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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.
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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.
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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.
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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.
Asunto(s)
Materiales Biocompatibles/química , Ácido Linoleico/química , Poliésteres/química , Ácido Succínico/química , Alquilación , Antifúngicos/síntesis química , Antifúngicos/química , Antifúngicos/farmacología , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/farmacología , Adhesión Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Humanos , Ácido Linoleico/síntesis química , Ácido Linoleico/farmacología , Poliésteres/síntesis química , Poliésteres/farmacología , Ácido Succínico/síntesis química , Ácido Succínico/farmacologíaRESUMEN
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.
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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.
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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.
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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.
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Biopelículas , Candida albicans/efectos de los fármacos , Candida albicans/fisiología , Colorantes Fluorescentes/química , Colorantes Fluorescentes/farmacología , Quinolinas/química , Quinolinas/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Biopelículas/efectos de los fármacos , Candida albicans/aislamiento & purificación , Farmacorresistencia Fúngica/efectos de los fármacos , Pruebas de Sensibilidad MicrobianaRESUMEN
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.