In supramolecular materials, molecular building blocks are designed to interact with one another via non‐covalent interactions in order to create function. This offers the opportunity to create ...structures similar to those found in living systems that combine order and dynamics through the reversibility of intermolecular bonds. For regenerative medicine there is a great need to develop materials that signal cells effectively, deliver or bind bioactive agents in vivo at controlled rates, have highly tunable mechanical properties, but at the same time, can biodegrade safely and rapidly after fulfilling their function. These requirements make supramolecular materials a great platform to develop regenerative therapies. This review illustrates the emerging science of these materials and their use in a number of applications for regenerative medicine.
The emerging science of supramolecular materials in regenerative medicine is reviewed. In supramolecular materials, molecular building blocks are designed to interact with one another via noncovalent interactions in order to create function, which allows the creation of structures similar to those found in living systems that combine order and dynamics through the reversibility of intermolecular bonds. For regenerative medicine there is a great need to develop materials that signal cells effectively, deliver or bind bioactive agents in vivo at controlled rates, have highly tunable mechanical properties, but at the same time, can biodegrade safely and rapidly after fulfilling their function.
Light-Driven Expansion of Spiropyran Hydrogels Li, Chuang; Iscen, Aysenur; Palmer, Liam C ...
Journal of the American Chemical Society,
05/2020, Letnik:
142, Številka:
18
Journal Article
Recenzirano
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The incorporation of molecular switches in organic structures is of great interest in the chemical design of stimuli-responsive materials that mimic the complex functions of living systems. ...Merocyanine dyes that convert to spiropyran moieties upon exposure to visible light have been extensively studied as they can be incorporated in hydrated covalent networks that will expel water when this conversion occurs and induce a volumetric shrinkage. We report here on a sulfonate-based water-soluble photoswitch that, in contrast to the well-known systems, triggers a volumetric expansion in hydrogels upon exposure to photons. Contraction is in turn observed under dark conditions in a highly reversible manner. The novel behavior of the photoswitch incorporated in the covalent network was predicted by coarse-grained simulations of the system’s chemical structure. Using pH control and polymeric structures that differ in lower critical solution temperature, we were able to develop hydrogels with highly tunable volumetric expansion. The novel molecular function of the systems developed here led to materials with the negative phototaxis observed in plants and could expand the potential use of hydrogels as sensors, soft robots, and actuators.
Organic materials naturally lend themselves to the crafting of structure and function using the strategies of self-assembly and supramolecular chemistry employed so effectively by biological systems. ...This perspective illustrates progress over the past two decades on self-assembly in materials chemistry through research on systems where function is directly linked to noncovalent interactions among molecules. The genesis of this approach in chemistry of materials involves the design of relatively simple structures using hydrogen bonding, π–π stacking, metal–ligand interactions, electrostatic forces, strong dipole–dipole association, hydrophobic forces, and steric repulsion. Gradually many new and exciting opportunities have emerged, such as supramolecular nanostructures that assemble into functional bulk materials and supramolecular polymers in which the motif of covalent connections among monomers is imitated by creating one-dimensional assemblies of an arbitrarily large set of molecules in both composition and size. Supramolecular polymers offer the opportunity to create structures that integrate unprecedented order in 1D assemblies with interesting dynamics through bond reversibility. Other fascinating systems are those in which intermolecular interactions and other forces can be used to create the hierarchical and highly functional structures ubiquitous in biology, such as bone and muscle, in which different types of order exist within the same structure at different length scales. Directions that have a bright future include nonequilibrium dynamic materials with the capacity to be adaptive, self-repairing, chemically alterable, and even replicativeall characteristics we see in living organic matter. Additional promising areas include 2D and 3D systems that are not necessarily classical crystals and the rational synthesis of functional organic–inorganic hybrid materials. The most exciting aspect of self-assembly and supramolecular chemistry is their open ended nature, and these are two areas of chemistry for which many new principles will be established in this century.
Layered perovskites with the formula (R–NH3)2PbI4 have excellent environmental stability but poor photovoltaic function due to the preferential orientation of the semiconducting layer parallel to the ...substrate and the typically insulating nature of the R–NH3 + cation. Here, we report a series of these n = 1 layered perovskites with the form (aromatic-O-linker-NH3)2PbI4 where the aromatic moiety is naphthalene, pyrene, or perylene and the linker is ethyl, propyl, or butyl. These materials achieve enhanced conductivity perpendicular to the inorganic layers due to better energy level matching between the inorganic layers and organic galleries. The enhanced conductivity and visible absorption of these materials led to a champion power conversion efficiency of 1.38%, which is the highest value reported for any n = 1 layered perovskite, and it is an order of magnitude higher efficiency than any other n = 1 layered perovskite oriented with layers parallel to the substrate. These findings demonstrate the importance of leveraging the electronic character of the organic cation to improve optoelectronic properties and thus the photovoltaic performance of these chemically stable low n layered perovskites.
Supramolecular Energy Materials Dumele, Oliver; Chen, Jiahao; Passarelli, James V. ...
Advanced materials (Weinheim),
04/2020, Letnik:
32, Številka:
17
Journal Article
Recenzirano
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Self‐assembly is a bioinspired strategy to craft materials for renewable and clean energy technologies. In plants, the alignment and assembly of the light‐harvesting protein machinery in the green ...leaf optimize the ability to efficiently convert light from the sun to form chemical bonds. In artificial systems, strategies based on self‐assembly using noncovalent interactions offer the possibility to mimic this functional correlation among molecules to optimize photocatalysis, photovoltaics, and energy storage. One of the long‐term objectives of the field described here as supramolecular energy materials is to learn how to design soft materials containing light‐harvesting assemblies and catalysts to generate fuels and useful chemicals. Supramolecular energy materials also hold great potential in the design of systems for photovoltaics in which intermolecular interactions in self‐assembled structures, for example, in electron donor and acceptor phases, maximize charge transport and avoid exciton recombination. Possible pathways to integrate organic and inorganic structures by templating strategies and electrodeposition to create materials relevant to energy challenges including photoconductors and supercapacitors are also described. The final topic discussed is the synthesis of hybrid perovskites in which organic molecules are used to modify both structure and functions, which may include chemical stability, photovoltaics, and light emission.
Self‐assembly is a bioinspired strategy to create soft materials for renewable and clean energy technologies. The field of supramolecular energy materials is described, covering work on self‐assembling molecules to craft light harvesting systems for photocatalysis and photovoltaics. Also, pathways to use supramolecular phases as templates for inorganic structures and electrodeposition for the synthesis of energy materials are discussed.
An interesting field within the broad subject of biomaterials is the chemical and physical crafting of materials that can functionally substitute or help regenerate the organs and tissues of the ...human body. Regeneration is the new dimension of this field as opposed to the more established area of permanent implants and devices to substitute natural structures and functions. With the advent of nanoscience, the field is experiencing a renaissance by embracing the vision that artificial nanostructures of the self-assembling type could be designed for highly specific functions to promote regenerative processes.
Supramolecular assembly of peptide-based monomers into nanostructures offers many promising applications in advanced therapies. In this Tutorial Review, we introduce molecular designs to control the ...structure and potential biological function of supramolecular assemblies. An emphasis is placed on peptide-based supramolecular nanostructures that are intentionally designed to signal cells, either directly through the incorporation of amino acid sequences that activate receptors or indirectly by recruiting native signals such as growth factors. Additionally, we describe the use and future potential of hierarchical structures, such as single molecules that assemble into nanoscale fibers which then align to form macroscopic strings; the strings can then serve as scaffolds for cell growth, proliferation, and differentiation.
Supramolecular assembly of peptide-based monomers into nanostructures offers many promising applications in advanced therapies. In this Tutorial Review, we introduce molecular designs to control the structure and potential biological function of supramolecular assemblies.
The production of polymers from ethylene requires the ethylene feed to be sufficiently purified of acetylene contaminant. Accomplishing this task by thermally hydrogenating acetylene requires a high ...temperature, an external feed of H
gas and noble-metal catalysts. It is not only expensive and energy-intensive, but also prone to overhydrogenating to ethane. Here we report a photocatalytic system that reduces acetylene to ethylene with ≥99% selectivity under both non-competitive (no ethylene co-feed) and competitive (ethylene co-feed) conditions, and near 100% conversion under the latter industrially relevant conditions. Our system uses a molecular catalyst based on earth-abundant cobalt operating under ambient conditions and sensitized by either Ru(bpy)
or an inexpensive organic semiconductor (metal-free mesoporous graphitic carbon nitride) under visible light. These features and the use of water as a proton source offer advantages over current hydrogenation technologies with respect to selectivity and sustainability.
Climate change and global energy demands motivate the search for sustainable transformations of carbon dioxide (CO2) to storable liquid fuels. Photocatalysis is a pathway for direct conversion of CO2 ...to CO, one step within light-powered reaction networks that could, if efficient enough, transform the solar energy conversion landscape. To date, the best performing photocatalytic CO2 reduction systems operate in nonaqueous solvents, but technologically viable solar fuels networks will likely operate in water. Here we demonstrate catalytic photoreduction of CO2 to CO in pure water at pH 6–7 with an unprecedented combination of performance parameters: turnover number (TON(CO)) = 72,484–84,101, quantum yield (QY) = 0.96–3.39%, and selectivity (S CO) > 99%, using CuInS2 colloidal quantum dots (QDs) as photosensitizers and a Co-porphyrin catalyst. At higher catalyst concentration, the system reaches QY = 3.53–5.23%. The performance of the QD-driven system greatly exceeds that of the benchmark aqueous system (926 turnovers with a quantum yield of 0.81% and selectivity of 82%), due primarily to (i) electrostatic attraction of the QD to the catalyst, which promotes fast multielectron delivery and colocalization of protons, CO2, and catalyst at the source of photoelectrons, and (ii) termination of the QD’s ligand shell with free amines, which capture CO2 as carbamic acid that serves as a reservoir for CO2, effectively increasing its solubility in water, and lowers the onset potential for catalytic CO2 reduction by the Co-porphyrin. The breakthrough efficiency achieved in this work represents a nonincremental step in the realization of reaction networks for direct solar-to-fuel conversion.
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