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The fabrication of functional tissue or organs substitutes has always been the pursuit of goals in the field of tissue engineering. But even biocompatible tissue-engineered scaffolds still suffer from immune rejection, subsequent long-term oxidative stress and inflammation, which can delay normal tissue repair and regeneration. As a well-known natural antioxidant, polyphenols have been widely used in tissue engineering in recent years. The introduced polyphenols not only reduce the damage of oxidative stress to normal tissues, but show specific affinity to functional molecules, such as receptors, enzyme, transcription and transduction factors, etc. Therefore, polyphenols can promote the recovery process of damaged tissues by both regulating tissue microenvironment and participating in cell events, which embody specifically in antioxidant, anti-inflammatory, antibacterial and growth-promoting properties. In addition, based on its hydrophilic and hydrophobic moieties, polyphenols have been widely used to improve the mechanical properties and anti-degradation properties of tissue engineering scaffolds. In this review, the research advances of tissue engineering scaffolds containing polyphenols is discussed systematically from the aspects of action mechanism, introduction method and regulation effect of polyphenols, in order to provide references for the rational design of polyphenol-related functional scaffolds.

A multisite-binding fluorescence turn-on probe of Rh6G NH PBA has been prepared in this study. The probe selectively responds to mitochondrion adenosine triphosphate (ATP) concentrations. The fluorescence intensity of Rh6G NH PBA toward ATP was enhanced by approximately 51-fold in water at 1.0 mM. In particular, Rh6G NH PBA exhibited good selectivity to ATP, surpassing other anions due to a cooperative effect from multisite-binding recognition. Live-cell imaging indicates that Rh6G NH PBA locates mainly into mitochondria with good biocompatibility. The results demonstrate that Rh6G NH PBA is a useful probe for the monitoring of mitochondria ATP-relevant processes.

In the present work, we developed a type of novel hyperbranched polymeric ionic liquid (HBPIL) that was derived from 1-allyl-3-methylimidazolium (AMIM), 1-allyl-3-methylpyridinium (AMPy), or 1-allyl-1-methylpiperidinium (AMPIP) cation with different anions, tetrafluoroborate (BF4), bis (trifluoromethylsulfonyl) amide (NTF2), and hexafluorophosphate (PF6), to elucidate the role of cations and anions on the reactivity and mechanical properties. The blending of HBPILs with bisphenol-F-based benzoxazines decreased the temperature required for opening the rings of the benzoxazines and improved the mechanical performances and thermal behaviors of the formed polybenzoxazoles. Moreover, differential scanning calorimetry, TGA, and Fourier transform infrared data exhibited the following differences: (i) the curing process was correlated to the structural differences of the anions, and the onset temperature was lower for the HBPIL with the PF6 anion in comparison to those with the NTF2 and BF4 anions; (ii) the type of cation had a significant influence on the curing reactivity of the benzoxazines, with the highest catalytic activity observed for the HBPIL containing AMIM, compared to those with (AMPy) and (AMPIP). Furthermore, the higher catalytic activity of the HBPILs for the benzoxazines suggested a higher crosslink density of the cured resin, which enabled the glass transition temperature to shift to a higher value and enhanced the mechanical strength and thermal stability of the obtained polybenzoxazoles.

Small interfering RNA (siRNA) has potential as therapeutic agents against various diseases because it can reversibly silence any gene with high efficiency and specificity. Unmodified siRNA is a hydrophilic molecule with negative charge, which is unstable in the bloodstream and cannot freely cross cell membranes. Therefore, the safe and effective delivery systems are necessary to achieve siRNA-based therapeutics. This review will summarize the polyester nanovehicles which are being employed to deliver siRNA, mainly including poly(lactic-co-glycolic acid) (PLGA), polylactic acid (PLA), polycaprolactone (PCL) and some other polyesters. The characteristics of these polyester nanovehicles including their structural properties and functional modifications will be thoroughly demonstrated, which is intended to improve the therapeutic effects of siRNA.

Epoxy-ended hyperbranched polymers (EHPs), as important type of functional thermosetting hyperbranched polymers, have attracted broad and continuing interest from both academic and industrial researchers. Benefiting from their high-crosslinking ability, void-containing topological structure and very low viscosity, EHPs have been widely applied in reinforcing and toughening diglycidyl ether of bisphenol-A (DGEBA) and in solvent-free or environmentally-friendly coatings. Therefore, the design and synthesis of EHPs provide a robust tool for controlling the interfacial interaction between EHPs and DGEBA to finally gain excellent comprehensive performance. In this review, the perspectives and recent advances of preparation methods, performance control and promising applications of various EHPs have been comprehensively summarized. In addition, a single toughening function, a simultaneously reinforcing and toughening function and the mechanism of DGEBA by EHPs are also discussed and investigated by integrating molecular simulations, dynamic mechanical analysis (DMA) and scanning electron microscope (SEM) technologies. EHPs with high contents of epoxy group show simultaneous reinforcing and toughening in DGEBA, regardless of their aliphatic and aromatic structures, and whether there is phase-separation or homogenous structure associated with the fractured surface. The simultaneous reinforcing and toughening mechanism changes the conventional conception of inter-contradiction between the toughening and reinforcing function. It was also found that EHPs with different synthetic strategies and diverse performance have allowed an increasing number of versatile industrial applications.

The development of biocompatible vector for hydrophobic drug delivery remains a longstanding issue in cancer therapy. We design and synthesis a drug delivery system based on HPG modified β-CD (β-CD-HPG) by conjugating HPG branches onto β-CD core and its structure was confirmed by NMR, FTIR, GPC and solubility. In vitro biocompatibility tests showed that HPG modification significantly improved red blood cells morphology alteration and hemolysis cause by β-CD and β-CD-HPG displayed cell safety apparently in a wide range of 0.01–1 mg/mL. An anti-cancer drug, docetaxel, was effectively encapsulated into β-CD-HPG which was confirmed by DSC analysis. This copolymer could form nanoparticles with small size (< 200 nm) and exhibited better DTX loading capacity and controlled release kinetics without initial burst release behavior compared with β-CD. Furthermore, antitumor assay in vitro show that β-CD-HPG/DTX effectively inhibited proliferation of human breast adenocarcinoma cells. Therefore, β-CD-HPG/DTX exhibit great potential for cancer chemotherapy.

A challenge to polymer scientists is to design new materials with superior overall performance in heat-resistance, cold-resistance, strength, and toughness. Here we report the synthesis of hyperbranched polymers containing epoxy and imide structure (EHPI-n, n = 6, 12, and 24) with various molecular weights and degrees of branching using a new synthetic diimide dicarboxylic acid. EHPI-n significantly decreases the gelation time and accelerates the curing of EHPI-n/diglycidyl ether of bisphenol-A (DGEBA). Both EHPI-6 and EHPI-12 significantly reduce the viscosity, activation energy, and average particle size of EHPI-n/DGEBA blends due to the disentangling function and compatibility of the EHPI-n. The toughness property, including elongation at break, impact strength, critical strain energy value (GIC) and critical stress intensity factor (KIC) of 12 wt % EHPI-12/DGEBA composites are improved over the neat DGEBA, by 144.72 %, 197.9 %, 168.4 % and 72.6 %, respectively, while their mechanical properties, including tensile strength, storage modulus and flexural strength are enhanced by 61.2 %, 89.9 %, 44.2 %. The heat-resistant index and β-relaxation peak temperatures of the composites are improved 14 °C and 15 °C, respectively, indicating both outstanding high-temperature resistance and outstanding low-temperature resistance. The simultaneous improvement on multiple performances is attributable to an in-situ homogeneous reinforcing and toughening mechanism, which is explained by free volume fraction, microstructure and surface micrograph. The EHPI-n present great potential as advanced materials for aerospace and wind turbine.

Cu2+ is an eminent trace metal ion in the human body as a structural cofactor that can enhance immune function. Aluminum is one of the most abundant elements found in the earth's crust and most biological tissues appear in Al3+ form. Hg2+ is probable to cause cancer with high toxicity. However, excess accumulation of Al3+, Cu2+ or Hg2+ in the body leads to many diseases. Therefore, detecting the level of Al3+, Cu2+ and Hg2+ are very important for human health. However, preparing a suitable single probe for the simultaneous detection of Al3+, Cu2+ and Hg2+ remains a challenge. TPE-based carbohydrazide derivative (TPE-Ch) was synthesized by the one-pot reaction. The TPE-Ch displayed notable AIE and AIEE phenomena and can act as a fluorescence sensor that turns on toward Al3+ in ethanol/water mixtures (fw = 70%) and turns off toward Cu2+ or Hg2+. TPE-Ch can produce various assemblies by coordination with Al3+, Cu2+ and Hg2+, including nanospheres, tree-like assembly morphology and belt-like superstructures. Optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and fluorescence spectrography were employed to characterize the self-assemblies.

Owing to the outstanding mechanical performance, diglycidyl ether of bisphenol A (DGEBA) becomes an important thermoset resin, but its brittleness and difficulties in degradation and recycling retard sustainable development. Herein, we have prepared several hyperbranched epoxy resins containing 1,3,5-hexahydro-s-triazine (HER-HTn, n = 3, 6, 12, 24) which showed versatility on modifying DGEBA, including simultaneous reinforcing and toughening function, rapid degradation and recycling, and good compatibility. The detailed results showed that the HER-HT12 could increase the flexural, impact and tensile strengths of cured DGEBA by 132.7%, 190.4%, and 57.7%, respectively, and also increase degradation degree from 37.2 wt% to 99.9 wt%. The mechanical performance of the cured HER-HTn/DGEBA reinforced in the beginning and then decreased with an increase in the content and the molecular weight of HER-HTn, however, their degradation degrees increased distinctly. The reinforcing and toughening mechanism and degradation mechanism of the composites were investigated by SEM micrographs and GC-MS spectra.

Hyperbranched epoxy resins (HERs) have attracted much interest due to improving homogeneously the ductility and strength of popular diglycidyl ether of bisphenol-A (DGEBA), but the preparation of HERs/DGEBA composites with low-temperature resistance and rapid degradation is still a challenge in the sustainable development of thermoset field. Here we represent self-curable hyperbranched epoxy resins (DSEHP-n, n = 3, 5, 7, 11) to modify DGEBA. DSEHP-n not only increases simultaneously the tensile strength, flexural strength, impact strength, modulus, and elongation by 64.8%, 38.1%, 93.7%, 70.4%, and 50%, respectively, and but also improve remarkably the low-temperature resistance and degradation degree. The improvement of mechanical properties is caused by the combined effect of crosslinking density, free volume, intermolecular cavity, hyperbranched topological structure, and good compatibility, the account of an in-situ reinforcing and toughening mechanism which substantiated by dynamic light scattering (DLS), SEM, DMA, and free volume analysis. The detailed analysis of degradation products from GC-MS spectra showed that the degradation of the composites was attributed to the cleavage of the C–N and ester bonds. This paper will bring a novel method to prepare highly-efficient degradable thermosets and composites.

Covalent organic frameworks (COFs) have emerged as promising electrode materials in flexible and wearable supercapacitors. However, achieving high electrical conductivity and high mechanical strength of flexible COF composite membranes is still a major challenge. Herein, we first prepared the COF complex by using hydroxyl-ended hyperbranched polymer (OHP) as a template via a simple solid-state mechanical mixing method, and the COF@OHP complex was then impregnated on a microporous carbon nanotube film (CNTF) to construct a composite membrane (CHCM) that can be prepared as CHCM electrodes for extensible and flexible supercapacitors. A large number of cavities, reactive end-groups and flexible polymer chains of the hyperbranched polymer are utilized to stabilize and disperse COFs and to enhance the COF-polymer’s interfacial interaction. CNTF is an attractive material for energy storage due to its excellent conductivity, slippability, flexibility, and high specific surface area. The CHCM electrode showed not only excellent electrochemical performance (high gravimetric capacitance of 249 F g−1 and charging-discharging stability of 80% after 10,000 cycles) in the relatively environmentally-friendly phosphoric acid (H3PO4) electrolyte, but also a high tensile strength of 180 MPa and an elongation of 10%. The gravimetric capacitance of the CHCM electrode reached 425 F g−1 in 2 M aq. H2SO4 electrolyte. This work will demonstrate a promising strategy for preparing wearable and flexible supercapacitors with high mechanical strength with potentially wide applications.

In this work, an efficient renewable approach to the toughening and strengthening of epoxy resins is presented by using agricultural byproducts. The resulting epoxy exhibits low viscosity and good mechanical performance and thermal properties, without sacrificing stiffness. First, we synthesized epoxidized konjac fly powder (EKFP) from konjac fly powder, an agricultural byproduct. Subsequently, the resulting EKFP was successfully used as a green reactive diluent to simultaneously improve the toughness and strength of petroleum-based epoxy diglycidyl ether of bisphenol-A (DGEBA). The experimental results indicated that the free volume of the epoxy resins was increased with the incorporation of the EKFP. The fracture morphology of the resulting epoxy thermosets displayed shallow cleavages and roughness that contribute to the increased toughness. The addition of the EKFP to the DGEBA significantly improved the tensile strength, flexural strength, and impact strength of the resulting epoxy thermosets. The tensile strength, tensile modulus, flexural strength, impact strength, fracture toughness and fracture energy of epoxy thermosets with 20 wt% EFKP are increased by 61.2 %, 29.7 %, 24.5 %, 119.3 %, 83.3 % and 159.1 %, respectively. The enhancement of the toughness and strength was associated with the increased free volume and reduction in internal stress of the epoxy. The simultaneous reinforcement and enhancement of the resin’s toughness demonstrated the possibility to use the byproducts of konjac glucomannan production for the creation of high-performance bio-based epoxy thermosets, which have the potential to be employed in coatings, the aerospace industry, and various electronic applications.

A novel hyperbranched flame-retardant polymer (referred to as ITA-HBP) was synthesized from itaconic anhydride as a renewable starting material. Upon the incorporation of ITA-HBP, both the toughness and flame-retarding ability of epoxy resins with low phosphorus contents increased simultaneously increased the toughness and flame retardant properties of epoxy resin with low phosphorus contents. The impact strength, fracture toughness and fracture energy of the epoxy resins are significantly enhanced by 133.2%, 78.7% and 124.7% respectively due to the in situ reinforcing and toughening effects induced by ITA-HBP. At the same time, the incorporated ITA-HBP exhibited a remarkable flame-retarding activity in the gas phase due to the production of phosphorus radicals and in the condensed phase due to the formation of a phosphorus-rich char layer of the epoxy resin. The addition of ITA-HBP considerably reduced the peak heat release rate, total heat release and smoke release of the epoxy resin. At a phosphorus content of 0.26 wt%, the ITA-HBP/epoxy thermosets scored V-0 rating in the UL-94 test and showed a limiting oxygen index of 36.3%.

We herein report the self-assemblies of H4tcbpe-MA by using 1,1,2,2-tetrakis (4-(4-carboxy-phenyl) phenyl) ethane (H4tcbpe) and melamine (MA) as building blocks. It was found that H4tcbpe-MA only gave weak emission in dimethyl formamide (DMF) solution, while strong fluorescence was observed upon addition of water in the solution (fw > 60%), implying their notable aggregation induced emission (AIE) property. Interestingly, the self-assemblies of H4tcbpe-MA showed various morphologies by changing the ratio of MA, evidenced by optical microscope (OM) and scanning electron microscopy (SEM) measurements. Nanofibers, tree-like, cuboidal microstructures and microbelts were generated with the ratio of H4tcbpe-MA at 1:0, 1:1.5, 1:3.0 and 1:6.0, respectively. The powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements indicated that the ionic interaction, hydrogen bonding (H-bonding) and π-π stacking were the main driving forces for the fabrication of H4tcbpe-MA assemblies. It is worth noting that the self-assemblies displayed different emission colors variation dependence on the MA concentration- and relative humidity (RH). The photo-oxidation behavior of H4tcbpe-MA in solution was also investigated under visible light and 254 nm UV light.

Benefiting from the high binding affinity of 1,3,6,8-tetrakis(p-benzoic acid) pyrene (H4TBAPy) with three different amines (urea, melamine (MA) and terminal amino hyperbranched polymer (HP)), H4TBAPy produced self-assemblies with various morphologies, such as small flower-like, long fibers, three-dimensional (3D) flower shape and banana-like etc. Fluorescence spectra, dynamic light scattering (DLS), optical micrographs (OM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) patterns, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were employed to monitor the self-assembly process and characterize the resultant assemblies. It was found that the π-π stacking of the planar aromatic pyrene core of H4TBAPy, electrostatic interaction and hydrogen bonding (H-bonding) interactions between the carboxylic acid group (-COOH) of H4TBAPy and the amino group of urea, MA, HP were the main driving forces for the self-assembly processes. This work may provide a powerful method to construct well-defined nanostructures with different morphologies by non-covalent interactions of two components.

Hyperbranched polymeric ionic liquids (HBPILs) with varying alkyl chain length have been synthesized and used as efficient catalysts for benzoxazine/epoxy thermosets. The values of activation energies for the thermal polymerization of benzoxazine/epoxy thermosets increase with increasing the alkyl chain length of HBPILs. The HBPILs significantly enhance the toughness of benzoxazine/epoxy thermosets. The phase morphologies of the benzoxazine/epoxy thermosets change from a homogeneous structure to a sea-island structure upon increasing the alkyl chain length of HBPILs, while the concentration changes were altered the interface behaviors between HBPILs and benzoxazine/epoxy. As the benzoxazine/epoxy thermosets formed phase separation structure, the toughness is significant improved compared to that of the continuous phase morphology. Moreover, the addition of HBPILs simultaneously improves the glass transition temperature (T g ) and thermal stability of benzoxazine/epoxy thermosets.

In the past few years, perylenediimide-cored (PDI-cored) dendrimers have been successfully prepared and applied in various fields. In this review, we focus on the structural design and synthesis strategies of PDI-cored dendrimers that involve convergent and divergent synthesis approaches. When building the outer shell of PDI-cored dendrimers, first hydrophobic and then hydrophilic macromolecules are introduced. The advantages of water-soluble PDI-cored dendrimers include strong red fluorescence, excellent photostability, low cytotoxicity, high quantum yield, and versatile surface modification. The biological application of water-soluble PDI-cored dendrimers is broad, including fluorescence live-cell imaging, fluorescent labeling, and gene delivery, owing to the rapid development of these materials in the past decade. The challenges and outlooks in this field will also be discussed.

A novel Et 3 N-catalyzed oxidative dehydrogenative coupling of α-unsubstituted carbonyl compounds with aryl diamines leading to quinoxaline derivatives using molecular oxygen as oxidant has been developed. Six hydrogen dissociations involving 2 sp 3 C–H bonds activation are realized under mild conditions in this approach. Plausible mechanism is proposed for this novel Et 3 N-catalyzed transformation on the basis of the aboratively designed mechanistic studies including the radical detection by EPR. © 2012 Elsevier Science. All rights reserved.