. M. P.; SILVA, G. D.; FALCAO, P. L.; SILVA, T. M.; OLIVEIRA, R. R.; VIEIRA, D. P.
The construction of an in vitro model that can accurately demonstrate the conditions found in vivo requires the production of a series of complexities that often transcend various areas of knowledge. In this context, the present study employed three-dimensional culture by magnetic aggregation to build a model that minimally satisfactorily represented conditions for studying cellular behaviors present in the tumor environment related to cell death and duplication. Thus, functionalized iron oxide nanoparticles were used for culturing tumor spheroids containing breast adenocarcinoma cell line (MCF7) and human fibroblast (HF002-J) within their structure. The spheroids were divided into concentration categories for each cell line, and after a screening process, the concentrations with greater stability were irradiated or received doses of a drug with known antitumor activity for treatment. The models were studied through X-ray diffraction (XRD), Transmission electron microscopy (TEM), cytotoxicity assays, and fluorescence microscopy. The obtained results proved to be a viable alternative for the analysis of cell viability, cytotoxicity, and the morphology of tumor spheroids.
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Impact of electron beam on PBAT/PLA (Ecovio) bags by Raman spectroscopy and thermogravimetry
2024 - COSTA, C. J.; MARCONDES, T.; CALVO, W. A.; KODAMA, Y.
Biodegradable polymers are compounds derived from renewable sources, such as biomass and organic components. They emerge as a promising alternative to reduce the environmental impact of traditional petroleum-derived polymers. These polymers have physico-chemical characteristics that allow faster degradation compared to conventional polymers, significantly reducing the time of residence in the soil and its negative impacts on the environment. Ecovio®, a sustainable and advantageous alternative, is composed of an aliphatic-aromatic copolymer Ecoflex® and polylactic acid (PLA), both biodegradable. Its formulation includes non-stick and slip agents to facilitate the processing of extrusion films. Romapack produces biodegradable bags with 55% PBAT (poly (butylenoadipate co-terephthalate)) and 45% PLA (polylactic acid) (Ecovio). In partnership with IPEN, these bags were irradiated with ionizing radiation of electron beams at absorbed doses of 25, 50 and 100 kGy to investigate possible improvements in their structure and time of degradation. Raman and thermogravimetric spectroscopy analyses were performed to observe possible changes in the polymeric chains of Ecovio bags at different doses. Thermogravimetry showed the variation of mass loss in relation to temperature and/or time, revealing improvements in relation to thermal stability. The results indicate that PLA(polylactic acid) is more susceptible to degradation compared with PBAT(poly(butylene adipate co-terephthalate)). Ionizing radiation has modified the properties of Ecovio® and expanded its range of applications, this contributes to the creation of more environmentally friendly products, as degradation contributes to their biodegradability.
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In vivo distribution dynamics of gold nanoparticles
2024 - BARBEZAN, A. B.; ROSERO, W. A. W.; ALMEIDA, L. F.; RIGO, M. E. Z.; SILVA, F. F. A.; ROSTELATO, M. E. C. M.
This study evaluated the biodistribution of gum arabic-functionalized gold nanoparticles (GA-AuNPs) in Balb/C Nude mice following intravenous administration. Two activity regimens (200 µCi and 600 µCi) were analyzed at two different time points (3 and 24 hours post-injection). The results showed predominant accumulation of GA-AuNPs in the liver, spleen, and gallbladder, suggesting hepatobiliary excretion as the primary clearance route. A reduction in liver uptake after 24 hours indicates potential nanoparticle metabolism or elimination. Although this study focused on intravenous delivery, previous work from our group using BSA-coated AuNPs administered intratumorally demonstrated higher tumor retention and reduced systemic accumulation, reinforcing the importance of the administration route and surface coating in determining nanoparticle biodistribution. These findings contribute to the understanding of how delivery strategies influence nanoparticle bioavailability and support the development of safer and more targeted therapeutic platforms.
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Evaluations of the possible mutagenic and genotoxic effects of 2-ACBs
2024 - BARBEZAN, A. B.; BISPO, A. C. A.; MENDES, B. M.; VIEIRA, D. P.; CARVALHO, L. R.; MACHADO-SANTELLI, G. M.; VILLAVICENCIO, A. L. C. H.
This study investigates the potential mutagenic and genotoxic effects of 2-alkylcyclobutanones (2-ACBs), by-products formed in irradiated foods. These compounds are generated during the irradiation of fat-containing foods and have been reported to possess potential genotoxic properties. The research focused on 2-dodecylcyclobutanone (2-dDCB) and 2-tetradecylcyclobutanone (2-tDCB), evaluating their mutagenicity using the micronucleus assay in hepatic cell lines (HepG2, BRL3A, and HTC) and their genotoxicity using the Ames test with five bacterial strains (TA-98, TA-100, TA-1535, TA-1537, and WP2uvrA). The Ames test results indicated that 2-dDCB and 2-tDCB did not significantly increase mutagenic reversion rates, while the micronucleus assays showed no evidence of genotoxic damage in the tested cell lines. It is concluded that, at the concentrations evaluated, 2-dDCB and 2-tDCB do not exhibit mutagenic or genotoxic potential, supporting the safety of irradiated foods. However, further studies are recommended to assess long-term effects and different irradiation conditions.