ALLAN BERECZKI
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
Artigo IPEN-doc 30048 Micro-Raman spectroscopy identification of hydroxyapatite in dental pulp stem cells2023 - SILVA, FLAVIA R.O.; PASCOAL, DIEGO R.C.; BERECZKI, ALLAN; SIPERT, CARLA R.; BRAGA, ROBERTO R.; BELLINI, MARIA H.; SILVA, LUIS F.T.; FREITAS, ANDERSON Z.; WETTER, NIKLAUS U.Cell differentiation using calcium phosphate nanoparticles was studied. The hydroxyapatite was internalized in human dental pulp stem cells and characterized by Raman spectroscopy. Raman spectra showed the hydroxyapatite distribution in nanoparticles nodules in the cells.Resumo IPEN-doc 29320 Micro-Raman spectroscopy for identification of microplastics in the São Vicente estuarine2022 - BERECZKI, ALLAN; PASCOAL, DIEGO R.C.; DIPOLD, JESSICA; GIMILIANI, GIOVANA T.; PARRA, DUCLERC F.; FREITAS, ANDERSON Z.; WETTER, NIKLAUSMicroplastics (MPs) are a concern regarding our environment due to the risks posed by the interactions of the large amounts of anthropogenic MPs dumped in the environment with biological systems. MPs have been vastly found in the environment and are transferred to the food chain with MPs being detected in foods, beverages and even in human blood and breastmilk. Understanding the behavior and characteristics of MPs is critical to assessing potential health risks (human and environmental) related to MPs and taking steps to prevent them from entering the ecosystem. Micro Raman spectroscopy is a powerful tool for measuring and characterizing MPs particles, being considered the gold standard because it allows identification of both the polymer matrix and possible pigments and contaminants. Furthermore it offers the possibility of characterizing both the chemical structure as well as the morphological features of the MPs. We utilized a Raman system to characterize MPs from the environment. Results from a standard MP sample were successfully measured and identified to reference spectra and even small portions of the sample as small as a few μm are suitable for obtaining a high quality spectrum for identification of the material (Fig1). Samples collected from at the São Vicente estuarine are being studied and by means of comparison with the Willey database it was possible to identify MP, additives and contaminants, thus demonstrating the power of the technique.Resumo IPEN-doc 29319 From micro to nano Raman2022 - WETTER, NIKLAUS; FREITAS, ANDERSON Z.; BERECZKI, ALLAN; PASCOAL, DIEGO R.C.; DIPOLD, JESSICA; PARRA, DUCLERC; ROSSI, WAGNER; CABRAL, FERNANDA V.; RIBEIRO, MARTHA S.The environmental accumulation of nanoplastics formed by material of anthropic origin has raised doubts about their safety, especially to the human body. While microplastics are accidentally consumed, nanoplastics (NPs) are even more concerning as they are much more likely to be absorbed by human body cells. It is known that plastics smaller than 200 nm can penetrate cell membranes and cross the blood-brain barrier. Studies have shown that polystyrene (PS) NPs from the environment carry a high load of toxins capable of compromising human brain cells. Very little is still known about what effects, cytotoxic or not, these plastics have on different organs. Understanding the property-function relationship of nanoparticles in various fields of application involves determining their physicochemical properties, which is still a formidable challenge to date. Our project focuses on the development of a methodology for the detection of micro- and NPs using micro-Raman, TERS (Tip Enhanced Raman Spectroscopy), collinear Raman and AFM, nuclear techniques, as well as a methodology for in vitro evaluation of the toxic effects of these materials through biochemical assays of cytotoxicity and genotoxicity. The project contemplates the determination of the adsorption capacity of metallic ions by NPs and the absorption of micro- and nanoplastics in cell cultures with radioactive tracers, the determination of microplastics in tissues from necropsies of marine animals and gamma spectroscopy of the cellular incorporation of NPs labeled with radioactive isotopes. In figure 1 we show examples of (a) the detection of microplastics from the Santos basin and comparison to Raman reference database (KnowItAll®), (b) detection of NPs in mouse fibroblast cells and (c) detection of very small particles (50 nm) which can be achieved by co-localized techniques of AFM + Raman using special, narrow (50 m), femtosecond laser written gratings on quartz.Resumo IPEN-doc 29318 Micro-Raman spectroscopy characterization of dental pulp stem cells differentiation induced by calcium phosphate nanoparticles2022 - SILVA, FLAVIA R.O.; PASCOAL, DIEGO R.C.; BERECZKI, ALLAN; SIPERT, CARLA R.; BRAGA, ROBERTO R.; BELLINI, MARIA H.; SILVA, LUIS F.T. da; FREITAS, ANDERSON Z.; WETTER, NIKLAUS U.Calcium phosphates are chemical compounds used in medicine for tissue engineering. This work analyzes the process of cell differentiation by nanoparticles in dental pulp stem cells for tissues regeneration and the development of new therapeutic methods. The most widely used synthetic calcium phosphate based bioceramic is hydroxyapatite [HA, Ca10(PO4)6(OH)2]. Micro-Raman spectroscopy assays are a powerful tool for measuring and characterizing calcium phosphates nanoparticles internalized by cells because of its capability to detect the chemical bonds of nanoparticles and collagen simultaneously and evidencing their interaction within the cell-nanoparticle system. Microscope images (Fig.1a) and Raman spectra (Fig.1b) were obtained for HA-incorporated stem cells where it was possible to observe the formed nodules of calcium phosphate and the matrix in the incorporated samples. HA and collagen peaks were detected in the samples, showing that the nanoparticles induced osteogenic differentiation of the stem cells. The spectra of the nodules showed HA characteristic peaks, while matrix spectra displayed characteristic collagen peaks. Studies have been carried out for the development of new and modified calcium phosphate nanoparticles that should further improve biostimulation.