Search

Collagen nanofibrous materials have become integral to tissue engineering due to their exceptional properties and biocompatibility. Dehydrothermal crosslinking (DHT) enhances stability and maintains structural integrity without the formation of toxic residues. The study involved the crosslinking of electrospun collagen, applying DHT with access to air and under vacuum conditions. Various DHT exposure times of up to 72 h were applied to examine the time dependance of the DHT process. The DHT crosslinked collagen was subsequently chemically crosslinked using carbodiimides. The material crosslinked in this way evinced elevated Young's modulus values and ultimate tensile strength values, a lower swelling rate and lower shrinkage ratio during crosslinking, and a higher degree of resistance to degradation than the material crosslinked solely with DHT or carbodiimides. It was shown that the crosslinking mechanism using DHT occupies different binding sites than those using chemical crosslinking. Access to air for 12 h or less did not exert a significant impact on the material properties compared to DHT under vacuum conditions. However, concerning longer exposure times, it was determined that access to air results in the deterioration of the properties of the material and that reactions take place that occupy the free bonding sites, which subsequently reduces the effectiveness of chemical crosslinking using carbodiimides. [ABSTRACT FROM AUTHOR]

The photosystem I (PSI) of the green alga Chlamydomonas reinhardtii associates with 10 light-harvesting proteins (LHCIs) to form the PSI-LHCI complex. In the context of state transitions, two LHCII trimers bind to the PSAL, PSAH and PSAO side of PSI to produce the PSI-LHCI-LHCII complex. In this work, we took advantage of chemical crosslinking of proteins in conjunction with mass spectrometry to identify protein–protein interactions between the light-harvesting proteins of PSI and PSII. We detected crosslinks suggesting the binding of LHCBM proteins to the LHCA1-PSAG side of PSI as well as protein–protein interactions of LHCSR3 with LHCA5 and LHCA3. Our data indicate that the binding of LHCII to PSI is more versatile than anticipated and imply that LHCSR3 might be involved in the regulation of excitation energy transfer to the PSI core via LHCA5/LHCA3. [ABSTRACT FROM AUTHOR]

Taking type A H1N1 inactivated influenza virus as an example, a rapid detection method with high sensitivity, specificity, biosafety and easy industrialization was established, referred as colorimetric assay using magnetic crosslinking precipitation coupled with gold nanoparticles（MCPGNP）. Firstly, the efficient capture of the inactivated virus was achieved by performing the chemical coupling between the activated carboxyl group on the magnetic bead and the primary amine group of the protein on the surface of the inactivated virus. Secondly, the aptamer was incubated with magnetic beads containing the captured viruses, followed by the magnetic separation and heat elution of the beadbound aptamer. The aptamer specifically recognized the H1N1 inactivated virus. Thirdly, the polymerase chain reaction （PCR） was performed to amplify the eluted aptamer. Finally, the colorimetric detection of the H1N1 inactivated virus was realized, which was based on the different binding affinity of single-strand primers and double-strand amplified products on GNP. When H5N1 inactivated virus was used as the blank control, the detection of limit（S/N=3）was 1 ng/L, which was 1/900 of the detection limit of the specific electrochemical impedance sensor previously reported by our research group. The colorimetric detection of clinical H1N1 inactivated virus positive throat swab samples with low viral load was also achieved for the first time. Under non-optimized conditions, the full process from virus capture to detection was completed within 3 h, demonstrating the clinical application value of MCP-GNP. In addition, all the results of colorimetric detection in this study were consistent with those of fluorescence quantitative PCR, which confirmed the reliability of our method. The core innovation of this work is the use of chemical coupling reaction to conveniently achieve the capture of inactivated virus at ultra-low concentration without the need of viral nucleic acid extraction and enrichment. In addition, the DNA aptamer targeting the H1N1 inactivated virus, instead of the active virus, was used for the specific recognition of the virus, enabling the high biosafety. [ABSTRACT FROM AUTHOR]

The environmental destruction caused by oil pollution has been an inescapable fact, and there is an urgent need for efficient separation materials to solve this problem. Generally speaking, Polyethylene terephthalate (PET) is relatively easy to modify into super-hydrophobic/super-oleophilic membranes due to its hydrophobic ester groups. However, there are some challenges in preparing them as underwater super-oleophobic films. Herein, this paper proposes a two-step coating method for the preparation of underwater super-oleophobic PET films by coating the surface of PET films with silicone to form a cross-linked layer through polymerization (Cross-linking), followed by coating the surface of the cross-linked layer with a fluorinated compound/SiO2 (Coating-F@SiO2). Experiments have shown that the new filter membrane exhibits excellent corrosion resistance and special wettability (> 150°). After 30 filtration cycles, it still maintains excellent oil–water separation efficiency (> 99.9%). This simple method for preparing oil–water separation membrane enriches the treatment process of oil pollution. The large-area and low-cost preparation route also provides a prospect for scalable applications. [ABSTRACT FROM AUTHOR]

Misfolding of mutant Cu/Zn‐superoxide dismutase (SOD1) has been implicated in familial form of amyotrophic lateral sclerosis (ALS). A natively folded SOD1 forms a tight homodimer, and the dimer dissociation has been proposed to trigger the oligomerization/aggregation of SOD1. Besides increasing demand for probes allowing the detection of monomerized forms of SOD1 in various applications, the development of probes has been limited to conventional antibodies. Here, we have developed Mb(S4) monobody, a small synthetic binding protein based on the fibronectin type III scaffold, that recognizes a monomeric but not dimeric form of SOD1 by performing combinatorial library selections using phage and yeast‐surface display methods. Although Mb(S4) was characterized by its excellent selectivity to the monomeric conformation of SOD1, the monomeric SOD1/Mb(S4) complex was not so stable (apparent Kd ~ μM) as to be detected in conventional pull‐down experiments. Instead, the complex of Mb(S4) with monomeric but not dimeric SOD1 was successfully trapped by proximity‐enabled chemical crosslinking even when reacted in the cell lysates. We thus anticipate that Mb(S4) binding followed by chemical crosslinking would be a useful strategy for in vitro and also ex vivo detection of the monomeric SOD1 proteins. [ABSTRACT FROM AUTHOR]

Photo- and chemical crosslinking of proteins have offered various avenues for studying protein structure and protein interactions with biomolecules. Conventional photoactivatable groups generally lack reaction selectivity toward amino acid residues. New photoactivatable groups reacting with selected residues have emerged recently, increasing crosslinking efficiency and facilitating crosslink identification. Traditional chemical crosslinking usually employs highly reactive functional groups, while recent advance has developed latent reactive groups with reactivity triggered by proximity, which reduce spurious crosslinks and improve biocompatibility. The employment of these residue selective chemical functional groups, activated by light or proximity, in small molecule crosslinkers and in genetically encoded unnatural amino acids is summarized. Together with new software development in identifying protein crosslinks, residue selective crosslinking has enhanced the research of elusive protein-protein interactions in vitro, in cell lysate, and in live cells. Residue selective crosslinking is expected to expand to other methods for the investigation of various protein-biomolecule interactions.

Poly(glycerol adipate) (PGA) is one of the aliphatic polyesters of glycerol. The most studied biomedical application of poly(glycerol adipate) is the use of its nanoparticles as drug delivery carriers. The PGA prepolymer can be crosslinked to network materials. The biomedical application of PGA-based network materials has largely remained unexplored till recently. The PGA-based network materials, such as poly(glycerol sebacate) elastomers, can be used in soft tissue regeneration due to their mechanical properties. The modulus of elasticity of PGA elastomers is within the range of MPa, which corresponds to the mechanical properties of human soft tissues. This short review aims at briefly summarizing the possible applications of PGA-based elastomers in tissue engineering, as indicated in recent years in research publications.

Replacing conventional plastics with other products obtained from biobased and biodegradable raw materials is an increasingly studied solution. In this line, the development of protein-based bioplastics is a promising alternative. However, for some applications, such as packaging it would be necessary to improve their properties by including an additional stage to crosslink the protein chains during the production of bioplastics. Therefore, pea protein-based bioplastics crosslinked with genipin, a natural non-toxic chemical crosslinking agent, are evaluated in this study. The bioplastics are obtained via injection moulding and genipin, is included in the initial formulation. Specifically, the concentration of genipin and the effects on the protein blends with genipin over days are evaluated. The evolution of the reaction is followed by the colour change of the blend, together with thermal analyses and infrared spectroscopy. Results showed the evolution of the crosslinking in the blends resulted in conformational changes that resulted in the modification of the initial yellowish colour to a blueish system. Respect their bioplastics, more deformable systems with a lower water absorption capability are obtained by using genipin as crosslinking agent. [ABSTRACT FROM AUTHOR]

Collagen nanofibrous materials have become integral to tissue engineering due to their exceptional properties and biocompatibility. Dehydrothermal crosslinking (DHT) enhances stability and maintains structural integrity without the formation of toxic residues. The study involved the crosslinking of electrospun collagen, applying DHT with access to air and under vacuum conditions. Various DHT exposure times of up to 72 h were applied to examine the time dependance of the DHT process. The DHT crosslinked collagen was subsequently chemically crosslinked using carbodiimides. The material crosslinked in this way evinced elevated Young’s modulus values and ultimate tensile strength values, a lower swelling rate and lower shrinkage ratio during crosslinking, and a higher degree of resistance to degradation than the material crosslinked solely with DHT or carbodiimides. It was shown that the crosslinking mechanism using DHT occupies different binding sites than those using chemical crosslinking. Access to air for 12 h or less did not exert a significant impact on the material properties compared to DHT under vacuum conditions. However, concerning longer exposure times, it was determined that access to air results in the deterioration of the properties of the material and that reactions take place that occupy the free bonding sites, which subsequently reduces the effectiveness of chemical crosslinking using carbodiimides.

Chitosan (CH) is a very well‐known biopolymer that has been widely used for the development of biomaterials with a wide range of applications in the biomedical field, such as the preparation of hydrogels, owing to its outstanding anti‐inflammatory, antibacterial and antifungal properties, biocompatibility and biodegradability, although they present limited mechanical properties. Chemical crosslinking is one of the most recurrent strategies for the reinforcement of these structures and, above all, crosslinking with natural‐origin compounds that do not compromise their biocompatibility is considered a hot topic in this research field. D‐fructose (F), obtained from the hydrolyzation and further isomerization of starch, an abundant raw material and genipin (G), which is extracted from the fruits of Gardenia jasminoides Ellis are used as natural crosslinkers. Chitosan‐based hydrogels crosslinked with each crosslinking agent are prepared and characterized through Fourier transform infrared (FTIR) spectroscopy, crosslinking and swelling degree determination, rheological, microstructural, and biological studies. The results demonstrate that crosslinking with G is more beneficial for chitosan‐based hydrogels since these samples showed more compact structures and better rheological performance. Additionally, excellent biological in vitro behavior due to the crosslinking with G, unlike that of F. [ABSTRACT FROM AUTHOR]

The photosystem I (PSI) of the green alga Chlamydomonas reinhardtii associates with 10 light-harvesting proteins (LHCIs) to form the PSI-LHCI complex. In the context of state transitions, two LHCII trimers bind to the PSAL, PSAH and PSAO side of PSI to produce the PSI-LHCI-LHCII complex. In this work, we took advantage of chemical crosslinking of proteins in conjunction with mass spectrometry to identify protein–protein interactions between the light-harvesting proteins of PSI and PSII. We detected crosslinks suggesting the binding of LHCBM proteins to the LHCA1-PSAG side of PSI as well as protein–protein interactions of LHCSR3 with LHCA5 and LHCA3. Our data indicate that the binding of LHCII to PSI is more versatile than anticipated and imply that LHCSR3 might be involved in the regulation of excitation energy transfer to the PSI core via LHCA5/LHCA3.

Abstract Chitosan (CH) is a very well‐known biopolymer that has been widely used for the development of biomaterials with a wide range of applications in the biomedical field, such as the preparation of hydrogels, owing to its outstanding anti‐inflammatory, antibacterial and antifungal properties, biocompatibility and biodegradability, although they present limited mechanical properties. Chemical crosslinking is one of the most recurrent strategies for the reinforcement of these structures and, above all, crosslinking with natural‐origin compounds that do not compromise their biocompatibility is considered a hot topic in this research field. D‐fructose (F), obtained from the hydrolyzation and further isomerization of starch, an abundant raw material and genipin (G), which is extracted from the fruits of Gardenia jasminoides Ellis are used as natural crosslinkers. Chitosan‐based hydrogels crosslinked with each crosslinking agent are prepared and characterized through Fourier transform infrared (FTIR) spectroscopy, crosslinking and swelling degree determination, rheological, microstructural, and biological studies. The results demonstrate that crosslinking with G is more beneficial for chitosan‐based hydrogels since these samples showed more compact structures and better rheological performance. Additionally, excellent biological in vitro behavior due to the crosslinking with G, unlike that of F.

Abstract This work studied the incorporation of organic acids as crosslinking agents and reaction time on the properties of poly(alcohol vinyl) (PVOH) hydrogels to act as scaffold systems to compounds incorporated into agriculture systems. PVOH hydrogels crosslinked with citric and L-malic acids were prepared, and the effects of heat-treatment time, and temperature on their swelling and hygroscopic performances were investigated by FTIR, thermal analysis and swelling. Both the swelling and rate of water uptake of hydrogels decreased with increasing heat-treatment time. While the swelling decreased with heat-treatment time, the chemical crosslinking shown in FTIR increased. DSC results indicated adsorbed water in the uncrosslinked PVOH and hydrogels, and the absorbed water changed the melting point and glass transition temperature. TGA analysis showed that the incorporation of organic acids brought thermal stability. The results obtained show effective crosslinking hydrogels by L-malic acids and possibilities to use in scaffold systems and controlled release.

BACKGROUND: The usage of natural polysaccharides is attractive to researchers around the world. At the same time, non‐/low‐toxic crosslinkers prepared by polysaccharides are expected to fabricate protein‐based films in many fields. Herein, different dialdehyde polysaccharides (DPs) were successfully synthesized and applied to prepare gliadin‐films under alkaline conditions. The functional properties and formation mechanisms of the films were fully investigated. RESULTS: The results showed that the mechanical properties, water‐resistant properties, thermal stability, and antibacterial properties of the gliadin‐films were improved by DPs and alkali treatment. Particularly dialdehyde dextrin (DAD) crosslinked gliadin‐films showed the highest tensile strength, but no additional effect on their elongation, or advancement on the other functional properties. The film‐forming mechanisms indicated that Schiff base bonds, hydrophobic interactions, electrostatic interactions, and hydrogen bonds were the main forces in the films, supporting their improvement in functional properties. CONCLUSION: DPs, especially DAD, can be a promising crosslinker in fabricating gliadin‐films. These findings have shown great promise to seek an effective crosslinker for fabricating gliadin/protein‐based packaging. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

As vaccine adjuvants, polyacrylate materials can induce a specific immune response in the body and have been widely studied in recent years due to their advantages, such as their safety, effectiveness, and low required dosage. In this study, a series of polyacrylates with hydrophobic physical crosslinking and chemical crosslinking were prepared using precipitation polymerization, and their structures were characterized by nuclear magnetic resonance spectroscopy and Fourier‐transform infrared spectroscopy. The optimal reaction conditions were determined according to the effect of reaction time, azodiisobutyronitrile, Span 60, allyl pentaerythritol, and octadecyl methacrylate (OMA) contents on the viscosity of the polyacrylate microgel, combined with the effects of allyl pentaerythritol and OMA contents on the subcutaneous immune safety of the polyacrylate microgel in BALB/c mice. The polyacrylate microgels with different OMA contents showed good biological safety. In addition, in vivo immunity experiments were carried out in mice to analyze the adjuvant properties of ovalbumin as a model antigen. Based on the titer results of the IgG1 and IgG2a antibodies, with 1 wt % OMA content, the polyacrylate microgel vaccine could optimally induce the body to produce an immune response type dominated by Th2‐type humoral immune response and supplemented by Th1‐type cellular immune response. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office 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.)

Detailed molecular information on G-actin assembly into filaments (F-actin), and their structure, dynamics, and interactions, is essential for understanding their cellular functions. Previous studies indicate that a flexible DNase I binding loop (D-loop, residues 40-50) plays a major role in actin's conformational dynamics. Phalloidin, a "gold standard" for actin filament staining, stabilizes them and affects the D-loop. Using disulfide crosslinking in yeast actin D-loop mutant Q41C/V45C, light-scattering measurements, and cryoelectron microscopy reconstructions, we probed the constraints of D-loop dynamics and its contribution to F-actin formation/stability. Our data support a model of residues 41-45 distances that facilitate G- to F-actin transition. We report also a 3.3-Å resolution structure of phalloidin-bound F-actin in the ADP-Pi-like (ADP-BeFx) state. This shows the phalloidin-binding site on F-actin and how the relative movement between its two protofilaments is restricted by it. Together, our results provide molecular details of F-actin structure and D-loop dynamics.

With the advance of experimental procedures obtaining chemical crosslinking information is becoming a fast and routine practice. Information on crosslinks can greatly enhance the accuracy of protein structure modeling. Here, we review the current state of the art in modeling protein structures with the assistance of experimentally determined chemical crosslinks within the framework of the 13th meeting of Critical Assessment of Structure Prediction approaches. This largest-to-date blind assessment reveals benefits of using data assistance in difficult to model protein structure prediction cases. However, in a broader context, it also suggests that with the unprecedented advance in accuracy to predict contacts in recent years, experimental crosslinks will be useful only if their specificity and accuracy further improved and they are better integrated into computational workflows.

Polyether imide (PEI) flat ultrafiltration membrane was prepared by immersion precipitation phase inversion method. The effects of polymer PEI concentration and additive polyvinylpyrrolidone (PVP) concentration on the structure and properties of membrane were investigated. In order to improve the solvent resistance of ultrafiltration membrane, hexamethylenediamine (HDA) was used for chemical crosslinking, and the difference of membrane performance under different crosslinking time was studied. The results show that the flux of the crosslinked membrane is effectively improved without reducing the membrane separation performance compared with the uncrosslinked ultrafiltration membrane. Under the operating pressure of 0.1 MPa, the flux of pure water is increased from 667.1 L/(m2·h) to 1126.1 L/(m2·h), while the rejection rate of 1.0 g/L BSA solution remains above 97%. After soaking in six different solvents for 48 h, it was found that the uncrosslinked membrane is completely dissolved in N, N-dimethylformamide (DMF), while the crosslinked membrane still maintains a good membrane morphology with an adsorption capacity of 0.86 g/g. The adsorption capacity in ethanol, isopropanol, n-hexane and 1 mol/L HCl solution is smaller than that of the uncrosslinked membrane, but is increased in 1 mol/L NaOH solution, which indicates that the prepared crosslinked membrane has good solvent resistance and strong acid resistance, but the strong alkali resistance becomes worse.

Sustainable materials fabricated from natural polymers have attracted much attentions because of their multiple advantages like abundant renewable resource, biocompatibility, biodegradability, and nontoxicity, while their actually application often restricted by mechanical properties. Chemical crosslinking method was usually used to improve the mechanical properties of cellulose materials such as hydrogel, film, aerogel, and so forth. Here, cellulose fibers were fabricated from cellulose solution in alkali/urea aqueous solvent by chemical crosslinking with epichlorohydrin in a PVC hose. The chemical crosslinked cellulose fibers exhibited smooth surface and circular cross‐section. Their tensile strength increased from 128 to 368 MPa by adjusting cellulose concentration, ECH concentration, and draw ratio. The crystallinity of the fibers changed from 43.1% to 49.8% after drawing process. Meanwhile, the fibers exhibited a brighter color after dyeing than the viscose rayon. This work promising an avenue for preparation of mechanical strong cellulose fibers. [ABSTRACT FROM AUTHOR]

VAR2CSA, a multidomain Plasmodium falciparum protein, mediates the adherence of parasite-infected red blood cells to chondroitin 4-sulfate (C4S) in the placenta, contributing to placental malaria. Therefore, detailed understanding of VAR2CSA structure likely help developing strategies to treat placental malaria. The VAR2CSA ectodomain consists of an N-terminal segment (NTS), six Duffy binding-like (DBL) domains, and three interdomains (IDs) present in sequence NTS-DBL1x-ID1-DBL2x-ID2-DBL3x-DBL4ε-ID3-DBL5ε-DBL6ε. Recent electron microscopy studies showed that VAR2CSA is compactly organized into a globular structure containing C4S-binding channel, and that DBL5ε-DBL6ε arm is attached to the NTS-ID3 core structure. However, the structural elements involved in inter-domain interactions that stabilize the VAR2CSA structure remain largely not understood. Here, limited proteolysis and peptide mapping by mass spectrometry showed that VAR2CSA contains several inter-domain disulfide bonds that stabilize its compact structure. Chemical crosslinking-mass spectrometry showed that all IDs interact with DBL4ε; additionally, IDs interact with other DBL domains, demonstrating that IDs are the key structural scaffolds that shape the functional NTS-ID3 core. Ligand binding analysis suggested that NTS considerably restricts the C4S binding. Overall, our study revealed that inter-domain disulfide bonds and interactions between IDs and DBL domains contribute to the stability of VAR2CSA structural architecture and formation of C4S-binding channel. [ABSTRACT FROM AUTHOR]

Protein crosslinking plays an important role in cereal food processing. In recent years, many studies have been carried out on the crosslinking of cereal proteins. However, it is not clear about the principles and molecular mechanisms of crosslinking of cereal proteins. In this review, three kinds of different methods, including physical cross-linking, chemical cross-linking and enzymatic cross-linking, for enhancing the crosslinking of cereal proteins in cereal food processing were summarized, and their recent advances were discussed. Moreover, the effects of the three kinds of protein crosslinking methods on the structural properties of cereal proteins and related products were analyzed. Finally, the possible problems in these three kinds of protein crosslinking methods were discussed and prospected.

Abstract As vaccine adjuvants, polyacrylate materials can induce a specific immune response in the body and have been widely studied in recent years due to their advantages, such as their safety, effectiveness, and low required dosage. In this study, a series of polyacrylates with hydrophobic physical crosslinking and chemical crosslinking were prepared using precipitation polymerization, and their structures were characterized by nuclear magnetic resonance spectroscopy and Fourier‐transform infrared spectroscopy. The optimal reaction conditions were determined according to the effect of reaction time, azodiisobutyronitrile, Span 60, allyl pentaerythritol, and octadecyl methacrylate (OMA) contents on the viscosity of the polyacrylate microgel, combined with the effects of allyl pentaerythritol and OMA contents on the subcutaneous immune safety of the polyacrylate microgel in BALB/c mice. The polyacrylate microgels with different OMA contents showed good biological safety. In addition, in vivo immunity experiments were carried out in mice to analyze the adjuvant properties of ovalbumin as a model antigen. Based on the titer results of the IgG1 and IgG2a antibodies, with 1 wt % OMA content, the polyacrylate microgel vaccine could optimally induce the body to produce an immune response type dominated by Th2‐type humoral immune response and supplemented by Th1‐type cellular immune response.

In this study, we developed a method to fabricate chitosan-based network polysaccharides via the condensation between amino groups in water-soluble chitosan (WSCS) and a carboxylate-terminated maltooligosaccharide crosslinker. We previously reported on the fabrication of network-polysaccharide-based macroscopic hydrogels via the chemical crosslinking of water-soluble chitin (WSCh) with the crosslinker. Because the molecular weight of the WSCS was much smaller than that of the WSCh, in the present investigation, the chemical crosslinking of the WSCS with the crosslinker was observed at the nanoscale upon the condensation between amino and carboxylate groups in the presence of a condensing agent, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide, affording nano-sized chitosan-based network polysaccharides. The occurrence of the crosslinking via the formation of amido linkages was supported by the IR analysis and 1H NMR measurements after the dissolution via acid hydrolysis in DCl/D2O. The products formed nanogels, whose sizes depended on the amino/carboxylate feed ratio. The nanoscale morphology and size of the products were evaluated via scanning electron microscopy, dynamic light scattering analyses, and transition electron microscopy. In the present study, we successfully developed the method to fabricate nanogel materials based on network polysaccharide structures, which can practically be applied as new polysaccharide-based 3D bionanomaterials. [ABSTRACT FROM AUTHOR]

For the effective clinical antibacterial application of biomaterials, such as for wound management and tissue repair, the biomaterials need to show proper antibacterial capability as well as non-cytotoxicity. Furthermore, the material needs to have suitable mechanical characteristics for further medical use. Chitosan hydrogel is a potential candidate for various antibacterial biomedical applications due to its amine functionalities that lead to antimicrobial characteristics. Nevertheless, its antimicrobial capability is dependent upon the degree of protonation of amine groups caused by the pH value. Moreover, its mechanical compressive strength may not be high enough for clinical use if not chemically or physically crosslinked. This study utilized a novel chemical crosslinker, mercaptosuccinic acid, to improve its mechanical characteristics. The natural antibacterial agent, cinnamaldehyde, was grafted onto the crosslinked chitosan to improve its antimicrobial capability. Meanwhile, to take advantage of the thiol functionality in the mercaptosuccinic acid, the bactericidal silver nanoparticles were incorporated through silver-thiol covalent bounding. NMR analyses indicated the chitosan was successfully mercaptosuccinic acid-crosslinked and grafted with cinnamaldehyde at different ratios. Combined the results from the mechanical assessment, swelling experiments, antimicrobial assessment, and cytotoxicity assay, the chitosan hydrogel with the highest crosslinked degree and grafted with cinnamaldehyde and silver nanoparticles is of great promise for further clinical uses. [ABSTRACT FROM AUTHOR]

Currently, the world faces difficulties related to the quantity and quality of water because of industrial expansion, population growth, and urbanization intensification. Biosorption is considered a promising technology that can be applied to remove toxic metals (TMs) and rare-earth metals (REMs) in wastewater at low concentrations, due to its efficiency and low cost. In this work, we investigated different non-conventional biosorbents to remove metallic ions (TMs and REMs) in biosorptive affinity tests. Metallic affinity assays among lanthanum and different biosorbents showed that greater affinities were found for sericin-alginate beads crosslinked with polyvinyl alcohol (SAPVA) (0.280 mmol/g) and polyethylene glycol diglycidyl ether (SAPEG) (0.277 mmol/g), expanded vermiculite (0.281 mmol/g), Sargassum filipendula seaweed (0.287 mmol/g), and seaweed biomass waste (0.289 mmol/g). Among the biosorbents evaluated, SAPVA and SAPEG beads, besides to sericin-alginate beads crosslinked with proanthocyanidins (SAPAs) were selected for affinity assays with other REMs and TMs. Compared to other particles, SAPVA beads showed higher potential for biosorption by REMs with the following order of affinity: Yb3+ > Dy3+ > Nd3+ > Ce3+ > La3+. Additionally, the biosorptive affinity of TMs by SAPVA beads followed the order: Al3+ > Cr3+ > Pb2+ > Cu2+ > Cd2+ > Zn2+ > Ni2+. [ABSTRACT FROM AUTHOR]

Skeletal muscles exhibit excellent properties due to their well-developed microstructures. Taking inspiration from nature that thick filaments and thin filaments are linked by "cross-bridges", leading to good stability and ion transport performance of muscles. In this work, extracted poplar lignin and microcrystalline cellulose (MCC) were connected by biomimetic covalent bonds, akin to biological muscle tissue, in which isophorone diisocyanate was used as the chemical crosslinking agent. Then, poplar lignin–MCC was mixed with polyacrylonitrile to serve as the precursor for electrospinning. The results show that due to the effective covalent-bond connection, the precursor fibers possess excellent morphology, smooth surface, good thermal stability, and high flexibility and toughness (average elongation-at-break is 51.84%). Therefore, after thermal stabilization and carbonization, derived lignocellulose-based carbon fibers (CFs) with a reduced cost, complete fiber morphology with a uniform diameter (0.48 ± 0.22 μm), and high graphitization degree were obtained. Finally, the electrodes fabrication and electrochemical testing were carried out. The results of electrochemical impedance spectroscopy (EIS) indicate that the Rs and Rct values of CFs supercapacitors are 1.18 Ω and 0.14 Ω, respectively. Results of cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) suggest that these CFs demonstrate great application potential in electrochemical materials. [ABSTRACT FROM AUTHOR]

Siderophores are high-affinity small-molecule chelators employed by bacteria to acquire iron from the extracellular environment. The Gram-negative bacterium Escherichia coli synthesizes and secretes enterobactin, a tris-catechol siderophore. Enterobactin is synthesized by six cytoplasmic enzyme activities: EntC, EntB (isochorismatase (IC) domain), EntA, EntE, EntB (aryl carrier protein (ArCP) domain), and EntF. While various pairwise protein-protein interactions have been reported between EntB, EntA, EntE, and EntF, evidence for an interaction between EntC and EntB has remained elusive. We have employed bacterial two-hybrid assays and in vivo crosslinking to demonstrate an intracellular EntC-EntB interaction. A T18-EntC/T25-EntB co-transformant exhibited a positive two-hybrid signal compared to a control T18-EntC/T25 co-transformant. In vivo formaldehyde crosslinking of E. coli cells co-expressing HA-tagged EntB and H6-tagged EntC resulted in an observable ∼80 kDa band on Western blots that cross-reacted with anti-HA and anti-H6, corresponding to one HA-EntB monomer (33 kDa) crosslinked with one H6-EntC monomer (45 kDa). This band disappeared upon sample boiling, confirming it to be a formaldehyde-crosslinked species. Bands of molecular masses greater than 80 kDa that cross-reacted with both antibodies were also observed. Automated docking of the crystal structures of monomeric EntC and dimeric EntB resulted in a top-ranked candidate docked ensemble in which the active sites of EntC and EntB were oriented in apposition and connected by an electropositive surface potentially capable of channeling negatively charged isochorismate. These research outcomes provide the first reported evidence of an EntC-EntB interaction, as well as the first experimental evidence of higher-order complexes containing EntC and EntB. • A bacterial two-hybrid approach provided evidence for intracellular EntC-EntB proximity. • In vivo crosslinking and Western blotting demonstrated direct intracellular interaction between EntC and EntB. • Docking simulations revealed a possible electrostatically positive tunnel that could facilitate channeling of isochorismate. [ABSTRACT FROM AUTHOR]

Chemically crosslinked acellular bovine pericardium (ABP) has been widely used in clinical practice as bioprostheses. To ensure its consistency and durability, crosslinkers are used in excess, with stability guided by indicators including the hydrothermal denaturation temperature, the enzymatic resistance and the degree of crosslinking. Yet, understanding of the intermolecular structure in collagen fibrils which imparts the intrinsic stability of the ABPs is lacking, and the discrepancies in the stability criteria in varied conditions are poorly explained. In this study, synchrotron small-angle X-ray scattering (SAXS) in combination with thermal and colorimetric methods are employed to investigate the changes in the structure and the stability of ABPs during crosslinking using glutaraldehyde (GA) or 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) at different concentrations. Based on the findings, a mechanism is proposed to explicate the crosslinking effects on collagen structure and the relationship between the structure and each stability indicator. At low crosslinker concentrations, the telopeptidyl-helical linkages are preferred, which cause rearrangements in the intermolecular structure of collagen, and efficiently contribute to its stabilities. Excess crosslinking is revealed by a revert trend in structural changes and the plateauing of the stabilities, assigning to the helical-helical linkages and monovalent bindings. The former would improve thermal stability but not collagenase resistance, whereas the latter have negligible effects. Overall, this study provides a mechanistic understanding of the chemical crosslinking of ABPs, which will contribute to the future development of more efficient and economically viable strategies to produce bioprostheses. Chemical crosslinking imparts suitable properties to acellular bovine pericardium (ABP) for clinical applications, yet the understanding is lacking on the structure-stability relationship especially under different crosslinking conditions. Structural evidence in this study differentiates the binding sites during crosslinking in collagen fibrils at different crosslinker concentrations, highlighting the excess usage in the conventional crosslinking treatments. The mechanism based on the structure of collagen also successfully explains the dissimilarity in hydrothermal and enzymatic stabilities with varied crosslinking conditions. Future researches focusing on developing biomaterials via chemical crosslinking of ABPs would benefit from this study, for its contribution to the better understanding of the relationship of collagen structure and functions. [Display omitted] [ABSTRACT FROM AUTHOR]

Porous starch materials are promising in several applications as renewable natural biomaterials. This study reports an approach combining methacrylation of starch and chemical crosslinked cryogelation to fabricate highly elastic macroporous starch (ST-MA) cryogels with impressed water/oil absorption capacity and wet thermal stability among starch based porous materials. Five different types of starch, including pea, normal corn, high amylose corn, tapioca, and waxy maize starch with different amylose content, have been studied. The methacrylation degree is not related with amylose content. All cryogels exhibited excellent compressive elasticity enduring 90 % deformation without failure and good robustness in cyclic tests. The ST-MA cryogels from pea starch exhibited the highest Young's modulus and compressive strength among five types of starch. These covalent cryogels exhibit high wet-thermal stability and enzymatic hydrolysis stability, while still are biodegradable. The dry ST-MA sponges (2 wt%) showed outstanding liquid absorption capacity, absorbing ~40 folds (g/g) of water or ~ 36 folds (g/g) of oil respectively. All types of starch have similar liquid absorption performance. This study provides a universal approach to fabricate highly elastic covalent starch macroporous materials with impressed liquid absorption capacity and outstanding stability, especially wet-thermal stability, and may expand their applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• The AlCl 3 /ZnCl 2 /H 2 O system is both a solvent for cellulose dissolution and a catalyst for ring-opening of epoxides. • The dissolution and chemical crosslinking of cellulose occur simultaneously and at room temperature. • The "one-pot" method of dissolving and crosslinking cellulose is universal to different epoxide crosslinkers. • Chemical crosslinking improves both mechanical properties and wet stability of cellulose films. • Cellulose films can be dissolved and reused again without degradation of mechanical properties. Cellulose has gained significant attention for its abundant sources, degradability, and biocompatibility in achieving the sustainable development goals. However, the mechanical and waterproof qualities of cellulose-based polymers are typically suboptimal, thereby constraining their potential for high-value applications. Moreover, the problematic recovery of cellulose solvents is challenging for resources and the environment. The aluminum chloride/ zinc chloride/ water (AlCl 3 /ZnCl 2 /H 2 O) system was utilized as the cellulose dissolving solvent and the chemical crosslinking catalyst in this investigation, enabling the production of high-performance cellulose films through a "one-pot" approach. By opening the ring in an acidic solution with epichlorohydrin (EPI), 1, 4-butanediol diglycidyl ether (BDDE), or polyethylene glycol diglycidyl ether (PEGDGE), efficient chemical crosslinking was achieved, reducing the number of reagents and optimizing the film performance in all aspects. The film tensile stress reached 197.37 MPa and elongation at break reached 33.13 %. Furthermore, after soaking in water for 180 days, the films exhibited good water stability without any evident swelling behavior. After being buried in the soil for 20 days, such films could be totally degraded. Moreover, the films could redissolve in the AlCl 3 /ZnCl 2 /H 2 O system without weakening mechanical properties. This safe cellulose film was a more environmentally friendly alternative to plastic packaging film. Furthermore, the AlCl 3 /ZnCl 2 /H 2 O system exhibited high recyclability, with salt recovery reaching 83% of the initial fresh solvent after five cycles. The excellent efficiency of the crosslinking approach and the overall greenness of the process present a novel notion for further research. [ABSTRACT FROM AUTHOR]

In the realization of the goal of circular economy, cellulose as one of sustainable biomass resources, have attracted much attention because of their abundant sources, biodegradability and renewability. However, the mechanical and waterproof performance of cellulose-based materials are usually not satisfying, which limits their high-value utilization. In this study, cellulose membrane with high-performance from the aspects of mechanical properties, water-resistance ability, oxygen barrier capacity and biodegradability, was prepared from bleached hardwood pulp (HBKP) in a AlCl 3 /ZnCl 2 /H 2 O solution. The AlCl 3 /ZnCl 2 /H 2 O acted as both solvent and catalyst to dissolve cellulose and facilitate the chemical crosslinking of epichlorohydrin (EPI) with cellulose, thus improved the overall performance of the obtained cellulose membrane. The addition sequence, amount and crosslinking time of EPI during chemical crosslinking had important effects on the properties of the membranes. When 7 wt% EPI was crosslinked for 24 h, the tensile stress reached 133 MPa and the strain reached 17 %. Moreover, the membrane had excellent oxygen insulation down to (1.1 ± 0.31) × 10−4 cm3/m2·d·Pa, and good water-resistance ability, no obvious swelling behavior after 450 days of immersion in distilled water. Furthermore, the membrane could be degraded by microorganisms in about 20 days. This cellulose-based membrane offers a sustainable and biodegradable packaging material. [ABSTRACT FROM AUTHOR]

• A covalent micro-crosslinking and hydrophobic association dual cross-linked copolymer AAS-L 4% -M 0.5‰ was synthesized as filtration reducer in drilling fluid. • The synergistic effects of covalent crosslinking and hydrophobic association on enhancing the performance of polymeric filtrate reducers was explored. • The polymeric filtrate reducer maintains excellent filtration properties under conditions of 200 °C and 36 wt% NaCl. • The dual-crosslinked copolymer filtrate reducers could minimize the unwanted foaming. Traditional linear polymeric filtrate reducers for water-based drilling fluids (WBDFs) are insufficient for drilling engineering requirements, even with adjustments in the type and proportion of functional groups in the copolymer, especially under high-temperature and high-salinity conditions. In this study, a dual cross-linked copolymer (named AAS-L 4% -M 0.5‰) was synthesized through free radical copolymerization using lauryl methacrylate (LMA) as hydrophobic associated segments and N, N '-methylene bisacrylamide (MBA) as the chemical crosslinker. The synergistic effect of covalent micro-crosslinking and hydrophobic association in AAS-L 4% -M 0.5‰ were systematically investigated and demonstrated. After aging at 220 °C for 16 h, the WBDFs containing 1 % AAS-L 4% -M 0.5‰ exhibited high-temperature/high-pressure filtration loss (FL HTHP) and American Petroleum Institute filtration loss (FL API) of 34 mL and 10 mL, respectively, representing reductions of 50 % and 38 % compared to the linear polymer AAS-L 0 -M 0. Even after aging at 200 °C in saturated salt solution conditions, the WBDFs containing AAS-L 4% -M 0.5‰ maintain excellent filtration properties with FL API value of 7.5 mL, achieving an 83 % reduction compared to AAS-L 0 -M 0. Moreover, because of the three-dimensional spatial network structure formed by dual cross-linking, AAS-L 4% -M 0.5‰ effectively inhibits unwanted foaming caused by the polyelectrolyte effect. Therefore, this work provides a simple but effective approach to develop temperature-resistant and salt-tolerant filtrate reducers with excellent workability. [ABSTRACT FROM AUTHOR]

Tremella polysaccharide (TP), one kind of green natural polysaccharide, exhibits different superior physical properties, which is a good choice to construct environmental‐friendly hydrogels. In the present study, TP hydrogels were designed with a "one‐step" approach, which via simply mixing TP solutions with different concentration of N,N‐methylenebis(acrylamide) (MBA) in NaOH/H2O solvent system. The experimental results showed that the NaOH concentration (1 %, 5 %, 10 %) and MBA concentration (6 mg/mL, 12 mg/mL and 18 mg/mL) had important influence on the gelation process of TP‐MBA hydrogels. When the concentrations of NaOH and MBA were 5 % and 18 mg/mL, respectively, the TP‐MBA hydrogel presented the shortest gelation time (2.5 h) and highest crosslinking density. Besides, the hydrogel formation mechanism was determined which suggested that the addition reaction between the −OH groups of tremella polysaccharide and the −C=C− bonds of MBA contributed to the formation of TP‐MBA hydrogels. In conclusion, this paper introduced a simple, efficient and green method for preparation of tremella polysaccharide‐based hydrogels. [ABSTRACT FROM AUTHOR]

In this study, a hybrid filler comprising cellulose nanofiber (CNF) and boron nitride (BN) (CNF-BN) was fabricated through the ball milling exfoliation method by introducing oxalic acid to provide hydroxyl groups, leading to better compatibility between CNF and BN via hydrogen bonding. After functionalization and CNF grafting, the filler was dispersed sufficiently into the CNF matrix with tetraethyl orthosilicate for chemical crosslinking. The c–CNF–BN/CNF film was then fabricated by vacuum infiltration. The voids and defects of the film surface decreased due to the tangled cellulose nanofiber with the help of a crosslinking agent, facilitating the construction of an efficient heat pathway. As a result, the through-plane thermal conductivity increased from 0.5 W m − 1 K − 1 to 1.69 W m − 1 K − 1 with 37.5 vol% BN loading, showing a thermal conductivity enhancement of 238% compared to the raw CNF film. Additionally, the mechanical property was also enhanced. The tensile stress was 42.2 MPa and elongation at break was 36.8%. Thus, the c–CNF–BN/CNF film can be used as a composite for efficient thermal management in electronic devices. [ABSTRACT FROM AUTHOR]

The electrostatic effects of protein crowding have not been systematically explored. Rather, protein crowding is generally studied with co‐solvents or crowders that are electrostatically neutral, with no methods to measure how the net charge (Z) of a crowder affects protein function. For example, can the activity of an enzyme be affected electrostatically by the net charge of its neighbor in crowded milieu? This paper reports a method for crowding proteins of different net charge to an enzyme via semi‐random chemical crosslinking. As a proof of concept, RNase A was crowded (at distances ≤ the Debye length) via crosslinking to different heme proteins with Z = +8.50 ± 0.04, Z = +6.39 ± 0.12, or Z = −10.30 ± 1.32. Crosslinking did not disrupt the structure of proteins, according to amide H/D exchange, and did not inhibit RNase A activity. For RNase A, we found that the electrostatic environment of each crowded neighbor had significant effects on rates of RNA hydrolysis. Crowding with cationic cytochrome c led to increases in activity, while crowding with anionic "supercharged" cytochrome c or myoglobin diminished activity. Surprisingly, electrostatic crowding effects were amplified at high ionic strength (I = 0.201 M) and attenuated at low ionic strength (I = 0.011 M). This salt dependence might be caused by a unique set of electric double layers at the dimer interspace (maximum distance of 8 Å, which cannot accommodate four layers). This new method of crowding via crosslinking can be used to search for electrostatic effects in protein crowding. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office 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.)

Considering that fruits are vulnerable to damage and waste during stockpiling, transport and marketing. Given this, an innovative curcumin inclusion compound (Cur@β-CD) was devised in this study to introduce oil-soluble curcumin (Cur) into water-soluble polyvinyl alcohol (PVA) materials, thereby fabricating food packaging films endowed with excellent properties. DPPH test manifested that the oxidation resistance for PCOMC-Cur@β-CD film was 95 % above PVA material. It was ascribed to the fact that the Cur@β-CD elevated the water solubility of Cur while the increase of water solubility heightened the antioxidant effect for Cur in the film. Additionally, the chitosan (CS) was crosslinked with malic acid (MA), which elevated the barrier property of the film, reduced the amount of oxygen transmission and further retarded the oxidation reaction of the fruits for packaging. The antibacterial test demonstrated that the antibacterial rates of PCOMC-Cur@β-CD film against E. coli and S. aureus reached 92 % and 95 %, respectively, which was attributed to the slow release of Cur when Cur@β-CD was dissolved in PVA material and the Schiff base reaction between Cur and amino groups on CS. These findings indicate that the PCOMC-Cur@β-CD film developed in this work can provide certain insights into the field of food packaging., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

This study evaluates the effects of different aqueous borax solutions on the morphology, mechanical, thermal and chemical properties of regenerated cellulose fiber woven fabric reinforced hydrogel composites. The fabric reinforced hydrogel composites were fabricated with PVA/viscose ring, PVA/viscose open-end (viscose OE), PVA/viscose continuous filament (viscose CF) blended woven fabrics. Mechanical tests results showed that regenerated cellulose fiber woven fabric reinforced hydrogel composites made from PVA/viscose CF (380 N) exhibited better mechanical performance than its viscose ring (258 N) and viscose OE (318 N) counterparts. Another significant result, evaluated using statistical package for social sciences (SPSS) data analysis showed that there was a high level positive and meaningful relationship between borax-water concentration and breaking force at the breaking points of regenerated cellulose woven fabric reinforced hydrogel composites in the warp direction. The results have suggested that the regenerated cellulose fabric reinforced hydrogel composites with enhanced mechanical properties could be used as agricultural water retention materials and in geotextiles applications. [ABSTRACT FROM AUTHOR]

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS 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.)

With the aim of effectively improving the performance of bio-friendly food packaging and circumventing the hazards associated with petroleum-based plastic food packaging, composite films of corn starch and polyvinyl alcohol were prepared using a new method that involved chemical cross-linking of glutaraldehyde and blending with cinnamon essential oil nanoemulsion (CNE). Glutaraldehyde and CNE enhance the film's network structure by chemical bonding and hydrogen bonding, respectively. This results in improved surface smoothness, mechanical properties, and UV shielding ability of the film. However, the films' surface hydrophilicity increased as a result of CNE, which is harmful for food preservation in high humidity. Overall, glutaraldehyde and CNE have a synergistic effect on some of the properties of the film which is mainly attributed to the films' structure improvement. The films have great potential for preparing flexible and UV-shielding films and offer new ideas for developing biodegradable films. [Display omitted] • Effect of glutaraldehyde (GLU) and nanoemulsion (CNE) on the film was studied. • GLU brings polymer chains closer together through covalent bonding. • CNE populated the interior of the matrix by hydrogen bonding. • GLU and CNE showed synergistic effects on structure and mechanics of the film. • The prepared films present improved toughness and UV shielding capacity. [ABSTRACT FROM AUTHOR]

This work used a proper content of citrus fiber (10 wt% ∼ 30 wt%, dry starch base) to improve the cell structures and functions of starch foam. The insoluble fiber promoted cell nucleation in the starch melt, whereas the soluble pectin improved the starch matrix's strength by forming ester bonding with starches as confirmed by FTIR results. This effectively modified the starch foaming process and endowed the obtained foams with an increased cell density (from 83.37 to 123.44 cell/cm3×104) and a reduced foam density (from 0.457 to 0.142 g/cm3). The foam containing 20 wt% citrus fiber exhibited the highest expansion ratio of 5.20. Due to the improved structures and the tortuous path effect of cellulose crystals, the prepared foams significantly presented a strengthened compression performance and improved moisture resistance. Meanwhile, the fiber-loaded foams displayed a high free radical-scavenging activity (60.30 % ∼ 85.75 %), showing good antioxidant activity. It is therefore believed that this study could provide a facile and green way for producing starch-based foams with desirable functions. [Display omitted] • Citrus fiber effectively improved the starch-based foam's structures and functions. • The insoluble fiber promoted cell nucleation during starch foaming. • Esterification crosslinking formed in the foam. • Compression and moisture resistance of the starch foam improved with fiber increasing. • Lignin endowed the developed foam with high antioxidant activity. [ABSTRACT FROM AUTHOR]

Hydrogels have found significant applications in flexible sensing due to their tunable modulus and excellent conformability to human skin. However, petroleum-based hydrogels (PPH), due to their origins from increasingly scarce petroleum resources and poor biocompatibility, still face limitations in widespread applications for detecting physiological signals in the human body. It is highly desirable to overcome these drawbacks and utilize new environmentally friendly materials. Hydrogels based on nanocellulose material (NCM) as fillers or substrates, are emerging as the most promising candidates for the next generation of flexible sensors, owing to their wide availability and excellent biocompatibility. This overview highlights the latest progress in utilizing nanocellulose-based hydrogel (NCH) to fabricate flexible sensors with diverse functionalities. We first provide a brief introduction of three types of NCM, including cellulose nanocrystal (CNC), bacterial cellulose (BC), and cellulose nanofibril (CNF). Following a discussion on the fundamental material characteristics essential for synthesizing flexible sensors, we outline the design principles and cross-linking strategies for hydrogels rooted in NCMs. Subsequently, we focus on the working principles and performance characteristics of flexible sensors for physical and chemical signals. Lastly, we summarize the challenges and prospects in the advancement of flexible sensors based on NCMs. [Display omitted] • Elucidated the design principles and general trends of nanocellulose based hydrogel (NCH). • High-performance NCHs based on different crosslinking strategies are detailed. • The application of NCHs in flexible sensors are summarized. • Several existing challenges are discussed and mitigation strategies are proposed. [ABSTRACT FROM AUTHOR]

The small ubiquitin-like modifier (SUMO) is involved in various cellular processes and mediates known non-covalent protein-protein interactions by three distinct binding surfaces, whose interactions are termed class I to class III. While interactors for the class I interaction, which involves binding of a SUMO-interacting motif (SIM) to a hydrophobic groove in SUMO-1 and SUMO-2/3, are widely abundant, only a couple of examples have been reported for the other two types of interactions. Class II binding is conveyed by the E67 loop region on SUMO-1. Many previous studies to identify SUMO binders using pull-down or microarray approaches did not strategize on the SUMO binding mode. Identification of SUMO binding partners is further complicated due to the typically transient and low affinity interactions with the modifier. Here we aimed to identify SUMO-1 binders selectively enriched for class II binding. Using a genetically encoded photo-crosslinker approach, we have designed SUMO-1 probes to covalently capture class II SUMO-1 interactors by strategically positioning the photo-crosslinking moiety on the SUMO-1 surface. The probes were validated using known class II and class I binding partners. We utilized the probe with p-benzoyl-phenylalanine (BzF, also termed BpF or Bpa) at the position of Gln69 to identify binding proteins from mammalian cell extracts using mass spectrometry. By comparison with results obtained with a similarly designed SUMO-1 probe to target SIM-mediated binders of the class I type, we identified 192 and 96 proteins specifically enriched by either probe, respectively. The implicated preferential class I or class II binding modes of these proteins will further contribute to unveiling the complex interplay of SUMO-1-mediated interactions.

Abstract Stretchable hydrogels have been used for a number of biomedical applications. This research focused on the study of a highly stretchable and tough hydrogel made of gelatin and polyacrylamide towards transdermal drug delivery applications. Four drug compounds, nicotine, lidocaine hydrochloride, diltiazem hydrochloride and diclofenac sodium, were used for the evaluation. The release rates of these compounds follow an order: lidocaine > diltiazem > nicotine > diclofenac, which showed a strong correlation between the release rate with their solubility in water at pH 5.5. The kinetics study showed a linear and sustainable release of all tested drugs in the first 8 hours. Experiments were conducted in vitro on replicated human skin. Cytotoxicity studies indicate hydrogel is nontoxic to human cells. The highly stretchable and tough characters of the hydrogel the strength of the hydrogel reduce the severity of wear and tear issues over time for transdermal drug release.

As an essential representative of novel anode materials with high capacity and safe voltage, Li 3 VO 4 (LVO) still suffers from the challenges of low electronic conductivity and low tap density of nanostructures. Herein, a strategy of nanoization and recombination is proposed to synthesize the integrated LVO and boron doped carbon microspheres (LVO/BC-MS-550) with high tap density via a chemical crosslink method to improve the Li-ion storage performance. LVO/BC-MS-550 is consisted of the well-dispersed LVO nano-crystals in tightly stacked carbon spheres derived from the cross-linked network of boric acid (BA) and polyvinyl alcohol (PVA). By introducing conductive and continuous carbon framework, the LVO crystals are controlled to grow in the confined region with mitigated volume changes, as well as the enhanced electronic conductivity. Benefiting from the constructive advantages, LVO/BC-MS-550 anode delivers a specific capacity of 512.1 mAh g−1 at the current density of 0.2 A g−1 (0.34 C) after 300 cycles, and ultra-long cycling performance of 231.8 mAh g−1 over 5000 cycles at the charging/discharging current density of 4/2 A g−1, exhibiting rapid pseudo-capacitance reaction kinetics. This work provides valuable insights into the fabrication of in situ three-dimensional crosslinked carbon and LVO composites for alternative grid-scale electrochemical applications. • LVO/BC-MS-550 microsphere was fabricated by chemical crosslinking. • LVO/BC-MS-550 exhibited high tap density and electrical conductivity. • LVO/BC-MS-550 exhibited good ion diffusion kinetics and mechanical stability. • LVO/BC-MS-550 exhibited high-rate capacity with long life. [ABSTRACT FROM AUTHOR]

Organic solvent ultrafiltration (OSU) membrane as the crucial supporting layer of thin-film composite (TFC) organic solvent nanofiltration (OSN) membrane can help the OSN technology to satisfy the rapidly growing demand for small-molecular separation and purification in organic solvent systems. Aiming at the two main bottlenecks of poor tolerance to strong polar solvents and low solvent flux of the conventional commercial polyimide (PI) ultrafiltration (UF) membrane, in this study, a facile method was proposed to prepare a novel polyimide/polyethyleneimine@TiO2 (PI/PEI@TiO2) OSU membrane with improved solvent resistance and permeability by synchronously coupling the non-solvent-induced phase transformation (NIPs), chemical crosslinking and interfacial in-situ biomineralization. Dut to the chemical crosslinking between PEI and PI, the PI/PEI@TiO2 membrane exhibited good resistance to more organic solvents including the strong polar aprotic solvents (e.g., DMF, NMP and DMSO), ordinary polar solvents (e.g., ethanol) and nonpolar solvents (e.g., n-hexane). At the same time, PEI synchronously catalyzed Ti-BALDH to in-situ generate the TiO2 nanoparticles via interfacial biomineralization, which improved the solvent flux of the PI/PEI@TiO2 membrane due to the creation of more channels and promoted the compatibility of TiO2 within PI/PEI matrix. Especially, the PI/PEI@TiO2-5 membrane with 5 wt% TiO2 loading showed the optimal solvent resistance and high flux in strong polar aprotic solvents (>50 L m−2 h−1·bar−1 in DMF). Therefore, the resultant new PI/PEI@TiO 2 OSU membrane will have a promising separation application in the organic solvent systems in the future. A novel organic solvent ultrafiltration membrane of polyimide/polyethyleneimine@TiO 2 (PI/PEI@TiO 2) was fabricated by synchronously coupling the non-solvent-induced phase transformation (NIPs), chemical crosslinking and interfacial in-situ biomineralization processes. The resultant PI/PEI@TiO 2 UF membrane exhibited good resistance to more organic solvents including the strong polar aprotic solvents (e.g., DMF, NMP and DMSO), ordinary polar solvents (e.g., ethanol) and nonpolar solvents (e.g., n-hexane), and high flux of strong polar aprotic solvents without sacrificing the molecular weight cutoff. [Display omitted] • A PI/PEI@TiO 2 membrane was fabricated by coupling the NIPs, chemical crosslinking and interfacial biomineralization. • The PI/PEI@TiO 2 membrane exhibited good resistance to more organic solvents including strong polar and non-polar solvents. • The PI/PEI@TiO 2 membrane showed high flux of strong polar aprotic solvents as well as lower MWCO. • The PI/PEI@TiO 2 membrane presented favorable long-term separation stability in strong polar aprotic solvent. [ABSTRACT FROM AUTHOR]

Developing scalable and durable superhydrophobic (SH) coatings in harsh rainy/icy/abrading environments is attractive for various applications, yet has proven challenging. Here we report an ultra-robust SH coating via physical bonding and chemical crosslinking of polystyrene microspheres (PS MPs). The facile preparation includes co-spray of PS MPs and perfluorinated nanoparticles, hot-press and thermal evaporation. The 3D interconnected polymeric network is enhanced due to the semidissolving-based bonding and Friedel-Crafts reaction-based chemical crosslinking of PS MPs. Compared with the pristine SH coatings, the durability of our SH coating is increased by 2230%, 340% and 1440% through bidirectional abrasion, water impact and freeze-thaw tests, respectively. Both the facile fabrication and the great durability highlight their applications in anti-icing, anti-corrosion, self-cleaning, etc. Our strategy provides a generic design for multifunctional engineering durable coatings based on polymeric network. [Display omitted] [ABSTRACT FROM AUTHOR]