Effect of graphene oxide on bacteria and peripheral blood mononuclear cells

"Background Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media. Furthermore, we performed experiments with peripheral blood mononuclear cells exposed to our GO materials. Methods Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the morphology and composition of different samples of GO: GO-H2O, GO-PBS and GO-MG. Our samples had 2D sizes of ?100 nm (GO-H2O and GO-PBS) and >2 µm (GO-MG). We tested antibacterial activity and cytotoxicity toward peripheral blood mononuclear cells of 3 different GO samples. Results A size-dependent growth inhibition of Escherichia coli (DH5 ?) in suspension was found, which proved that this effect depends strongly on the protocol followed for exposure. Hemocompatibility was confirmed by exposing peripheral blood mononuclear cells to materials for 24 hours; viability and apoptosis tests were also carried out. Conclusions Our experiments provide vital information for future applications of GO in suspension. If its antibacterial properties are to be potentiated, care should be taken to select 2D sizes in the micrometer range, and exposure should not be carried out in the presence of grow media.

Quando os nervos gritam: Uma abordagem neurobiológica da dor

Pain, a complex phenomenon that transcends physical perception, emerges as a warning signal from the nervous system, playing a crucial role in the survival and protection of the organism. In this context, the objective of this article is to deepen the understanding of the multiple nature of pain, encompassing its sensory and emotional aspects. The exploration of neurobiological mechanisms and the differentiation between acute and chronic pain underscore the imperative need for a biopsychosocial approach to address chronic pains. Additionally, there is a quest to investigate the intricate interrelation between physical and emotional pain, in light of recent discoveries in neuroscience. Furthermore, rare cases of insensitivity to pain due to genetic mutations are examined. This study aims for a holistic comprehension of pain, integrating clinical, neurobiological, and genetic perspectives to enhance therapeutic strategies. Understanding the neurobiological mechanisms of pain is crucial to improve the well-being of individuals facing persistent discomforts. This research, of a basic and theoretical nature, adopts a qualitative exploratory approach. The literature review was conducted on academic and scientific platforms, employing specific terms such as "pain," "neurobiology," and "nervous system" to identify relevant studies. Throughout the investigation, the finding emerged that recent studies indicate a lack of differentiation in the human brain between physical and emotional pain, highlighting the intrinsic interconnection between psychological and physiological aspects of pain. Understanding the neurochemical and electrical circuits underlying pain transmission becomes crucial for the development of more effective and personalized treatment strategies.A dor, um fenômeno complexo que transcende a percepção física, emerge como um sinal de alerta do sistema nervoso, desempenhando um papel importante na sobrevivência e proteção do organismo. Nesse contexto, objetiva-se o presente artigo aprofundar a compreensão da natureza múltipla da dor, abarcando seus aspectos sensoriais e emocionais. A exploração dos mecanismos neurobiológicos e a diferenciação entre dor aguda e crônica ressaltam a imperiosidade de uma abordagem biopsicossocial para enfrentar as dores crônicas. Além disso, busca-se investigar a intricada inter-relação entre dor física e emocional, à luz de descobertas recentes na neurociência. Adicionalmente, examinam-se casos raros de insensibilidade à dor decorrentes de mutações genéticas. Este estudo visa uma compreensão holística da dor, integrando perspectivas clínicas, neurobiológicas e genéticas para aprimorar estratégias terapêuticas. A compreensão dos mecanismos neurobiológicos da dor é crucial para aprimorar o bem-estar de indivíduos que enfrentam desconfortos persistentes. Esta pesquisa, de caráter básico e teórico, adota uma abordagem exploratória qualitativa. A revisão bibliográfica foi conduzida em plataformas acadêmicas e científicas, empregando termos específicos como "dor", "neurobiologia" e "sistema nervoso" para identificar estudos pertinentes. Ao longo da investigação, emergiu a constatação de que estudos recentes indicam a ausência de diferenciação, no cérebro humano, entre a dor física e emocional, evidenciando a intrínseca interconexão entre aspectos psicológicos e fisiológicos da dor. A compreensão dos circuitos neuroquímicos e elétricos subjacentes à transmissão da dor torna-se crucial para o desenvolvimento de estratégias de tratamento mais eficazes e personalizadas

The parabasal filaments of Trichomonas vaginalis: A new filament and observations using 0.8 nm-resolution scanning electron microscopy

Trichomonas vaginalis is the etiologic agent of trichomoniasis, the most common nonviral sexually transmitted infection worldwide, with an estimated 260 million new cases annually. T. vaginalis contains organelles common to all eukaryotic cells, uncommon cell structures such as hydrogenosomes, and a complex and elaborate cytoskeleton constituting the mastigont system. The mastigont system is mainly formed by several proteinaceous structures associated with basal bodies, the pelta-axostylar complex made of microtubules, and striated filaments named the costa and the parabasal filaments (PFs). Although the structural organization of trichomonad cytoskeletons has been analyzed using several techniques, observation using a new generation of scanning electron microscopes with a resolution exceeding 1 nm has allowed more detailed visualization of the three-dimensional organization of the mastigont system. In this study, we have investigated the cytoskeleton of T. vaginalis using a diverse range of scanning probe microscopy techniques, which were complemented by electron tomography and Fast-Fourier methods. This multi-modal approach has allowed us to characterize an unknown parabasal filament and reveal the ultrastructure of other striated fibers that have not been published before. Here, we show the differences in origin, striation pattern, size, localization, and additional details of the PFs, thus improving the knowledge of the cell biology of this parasite

Effect of Graphene Oxide on Bacteria and Peripheral Blood Mononuclear Cells

"Background Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media. Furthermore, we performed experiments with peripheral blood mononuclear cells exposed to our GO materials. Methods Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the morphology and composition of different samples of GO: GO-H2O, GO-PBS and GO-MG. Our samples had 2D sizes of ?100 nm (GO-H2O and GO-PBS) and >2 µm (GO-MG). We tested antibacterial activity and cytotoxicity toward peripheral blood mononuclear cells of 3 different GO samples. Results A size-dependent growth inhibition of Escherichia coli (DH5 ?) in suspension was found, which proved that this effect depends strongly on the protocol followed for exposure. Hemocompatibility was confirmed by exposing peripheral blood mononuclear cells to materials for 24 hours; viability and apoptosis tests were also carried out. Conclusions Our experiments provide vital information for future applications of GO in suspension. If its antibacterial properties are to be potentiated, care should be taken to select 2D sizes in the micrometer range, and exposure should not be carried out in the presence of grow media.