Search

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pectin cellulose grafted with glycidyltrimethylammoniochloride (GTMAC) was successfully obtained following the processes of depectinfibrillation and cellulose cationization using ordinary Shatian pomelo peel produced in Yongzhou, Hunan, as the raw material. This is the first report on a new type of functionalized sodium alginate-immobilized material prepared from the fibers of pomelo peel. The material was prepared by combining modified pomelo peel cellulose and sodium alginate following the processes of physical and chemical double cross-linking. The prepared material was used to embed the target bacteria to achieve the biodegradation of p-aniline. The concentration of CaCl2 was adjusted when the alginate gelled, and the alginate to yuzu peel cellulose ratio was tuned. The immobilized material-embedded bacteria help achieve the best degradation effect. Bacteria are embedded during the process of the degradation of aniline wastewater, and the functionalization of the cellulose/sodium alginate-immobilized material results in unique surface structure performance. The performance of the prepared system is better than that of the single sodium alginate-based material characterized by a large surface area and good mechanical properties. The degradation efficiency of the system is improved significantly for the cellulose materials, and the prepared materials can potentially find applications in the field of bacteria-fixed technology. HIGHLIGHTS Pomelo peel fiber was extracted for the first time and used in the preparation of immobilized material.; By combining with sodium alginate, the specific surface area of the fixed material can be increased by the pomelo peel fiber with a spiral tube shape and rough surface.; The cationic-modified pomelo peel fiber can improve the mechanical properties and stability of the immobilized material by ionic bonding.;

Excessive biofluid around wounds can cause infection and prevent healing. In this study, an anisotropic quaternized chitosan (QC)/sodium alginate (AL)-based aerogel wound dressing was prepared via a directional freeze-drying technique inspired by the channel structure used for water transport in trees. The aligned channels provided the dressing with self-pumping ability, allowing it to rapidly and completely remove biofluids and absorb biofluids up to 1292.5 % of its own weight. To enhance the strength of the dressing, a double cross-linked network was constructed based on the QC-AL electrostatic attraction and AL-Ca2+ chelation interaction. The axial compressive strength of the double cross-linked dressing reached 207.3 kPa (ε = 50 %). In addition, the dressing exhibited strong conductive properties (conductivity = 13.0 S/m), antioxidant activities [reactive oxygen species (ROS) scavenging ability = 88.0 %], and hemostatic characteristics (blood coagulation index = 1.8 %). The dressing also exhibited powerful antibacterial performance, exhibiting over 98.0 % inhibition of E. coli and S. aureus. Experiments on diabetic mouse models revealed that the dressing considerably promoted wound healing. On day 3, the wound healing rate was 96.7 % faster in the QAC group than in the gauze group. Therefore, the developed dressing may have great potential for chronic wound care.

BACKGROUND: Aspirin is a classic non-steroidal anti-inflammatory drug. Appropriate doses of aspirin can regulate immunity and promote osteogenesis. The preparation of bone tissue engineering materials, which can release aspirin, regulate the immune microenvironment of the bone defect area and accelerate the repair of the bone defect, and is a current research focus. OBJECTIVE: To prepare a novel hydrogel scaffold that can modulate the immune microenvironment and quickly repair the bone defect area. METHODS: Hydrogel scaffolds containing 0%, 10% and 20% of nano-hydroxyapatite/aspirin/polyvinyl alcohol/gelatin/sodium alginate were prepared. The microstructure, porosity, chemical composition, crystal structure, drug release properties, mechanical properties, swelling properties and degradation properties of the hydrogel scaffolds were characterized. The biocompatibility of the hydrogel scaffolds was evaluated by cell proliferation and cytotoxicity experiments. RESULTS AND CONCLUSION: (1) Scanning electron microscope and porosity results showed that hydrogel scaffolds in the 0% nano-hydroxyapatite group and 10% nano-hydroxyapatite group had better biomimetic hierarchical porous structure, pore connectivity, and porosity. (2) The results of Fourier transform infrared spectroscopy and X-ray diffraction showed that the raw materials in the hydrogel scaffold were combined by physical and chemical double crosslinking, and the crystal phase structure of nano-hydroxyapatite was not be destroyed. (3) The results of mechanical properties showed that the 10% nanohydroxyapatite group had the best compressive modulus and compressive strength. (4) The results of drug release properties showed that the cumulative release rate of aspirin decreased with the increase of nano-hydroxyapatite, but the drug burst release rate decreased and the sustained release time prolonged. (5) The results of swelling properties and degradation properties showed that with the increase of nano-hydroxyapatite, the swelling rate and degradation rate of hydrogel scaffolds of each group decreased. (6) Using the hydrogel scaffold extract to culture mouse pre-osteoblasts, the results of cell proliferation and cytotoxicity experiments showed that the hydrogel scaffold extract could promote cell proliferation, without cytotoxicity. (7) It is concluded that 10% nanohydroxyapatite hydrogel scaffolds have better bionic characterization and biocompatibility, and are expected to be used as bone tissue engineering scaffolds for further studies of osteogenesis and immunomodulatory potential. [ABSTRACT FROM AUTHOR]

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the third generation of novel aerogels, cellulose aerogels exhibit broad applications in various fields, indicating its great development potential. Whereas the flammability and poor mechanical performance of cellulose aerogel restrict its practical application. Herein, a kind of flame retarded and reinforced aerogel was fabricated using cellulose nanofibrils (CNFs) and sodium alginate (SA) as compound matrix (CA) based on double cross-linking strategy. Boric acid (BA)/Ca2+ were used as synchronous flame retardants and cross-linking agents. FT-IR spectra of compound aerogels confirmed the occurrence of cross-linking reaction. Due to the formation of interpenetrating networks, especially the specific eggbox structure formed by the cross-linking between Ca2+ and SA, the double cross-linked specimen (CA/Ca/BA-3) exhibited decreased pore size and porosity, also resulting in the improved mechanical performance. The double cross-linked aerogel also exhibited excellent flame-resistant properties. The limiting oxygen index (LOI) of CA/Ca/BA-3 increased from 20.4 to 35.6%, and vertical combustion test (UL-94) rating reached V-0 level. The results of microcalorimetry showed that the maximum heat release rate (pHRR) and total heat release (THR) of CA/Ca/BA-3 decreased by 48% and 62% in comparison with control specimen (CS), respectively. The analysis of carbon residues showed that both condensed phase and gaseous phase flame-retardant mechanisms existed, and synergistic effect between BA and CaCO3 occurred during combustion. Moreover, the very low thermal conductivity of compound aerogels permitted their application as heat insulation materials. This investigation is helpful to promote the functionalization of cellulose aerogel while taking into account the increasingly stringent environmental requirements. [ABSTRACT FROM AUTHOR]

Cellulose aerogels, known for their biocompatibility and biodegradability, often suffer from poor mechanical properties, limiting their practical use. In this study, a double cross-linking strategy was employed using poly(vinyl alcohol) (PVA) and 3-aminopropyltriethoxysilane (KH550) to reinforce cellulose aerogels, forming a stable 3D network through hydrogen and chemical bonding. The resulting aerogel exhibits remarkable mechanical strength, with a compressive stress of 2.16 MPa at 80 % strain, an 854 % improvement over pure cellulose aerogels (CA). PVA/KH550 cross-linked CA aerogel also shows excellent durability, maintaining 82 % strain recovery after 30 cycles at 50 % strain. The PVA/KH550 cross-linked aerogel demonstrates excellent acoustic and thermal insulation properties. The PVA/KH550 cross-linked CA effectively attenuates sound transmission with an average sound transmission loss of 34.35 dB across the frequency range of 800–6300 Hz under an intensity of sound source of 85 dB. Additionally, the aerogel exhibits outstanding thermal insulation with low thermal conductivity of 0.0324 W/m·K. The aerogel shows a promising potential for robust, energy-efficient, lightweight, fireproof, and sound insulation materials. [Display omitted] • The double cross-linking enhances the 3D network via chemical and hydrogen bonds. • The PVA/KH550 cross-linked aerogel shows a compressive stress of 2.16 MPa at 80 % strain. • This aerogel possesses excellent insulation properties with a low thermal conductivity of 0.0324 W/m·K. • The average sound transmission loss achieves 34.35 dB in the frequency from 800–6300 Hz with a source intensity of 85 dB. [ABSTRACT FROM AUTHOR]

In order to overcome the disadvantage of highly flammable and poor mechanical performance of cellulose aerogel, herein, cellulose nanofibrils (CNF) were cross-linked by melamine formaldehyde (MF), and further cross-linked and surface decorated by methyltrimethoxysilane (MTMS) to obtain flame retarded compound aerogels. FT-IR spectra confirmed that cross-linking reaction occurred between MF/MTMS and CNF matrix. The morphological analysis demonstrated that the pore size shrinked, whereas the pore amount of compound aerogels increased after cross-linking, thereby resulting in the improvement of mechanical performance. Via double cross-linking, the compound aerogels also exhibited excellent hydrophobicity (contact angle up to 132.3°) and flame retardant properties. The limited oxygen index (LOI) value of double cross-linked specimen (Si-CNF/MF) increased from 19.5% to 37.1%, and the vertical combustion test (UL-94) reached V-0 grade. Microcalorimetry measurement showed that the peak heat release rate (pHRR) and total heat release (THR) of Si-CNF/MF decreased by 50.6% and 64.3% in comparison with pure CNF aerogel, respectively. The analysis results of char residue showed that both condensed phase and gas phase flame retardant mechanisms occurred during combustion, and synergistic effect existed between MF and MTMS. Moreover, the very low thermal conductivity of compound aerogels permitted their application as heat preservation materials.

Starch adhesives are promising biomass adhesives. However, their polyhydroxy structure leads to poor water resistance. In this study, DAS-HBP adhesive with a densely cross-linked structure was prepared by reacting dialdehyde starch (DAS) with hyperbranched polyamide (HBP) via the Schiff base. In order to increase the water resistance, glucose was introduced for secondary cross-linking to obtain DAS-HBP-G adhesive with a double cross-linked structure. The cross-linking mechanism of glucose and DAS-HBP was investigated by FTIR, XPS, LC-MS, and 13C NMR. Glucose was oxidized to various aldehyde structures under heating conditions to provide sufficient reactive groups for secondary cross-linking. The introduction of glucose not only reduced the curing temperature of the adhesive and enhanced its thermal stability but, most importantly, substantially enhanced its water resistance. The wet strength of DAS-HBP was 0.72 and 0.67 MPa, respectively, while DAS-HBP-G reached 1.26 and 1.15 MPa. The excellent water resistance is attributed to the synergistic effects of the internal hyperbranched structure of the adhesive, hydrogen bonding, imide, and amide bonding. This double cross-linking strategy provides a potential approach for the development of water-resistant starch adhesives. [Display omitted] • Synthesis of wood adhesives using starch and glucose. • Schiff base reaction strategy and air oxidation crosslinking strategy for the construction of wood adhesives. • Biomass adhesives with excellent boiling water resistance. [ABSTRACT FROM AUTHOR]

In this study, a three‐dimensional nitrogen‐doped graphene (3DNG)‐Fe3+/poly(acrylic acid‐co‐N,N‐dimethylacrylamide) (3DNG‐Fe3+/P(AA‐co‐DMA)) hydrogel with strong flexibility and excellent self‐healing property was prepared. The 3DNG‐Fe3+/P(AA‐co‐DMA) hydrogel was characterized by Fourier transform infrared spectrometer (FT‐IR), scanning electron microscope (SEM). The specific surface area and pore size distribution of the 3DNG‐Fe3+/P(AA‐co‐DMA) hydrogel were measured by using Brunauer‐Emmett‐Teller (BET) method. The experimental results demonstrate that when 6 mol% FeCl3 was added, the breaking strain of Fe3+/P(AA‐co‐DMA) hydrogel reaches 1149 %, and the tensile strength reaches 689 kPa. Furthermore, the recovery degree of Fe3+/P(AA‐co‐DMA) hydrogel was almost 100 % after 24 h. The supercapacitors based on 3DNG‐Fe3+/P(AA‐co‐DMA) hydrogel have a specific capacitance value of 231.8 F g−1 at 1 A⋅g−1, and conductivity is 0.053 S⋅cm−1. When the power density is 5 kW kg−1, the energy density of the device is 38.7 Wh kg−1. [ABSTRACT FROM AUTHOR]

Surface wrinkling structures based on a bilayer system are widely employed in storing and encrypting specific optical information. However, constructing a stable wrinkling structure with high-level security remains an extensive challenge due to the delamination issue between the skin layer and the substrate. Herein, a double cross-linking strategy is introduced between a hydrogel layer doped with fluorescent molecules and polydimethylsiloxane to establish a stable interfacial wrinkling structure with dual-mode functionality, in which the light reflection of the wrinkles and fluorescence intensity of fluorescent molecules can be simultaneously regulated by the modulus ratio between the two layers. The spontaneous wrinkling structures with a physically unclonable function can enhance the photoluminescence emission intensity of the wrinkling area under ultraviolet radiation. Meanwhile, the skin layer constructed of acrylamide and acrylic acid copolymer protects the interfacial wrinkling patterns from the loss of a detailed structure for authentication due to external damage. The stable interfacial wrinkling structures with fluorescence can find potential applications in the fields of information storage and encryption.

[Display omitted] • Insulating and flame-retardant biomass composite aerogels with a double cross-linked gel network structure. • Ca2+ induces a sol-gel process to form a second strong binding layer that supports the aerogel backbone structure. • SAA aerogels have low thermal conductivity, great mechanical strength, and superior flame and smoke retardant properties. • SAA aerogels present desirable self-cleaning and biofriendliness that can be better adapted in different environments. The severe environmental pollution issues require the urgent development of new green building insulation materials. Biomass aerogel is deemed as an optimal candidate to replace petroleum-based insulation materials owing to its significant advantages such as low thermal conductivity, eco-friendliness, and high biocompatibility. The interaction of the composite two-phase interface and the fabrication of multilevel pore structures have a significant impact on the comprehensive performance of aerogel applications. In this study, a tunable double-crosslinked network skeleton structure construction of sodium alginate (SA) composite with Al 2 O 3 fibers is proposed, where Ca2+ induces the sol–gel transition to form a second layer of strong bonding force to effectively support the skeleton structure, and various cross-linking modes, such as ionic bonding, hydrogen bonding and physical cross-linking, are used to synergistically improve the SA aerogel and endow it with multifunctionality. The prepared Al 2 O 3 fiber/SA (SAA) aerogels achieve excellent flame retardancy and self-extinguishing smoke suppression (peak heat release rate as low as 9.7 kW m−2, and total smoke release rate in the low range of 0.5 m2 m−2). It also has superior mechanical strength (high specific compression modulus of ∼53.3 KN m kg−1) and can withstand weights over 2600 times its own weight without deformation, besides the broad range of self-cleaning properties and outstanding biocompatibility. The creation of a double-crosslinked three-dimensional aerogel network via reinforcement of inorganic electrospun fibers provides new insights for eco-friendly insulation materials in construction. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present study is to obtain, for the first time, polymeric nanocarriers based on the chitosan grafted-poly(ethylene glycol) methacrylate derivative. The strategy involves the use of chitosan grafted-poly(ethylene glycol) methacrylate with high solubility in water, obtained via Michael addition, in order to prepare potentially non-toxic micro/nanoparticles (MNPs). By modifying chitosan, its solubility in aqueous media was improved. Micro/nanoparticles-based chitosan grafted-poly(ethylene glycol) methacrylate were obtained under mild condition, with good and controlled swelling properties in acetate buffer solution (ABS) and phosphate buffer solution (PBS). The technique selected for the preparation of the MNPs was a double crosslinking (ionic and covalent) process in reverse emulsion which provide the mechanical stability of the polymeric nanocarrier. The chitosan derivative and MNPs were thoroughly characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM). The Scanning Electron Microscopy photographs revealed that prepared MNPs have different diameters depending on the used stirring rate and polymer concentration. Nanoparticles potential as drug delivery system was analyzed by loading bevacizumab (BEV) a full-length monoclonal antibody. Also, the prepared particles were found suitable from the cytotoxicity and hemocompatibility point of view enabling their potential use as delivery system for the treatment of posterior segment of the eye conditions. Graphical abstract Unlabelled Image Highlights • Chitosan (CS) grafted poly(ethylene glycol) methacrylate (CS- g -PEGMA) was synthesized by Michael addition reaction. • Micro/nanoparticles-based CS- g -PEGMA were prepared via double crosslinking (ionic and covalent) reaction in reverse emulsion. • NPs displayed drug (BEV) release properties showing their potential for treatment of the posterior eye diseases. • In vitro tests showed that the NPs are not cytotoxic and the release BEV was during several days in a controlled manner. [ABSTRACT FROM AUTHOR]

[Display omitted] • Directional freeze-drying technology was applied to the preparation of dressings. • The double cross-linked effect enhanced the strength of the dressings. • Aligned channels allowed anisotropic dressings to absorb exudate effectively. • This dressing could significantly accelerate diabetic wound healing. Excessive biofluid around wounds can cause infection and prevent healing. In this study, an anisotropic quaternized chitosan (QC)/sodium alginate (AL)-based aerogel wound dressing was prepared via a directional freeze-drying technique inspired by the channel structure used for water transport in trees. The aligned channels provided the dressing with self-pumping ability, allowing it to rapidly and completely remove biofluids and absorb biofluids up to 1292.5 % of its own weight. To enhance the strength of the dressing, a double cross-linked network was constructed based on the QC-AL electrostatic attraction and AL-Ca2+ chelation interaction. The axial compressive strength of the double cross-linked dressing reached 207.3 kPa (ε = 50 %). In addition, the dressing exhibited strong conductive properties (conductivity = 13.0 S/m), antioxidant activities [reactive oxygen species (ROS) scavenging ability = 88.0 %], and hemostatic characteristics (blood coagulation index = 1.8 %). The dressing also exhibited powerful antibacterial performance, exhibiting over 98.0 % inhibition of E. coli and S. aureus. Experiments on diabetic mouse models revealed that the dressing considerably promoted wound healing. On day 3, the wound healing rate was 96.7 % faster in the QAC group than in the gauze group. Therefore, the developed dressing may have great potential for chronic wound care. [ABSTRACT FROM AUTHOR]

The aim of the present work is to demonstrate a novel alkaline anion-exchange membrane composed of chitosan (CS) and poly (acrylamid-co-diallyldimethylammonium chloride) (PAADDA) for electrical double layer capacitors (EDLCs). The CS-PAADDA-OH - membranes were prepared through a combined thermal and chemical cross-linking strategy and their physical-chemical properties were investigated. As a notable example, when the mass fraction of PAADDA was about 33%, the CS-PAADDA-OH - membrane exhibits excellent OH − conductivity, reaching high as 0.0151 S cm −1 , while its water uptake is only about 32.23%. Such membrane also showed optimal mechanical property and excellent thermal stability, due to the compact and dense network. Moreover, all the testing membranes showed high oxidative stability in 30% H 2 O 2 solution, and a robust alkaline stability in 8 M KOH at 60 °C for 320 h of evaluation. The resultant EDLC device demonstrated a voltage window at about 1.2 V, sustaining a cycle-life over 2000 cycles. Even when the scan rate is up to 5 V s −1 , the device still maintained excellent rate capability. This study provides feasibility of transforming bulky liquid devices to safer and solid thin devices. [ABSTRACT FROM AUTHOR]

• Stable GO membrane was obtained by double cross-linking method. • High permeability and stability of GSM membrane was fabricated by MoS 2 nanosheets intercalation. • GSM membrane showed high rejection (>99%) and high permeability (112.5 L m−2 h−1 bar−1). • GSM membrane demonstrated excellent stability in water and even in acid and alkali solutions. Graphene oxide (GO)-based membrane has shown great potential in water purification due to its unique physicochemical properties and high permeability. However, it is a challenge to pursue highly permeable GO membranes without compromising stability. Here we employed sodium alginate (SA) together with Ca2+ as cross-linkers to double crosslink GO membrane to obtain stable GS membrane. Further, MoS 2 nanosheets were inserted between GO nanosheets to obtain GSM membrane with high permeability. The double cross-linked MoS 2 intercalation GO membrane, GSM-1:4, showed high removal of multiple dyes (>99%) and enhanced pure water permeance (112.5 L m−2 h−1 bar−1, 1.9 times and 5.8 times of the pure GO membrane and the double cross-linked GS-0.5 membrane, respectively). Meanwhile, the GSM-1:4 membrane demonstrated excellent stability in water and even in acid and alkali solutions. Our work provides new insights into the design of stable and highly efficient GO-based membranes with a two-dimensional layered structure for water treatment. [ABSTRACT FROM AUTHOR]

The increasing accumulation of plastic waste has brought serious environmental issues. Biodegradable plastics are promising candidates to solve the problem but still remain a scientific challenge. Here, xylan plastic (XP) was fabricated by a strategy of double cross-linking through etherification combined with hot pressing. The mechanical properties, particularly the toughness of XP, were significantly enhanced by the incorporation of chemical and physical cross-linking domains. The tensile strength, toughness, and modulus of XP can reach up to 55 MPa, 2.2 MJ/m 3 , and 1.7 GPa, respectively, which are superior to most traditional plastics. Dynamic mechanical analysis (DMA) characterizations confirmed that XP is thermoplastic and can be hot formed. Additionally, the reversible hydrogen bond interaction between xylan chains could be simply regulated by water molecules, rendering XP readily transformed and repeatedly reprogrammed into versatile 2D/3D shapes. Moreover, XP showed a low thermal expansion coefficient and excellent optical properties. Cytotoxicity and degradability tests demonstrated that XP had excellent nontoxicity and can be biodegraded in 60 days. This work thus suggests an avenue for the scalable production of high-performance xylan-based plastics, in which the raw material comes from industrial wastes and exhibits great potential in response to plastic pollution.

The concept of profile control is one of the most important strategies to enhance oil recovery in a high water production field, with polymer gels being used as a gelant matrix in various reservoirs around the globe. In an effort to reach a suitable profile control, previous attempts lead to an increase of polymer concentration, resulting in a poor injection and insufficient in-depth profile control. The work presented here introduces a novel gel system, using both key functional groups on HPAM to react with two types of cross-linking agents. Different formulations and the properties of this double cross-linked HPAM gel system have been studied. The experimental results indicate that the studied double cross-linked HPAM gel system exhibits a higher gel strength, an improved salt and shear resistance as well as an improved plugging effect compared to a single cross-linked HPAM gel system. Moreover, as a result of higher gel strength, the double cross-linked HPAM gel system also shows a longer gelation time, a parameter particularly useful for in-depth profile control. The gel microstructures have been evaluated, with the double cross-linked HPAM gel exhibiting a molecular structure that is more compact. The latter is a clear indication for the improved properties of the system as will be detailed in subsequent sections. [ABSTRACT FROM PUBLISHER]

The formation of double cross-linked (ionic and covalent) gelatin (G) and chitosan (CS) hydrogels was studied. The covalent cross-linking consists in the reaction between the carbonyl groups of glutaraldehyde with the free amine groups from the two polymers; the ionic cross-linking is based on sulfate anions interaction with protonated amine groups of the polymers solubilized in acetic acid. The structural and morphological characterization of the obtained hydrogels was performed using FT-IR and scanning electron microscopy (SEM). The influence of different parameters on the cross-linking density (indirectly assessed by water swelling capacity) and the ability to include hydrosoluble active principles such as the ratio between polymers (G/CS), the amount of ionic cross-linker, and the cross-linking time were investigated. The morphological and structural characteristics, mechanical stability, elasticity of the network, the interaction with aqueous weak alkaline solutions, and the capacity to load and release a model drug were analyzed for the obtained hydrogels. Rheological tests were performed to study the mechanical stability of the hydrogels and the results show, generally, elastic and stable networks. [ABSTRACT FROM PUBLISHER]

Gelatin/chitosan particles suitable for application in ocular drug administration were prepared by a two-step cross-linking process performed in an emulsion-phase separation system. The particles were characterized by scanning electron microscopy and laser diffractometry, and the diameters were 0.202-4.596 mm. The microparticles pH-dependent behavior was monitored by their mean diameter changes in aqueous environment. Adrenalin was drug used to study loading and release characteristics. The prepared particles were nontoxic, with the DL50 values of 6.9-8.19 g/kg body mass. The in vivo biocompatibility tests consisted of subcutaneous administration of a microparticle suspension in physiological serum followed by morpho histological analysis of the implantation site. The in vivo adrenalin ocular delivery was tested on both animals and a voluntary human patient to determine the adrenalin action and by tears. The particles showed good adherent properties without irritation to the patient; adrenalin was released cleared the ocular congestion. [ABSTRACT FROM AUTHOR]

This work prepared a double-cross-linked biohybrid aerogel (DCBA) bead biosorbent from waste bamboo paper and chitosan by sequential physical (hydrogen bonding and electrostatic interaction between -COO- and -NH 3 + groups) and chemical (polymerization reaction between -COOH and -NH 2 , dehydration condensation between Si-OH and -OH) cross-linkings. The resulting DCBA bead was applied to remove cationic (Methylene blue, MB) and anionic (Congo red, CR) dyes in both single and binary systems. The MB and CR adsorption capacities of DCBA bead increased with increasing adsorbent dosage, contact time, temperature and initial dye concentration. With increasing solution pH, the MB adsorption capacity increased, while that for CR increased first and then decreased. The maximal adsorption capacities for MB and CR were 653.3 and 559.6 mg/g, respectively, in the single system. The thermodynamic analysis results showed a spontaneous and endothermic adsorption process. DCBA bead had a good stability and reusability with the removal efficiencies of 49.4% and 60.6% for MB and CR, respectively, after five cycles of adsorption-desorption. In the binary system, the adsorption of MB was inhibited by CR, while the removal of CR was enhanced by MB. • DCBA biosorbent was prepared using double cross-linking method. • The DCBA bead exhibited excellent stability and recyclability. • The maximum adsorption capacities of MB was 653.3 mg/g. • The maximum adsorption capacities of CR was 559.6 mg/g. • The adsorption mechanisms in single and binary systems were investigated. [ABSTRACT FROM AUTHOR]

Ion-exchange membranes (IEMs) are a core component that greatly affects the performance of electrochemical energy conversion processes such as reverse electrodialysis (RED) and all-vanadium redox flow battery (VRFB). The IEMs used in electrochemical energy conversion processes require low mass transfer resistance, high permselectivity, excellent durability, and also need to be inexpensive to manufacture. Therefore, in this study, thin-reinforced anion-exchange membranes with excellent physical and chemical stabilities were developed by filling a polyethylene porous substrate with functional monomers, and through in situ polymerization and post-treatments. In particular, the thin-reinforced membranes were made to have a high ion-exchange capacity and a limited degree of swelling at the same time through a double cross-linking reaction. The prepared membranes were shown to possess both strong tensile strength (>120 MPa) and low electrical resistance (<1 Ohm cm 2 ). As a result of applying them to RED and VRFB, the performances were shown to be superior to those of the commercial membrane (AMX, Astom Corp., Japan) in the optimal composition. In addition, the prepared membranes were found to have high oxidation stability, enough for practical applications.

• Novel aerogels with chemically and physically double cross-linked networks were fabricated. • The aerogel showed ultrahigh compressive modulus of 41.9 MPa. • The aerogel maintained high modulus at high temperatures. • The aerogel showed excellent fire resistance and high-temperature thermal insulation. Aerogels with low density and excellent thermal insulation are seriously plagued by poor mechanical properties with low compressive moduli in the kPa range, especially in extreme conditions such as high temperatures and fires. In this work, a new double chemical cross-linking and physical cross-linking strategy is developed to synthesize ultrahigh-modulus aerogels with extreme-condition resistance from low-cost polyvinyl alcohol (PVA), bio-based phytic acid (PA) and montmorillonite (MMT). The resultant aerogels consist of interpenetrating networks with chemically cross-linked domains between PVA and PA and physically cross-linked domains among PVA, PA and MMT, leading to an ultrahigh compressive modulus of 41.9 MPa and a specific modulus of 455.4 MPa·cm3·g−1, which can even withstand a car crush. Benefitting from the formation of ultra-strong network backbones containing phosphorus and clay, the aerogels amazingly show excellent fire resistance and high-temperature thermal insulation features. This robust porous material can maintain its structural integrity and high modulus (~2 MPa) after exposure to extremely high-temperature flame (~1300 °C), and also exhibits high mechanical modulus of ~4 MPa after heating treatment at 900 °C. These special characteristics make the aerogel a promising insulation candidate in the fields of aviation, aerospace and other applications. [ABSTRACT FROM AUTHOR]

This article focused on the formation, physicochemical properties, and functionality of whey protein isolate (WPI) emulsion gels induced by crosslinking with transglutaminase and/or Ca2+ ions. The emulsion gels were fabricated using the combination of high-energy homogenization and cold-gelation. The microstructure, rheology and processing characteristics of the emulsion gels were then evaluated. Cross-linking with transglutaminase led to the formation of emulsion gels containing small particle aggregates, whereas cross-linking with Ca2+ led to the formation of larger particle aggregates. As expected, the apparent viscosity, strength, water holding capacity and hardness of the emulsion gels increased after crosslinking, especially when transglutaminase and Ca2+ ions were added together. Moreover, WPI hydrogels had higher gel strength in the presence of oil droplets than in their absence, suggesting that the droplets reinforced the gel structure. FTIR confirmed that the crosslinking agents promoted the aggregation of the proteins, thus forming an emulsion gel network. The results of this study may facilitate the design of new food materials with novel or improved textural and sensory characteristics. Image 1 • WPI hydrogel and emulsion gel were prepared by homogenization and cold-gelation. • Double crosslinkers promoted the aggregation of the proteins to form emulsion gel networks. • Emulsion gel exhibited a stronger gel network structure than hydrogel. • Emulsion gel with transglutaminase and calcium ions led to improved functional attributes. [ABSTRACT FROM AUTHOR]

With double cross-linking of chitosan (CS) and sodium alginate (SALG), a colon-targeting CS/SALG hydrogel bead was prepared and used for the colon-targeted release of doxorubicin hydrochloride (DOX). The CS/SALG hydrogel bead showed the improved mechanical property to withstand the simulated colon intestinal fluid (SCF), small intestinal fluid (SIF), as well as gastric fluid (SGF). DOX was released slightly in SGF and SIF and rapidly in SCF, showing a controlled DOX release from the CS/SALG hydrogel bead under different physiological conditions. In vitro cytotoxicity and in vivo toxicity assays indicated that the DOX-loaded CS/SALG hydrogel bead displayed obvious inhibition to tumor cells. These results suggested that the CS/SALG hydrogel bead had the potential application as a colon-targeting oral formulation for DOX transport.

Chromatin immunoprecipitation coupled with high-throughput, next-generation DNA sequencing (ChIP-seq) has enabled researchers to establish the genome-wide patterns of chromatin modifications and binding of chromatin-associated proteins. Well-established protocols produce robust ChIP-seq data for many proteins by sequencing the DNA obtained following immunoprecipitation of fragmented chromatin using a wide range of specific antibodies. In general, the quality of these data mainly depends on the specificity and avidity of the antibody used. However, even using optimal antibodies, ChIP-seq can become more challenging when the protein associates with chromatin via protein-protein interactions rather than directly binding DNA. An example of such a protein is the alpha-thalassaemia mental retardation X-linked (ATRX) protein; a chromatin remodeler that associates with the histone chaperone DAXX, in the deposition of the replication-independent histone variant H3.3 and plays an important role in maintaining chromatin integrity. Inherited mutations of ATRX cause syndromal mental retardation (ATR-X Syndrome) whereas acquired mutations are associated with myelodysplasia, acute myeloid leukemia (ATMDS syndrome), and a range of solid tumors. Therefore, high quality ChIP-seq data have been needed to analyze the genome-wide distribution of ATRX, to advance our understanding of its normal role and to comprehend how mutations contribute to human disease. Here, we describe an optimized ChIP-seq protocol for ATRX which can also be used to produce high quality data sets for other challenging proteins which are indirectly associated with DNA and complement the ChIP-seq toolkit for genome-wide analyses of histone chaperon complexes and associated chromatin remodelers. Although not a focus of this chapter, we will also provide some insight for the analysis of the large dataset generated by ChIP-seq. Even though this protocol has been fully optimized for ATRX, it should also provide guidance for efficient ChIP-seq analysis, using the appropriate antibodies, for other proteins interacting indirectly with DNA.