Electron Microscopy of Neurons on Biomimetic Substrates.

Recent advancements in nano- and microfabrication techniques have led to the development of highly biomimetic patterned substrates able to guide neuronal sprouting, routing, elongation, and branching. Such substrates, recapitulating shapes and geometries found in the native brain, may pave the way toward the development of cell instructive paradigms able to guide morphogenesis at the neuron-material interface. In this scenario, high-resolution electron microscopy approaches, owing to their ability of discerning the details of neural morphogenesis at a nanoscale resolution, may play a crucial role in unravelling the fine ultrastructure of neurons interfacing with biomimetic structured substrates.

An organic brain-inspired platform with neurotransmitter closed-loop control, actuation and reinforcement learning.

Organic neuromorphic platforms have recently received growing interest for the implementation and integration of artificial and hybrid neuronal networks. Here, achieving closed-loop and learning/training processes as in the human brain is still a major challenge especially exploiting time-dependent biosignalling such as neurotransmitter release. Here, we present an integrated organic platform capable of cooperating with standard silicon technologies, to achieve brain-inspired computing via adaptive synaptic potentiation and depression, in a closed-loop fashion. The microfabricated platform could be interfaced and control a robotic hand which ultimately was able to learn the grasping of differently sized objects, autonomously.

Negatively-charged supported lipid bilayers regulate neuronal adhesion and outgrowth.

One of the main challenges in neuroelectronics is the implementation of electronic platforms able to secure a tight coupling with neuronal cells and achieve an optimal signal to noise ratio during stimulation/recording of electrophysiological activity. In this context, supported lipid bilayers (SLBs), recapitulating the structure and the dynamicity of the biological plasma membrane, offer a promising biomimetic approach to trick cells to recognize a device as part of their native environment, tightening the cell-chip coupling. Among possible functionalization strategies used to improve cell adhesion on SLBs, the modification of the bilayer surface charge has been exploited to enhance the electrostatic interaction between the artificial membrane and its biological counterpart. In this work, several SLBs with different lipidic composition were synthesized and interfaced with primary neurons. Starting from a neuron-inspired biomembrane, the negative charges were increased through the addition of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(succinyl) (succinyl-PE), a lipid exposing phosphate (PO4 -) groups; furthermore, the reactivity of the succinyl carboxylate group enabled the subsequent addition of negatively charged sulfonate (SO3 -) groups. The synthesized SLBs were then tested as platforms for neuronal adhesion and network formation. Despite the expected repulsive electrostatic interactions, our work suggests that negatively charged SLBs may influence neurite elongation and branching, highlighting the potential of surface charge to tune neuronal processes at the neuron-SLB interface.

Modulation of Early Stage Neuronal Outgrowth through Out-of-Plane Graphene.

The correct wiring of a neural network requires neuron to integrate an incredible repertoire of cues found in their extracellular environment. The astonishing efficiency of this process plays a pivotal role in the correct wiring of the brain during development and axon regeneration. Biologically inspired micro- and nanostructured substrates have been shown to regulate axonal outgrowth. In parallel, several studies investigated graphene's potential as a conductive neural interface, able to enhance cell adhesion, neurite sprouting and outgrowth. Here, we engineered a 3D single- to few-layer fuzzy graphene morphology (3DFG), 3DFG on a collapsed Si nanowire (SiNW) mesh template (NT-3DFGc), and 3DFG on a noncollapsed SiNW mesh template (NT-3DFGnc) as neural-instructive materials. The micrometric protruding features of the NWs templates dictated neuronal growth cone establishment, as well as influencing axon elongation and branching. Furthermore, neurons-to-graphene coupling was investigated with comprehensive view of integrin-mediated contact adhesion points and plasma membrane curvature processes.

Bioinspired micro- and nano-structured neural interfaces.

The development of a functional nervous system requires neurons to interact with and promptly respond to a wealth of biochemical, mechanical and topographical cues found in the neural extracellular matrix (ECM). Among these, ECM topographical cues have been found to strongly influence neuronal function and behavior. Here, we discuss how the blueprint of the architectural organization of the brain ECM has been tremendously useful as a source of inspiration to design biomimetic substrates to enhance neural interfaces and dictate neuronal behavior at the cell-material interface. In particular, we focus on different strategies to recapitulate cell-ECM and cell-cell interactions. In order to mimic cell-ECM interactions, we introduce roughness as a first approach to provide informative topographical biomimetic cues to neurons. We then examine 3D scaffolds and hydrogels, as softer 3D platforms for neural interfaces. Moreover, we will discuss how anisotropic features such as grooves and fibers, recapitulating both ECM fibrils and axonal tracts, may provide recognizable paths and tracks that neuron can follow as they develop and establish functional connections. Finally, we show how isotropic topographical cues, recapitulating shapes, and geometries of filopodia- and mushroom-like dendritic spines, have been instrumental to better reproduce neuron-neuron interactions for applications in bioelectronics and neural repair strategies. The high complexity of the brain architecture makes the quest for the fabrication of create more biologically relevant biomimetic architectures in continuous and fast development. Here, we discuss how recent advancements in two-photon polymerization and remotely reconfigurable dynamic interfaces are paving the way towards to a new class of smart biointerfaces forin vitroapplications spanning from neural tissue engineering as well as neural repair strategies.

Advances in Cell-Conductive Polymer Biointerfaces and Role of the Plasma Membrane.

The plasma membrane (PM) is often described as a wall, a physical barrier separating the cell cytoplasm from the extracellular matrix (ECM). Yet, this wall is a highly dynamic structure that can stretch, bend, and bud, allowing cells to respond and adapt to their surrounding environment. Inspired by shapes and geometries found in the biological world and exploiting the intrinsic properties of conductive polymers (CPs), several biomimetic strategies based on substrate dimensionality have been tailored in order to optimize the cell-chip coupling. Furthermore, device biofunctionalization through the use of ECM proteins or lipid bilayers have proven successful approaches to further maximize interfacial interactions. As the bio-electronic field aims at narrowing the gap between the electronic and the biological world, the possibility of effectively disguising conductive materials to "trick" cells to recognize artificial devices as part of their biological environment is a promising approach on the road to the seamless platform integration with cells.

Tutorial: using nanoneedles for intracellular delivery.

Intracellular delivery of advanced therapeutics, including biologicals and supramolecular agents, is complex because of the natural biological barriers that have evolved to protect the cell. Efficient delivery of therapeutic nucleic acids, proteins, peptides and nanoparticles is crucial for clinical adoption of emerging technologies that can benefit disease treatment through gene and cell therapy. Nanoneedles are arrays of vertical high-aspect-ratio nanostructures that can precisely manipulate complex processes at the cell interface, enabling effective intracellular delivery. This emerging technology has already enabled the development of efficient and non-destructive routes for direct access to intracellular environments and delivery of cell-impermeant payloads. However, successful implementation of this technology requires knowledge of several scientific fields, making it complex to access and adopt by researchers who are not directly involved in developing nanoneedle platforms. This presents an obstacle to the widespread adoption of nanoneedle technologies for drug delivery. This tutorial aims to equip researchers with the knowledge required to develop a nanoinjection workflow. It discusses the selection of nanoneedle devices, approaches for cargo loading and strategies for interfacing to biological systems and summarises an array of bioassays that can be used to evaluate the efficacy of intracellular delivery.

Amebíase no contexto da emergência: análise do perfil de internações e morbimortalidade nos Estados brasileiros em 5 anos / Amebiasis in the context of emergency: an analysis of the profile of hospitalizations and morbidity/mortality in the states of Brazil in 5 years

Objetivo: Trazer um panorama atualizado acerca dos índices de internações e mortalidade por amebíase nos últimos 5 anos pelo sistema de saúde público brasileiro. Métodos: As informações analisadas foram pesquisadas no banco de dados do Departamento de Informática do Sistema Único de Saúde, considerandose as seguintes variáveis: amebíase; internações e mortalidade; sexo; faixa etária; e período de 2012 a 2016. Resultados: De 14.268 internações por amebíase em todo o Brasil, 4.252 foram em 2012, 3.248 em 2013, 2.552 em 2014, 2.033 em 2015 e 2.183 em 2016. Na Região Norte, encontraram-se os dois Estados com maior e menor número de internações da região e do país: o Pará, com 4.379 casos, e Roraima, com 5. Na Região Nordeste, o Maranhão foi o Estado com mais notificações (4.114) e o segundo maior do Brasil. Na Região Sudeste, Minas Gerais apresentou maior número de registros (793); no Sul, foi o Paraná (325) e, no Centro-Oeste, Goiás (731). Dos Estados com registro de mortalidade, na Região Norte, o Amazonas obteve maior valor (1,02); no Nordeste, foi o Sergipe (5,26); no Sudeste, o Rio de Janeiro (7,81); no Sul, o Rio Grande do Sul (5,26); e, no Centro-Oeste, o Mato Grosso (1,22). Conclusão: Apesar de uma redução no número de internações, as estatísticas para a amebíase ainda continuam altas, principalmente, considerando- se que se trata de uma patologia que poderia ser evitada. É necessário investir em mais medidas educativas, que ensinem a população a evitar a contaminação pelo Entamoeba spp., bem como que seja promovidas ações de saneamento básico e abastecimento de água potável adequados para todas as regiões do Brasil. (AU)

Objective: To provide an updated picture of the hospitalization rates, and mortality due to amebiasis in the last 5 years in the Brazilian public health system. Methods: The information analyzed was searched in the Informatics Department of the Unified Health System database, considering the following variables: amebiasis; hospitalizations and mortality; gender; age group; and period from 2012-2016. Results: Of 14,268 hospitalizations for amebiasis throughout Brazil, 4,252 were in 2012, 3,248 in 2013, 2,552 in 2014, 2,033 in 2015, and 2,183 in 2016. In the North Region, there were the two states with the highest and lowest number of hospitalizations in the region and in the country: the state of Pará, with 4,379 cases, and of Roraima with 5. In the Northeast region, the state of Maranhão was the one with more notifications (4,114), and the second largest one in Brazil. In the Southeast region, the stat of Minas Gerais presented the highest number of records (793); in the South region, it was the state of Paraná (325); and in Center-West, Goiás (731). Of the states with mortality records, in the North region Amazonas reached the highest value (1.02); in the Northeast, Sergipe (5,26); in the Southeast, Rio de Janeiro (7.81); in the South, Rio Grande do Sul (5.26); and in the Center-West region, Mato Grosso (1,22). Conclusion: Despite a reduction in the number of hospitalizations, the statistics for amebiasis are still high, mainly considering that it is a pathology that could be avoided. It is necessary to invest in more educational measures, which teach the population how to avoid contamination by Entamoeba spp., as well as to promote basic sanitation actions, and drinking water supply suitable for all regions of Brazil. (AU)