Gotowa bibliografia na temat „Bio-inspired Small Molecules”

This account reviews our recent research activities in the field of CO2 reduction. We discuss here the potential of the bio-inspired approach for the design of electrocatalytic systems for small molecule transformation. Exploiting the billion years of evolution of natural systems, we illustrate the potential of bio-inspired strategies across multiple scales to design catalytic systems. We demonstrate in particular how the shape of biological systems as well as enzymatic active sites and their environment can constitute effective sources of inspiration for the design of electrocatalysts with improved performances.

The development of alternative ecological and effective antifouling technologies is still challenging. Synthesis of nature-inspired compounds has been exploited, given the potential to assure commercial supplies of potential ecofriendly antifouling agents. In this direction, the antifouling activity of a series of nineteen synthetic small molecules, with chemical similarities with natural products, were exploited in this work. Six (4, 5, 7, 10, 15 and 17) of the tested xanthones showed in vivo activity toward the settlement of Mytilus galloprovincialis larvae (EC50: 3.53–28.60 µM) and low toxicity to this macrofouling species (LC50 > 500 µM and LC50/EC50: 17.42–141.64), and two of them (7 and 10) showed no general marine ecotoxicity (<10% of Artemia salina mortality) after 48 h of exposure. Regarding the mechanism of action in mussel larvae, the best performance compounds 4 and 5 might be acting by the inhibition of acetylcholinesterase activity (in vitro and in silico studies), while 7 and 10 showed specific targets (proteomic studies) directly related with the mussel adhesive structure (byssal threads), given by the alterations in the expression of Mytilus collagen proteins (PreCols) and proximal thread proteins (TMPs). A quantitative structure-activity relationship (QSAR) model was built with predictive capacity to enable speeding the design of new potential active compounds.

The fate of macromolecules of biological or pharmacological interest that enter the mucus barrier is a current field of investigation. Studies of the interaction between the main constituent of mucus, mucins, and molecules involved in topical transmucoidal drug or gene delivery is a prerequisite for nanomedicine design. We studied the interaction of mucin with the bio-inspired arginine-derived amphoteric polymer d,l-ARGO7 by applying complementary techniques. Small angle X-ray scattering in bulk unveiled the formation of hundreds of nanometer-sized clusters, phase separated from the mucin mesh. Quartz microbalance with dissipation and neutron reflectometry measurements on thin mucin layers deposited on silica supports highlighted the occurrence of polymer interaction with mucin on the molecular scale. Rinsing procedures on both experimental set ups showed that interaction induces alteration of the deposited hydrogel. We succeeded in building up a new significant model for epithelial tissues covered by mucus, obtaining the deposition of a mucin layer 20 Å thick on the top of a glycolipid enriched phospholipid single membrane, suitable to be investigated by neutron reflectometry. The model is applicable to unveil the cross structural details of mucus-covered epithelia in interaction with macromolecules within the Å discreteness.

The precise synthesis of materials and devices with tailored complex structures and properties is a requisite for the development of the next generation of products based on nanotechnology. Nowadays, the technology for the generation of this type of devices lacks the precision to determine their properties and is accomplished mostly by ‘trial and error’ experimental approaches. The use of bottom-up approaches that rely on highly specific biomolecular interactions of small and simple components is an attractive approach for the templating of nanoscale elements. In nature, protein assemblies define complex structures and functions. Engineering novel bio-inspired assemblies by exploiting the same rules and interactions that encode the natural diversity is an emerging field that opens the door to create nanostructures with numerous potential applications in synthetic biology and nanotechnology. Self-assembly of biological molecules into defined functional structures has a tremendous potential in nano-patterning and the design of novel materials and functional devices. Molecular self-assembly is a process by which complex 3D structures with specified functions are constructed from simple molecular building blocks. Here we discuss the basis of biomolecular templating, the great potential of repeat proteins as building blocks for biomolecular templating and nano-patterning. In particular, we focus on the designed consensus tetratricopeptide repeats (CTPRs), the control on the assembly of these proteins into higher order structures and their potential as building blocks in order to generate functional nanostructures and materials.

A trap-mediated solution-processed small molecule based artificial synaptic device is presented. This work reveals great potential for a small molecule based artificial synapse to serve in neuromorphic computing.

L’objectif de ma thèse était d’améliorer les connaissances sur le rôle des liaisons métal-thiolates au sein des métalloenzymes en utilisant une approche bio-inspirée par l’étude des propriétés structurales, électroniques et/ou magnétiques de modèles chimiques ainsi que de leur réactivité.Dans ce contexte, nous avons synthétisé deux complexes de NiFe, modèle structuraux et fonctionnels de l’hydrogénase [NiFe], capables de produire H2 efficacement de manière électrocatalytique de H2. Des espèces intermédiaires ont été synthétisées et caractérisées par différentes techniques spectroscopiques. L’inhibition réversible de l’activité catalytique de ces catalyseurs en présence de CO a été étudiée et discutée.Nous décrivons également un nouvel exemple de complexe de Mn-thiolate, dont l’un des thiolates coordonné à un Mn est protoné. Ce complexe est capable d’activer l’oxygène moléculaire (O2) et de le réduire de manière catalytique par un processus à deux électrons en présence d’une source de protons et d’un agent de réduction. L’activation et la réduction de l’oxygène ont été étudiées en conditions stœchiométriques et catalytiques. Des complexes de Mn à hauts degrés d’oxydation résultant de l’activation d’O2 ont été isolés et caractérisés. Leur réactivité vis-à-vis de l’hydrogène (HAT) et de l’oxygène (OAT) a été évaluée.Une série de complexes métal-halogénure pentacoordinés, MIIIX (M = Mn ou Co ; X = Cl, Br, I) a été étudiée pour comprendre le rôle du métal dans la conversion disulfure/thiolate. Il a été montré que cette conversion est réversible pour les deux ions métalliques mais que le processus est plus rapide et quantitatif dans le cas du système à base de Co par rapport à celui du Mn. Ce travail nous a permis de comprendre comment les propriétés redox et électroniques du métal peuvent intervenir sur l’efficacité de cette interconversion.Enfin les propriétés magnétiques de la série des complexes de CoIII contenant un halogénure ont été étudiées. Ces complexes présentent un spin S = 1 intermédiaire et leur anisotropie magnétique est sensible à la nature de l’halogénure de manière inattendue : la plus grande valeur de D a été mesurée pour le complexe chloré et la plus petite pour le composé iodé. Ce comportement a été rationalisé au travers d’une étude théorique
The aim of my thesis was to improve the knowledge on the role of metal-thiolate bonds in metalloenzymes using a bio-inspired approach by investigating the structural, electronic and/or magnetic properties of chemical models as well as their reactivity.In this context, we report the synthesis and analysis of two heterodinuclear NiFe complexes, structural and functional models of the active site of [NiFe] hydrogenase, which produce H2 electrocatalytically at high rates. Intermediate species have been generated and characterized by different spectroscopic techniques. The reversible inhibition of the catalytic activity by CO has been also investigated and discussed.We also describe the synthesis and characterization of a new manganese-thiolate complex, bearing a pendant thiol group bound (in its -SH form) to one MnII ion. This complex is capable of activating dioxygen, and is an active catalyst for selective 2-electron O2 reduction in the presence of a one-electron reducing agent and a proton source. The O2 activation and reduction pathways have been studied under both stoichiometric and catalytic conditions. Several high valent Mn complexes resulting from O2 activation have been isolated and characterized and their reactivity toward hydrogen or oxygen atom transfer (HAT or OAT, respectively) has been evaluated.A series of pentacoordinated metal-halide complexes MIIIX (M = Co and Mn ; X = Cl, Br, I) has been investigated with the aim of understanding the role of the metal ion in disulphide/thiolate interconversion. While such conversion is reversible in the presence of both Co and Mn, the process becomes much faster and quantitative for the Co–based system with respect to the Mn one. Besides, this work has allowed improving the understanding of how the electronic and redox properties of the metal centers should be fine-tuned to permit a disulphide/thiolate (inter)conversion, mediated by metal ions, to occur efficiently.Finally, the magnetic properties of the series of mononuclear CoIIIX complexes have been investigated. They display a rare intermediate S = 1 spin state and their magnetic anisotropy is sensitive to the nature of the halide in an unexpected way: the largest D-value has been measured for the chloride compound and the smallest for the iodide one. This behavior has been rationalized through a theoretical study

Abstract Previous studies have shown that cicada wings has the ability to kill the bacteria on contact. Study of natural bactericidal surface in cicada wings has opened new dimensions of scientific research in bio-inspired chemical-free bactericidal surfaces. To develop and design such biomimetic bactericidal surface, it is necessary to understand the mechanical bactericidal effects of nanopillars in the presence of bacteria, which is extremely challenging due to the small relevant length and time scales. In this study, we have conducted molecular dynamics (MD) simulations to investigate the biomimetic surface with various nanopillars configurations. MD simulations is an exceptional method to simulate materials with small time and length scales with good accuracy and low computational costs. We have simulated the bacteria’s model using coarse-grained modelling and conducting MD simulations. Effects of nanopillar spacing, diameter and height on the lysis process is studied in this article. It is expected that this study will provide us insights on designing nanopillars in terms of height, spacing and diameter for optimal bactericidal effects that can help in the development of chemical-free antibacterial surface.