Cell membranes and the cytoskeleton play crucial roles in the regulation of cellular responses by mediating mechanical forces and physical stimuli from the microenvironment through their viscoelastic properties. Investigating these properties provides valuable insights into disease mechanisms and therapeutic strategies. Gold nanorods (GNRs), especially under irradiation, exhibit lethal effects against Leishmania parasites through plasmonic photothermal conversion. In this study, we focus on evaluating the effects of non-irradiated GNRs on macrophage properties to better understand their intrinsic interactions with cells and support the development of future phototherapy applications. Here, defocusing microscopy (DM), a quantitative phase microscopy technique, was used to analyze membrane fluctuations in macrophages ($M\varnothing s$) exposed to GNRs (average length of $43\pm 8 \mathrm{n}\mathrm{m}$ and diameter of $20\pm 4 \mathrm{n}\mathrm{m}$) and infected with Leishmania amazonensis. By quantifying membrane–cytoskeleton fluctuation from defocused images, we extracted viscoelastic parameters, including bending modulus ($k_c$) and viscosity ($\eta$), to characterize membrane behavior in detail. Our results show that infection increases both $k_c$ and $\eta$, while treatment at IC₅₀ reduces infection and selectively increases $k_c$ without affecting $\eta$. In healthy macrophages, exposure to GNRs resulted in a reduction in both parameters, indicative of increased membrane fluidity and cytoskeletal rearrangement. These findings provide new insights into the biomechanical effects of GNRs on macrophages and may enlighten the design of future phototherapeutic approaches.

Cell membranes and cytoskeleton play a crucial role in regulating cellular responses by mediating mechanical forces and physical stimuli from the microenvironment through their viscoelastic properties. Investigating these properties provides valuable insights into disease mechanisms and therapeutic strategies. Gold nanorods (GNRs), especially under irradiation, exhibit lethal effects against Leishmania parasites through plasmonic photothermal conversion. However, their mechanical interaction with cells remains poorly understood. Here, Defocusing Microscopy (DM), a quantitative phase microscopy technique, was employed to analyze membrane fluctuations in macrophages (M∅s) exposed to GNRs and infected with Leishmania amazonensis. Measuring the membrane-cytoskeleton fluctuation of defocused images, we quantified viscoelastic parameters such as bending modulus (kc) and viscosity (η), enabling a detailed char-acterization of membrane behavior. Results indicate that infection increases both kc and η, while IC50 treatment reduces infection and selectively increases kc without affecting viscosity. In healthy macrophages, GNRs reduced both parameters, suggesting a fluidizing effect. These findings contribute to a deeper understanding of GNRs' therapeutic performance and cytotoxicity, contributing to improved phototherapy applications.

A educação básica brasileira encontra-se em mudança, em particular pela implementação da Base Nacional Comum Curricular (BNCC), um documento orientador ao professor e aos sistemas de ensino. Entretanto, os livros didáticos (LD) recomendados pelo Programa Nacional do Livro e Material Didático (PNLD) por serem anteriores à BNCC não refletem em sua totalidade as orientações. Nessa perspectiva, visando auxiliar o professor na elaboração de tarefas capazes de promover o desenvolvimento das competências e habilidades preconizadas pela Base, foi analisado o volume 2 da coleção Conexões com a Física, recomendado pelo PNLD 2018, que interpela no discorrer do livro o desenvolvimento das competências e habilidades da área de Física. Verificou-se que o LD não potencializa o desenvolvimento de certas competências e habilidades da BNCC. Para suprir tal lacuna foi elaborado um material complementar de Física, constituído de um estudo dirigido sobre aquecedores solares, estruturado em três etapas de objetivos (síncrese, análise e síntese). O material foi aplicado em uma escola estadual de Belo Horizonte e os resultados obtidos apontam que as competências analisadas no LD foram potencializadas em no mínimo 80%, auxiliando os estudantes na construção do conhecimento científico, em um eficaz processo ensino-aprendizagem e na associação dos conceitos de Física.