Como estudar interações entre nanopartículas e sistemas biológicos

Abstract

Recebido em 02/05/2016; aceito em 15/06/2016; publicado na web em 16/08/2016 STUDYING THE INTERACTIONS BETWEEN NANOPARTICLES AND BIOLOGICAL SYSTEMS. Although in recent years there has been an increasing amount of literature on nanotechnology and their clinical applications, it is still scarce a deep understanding of the interactions at the molecular levels between nanoparticles and cells. Studies demonstrating the underlying mechanisms of nanoparticles endocytosis, intracellular trafficking, and cellular processing are imperative to understand better how cells interact with those materials and their possible undesired effects, e.g. nanotoxicity. The rising awareness concerning nanoparticles applications and its interactions with the cellular environment is part of the new research field called Nanotoxicology. The cumulative knowledge in nanotoxicology will allow us to foresee toxic effects, establish regulations and limits for nanoparticles applications. In this work, we discuss the theoretical concepts about studying endocytosis and intracellular trafficking of nanoparticles. The nanoparticles-cell interactions are a multi-step process, which can be divided into nanoparticles' internalization, intracellular processing and triggering effects of nanomaterials on eukaryotic cells. Finally, we discuss the main techniques used to study this process: flow cytometry, use of endocytosis inhibitors and confocal microscopy.Keywords: endocytosis; intracellular trafficking; nanoparticles, nanotoxicology; nano-cell interactions. INTRODUÇÃONanotecnologia é um dos ramos mais promissores de tecnologia, sobre o qual se deposita grandes expectativas. 1 Somente em 2015, foram publicados cerca de 9400 artigos relacionados ao termo "Nanotechnology" no banco de dados Science Direct; além disso, diversos produtos têm sido testados e comercializados, por exemplo, protetores solares, cosméticos, produtos biomédicos, biosensores e sistemas para transporte e entrega de fármacos. 2 Entretanto, há uma crescente preocupação com a segurança e possíveis efeitos nocivos de nanomateriais que vêm sendo desenvolvidos, 3 pois dados e regulamentações internacionais referentes à segurança e uso desses materiais ainda são escassos, ainda estão em debate ou em fase de implementação. 4 Uma nova área da ciência destinada ao estudo de efeitos adversos de nanomateriais foi recentemente criada, a Nanotoxicologia. 5 O conhecimento acumulado nessa área tem como objetivo prever efeitos tóxicos e auxiliar nas regulamentações e diretrizes para aplicação da nanotecnologia 6 e uso de produtos a ela relacionados. A Figura 1 mostra o crescimento do número de artigos científicos que contêm o termo "nanotoxicology" e estão no banco de dados do National Center for Biotechnology Information (NCBI), subdivisão do National Institute of Health (NIH/USA).Apesar do número de artigos em nanotoxicologia ser crescente, esta é uma área ainda muito recente (com menos de uma década), e ainda não é possível determinar exatamente quais impactos os sistemas naturais e artificiais co...

Polymeric nanoparticles containing Tithonia diversifolia (hemsl) a. Gray flowers alcoholic extract and coated by hyaluronic acid_ development, synthesis, and characterization

“…The zeta potential is associated with the surface potential of particles. Results obtained showed slightly negative values, which may be associated with the fact that the reaction occurs in an acidic medium (lower pH), contributing to a reduced dissociation of the free acrylic acid groups (REDDY & MURTHY, 2004).…”

“…Th e resulting graphs can be used to obtain information regarding the thermal stability of the substance, its composition and intermediate products/ residues formed (SILVA et al, 2007). TG analysis was carried out in a Netzsch cell (STA 449F3a) with nitrogen atmosphere.…”

“…Contemplated within the Asteraceae family, the species Tithonia diversifolia (Hemsl) A. Gray has been used as a medicinal plant (LACERDA et al, 2011), having anti-inflammatory action (OWOYELE et al, 2004) and containing chemical compounds such as total phenols, tannins and flavonoids that also contribute to an antioxidant (GAMA et al, 2013), anticancer (CHOWDHURY et al, 2002;CAI et al, 2004), antimicrobial (NASCI-MENTO et al, 2000;CUSHINE & LAMB, 2005) and healing action (NAYAK & PEREIRA, 2006).…”

SCryPTA:A web-based platform for analyzing Small-Angle Scattering curves of lyotropic liquid crystals

“…In particular, LLC structures can be mainly classified into different phases, as micellar, lamellar, cubic, and hexagonal according to their structures 4,5 . LLC are found in vivo 6,7 , they can be used in the crystallization of membrane proteins 8,9 , control of chemical reaction in food 10 and as drug delivery systems [11][12][13][14] .…”

“…SAXS is able to give information on the scattering particle structure, in particular in the nanometer range, as well as in the water channel dimension, in the case of some cubic structures and hexagonal as well 28 . An important feature of SAXS is the ability of performing measurements of systems in solution, simulating the natural environmental conditions in which the LC dispersions would be used 29 . Depending on the crystallographic arrangement of the studied system, SAXS profiles may present some, or even several peaks.…”