In biopolymers such as proteins and nucleic acids, monomer sequence encodes for highly specific intra- and intermolecular interactions that direct self-assembly into complex architectures with high ...fidelity. This remarkable structural control translates into precise control over the properties of the biopolymer. Polymer scientists have sought to achieve similarly precise control over the structure and function of synthetic assemblies. A common strategy for achieving this goal has been to exploit existing biopolymers, known to associate with specific geometries and stoichiometries, for the assembly of synthetic building blocks. However, such systems are neither scalable nor amenable to the relatively harsh conditions required by various materials science applications, particularly those involving non-aqueous environments. To overcome these limitations, we have synthesized sequence-defined oligocarbamates (SeDOCs) that assemble into duplexes through complementary hydrogen bonds between thymine (
T
) and diaminotriazine (
D
) pendant groups. The SeDOC platform makes it simple to incorporate non-hydrogen-bonding sites into an oligomer's array of recognition motifs, thereby enabling an investigation into this unexplored handle for controlling the hybridization of complementary ligands. We successfully synthesized monovalent, divalent, and trivalent SeDOCs and characterized their self-assembly
via
diffusion ordered spectroscopy,
1
H-NMR titration, and isothermal titration calorimetry. Our findings reveal that the binding strength of monovalent oligomers with complementary pendant groups is entropically driven and independent of monomer sequence. The results further show that the hybridization of multivalent oligomers is cooperative, that their binding enthalpy (Δ
H
) and entropy (
T
Δ
S
) depend on monomer sequence, and that sequence-dependent changes in Δ
H
and
T
Δ
S
occur in tandem to minimize the overall change in binding free energy.
Sequence-defined oligocarbamates with thymine and diaminotriazine pendant groups assemble into duplexes. The binding strength (
K
a
), enthalpy (Δ
H
), and entropy (Δ
S
) of hybridization depend on the valency and sequence of the interacting ligands.
Diamond and diamond-like carbon coatings are used in many applications ranging from biomedicine to tribology. A wide range of dopants have been tested to modify the hydrophilicity of these surfaces, ...since this is central to their biocompatibility and tribological performance in aqueous environments. Despite the large number of experimental investigations, an atomistic understanding of the effects of different dopants on carbon film hydrophilicity is still lacking. In this study, we employ ab initio calculations to elucidate the effects of B, N, and O dopants in several mechanisms that could modify interactions with water molecules and thus hydrophilicity. These include the adsorption of intact water molecules on the surfaces, minimum energy pathways for water dissociation, and subsequent interactions of hydrogenated and hydroxylated surfaces with water molecules. We find that all of the dopants considered enhance hydrophilicity, but they do so through different means. Most notably, B dopants can spontaneously chemisorb intact water molecules and increase its interactions in H-bond networks.
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•The microscopic mechanisms for interaction between water molecules and B-, N-, and O-doped diamond were elucidated.•All dopants presented mechanisms to enhance hydrophilicity.•B dopants chemisorb intact water molecules and enhance their participation in the H-bond network.•N dopants increase wettability through polar N–C and N–H bonds.•O dopants in bridge locations increase wettability through induced dangling bonds in an unsaturated surface.
In terms of energy resource recovery and environmental protection, the separation of U(VI) from aqueous solutions is vital. Adsorption and solvent extraction are the most common separation ...technologies, which are also widely used for uranium recovery or removal from aqueous solution. The linear structure of uranyl ion and its multiple coordination feasibilities offer great opportunities for its extractive and adsorptive separation. This review briefly summarized and analyzed the recent advances in the separation of uranyl ions from aqueous solutions, mainly focusing on the selective extraction and adsorption using affinity ligands-based technology, which is promising method due to the high selectivity, capable of recovering uranium at low concentration and complicate aqueous environment. The affinity ligands for uranyl ions, including organophosphorus, calixarenes, amidoxime, imidazole and other derivatives were introduced. These donor ligands for design of extraction solvents or adsorbents for the separation of uranyl ions were summarized. The further research on the coordination chemistry towards uranyl ions and removal mechanisms would provide vital information for the development of more effective ligands with higher affinity, stability and compatibility in various systems, which is still challenging.
Nanotechnology and molecular imprinting both are omnipresent in the modern scientific world. Molecular recognition in the biological systems was mimicked to an extreme extent with its difficulties ...through molecular imprinting. Solving the problems related to this mimicking was the goal of science and technology. Some challenges like difficulties with the imprinting of protein, poor compatibility with aqueous environments, template leakage, and heterogeneous populations of binding sites in the polymers that contribute to a high level of nonspecific binding sites were addressed with recent advancement in the modern era. These issues were solved later with nano level instrumentations and inventions. Different types of nanomaterials were employed for this research on molecular recognition through MIPs to enhance selectivity, sensitivity and stability to specific systems such as sensors. This review paper attempts to give all the recent advances in molecular imprinting and the potential of nanomaterials in electrochemical sensors.
The existing concerns on the limited stability of Zn 4 O-based MOFs upon exposure to humidity or aqueous environments, as well as on the excitation mechanisms, are discussed on the basis of Raman, ...FTIR, DR-UV and XRD measurements. This paper demonstrates that MOF-5 dispersed in water produces a relatively stable new phase, MOF-5W, which slowly degrades to MOF-5H, a mixture of MOF-5W and zinc terephthalate dihydrate (ZTDH). The structure and optical properties of MOF-5W and MOF-5H and their optical and photocatalytic properties reveal the main role played by the organic moiety in determining the final properties of these structures, supporting the idea of a ligand to ligand charge transfer (LLCT) excitation mechanism rather than the usually assumed ligand to metal charge transfer (LMCT).
Room temperature phosphorescence (RTP) materials are increasingly recognized for their superior luminescent properties, which are pivotal in applications such as anti-counterfeiting, information ...storage, and optoelectronics. Despite this, the sensitivity of most RTP systems to humidity presents a significant challenge in achieving durable RTP performance in aqueous environments. This study proposes a strategy to enhance organic room-temperature phosphorescence through racemization. By incorporating external racemates of various chiral phosphors-NDBD-Ph, NDBD-Ph-Ph, NDBD-CH
3
, and NDBD-O-CH
3
-into a polyacrylonitrile (PAN) matrix, we significantly enhance the RTP properties (quantum yield, lifetime, and afterglow-time) of the resultant films. This enhancement can be attributed to the increased density of racemic molecules in the matrix and the increased spin-orbit coupling (SOC), facilitating the development of a long-lasting polymer RTP system in water. Notably, the racemic rac-NDBD-Ph@PAN film exhibits a persistent bright turquoise afterglow, even after immersion in water for a month. Furthermore, for the first time, we achieved an enhanced green to cyan RTP response to pH variations under both acidic and alkaline conditions (pH = 2-12), with the maximum phosphorescence emission intensity increasing up to threefold. The remarkable water stability, reversible response characteristics, and enhanced phosphorescence properties of this system offer promising potential for dynamic information encryption in aqueous environments.
Room temperature phosphorescence (RTP) materials are increasingly recognized for their superior luminescent properties, which are pivotal in applications such as anti-counterfeiting, information storage, and optoelectronics.
Continuous monitoring of biochemical analytes like oxygen is of interest in biomedicine to provide insight into physiology and health. Silk‐protein biomaterials are particularly useful as the ...scaffold material in oxygen sensors due to silk's unique amphiphilic chemistry, which promotes noncovalent stabilization of the protein and additives in aqueous environments. Silk films containing a water‐insoluble oxygen‐sensing chromophore, Pd (II) tetramethacrylated benzoporphyrin (PdBMAP), are evaluated as optical oxygen sensors in vitro and in vivo. These silk‐chromophore composites are stabilized by the self‐assembled, physically crosslinked protein network. The deaerated phosphorescence lifetime (τm,0 ≈300 µs) of the chromophore in vitro is quenched to 50% of its initial value at ≈31 µm dissolved oxygen, indicating sensing functionality within physiological ranges of oxygen. In vitro enzymatic degradation of the silk films with and without the chromophore is demonstrated. The silk‐chromophore composite films are cytocompatible in vitro, biocompatible in vivo upon implantation in rats, and displayed mechanical properties suitable for subcutaneous implantation. Further, the films maintain oxygen‐sensing function in vivo and demonstrate real‐time sensing capabilities throughout various physiological states (i.e., hyperoxia, normoxia, and hypoxia).
This study characterizes and demonstrates the functionality of an optical oxygen sensor comprised of a natural silk protein scaffold and chromophore composite. The silk‐chromophore sensing system is assessed for material integrity, degradation, and oxygen sensitivity in vitro before confirming the function of the platform in vivo when implanted subcutaneously in rats.
Novel bio-magnetic membrane capsules (BMMCs) were prepared by a simple two-step titration-gel cross-linking method using a polyvinyl alcohol (PVA) and sodium alginate (SA) matrix to control the ...disintegration of phytogenic magnetic nanoparticles (PMNPs) in an aqueous environment, and their performance was investigated for adsorbing cationic malachite green (MG) dye from water. The prepared BMMCs were characterized by FTIR, powder XRD, SEM, EDX, XPS, VSM and TGA techniques. The findings revealed that the hysteresis loops had an excellent superparamagnetic nature with saturation magnetization values of 11.02 emu g
. The prepared BMMCs not only controlled the oxidation of PMNPs but also improved the adsorptive performance with respect to MG dye (500 mg g
at 298.15 K and pH 6.5) due to the presence of a large amount of hydrophilic functional groups (hydroxyl/-OH and carboxyl/-COOH) on/in the BMMCs. The smooth encapsulation of PMNPs into the PVA-SA matrix established additional hydrogen bonding among polymer molecular chains, with improved stability, and adsorptive performance was maintained over a wide range of pH values (3-12). Importantly, the prepared BMMCs were easily regenerated just by washing with water, and they could be re-utilized for up to four (4) consecutive treatment cycles without observing any apparent dissolution of iron/Fe
or damage to the morphology. According to the mass balance approach, an estimated amount of 100 mL of treated effluent can be obtained from 160 mL of MG dye solution (25 mg L
) just by employing a 0.02 g L
adsorbent dosage. Finally, a model of BMMCs based on zero-effluent discharge was also proposed for commercial or industrial applications. The prepared BMMCs are greatly needed for improving the water/wastewater treatment process and they can be utilized as an excellent adsorbent to remove cationic pollutants for various environmental applications.
Nickel–titanium (NiTi) alloys have recently attracted considerable attention due to their unique properties, i.e., shape memory effect and superelasticity. In addition, these promising alloys ...demonstrate unique biocompatibility, represented in their high stability and corrosion resistance in aqueous environments, qualifying them to be used inside the human body. In recent years, additive manufacturing (AM) processes have been envisioned as an enabling method for the efficient production of NiTi components with complex geometries as patient-specific implants. In spite of its great capabilities, AM as a novel fabrication process may reduce the corrosion resistance of NiTi parts leading to the excess release of the harmful Ni ions as the main corrosion byproducts. The main goal of this study is to create and evaluate a micro-arc oxidation (MAO) coating in order to enhance the corrosion resistance of additively manufacture NiTi medical devices. To this end, the process voltage and electrolyte used to produce MAO coating have been investigated and optimized. The corrosion characteristics of the MAO-coated specimens revealed that the proposed coating methodology significantly improves the corrosion resistance of NiTi parts produced using AM process.
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