Bombyx mori Silk Fibroin Regeneration in Solution of Lanthanide Ions: A Systematic Investigation

Silk Fibroin (SF) obtained from Bombyx mori is a very attractive biopolymer that can be useful for many technological applications, from optoelectronics and photonics to biomedicine. It can be processed from aqueous solutions to obtain many scaffolds. SF dissolution is possible only with the mediation of chaotropic salts that disrupt the secondary structure of the protein. As a consequence, recovered materials have disordered structures. In a previous paper, it was shown that, by modifying the standard Ajisawa’s method by using a lanthanide salt, CeCl3, as the chaotropic agent, it is possible to regenerate SF as a fibrous material with a very ordered structure, similar to that of the pristine fiber, and doped with Ce+3 ions. Since SF exhibits a moderate fluorescence which can be enhanced by the incorporation of organic molecules, ions and nanoparticles, the possibility of doping it with lanthanide ions could be an appealing approach for the development of new photonic systems. Here, a systematic investigation of the behavior of degummed SF in the presence of all lanthanide ions, Ln+3, is reported. It has been found that all lanthanide chlorides are chaotropic salts for solubilizing SF. Ln+3 ions at the beginning and the end of the series (La+3, Pr+3, Er+3, Tm+3, Yb+3, Lu+3) favor the reprecipitation of fibrous SF as already found for Ce+3. In most cases, the obtained fiber preserves the morphological and structural features of the pristine SF. With the exception of SF treated with La+3, Tm+3, and Lu+3, for all the fibers re-precipitated a concentration of Ln+3 between 0.2 and 0.4% at was measured, comparable to that measured for Ce+3-doped SF

Bombyx mori Silk Fibroin Regeneration in Solution of Lanthanide Ions: A Systematic Investigation

Silk Fibroin (SF) obtained from Bombyx mori is a very attractive biopolymer that can be useful for many technological applications, from optoelectronics and photonics to biomedicine. It can be processed from aqueous solutions to obtain many scaffolds. SF dissolution is possible only with the mediation of chaotropic salts that disrupt the secondary structure of the protein. As a consequence, recovered materials have disordered structures. In a previous paper, it was shown that, by modifying the standard Ajisawa’s method by using a lanthanide salt, CeCl3, as the chaotropic agent, it is possible to regenerate SF as a fibrous material with a very ordered structure, similar to that of the pristine fiber, and doped with Ce+3 ions. Since SF exhibits a moderate fluorescence which can be enhanced by the incorporation of organic molecules, ions and nanoparticles, the possibility of doping it with lanthanide ions could be an appealing approach for the development of new photonic systems. Here, a systematic investigation of the behavior of degummed SF in the presence of all lanthanide ions, Ln+3, is reported. It has been found that all lanthanide chlorides are chaotropic salts for solubilizing SF. Ln+3 ions at the beginning and the end of the series (La+3, Pr+3, Er+3, Tm+3, Yb+3, Lu+3) favor the reprecipitation of fibrous SF as already found for Ce+3. In most cases, the obtained fiber preserves the morphological and structural features of the pristine SF. With the exception of SF treated with La+3, Tm+3, and Lu+3, for all the fibers re-precipitated a concentration of Ln+3 between 0.2 and 0.4% at was measured, comparable to that measured for Ce+3-doped SF

How do cardiologists select patients for dual antiplatelet therapy continuation beyond 1 year after a myocardial infarction? Insights from the EYESHOT Post-MI Study

Background: Current guidelines suggest to consider dual antiplatelet therapy (DAPT) continuation for longer than 12 months in selected patients with myocardial infarction (MI). Hypothesis: We sought to assess the criteria used by cardiologists in daily practice to select patients with a history of MI eligible for DAPT continuation beyond 1 year. Methods: We analyzed data from the EYESHOT Post-MI, a prospective, observational, nationwide study aimed to evaluate the management of patients presenting to cardiologists 1 to 3 years from the last MI event. Results: Out of the 1633 post-MI patients enrolled in the study between March and December 2017, 557 (34.1%) were on DAPT at the time of enrolment, and 450 (27.6%) were prescribed DAPT after cardiologist assessment. At multivariate analyses, a percutaneous coronary intervention (PCI) with multiple stents and the presence of peripheral artery disease (PAD) resulted as independent predictors of DAPT continuation, while atrial fibrillation was the only independent predictor of DAPT interruption for patients both at the second and the third year from MI at enrolment and the time of discharge/end of the visit. Conclusions: Risk scores recommended by current guidelines for guiding decisions on DAPT duration are underused and misused in clinical practice. A PCI with multiple stents and a history of PAD resulted as the clinical variables more frequently associated with DAPT continuation beyond 1 year from the index MI

Synthesis of electroluminescent conjugated polymers for OLEDs

This chapter discusses the most important synthetic routes to the main classes of electroluminescent -conjugated polymers, highlighting advantages and limitations of the different methods in terms of versatility, stereo- and regioselectivity, efficiency. The discussion covers not only the synthesis of basic classes of polymers such as polyarylenes, poly(arylenevinylene)s, poly(aryleneethynylene)s, but describes routes to systems with more complex structures, including multifunctional copolymers and coordination polymers

Synthesis of electroluminescent conjugated polymers for OLEDs

This chapter discusses the most important synthetic routes to the main classes of electroluminescent -conjugated polymers, highlighting advantages and limitations of the different methods in terms of versatility, stereo- and regioselectivity, efficiency. The discussion covers not only the synthesis of basic classes of polymers such as polyarylenes, poly(arylenevinylene)s, poly(aryleneethynylene)s, but describes routes to systems with more complex structures, including multifunctional copolymers and coordination polymers

Bioinspired Biomaterial Composite for All-Water-Based High-Performance Adhesives

The exceptional underwater adhesive properties displayed by aquatic organisms, such as mussels (Mytilus spp.) and barnacles (Cirripedia spp.) have long inspired new approaches to adhesives with a superior performance both in wet and dry environments. Herein, a bioinspired adhesive composite that combines both adhesion mechanisms of mussels and barnacles through a blend of silk, polydopamine, and Fe3+ ions in an entirely organic, nontoxic water-based formulation is presented. This approach seeks to recapitulate the two distinct mechanisms that underpin the adhesion properties of the Mytilus and Cirripedia, with the former secreting sticky proteinaceous filaments called byssus while the latter produces a strong proteic cement to ensure anchoring. The composite shows remarkable adhesive properties both in dry and wet conditions, favorably comparing to synthetic commercial glues and other adhesives based on natural polymers, with performance comparable to the best underwater adhesives with the additional advantage of having an entirely biological composition that requires no synthetic procedures or processing

Direct Arylations via C–H Bond Functionalization of 1,2,3-Triazoles by a Reusable Pd/C Catalyst Under Solvent-Free Conditions

Fully substituted triazoles are synthesized by a sustainable direct arylation reaction performed under solvent-free conditions and in the presence of a recyclable Pd/C heterogeneous catalyst. Exclusion of air as well as anhydrous conditions are not required, enabling a convenient synthesis of 1,4,5-trisubstituted 1,2,3-triazoles and 1,2,3-triazole-fused isoindolines starting from 1,4-disubstituted 1,2,3-triazoles, easily prepared via click chemistry, and functionalized aryl iodides

New insights in luminescent fluorinated transition metal compounds

This chapter aims to provide new insights about organometallic compounds having at least one organic ligand substituted with a fluorine atom. Actually, fluorine substitution is a powerful tool for tuning several properties of the complex, such as optical properties, thermal stability, aggregation at the solid state, charge injection, energy transfer, or interactions with the surrounding environment even in biological tissues. Moreover, fluorinated ligands own a peculiar reactivity opening new routes to molecular design of organometallic complexes. After a brief introduction about the photophysics of these systems, various examples of fluorinated complexes will be discussed, highlighting the key role of fluorination on properties of complexes. Attention is also focused on electroluminescent fluorinated lanthanide, iridium and platinum complexes, due to their application in optoelectronics, providing a spread overview on the state of the art in this research field

Chlorophylls as Molecular Semiconductors: Introduction and State of Art

Chlorophylls (Chls) and their derivatives are the most common pigments used for light absorption, energy transfer, and charge separation in photosynthetic organisms. Their functions change upon different aggregation states and specific pigment–protein interactions. Differences in the aromatic π-system and substituents finely tune Chls electronic, spectroscopic, and supramolecular characteristics. The varieties of Chls species and the possibility of chemical manipulation, together with their exceptional absorption cross section, make them attractive materials for applications as sensitizer in energy conversion devices. Moreover, when deposited as thin films, Chls and their semi-synthetic derivatives exhibit the typical behavior of molecular organic semiconductors with good charge carrier mobility and Fermi level suitable for their use in optoelectronic devices like phototransistors. This review aims at bridging the possible knowledge and language gap between biochemists and biophysicists working on Chls, and material scientists developing organic optoelectronic devices. Starting from the structural features, and proceeding towards optoelectronic devices, the review offers a critical overview on the uses of Chls as light-responsive molecular semiconductors known so far. Exploiting the high efficiency of these renewable, biocompatible, and recyclable natural systems can pave the way for next generation biooptoelectronics, including artificial light energy converters, photodetectors, and, more in general, forward-thinking technologies

A novel regio- and stereoselective formal cross-coupling reaction of unsaturated silanes with arenediazonium tetrafluoroborates

A procedure is developed to use vinyl and polyenyl silanes in highly regio- and stereoselective Pd-catalyzed cross-coupling reactions with arenediazonium tetrafluoroborates. The possibility of employing the unsaturated silanes in sequential cross-coupling reactions with bromoarene diazonium salts demonstrates the synthetic potential of these versatile substrates