Characterization by Gel Permeation Chromatography of the Molecular Weight of Supramolecular Polymers Generated by Forming Polyrotaxanes through the Introduction of External Stoppers.

Supramolecular polymers find wide applications across diverse domains, and the molecular weight exerts a critical influence on their applicability. Consequently, the measurement of molecular weight for supramolecular polymers assumes paramount significance. Gel Permeation Chromatography (GPC) requiring low-concentration condition is a common characterization employed for molecular weight determination, which is not suitable for supramolecular polymers possessing concentration-independence property. Here, to break this threshold, we synthesized M1 embodying dibenzo-24-crown-8 (DB24C8) moiety as well as dibenzylammonium salt (DBA) group, which was capable of self-assembling into supramolecular polymers terminated with aldehyde groups at its end. Upon the addition of (4- (1,2,2-Triphenylvinyl) phenyl) methylamine (TPE-NH2), supramolecular polymers underwent a transition into polyrotaxanes, for which it was led by the generation of imine bonds. By virtue of GPC, the molecular weight of polyrotaxanes was obtained, then it was available to gain the molecular weight of supramolecular polymers with the help of transformation efficiency.

Construction of Supramolecular Polymers and Covalent Polymers via the Same Monomers.

Nature owns the ability to construct structurally different polymers from the same monomers. While polymers can be classified as covalent polymers (CPs) and supramolecular polymers (SPs), it is still difficult to synthesize CPs and SPs using same monomers like nature do. Herein, M1 with two diazo salts on both the ends was designed. Additionally, hydroquinone was chosen to be M2 for the existence of two hydroxyl groups. When mixing at room temperature, M1 and M2 self-assembled to SPs via N…H hydrogen bonds. In another way, upon the exposure to ultraviolet irradiation when blending M1 with M2, CPs were fabricated in the presence of covalent bonds. The excellent thermal stability of CPs was determined by TGA and DSC, while the great corrosion resistance of covalent polymers was detected by acid or alkali immersion. In this way, constructing two kinds of polymers using the same monomers was successfully achieved. This shows tremendous potential in fields of polymer science, supramolecular chemistry, which would boom the development of polymers.

Application of Organic Gel on Skin Realized by Hydrogel/Organic Gel Adhesion.

Diversity in solvent selection bestows the organic gel with appealing characteristics embracing antidrying, anti-icing, and antifouling abilities. However, organic gel, subjected to the "toxic" inherent property of solvent, is not able to be manipulated on skin. Herein, introducing the hydrogel layer amid organic gel and skin is envisaged to realize application of organic gel on skin. Hydrogel, inserted as the medium layer, works for the coupling role between skin and organic gel, also avoids the direct contact of organic gel toward skin. First, hydrogel system composed of acrylic acid is fabricated, meanwhile organic gel is prepared employing 2-hydroxyethyl methacrylate, ethylene glycol (EG) as solvent. Organic gel is able to adhere to hydrogel by hydrogen bonding resulting from carboxyl groups of polyacrylic acid chains and hydroxyl groups occurring on 2-hydroxyethyl methacrylate or EG. Additionally, hydrogen bonding enables the hydrogel to be firmly attached to skin, thus organic gel/hydrogel/skin assembly is produced. The further application of organic gel is exploited by incorporating stimuli-responsive dyes including spiropyran and rhodamine derivative.

Muscle-Like Supramolecular Polymers with Dual Motion Patterns.

Benefiting from the features like polymeric linear structures, stimuli-responsiveness and dynamic adaptiveness, supramolecular polymers (SPs) are favored as exploiting muscle-like materials, allowing for imitating the muscle functions. However, a substantial part of these materials barely owned an unitary motion orientation while it was obviously known that muscle movements involved distinct orientations. Herein, M1 holding the structure of 44-membered macrocycle with two aldehyde groups was designed, meanwhile, M2 comprising of secondary ammonium ions, 3,5-di-tert-butylphenyl groups as well as the alkyl chains was fabricated, for which it could be assembled with M1 to generate SPs based on host-guest interactions from a large macrocycle and two secondary ammonium ions. SPs underwent vertical compression upon the addition of N2 H4 owing to the forming dynamic covalent bonds, notably, mechanically interlocked structures were also generated. Afterwards, the vertically compressed SPs experienced horizontal shrinkage when tetrabutylammonium chloride was contributed due to the destruction of host-guest interactions.

Pillar[5]arene-Based AIE Supramolecular Polymer Networks Exhibiting Various Fluorescence to Achieve Visible Surveillance.

Supramolecular polymer networks (SPNs) based on pillar[n]arene are widely studied and it is known that evolution from linear polymers to SPNs occurs as a progressive process, which is of importance to monitor the detailed morphology throughout the process. Yet, the current reports related to that distinction by employing fluorescence approach have realized confined success, it still remains a challenge to distinguish the various states visually. Herein, a fluorescent group of the pyrene benzohydrazonate-based (PBHZ-based) derivative is introduced into the pillar[5]arene based SPNs gained from host-guest recognition, enabling the visual monitoring during the formation of SPNs. The whole visual detection was based on the fluorescence color transition ranging from blue to green relying on the gradual aggregated PBHZ molecules upon the increasing cross-linking degree. Besides, the stimuli-responsiveness of this SPNs was confirmed that increasing the temperature or adding a reducing agent would reduce the cross-linking degree.

Hydrogel-Based Macroscopic Click Chemistry.

The click reaction has found good utility across various fields due to the characteristics of high efficiency, atom economy, simple and mild reaction conditions. Click chemistry is usually utilized for connecting components of microscopic level, while it is still unable for joining macroscopic building blocks. Materials consisting of macroscopic building blocks realize the flexible fabrication of three-dimensional structures at macroscopic level, exerting significance on parallel manufactures. In this work, we reported macroscopic click chemistry utilizing hydrogel as macroscopic building blocks. Hydrogels G1 and G2 were prepared by incorporating M1 (N,N'-dimethyl-1,2-ethanediamine) and P1 (alkyne functionalized polyethylene glycol) respectively, where polymer chains formed through diffusion-induced amino-yne click reaction entangled different hydrogel networks together. Additionally, chain-like aggregates and complicated 3D structures such as tetrahedron and quadrangular pyramid were constructed based on the adhesion of the hydrogel blocks. The approach enables us to find more possibilities in the delicate designation of 3D aggregations as well as large-scale manufacturing.

A Strategy Based on Aggregation-Induced Ratiometric Emission to Differentiate Molecular Weight of Supramolecular Polymers.

Molecular weight has an important bearing on the properties of supramolecular polymers. However, the intuitive differentiation of the molecular weight of supramolecular polymers remains challenging. Given this situation, establishing a reliable relationship between fluorescence properties and molecular weight may be a promising strategy. Herein, we prepared a supramolecular monomer M1 with aggregation-induced ratiometric emission characteristics. With the increasing M1 concentration (0.100-100 mM), the average degree of polymerization (DPDOSY ) rose from 1.00 to 293. Meanwhile, the color changed from dark blue to cyan, finally to yellow-green in the same concentration range. Hence, the intuitive relationship between DPDOSY and fluorescence colors was constructed, allowing the visual differentiation of molecular weight. Moreover, the fluorescence color could be regulated by introducing a competitive molecule to induce the depolymerization of supramolecular polymers.

Learning Rates of Deep Nets for Geometrically Strongly Mixing Sequence.

The great success of deep learning poses an urgent challenge to establish the theoretical basis for its working mechanism. Recently, research on the convergence of deep neural networks (DNNs) has made great progress. However, the existing studies are based on the assumption that the samples are independent, which is too strong to be applied to many real-world scenarios. In this brief, we establish a fast learning rate for the empirical risk minimization (ERM) on DNN regression with dependent samples, and the dependence is expressed in terms of geometrically strongly mixing sequence. To the best of our knowledge, this is the first convergence result of DNN methods based on mixing sequences. This result is a natural generalization of the independent sample case.

Multiscale structure changes and mechanism of polyphenol-amylose complexes modulated by polyphenolic structures.

This study was designed to investigate the effect of polyphenolic structure on the interaction strength and process between polyphenols (gallic acid (GA), epigallocatechin gallate (EGCG) and tannic acid (TA)) and amylose (AM). The results of Fourier transform infrared spectroscopy, isothermal titration calorimetry, X-ray photoelectron spectroscopy and molecular dynamic simulation (MD) suggested that the interactions between the three polyphenols and AM were noncovalent, spontaneous, low-energy and driven by enthalpy, which would be enhanced with increasing amounts of pyrogallol groups in the polyphenols. The results of turbidity, particle size and appearance of the complex solution showed that the interaction process between polyphenols and AM could be divided into three steps and would be advanced by increasing the number of pyrogallol groups in the polyphenols. At the same time, MD was intuitively employed to exhibit the interaction process between amylose and polyphenols, and it revealed that the interaction induced the aggregation of amylose and that the agglomeration degree of amylose increased with increasing number of pyrogallol groups at polyphenols. Last, the SEM and TGA results showed that TA/AM complexes had the tightest structure and the highest thermal stability (TA/AM˃EGCG/AM˃GA/AM), which could be attributed to TA having five pyrogallol groups.

Shengmai injection inhibits palmitic acid-induced myocardial cell inflammatory death via regulating NLRP3 inflammasome activation.

Objective: To determine the protective effect of Shengmai injection (SMI) on myocardial injury in diabetic rats and its mechanism based on NLRP3/Caspase1 signaling pathway. Materials and methods: Rat H9c2 cardiomyocytes were cultured in vitro, and the cell survival rate of different concentrations of palmitate acid (PA) and different concentrations of SMI were detected by CCK-8. The myocardial injury cell model was induced with PA, treated with SMI, and combined with NLRP3 specific inhibitor (MCC950) to interfere with the high-fat-induced rat H9c2 myocardial cell injury model. The cell changes were observed by Hoechst/PI staining and the expression levels of MDA, SOD, and ROS in each group were detected. The protein and gene changes of the NLRP3/Caspase-1 signaling pathway were detected by Western blot and RT-qPCR, respectively. Results: 200 µmol/L of PA were selected to induce the myocardial injury cell model and 25 µL/mL of SMI was selected for intervention concentration. SMI could significantly reduce MDA expression, increase SOD level, and decrease ROS production. SMI could decrease the gene expression levels of NLRP3, ASC, Caspase-1, and GSDMD, and the protein expressions of NLRP3, ASC, Cleaved Caspase-1, GSDMD, and GSDMD-N. Conclusion: SMI can inhibit the high-fat-induced activation of the NLRP3/Caspase-1 signaling pathway, intervene in cardiomyocyte pyroptosis, and prevent diabetic cardiomyopathy.

Enhancing Mechanical Performance of a Polymer Material by Incorporating Pillar[5]arene-Based Host-Guest Interactions.

Polymer gels have been widely used in the field for tissue engineering, sensing, and drug delivery due to their excellent biocompatibility, hydrophilicity, and degradability. However, common polymer gels are easily deformed on account of their relatively weak mechanical properties, thereby hindering their application fields, as well as shortening their service life. The incorporation of reversible non-covalent bonds is capable of improving the mechanical properties of polymer gels. Thus, here, a poly(methyl methacrylate) polymer network was prepared by introducing host-guest interactions between pillar[5]arene and pyridine cation. Owing to the incorporated host-guest interactions, the modified polymer gels exhibited extraordinary mechanical properties according to the results of the tensile tests. In addition, the influence of the host-guest interaction on the mechanical properties of the gels was also proved by rheological experiments and swelling experiments.