Molecular Systems Design & Engineering最新文献

Correction for ‘Describing the adsorption of doxorubicin on a PAMAM dendrimer by ab initio calculations’ by Handriela Hoff de Oliveira Sobrinho et al., Mol. Syst. Des. Eng., 2023, https://doi.org/10.1039/d3me00060e.

Graphene is widely incorporated into rubber matrices to enhance mechanical, electrical, and thermal properties in nanocomposites. However, its hydrophobicity and lack of functionalities cause agglomeration, impacting nanocomposite properties. Intense agitation techniques like mechanical blending, grinding, and sonication modify graphene and disrupt π–π interactions between sheets. Hybrid fillers, such as carbon nanotubes, metals, nanocellulose, and nanocrystals, enhance graphene's dispersibility and create new value in nanocomposites. Graphene's exceptional properties make it applicable in the medical, electronics, and tire industries. Optimizing graphene incorporation is crucial to exploit its benefits. Response surface methodology (RSM) optimizes graphene nanocomposites effectively and efficiently, surpassing traditional methods. The review discusses recent advancements in graphene modification, hybridization, and applications in rubber products. Furthermore, RSM utilization for optimizing graphene–rubber nanocomposites is explored. The paper concludes with future prospects for graphene in rubber formulations.

Lysozyme crystallisation was first-time performed in a microfluidic device in the presence of different gases: helium, nitrogen, oxygen, and carbon dioxide microbubbles. It was found that protein adsorbed on the gas–liquid interface stabilised the gas bubbles in the aqueous solution, and bubble stability increased with the protein concentration in the solution. The heterogeneous nucleation of protein on the gas–liquid interface was preferred than on the capillary glass wall, limiting the fouling inside the capillary. The crystals formed with curved surfaces, and the crystals floated in the solution with gas bubbles. The population density of lysozyme crystals increased with an increase in the solubility of four types of gases. Three stages of the protein crystallisation on the gas–liquid, gas–solid and liquid–solid interfaces were discussed.

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Artificial materials which show negative dispersion of retardation are of great importance and interest for applications to geometric phase retarders, compensation films, and augmented reality. Nevertheless, few negative dispersion materials have been reported and the exact correlation between the dispersion and the molecular structure has not been clearly elucidated yet. Here, new H-shaped reactive molecules with different chemical structures were synthesized and an early conversion from positive to negative dispersion of retardation was observed. The effect of the molecular structure on the dispersion of retardation was investigated experimentally as well as theoretically from the view point of molecular orientation and intrinsic molecular refractive index dispersion. The cyclohexane-inserted H-shaped reactive molecule represented a better planar orientation where the central linkage groups are aligned parallel to the surface plane. The relative UV absorption intensity along the long molecular axis was reduced compared to that of the molecule without a cyclohexane ring, while the absorption peak wavelength was not changed. By these two effects, the conversion from positive to negative dispersion could be shown at a lower concentration of the H-shaped molecules.

Multiple ring-closing metathesis of oligomeric bithiophene smoothly formed a winding vine-shaped oligomer with molecular asymmetry. Stereochemical studies suggested that the dimeric 1 : 1 meso and racemic stereochemical mixture showed the conversion to a meso-enriched product upon standing in the solid state, while the obtained meso compound reverted to the meso and racemic mixture upon heating the solution in chloroform at 50 °C for 30 min. On the other hand, heating of the meso isomer in the solid state at 80 °C for 3 days did not lead to isomerization.

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The state of proteins in aqueous solution is determined by weak, nonspecific interactions affected by pH, solvent composition, and ionic strength. Protein–protein interactions play a crucial role in determining protein stability and solubility. The second osmotic coefficient (B₂₂) provides insight into effective interactions between proteins in solution. Models for calculating B₂₂ are valuable for estimating interactions, explaining measured phenomena, and reducing experimental time. However, existing models, like the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, assume a simple spherical shape for proteins. Owing to the fact that proteins exhibit diverse shapes and charge distributions, influencing their electrostatic properties and overall interactions, DLVO accuracy is significantly reduced for nonspherical proteins. To address this limitation, we introduce the xDLVO-CGhybr model, which combines Poisson–Boltzmann (PB) and Debye–Hückel (DH) theories to account for electrostatic interactions between proteins. PB is used for short intermolecular distances (<2 nm) with an all-atom resolution, while DH is employed for longer distances on a coarse-grained level. Additionally, xDLVO-CGhybr incorporates an improved coarse-grained Lennard-Jones (LJ) potential derived directly from the all-atom potential to capture dispersion interactions. This model improves the calculated B₂₂ values compared to existing models and can be applied to proteins with arbitrary shape and charge under various solvent conditions (up to 1 M monovalent salt concentration). We demonstrate the application of xDLVO-CGhybr to bovine trypsin inhibitor, ribonuclease A, chymotrypsinogen, concanavalin A, bovine serum albumin, and human immunoglobulin type I proteins, validating the model against experimental data.

A donor–π–acceptor type photoinitiator, composed of boron–thienothiophene–triphenylamine (DMB–TT–TPA) to be used as a synthesizer under white LED irradiation, was studied for cationic and radical polymerization of mono and difunctional monomers. The monomers methyl methacrylate (MMA), styrene (Sty), cyclohexene oxide (CHO), isobutyl vinyl ether (IBVE), triethylene glycol dimethacrylate (TEGDMA) and bisphenol A diglycidyl ether (BADGE) were exposed to irradiation under a white LED source in CH₂Cl₂ with DMB–TT–TPA, in the presence of diphenyliodonium hexafluorophosphate (DPI). Of the spectroscopic techniques, fluorescence was used to investigate the photophysical characteristics of DMB–TT–TPA to gather data that would be helpful in affirming the initiation process. The presence of the synthesizer in all the polymer structures was proved by NMR spectroscopy studies. The importance of the described photoinduced electron transfer process with respect to the initiation of radical and cationic polymerizations and formation of conjugated polymers was demonstrated.

Ring-opening metathesis polymerisation (ROMP) has become a popular method for synthesising complex functional polymers owing to the high functional group tolerance of metathesis catalysts. In recent years, ROMP has emerged as an indispensable approach for the design and synthesis of polymeric biomaterials, allowing for precise control of polymer structure and introduction of complex polar functional groups that are challenging to access through conventional polymerisation methods. In this review, we present examples of precision polymer synthesis with polar functional groups and their utilisation as soft-biomaterials in biotechnology and biomedical fields. Specifically, we focus on two approaches: the underexplored ROMP of functionalised monocyclic alkenes and the dominant methods of synthesising biomaterials using functionalised norbornene.