Abstract This work provides a convenient strategy for preparation of conducting polycaprolactone (PCL)/polyaniline (PAni) nanofibers, useful for development of optoelectronic sensors and devices. PCL/PAni nanofibers were obtained by electrospinning technique and characterized by SEM, FTIR, thermal analysis, and DC electrical conductivity. The influence of the experimental conditions in the electrospinning process, such as the applied voltage, on the nanofiber morphology was discussed in detail. Incorporation of PAni into PCL nanofibers significantly increased the electrical conductivity from a non-detectable level for the neat PCL to 0.032 ± 0.022 S/cm for the nanofibers containing 7.5 wt.% PAni. Therefore, electrospun PCL/PAni nanofiber mats presented optical and electrical properties, that awaken the possibility of applications for these materials as acid-base sensors and electrochromic devices.

Abstract This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fourier-transform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents.

The present prospective work of scientific articles related to foods and natural products with anti-Covid activity in databases in order to present a scientific community, to governments and society as main foods, nutraceuticals and medicinal plants as strategies used by countries during the COVID-19 pandemic. A review of articles on food, medicinal plants and biotechnology was carried out in databases of scientific articles such as: CAPES journals, PubMed, Elsevier's Science Direct, Willey on library library, Taylor & Francis Springer-Nature database, BMC, Hindawi, Scielo, ACS - American Chemical Society, Google Scholar, in addition to the Patent Database “The LENS” and “Questel-Orbit”. Foods used in daily life such as garlic, ginger, turmeric, sour orange, vegetables, lactobacilli demonstrate proven anti-virus action. Medicinal plants used by Traditional Chinese, Korean and Indian Medicine also demonstrate anti-Covid activity and used during the coronavirus outbreak. Some medicinal plants, green propolis extract, red propolis extract, royal gelly, polen, honey have also been cited as anti-covid, natural anti-inflammatory and immunomodulatory products.

O presente trabalho prospectou artigos científicos relacionadas à alimentos e produtos naturais com atividade anti-Covid com o intuito de apresentar, à comunidade científica, aos governos e à sociedade, dados sobre as principais estratégias nutracêuticas, biotecnológicas e plantas medicinais utilizadas em alguns países durante o enfrentamento da pandemia COVID-19. A revisão de artigos sobre alimentos, plantas medicinais e produtos biotecnológicos foi realizada nas bases de dados periódicos da CAPES, PubMed, Science Direct, Willey on line library, Springer-Nature, Taylor & Francis, BMC, Hindawi, Scielo, ACS – American Chemical Society, Google acadêmico, “The LENS” e Questel-Orbit. Alimentos de uso frequente como alho, gengibre, cúrcuma, laranja azeda, vegetais e lactobacilos demonstraram ação anti-coronavirus comprovada. Foram descritos usos de plantas medicinais da Medicina tradicional Chinesa, Coreana, Indiana bastante utilizadas durante a pandemia. Algumas plantas medicinais e nutracêuticos como: extrato de própolis verde e extrato de própolis vermelha brasileiras, geleia real, pólen e mel também foram citados como produtos anti-covid, antiinflamatórios naturais e imunomodulatórios.

The conditions of chemical synthesis can be crucial for polymerization of styrene in such a way that it can be produced latex beads at nanometric range (ϕ < 400nm). In this work, it will be analyzed how the absence of N2 and surfactant will result in colloidal particles with high affinity to agglomerate forming two kinds of nanostructured assemblies: colloidal crystals and nanowires. Four syntheses were realized and four parameters were changed: temperature, impeller speed, and initiator and styrene concentrations. The dispersion was filtered and coated on glass slides by evaporation induced self-assembly (EISA) process. Morphology and topography were observed at Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) respectively. They show how the synthesis conditions play a vital a role on the formation of self assembly nanostructures that can be applied as templates for sensors and biomaterials devices.