Abstract The objective of this study was to evaluate the influence of vitamin C (VC) on the stability of stored liposomes under different climatic conditions. Liposomal formulations containing 1 mg/mL of VC (LIP-VC) and blank formulations (LIP-B) were prepared by the reverse-phase evaporation method. After preparation, they were characterized according to their refractive index, average vesicle diameter, polydispersity index (PDI), zeta potential, pH, content, encapsulation efficiency (EE%), morphology, stability and antioxidant activity. For stability, LIP-VC and LIP-B were stored in different climatic conditions (4 °C, 25 °C and 40 °C) for 30 days. The LIP-VC presented 1.3365 refractive index, 161 nm of mean diameter, 0.231 PDI, -7.3 mV zeta potential, 3.2 pH, 19.4% EE%, spherical morphology, 1 mg/mL of VC content, and antioxidant activity of 12 and 11.4 μmol of TE/mL for the radical DPPH and ABTS+, respectively. During stability, the LIP-B stored in 40 °C showed an instability in the parameters: PDI, vesicle size and zeta potential after 15 days, while the LIP-VC remained stable in its size and PDI for 30 days. After that, it is shown that VC can be used as an antioxidant and stabilizer in liposomes to increase the stability and shelf-life of vesicles.

Resumo: Este artigo evidencia e discute as perspectivas de inserção de tópicos de Nanociência e Nanotecnologia (N&N) no ensino, na visão de professores. Para tanto, apoia-se nos resultados de pesquisa de natureza qualitativa, com base na análise de conteúdo, realizada com professores de matemática e de ciências da natureza dos ensinos médio e superior. Além disso, foram analisados documentos legais das áreas de N&N, nos quais esses tópicos são referenciados. Os resultados apontam três perspectivas de inserção dos tópicos de N&N nas práticas profissionais: abordagem de base para desenvolver um conteúdo, integrada a um conteúdo curricular, e suplementar às atividades de sala de aula. Nesta última perspectiva, o professor busca suplementar abordagens de sala de aula com atividades extraclasse em que é possível aprofundar os conhecimentos, com ênfase em ciência e tecnologia. Existe, portanto, amparo legal para a inserção destes tópicos de N&N, bem como necessidades sociais, econômicas e ambientais emergentes que carecem de formação profissional compatível e, consequentemente, de mais investimentos na área de educação.

Abstract: This article addresses and highlights the possibilities for the insertion of Nanoscience and Nanotechnology (N&N) topics in teaching, according to teachers’ views. To do so, the article centers on the results of a qualitative study based on content analysis, which was carried out with mathematics and natural science teachers in secondary and higher education. In addition, required curriculum documents were analyzed which concern these fields of knowledge and cover those specific topics. The results point to three perspectives for the insertion of N&N topics in professional practices: a basic approach to developing content, integrated curricular content, and supplementary classroom activities. In this last perspective, the teacher seeks to supplement classroom approaches with extra class activities in which it is possible to deepen knowledge, with an emphasis on science and technology. Therefore, there is legal support for the insertion of N&N topics, as well as emerging social, economic and environmental needs that require compatible professional training and, consequently, more investments in education.

Carbon nanotubes are very stable systems having considerable chemical inertness due to the strong covalent bonds of the carbon atoms on the nanotube surface. Many applications of carbon nanotubes require their chemical modification in order to tune/control their physico-chemical properties. One way of achieving this control is carrying out functionalization processes where atoms and molecules interact (covalent or non-covalent) with the nanotubes. We review some of the progress that has been made in chemical functionalization of carbon nanotubes. Emphasis is given to chemical strategies, the most used techniques, and applications.