Understanding the unorthodox stabilization of liquid phase exfoliated molybdenum disulfide (MoS2) in water medium.

Molybdenum disulfide is a highly esteemed 2D material with interesting applications in nanoelectronics, composites, biotechnology and beyond. Its production through liquid-phase exfoliation in H2O is low-cost and eco-friendly. Herein, we present a detailed experimental and theoretical investigation seeking to explain the peculiar stability of MoS2 in H2O medium. By combining different microscopic (SEM, AFM and OM), spectrometric (Raman, UV-vis and AFM-FTIR), scattering (DLS) and ab initio simulation techniques, an edge-functionalization hypothesis for the excellent solvent properties of water for producing few-layer MoS2 has been demonstrated.

Graphene oxide classification and standardization.

There is a need to classify and standardize graphene-related materials giving the growing use of this materials industrially. One of the most used and more difficult to classify is graphene oxide (GO). Inconsistent definitions of GO, closely relating it to graphene, are found in the literature and industrial brochures. Hence, although they have very different physicochemical properties and industrial applications, commonly used classifications of graphene and GO definitions are not substantial. Consequently, the lack of regulation and standardization create trust issues among sellers and buyers that impede industrial development and progress. With that in mind, this study offers a critical assessment of 34 commercially available GOs, characterized using a systematic and reliable protocol for accessing their quality. We establish correlations between GO physicochemical properties and its applications leading to rationale for its classification.

Glass ionomer cement modified by a imidazolium salt: adding antifungal properties to a biomaterial.

We present the structural modification of a commercially available glass ionomer cement by inserting the imidazolium salt 1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl), composing a new biomaterial with antifungal biofilm activity. Test specimens were prepared using a commercial glass ionomer cement to which 10 ppm of cetylpyridinium chloride (reference ionic antifungal agent) or C16MImCl were added. The feasibility and hypoallergenicity of the new biomaterial were assessed by microhardness plastic deformation and chorioallantoic membrane assays. Colony counting and scanning electron microscopy were used to evaluate the modified specimens' antibiofilm activity against three multidrug-resistant Candida species. The modified glass ionomer cement presented a strong antibiofilm activity against Candida spp., without losing its original micromechanical and hypoallergenic properties, rendering it a promising candidate for further application in dentistry.

2D Electrolytes: Theory, Modeling, Synthesis, and Characterization.

A class of compounds sharing the properties of 2D materials and electrolytes, namely 2D electrolytes is described theoretically and demonstrated experimentally. 2D electrolytes dissociate in different solvents, such as water, and become electrically charged. The chemical and physical properties of these compounds can be controlled by external factors, such as pH, temperature, electric permittivity of the medium, and ionic concentration. 2D electrolytes, in analogy with polyelectrolytes, present reversible morphological transitions from 2D to 1D, as a function of pH, due to the interplay of the elastic and Coulomb energies. Since these materials show stimuli-responsive behavior to the environmental conditions, 2D electrolytes can be considered as a novel class of smart materials that expand the functionalities of 2D materials and are promising for applications that require stimuli-responsive demeanor, such as drug delivery, artificial muscles, and energy storage.

Human metabolite-derived alkylsuccinate/dilinoleate copolymers: from synthesis to application.

The advances in polymer chemistry have allowed the preparation of biomedical polymers using human metabolites as monomers that can hold unique properties beyond the required biodegradability and biocompatibility. Herein, we demonstrate the use of endogenous human metabolites (succinic and dilinoleic acids) as monomeric building blocks to develop a new series of renewable resource-based biodegradable and biocompatible copolyesters. The novel copolyesters were characterized in detail employing several standard techniques, namely 1H NMR, 13C NMR, and FTIR spectroscopy and SEC, followed by an in-depth thermomechanical and surface characterization of their resulting thin films (DSC, TGA, DMTA, tensile tests, AFM, and contact angle measurements). Also, their anti-fungal biofilm properties were assessed via an anti-fungal biofilm assay and the biological properties were evaluated in vitro using relevant human-derived cells (human mesenchymal stem cells and normal human dermal fibroblasts). These novel highly biocompatible polymers are simple and cheap to prepare, and their synthesis can be easily scaled-up. They presented good mechanical, thermal and anti-fungal biofilm properties while also promoting cell attachment and proliferation, outperforming well-known polymers used for biomedical applications (e.g. PVC, PLGA, and PCL). Moreover, they induced morphological changes in the cells, which were dependent on the structural characteristics of the polymers. In addition, the obtained physicochemical and biological properties can be design-tuned by the synthesis of homo- and -copolymers through the selection of the diol moiety (ES, PS, or BS) and by the addition of a co-monomer, DLA. Consequently, the copolyesters presented herein have high application potential as renewable and cost-effective biopolymers for various biomedical applications.

Keratin Associations with Synthetic, Biosynthetic and Natural Polymers: An Extensive Review.

Among the biopolymers from animal sources, keratin is one the most abundant, with a major contribution from side stream products from cattle, ovine and poultry industry, offering many opportunities to produce cost-effective and sustainable advanced materials. Although many reviews have discussed the application of keratin in polymer-based biomaterials, little attention has been paid to its potential in association with other polymer matrices. Thus, herein, we present an extensive literature review summarizing keratin's compatibility with other synthetic, biosynthetic and natural polymers, and its effect on the materials' final properties in a myriad of applications. First, we revise the historical context of keratin use, describe its structure, chemical toolset and methods of extraction, overview and differentiate keratins obtained from different sources, highlight the main areas where keratin associations have been applied, and describe the possibilities offered by its chemical toolset. Finally, we contextualize keratin's potential for addressing current issues in materials sciences, focusing on the effect of keratin when associated to other polymers' matrices from biomedical to engineering applications, and beyond.

Ultrasound exfoliation of graphite in biphasic liquid systems containing ionic liquids: A study on the conditions for obtaining large few-layers graphene.

Herein we describe a successful protocol for graphite exfoliation using a biphasic liquid system (water/dichloromethane, DCM) containing ionic liquids (ILs; 1,3-dibenzylimidazolium benzoate- and 1-naphthoate). The use of (surface active) IL and sonication led to stable DCM/water (O/W) emulsion, which enhanced graphene formation, suppressed its re-aggregation and decreased shear/cavitation damage. The O/W emulsion stabilization by the ILs was studied by dynamic light scattering (DLS), whereas their interaction with the graphene sheets were described by Density Functional Theory (DFT) calculations. Moreover, a comprehensive investigation on cavitation-based exfoliation in the O/W systems was performed to assess the importance of operational parameters, including, the type of ultrasound processor, ultrasound power and insonation, and the influence of the exfoliation medium.

Ionic Liquids as Surfactants for Layered Double Hydroxide Fillers: Effect on the Final Properties of Poly(Butylene Adipate-Co-Terephthalate).

In this work, phosphonium ionic liquids (ILs) based on tetra-alkylphosphonium cations combined with carboxylate, phosphate and phosphinate anions, were used for organic modification of layered double hydroxide (LDH). Two different amounts (2 and 5 wt %) of the organically modified LDHs were mixed with poly(butylene adipate-co-terephthalate) (PBAT) matrix by melt extrusion. All prepared PBAT/IL-modified-LDH composites exhibited increased mechanical properties (20-50% Young's modulus increase), decreased water vapor permeability (30-50% permeability coefficient reduction), and slight decreased crystallinity (10-30%) compared to the neat PBAT.

Ionic Liquid-Silica Precursors via Solvent-Free Sol-Gel Process and Their Application in Epoxy-Amine Network: A Theoretical/Experimental Study.

This work describes the solvent-free sol-gel synthesis of epoxy-functionalized silica-based precursors in the presence of 1-butyl-3-methylimidazolium-based ionic liquids (ILs) containing different anions: chloride (Cl-) and methanesulfonate (MeSO3-). The IL-driven sol-gel mechanisms were investigated in detail using experimental characterizations (29Si NMR and ATR FTIR spectroscopy) and a theoretical computational method based on density functional theory (DFT). We observed complex IL influence on both hydrolysis and condensation steps, involving especially H-bonding and Coulomb coupling stabilization of the process intermediates. The obtained IL-silica precursors and their further xerogels were widely characterized (rheology measurements, MALDI TOF, 29Si NMR, ATR FTIR, and DFT simulation), which allowed observation of their precise silica structures and established their most energetically favorable conformations. The detected silica structures were dependent on the IL type and varied from highly condensed 3D cage-like to branched ladder-like and cyclic ones. The application of prepared IL-silica precursors as reinforcing additives into the epoxy-amine network led to an improvement in the organic/inorganic interphase interactions through chemical and physical bonding. Uniform and well-dispersed silica aggregates, in the size of ∼30 nm, were formed when ≤6.8 wt % of each IL-silica precursor was applied into the epoxy-amine network. The use of imidazolium-based ILs contributed to a significant improvement in thermomechanical properties of hybrids and reduced their UV absorption ability compared to that of the reference matrix. All hybrids exhibited an increase in energy to break (up to ∼53%), elongation at break (up to ∼43%), shear storage modulus in the rubbery region (up to 4 times), and thermo-oxidative stability.

Bifunctional fluorescent benzimidazo[1,2-α]quinolines for Candida spp. biofilm detection and biocidal activity.

Biofilms provide an ideal environment for protecting the microbial cells from damage caused by humoral and cellular immune system components, promoting resistance, infections and increasing mortality and morbidity of patients in health facilities. In an attempt to provide an innovative solution for preventing contamination in hospital environments, this study evaluated nine structural complementary fluorescent benzimidazo[1,2-α]quinolines as bifunctional agents that both detect and have biocidal activity against yeast biofilms on stainless steel surfaces. The benzimidazoles' staining capability was determined by a fluorescence microscopy study and spraying the substance on yeast biofilm contaminated stainless steel surfaces. Furthermore, their in vitro human leukocyte cytotoxicity was evaluated with trypan blue and their biocidal activity was determined as the minimum inhibitory concentration against Candida tropicalis, C. albicans and C. parapsilosis strains. Moreover, scanning electron micrographs were recorded to study the biocidal activity. This resulted in the identification of 7, which presents all the desired characteristics (such as solubility) and capabilities (staining and biocide activity against all tested biofilm forming yeast strains) at the same time. As such, benzimidazole 7 has the potential to guarantee the use of disinfected medical and surgical instruments in clinical and surgical procedures, consequently, contributing to an increased safety for patients.

The role of ether-functionalized ionic liquids in the sol-gel process: effects on the initial alkoxide hydrolysis steps.

The ether-functionalized imidazolium ionic liquids (IL) applied in the silica sol-gel process demonstrated a defined coordination potential. These IL display the capacity to control the system organization from the reactions' first moments through a dynamic system-assembling ability, being the sum of ionic and physical interactions, i.e. Coulomb forces, H-bonding and London forces. The initial hydrolysis steps of tetraethyl orthosilicate (TEOS) in the presence of these IL were followed by Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS), both in time-resolved experiments, in an attempt to correlate the structuring and the bonding dynamics of these systems.

Evaluación de la Calidad en Salud en la Medicina Familiar y en la Atención Primaria en Iberoamérica / Health Quality Assessment in Family Medicine and Primary Care in Ibero America / Avaliação da Qualidade em Saúde na Medicina de Familia e na Atenção Primária na Ibero-América

El propósito de este estudio es contribuir al desarrollo del concepto y de los procesos relacionados a la evaluación de la Calidad en la Atención Primaria de Salud, bajo la perspectiva de Médicos de Familia y Comunidad (MFyC). Fue basado en la lectura de textos, discusión en grupo de trabajo y en una investigación con la aplicación de una encuesta semi estructurada a MFyC y otros profesionales provenientes de 19 países. Fueran obtenidas informaciones acerca de los servicios de AP y de las percepciones de sus procesos evaluativos, incluyendo los relacionados a la educación permanente, a la motivación y la sobrecarga de trabajo. Los resultados sugieren que evaluar de forma sistemática y adecuada la calidad de la AP en Iberoamérica aún es un proceso muy incipiente. Además, excepto por algunos pocos países, ni siquiera existe una APS universal con MFyCs en los equipos de salud. Por otro lado, si consideramos los principios y las practicas de la MFyC, parece haber una limitación de los instrumentos utilizados para evaluar la calidad en AP. Se concluye que para alcanzar una evaluación de calidad que pueda ser propulsora de una mejora continua de los servicios en la AP es necesario incluir indicadores relacionados a los conceptos y herramientas de la MFyC. Un concepto de Calidad en AP es propuesto y se indica las dimensiones a ser incluidas en los procesos evaluativos, considerando las competencias de la MFyC

The purpose of this study is to contribute to the development of the concept and the assessment of Quality in Primary Care, under the perspective of Family and Community Medicine (FCM). The study was based on texts reading, discussion in a working-group, and a survey with the application of a semi-structured questionnaire to FCM and other professionals from 19 countries. Information about PC services, as well as the perception of its evaluation processes, including those related to permanent education, motivation and work overload was obtained. The results suggest that the quality assessment of PC in Iberoamerica is still a very incipient process. In addition, with the exception of a few countries, there is not even a universal PC with FCM in the health teams. Considering the principles and practices of the FCM, it seems that there is a limitation of the instruments commonly used to evaluate the quality in PC. It is concluded that to achieve a better quality assessment in order to conduct continuous improvements in the PC services, it is necessary to include indicators related to the concepts and tools of FCM. Considering the competences of the FCM, a quality concept in PC is proposed and dimensions to be included in the evaluation processes are indicated.

O objetivo deste estudo é contribuir para o aperfeiçoamento do conceito e dos processos relacionados à avaliação da qualidade na Atenção Primária à Saúde (APS), sob a perspectiva de Médicos de Família e Comunidade (FCM). O estudo foi realizado com base na leitura de textos, discussão em grupo de trabalho e uma pesquisa com a aplicação de um questionário semi-estruturado a MFC e outros profissionais provenientes de 19 países. Foram obtidas informações sobre os serviços de APS e das percepções sobre seus processos de avaliação, incluindo os relacionados à educação permanente, motivação e sobrecarga de trabalho. Os resultados sugerem que avaliar adequadamente e sistematicamente a qualidade da APS na Ibero-América ainda é processo muito incipiente. Além disso, com exceção de alguns países, não existe sequer uma APS universal com MFCs nas equipes de saúde. Por outro lado, se considerarmos os princípios e práticas de MFC parece ser uma limitação dos instrumentos utilizados para avaliar a qualidade em APS, Conclui-se que para alcançar uma avaliação de qualidade que possa ser condutora de uma melhoria contínua dos serviços de APS é necessário incluir indicadores relacionados aos conceitos e ferramentas da MFC. Um conceito de Qualidade na APS é proposto e são indicadas dimensões para ser incluídas nos processos de avaliação, considerando-se as competências da MFC.