Interactions Including Hydrogen Bonds Research Articles

Mannich Base Derived from Lawsone Inhibits PKM2 and Induces Neoplastic Cell Death.

Background/Objectives: Pyruvate kinase M2, a central regulator of cancer cell metabolism, has garnered significant attention as a promising target for disrupting the metabolic adaptability of tumor cells. This study explores the potential of the Mannich base derived from lawsone (MB-6a) to interfere with PKM2 enzymatic activity both in vitro and in silico. Methods: The antiproliferative potential of MB-6a was tested using MTT assay in various cell lines, including SCC-9, Hep-G2, HT-29, B16-F10, and normal human gingival fibroblast (HGF). The inhibition of PKM2 mediated by MB-6a was assessed using an LDH-coupled assay and by measuring ATP production. Docking studies and molecular dynamics calculations were performed using Autodock 4 and GROMACS, respectively, on the tetrameric PKM2 crystallographic structure. Results: The Mannich base 6a demonstrated selective cytotoxicity against all cancer cell lines tested without affecting cell migration, with the highest selectivity index (SI) of 4.63 in SCC-9, followed by B16-F10 (SI = 3.9), Hep-G2 (SI = 3.4), and HT-29 (SI = 2.03). The compound effectively inhibited PKM2 glycolytic activity, leading to a reduction of ATP production both in the enzymatic reaction and in cells treated with this naphthoquinone derivative. MB-6a showed favorable binding to PKM2 in the ATP-bound monomers through docking studies (PDB ID: 4FXF; binding affinity scores ranging from -6.94 to -9.79 kcal/mol) and MD simulations, revealing binding affinities stabilized by key interactions including hydrogen bonds, halogen bonds, and hydrophobic contacts. Conclusions: The findings suggest that MB-6a exerts its antiproliferative activity by disrupting cell glucose metabolism, consequently reducing ATP production and triggering energetic collapse in cancer cells. This study highlights the potential of MB-6a as a lead compound targeting PKM2 and warrants further investigation into its mechanism of action and potential clinical applications.

Functionalization and morphology control of graphene oxide for intelligent barrier coatings against corrosion

Designing intelligent fillers for high-performance corrosion protection coatings, especially for the strong corrosion harsh environment of desulfurized flue gas, remains a huge challenge. In this paper, a novel graphene-based intelligent nanofiller with tunable morphology was successfully synthesized via a self-assembly strategy. Using polydopamine (PDA) as gatekeeper, the mesoporous silica nanocontainer (MSNs) was loaded with the corrosion inhibitor benzotriazole (BTA), preparing the pH response MSNs-BTA/PDA (PBM) nanocontainers. Graphene oxide (GO) was modified by PBM through non-covalent interactions including hydrogen bond and π-π stacking. A self-unfolding GO/PBM (GO@PBM-5) was obtained through adjusting the ratio of GO to PBM. The active/passive corrosion protection properties of the novolac epoxy coating (EPN) are endowed by the GO@PBM-5 intelligent nanofiller with a self-unfolding structure, which can be ascribed to the corrosion inhibition and labyrinth effect. As a result, the value of |Z|0.01Hz of coating reinforced with GO@PBM-5(GO@PBM-5/EPN) remained above 1010 Ω cm2 after immersion in 10 wt% H2SO4 solution at 55 °C for 60 days. The thermal conductivity of GO@PBM-5/EPN is 0.312 W m−1 K−1. In addition, no cracking occurred after 400 cycles of −60–140 °C cold-thermal shock. Moreover, the GO@PBM-5/EPN is intact and no rust spots, bubbles, or peeling occur after the salt spray test for 14 days. Showing extremely strong barrier performance as well as thermal conductivity, cold-thermal shock resistance and high self-healing properties. This study opens a new avenue for improving the service life of organic coating in the strong corrosion environment of desulfurized flue gas.

An in silico study of new 1-aminoquinoline-2(1H)-one derivatives as tyrosine kinase inhibitors

The field of oncology has been revolutionized by the discovery and development of targeted therapies for cancer. A study focuses on the development of tyrosine kinase inhibitors (TKIs) as effective targeted therapies. Although TKIs have shown promise in targeting cancer cell signaling pathways, the emergence of resistance poses a significant challenge, necessitating the development of novel and potent inhibitors. Virtual docking simulations, which use molecular docking algorithms and scoring functions, predict how these TKIs bind to the enzyme and assess their binding strength. Preliminary results show that several of the designed TKIs have a strong binding affinity and form key interactions with the target tyrosine kinase. These interactions include hydrogen bonds, hydrophobic interactions, and electrostatic interactions, which are crucial for stabilizing the complex between the TKI and the enzyme. Additionally, the study identifies specific amino acid residues within the tyrosine kinase binding site that enhance the binding affinity of the TKIs. This detailed information is valuable for further optimizing TKI design and developing more effective inhibitors with improved binding properties.

Synthesis, crystal structure, Hirshfeld surface analysis, DFT studies and biological evaluation of bis(acetonitrile)bromido(η6-1-isopropyl-4-methylbenzene)osmium(II) hexafluoroantimonate

The complex bis(acetonitrile)bromido(η6-1-isopropyl-4-methylbenzene)osmium(II) hexafluoroantimonate, [OsBr(C10H14)(CH3CN)2]SbF6 (1) crystallizes as a triclinic system in space group P1 (no. 2), consisting of two cationic osmium(II) complex ions and two anionic hexafluoroantimonate counterions in each cell. Density Functional Theory (DFT) calculations were performed at the B3LYP/LanL2DZ and B3LYP/Def2 − SVP/Def2 − TZVP levels of theory. Reactivity descriptors and charge transfer properties were computed using frontier molecular orbital analysis. The DFT-optimized model systems from both basis sets were comparable to the experimentally determined X-ray diffraction results. Hirshfeld surface analysis shows significant non-covalent interactions including hydrogen bonds and halogen interactions. The MTT technique was utilized to conduct an in vitro cytotoxicity assay of 1 against cancerous cell lines (MCF-7 and A549) and normal cells (HEK293). Complex 1 is potent towards cancer cells as evidenced by the IC50 values of 5.02 ± 0.05 µM for MCF-7 cells and 13.36 ± 0.04 µM for A549 cells. Complex 1 demonstrated lower toxicity to normal cells with an IC50 value of 26.76 ± 0.08 µM for the HEK293 cell line compared to the doxorubicin standard with an IC50 value of 1.2 ± 0.1 µM.

A self-healing and recyclable carrageenan based gel based on multi-dynamic interactions for multifunctional sensor

Preparation of high performance and recyclable gels remain a challenge. In this study, a zwitterionic ion poly-[2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (PDMAPS) network was constructed in renewable polysaccharide carrageenan to obtain CMM gel. The multiple reversible cross-linking network in CMM gel was engineered by molecular-level multi-dynamic interactions including hydrogen bonds among the molecular chains, two-dimensional MXene and tannic acid (TA), as well as electrostatic interaction. CMM gels exhibited enhanced mechanical strain, low-temperature resistance, self-healing performance (∼95 %), recyclable property, and antibacterial ability. CMM gel can be directly served as a strain sensor with short responsive time to accurately discern subtle and macro bodily motions, handwriting and personal physiological state, even after self-healing and recycling. Additionally, CMM gel can be used as solid electrolyte with polyaniline(PANI) on both sides to obtain sandwich structure CMM-PANI gel, which can be fabricated as all-solid state capacitor with high area specific capacitance of 478 mF/cm2 at 2 mA/cm2. Furthermore, a self-powered sensing device was assembled by the combination of the CMM gel and the capacitor, which demonstrates the sensing performance on various physical activities. This study gives an essential strategy for designing and fabricating self-healing and recyclable gels, and opens up new avenues for the practical application of gels.

Counteranion-mediated efficient iodine capture in a hexacationic imidazolium organic cage enabled by multiple non-covalent interactions

Developing efficient adsorbents to capture radioactive iodine produced from nuclear wastes is highly desired. Here we report the facial synthesis of a hexacationic imidazolium organic cage and its iodine adsorption properties. Crucial role of counteranions has been disclosed for iodine capture with this cage, where distinct iodine capture behaviors were observed when different counteranions were used. Mechanistic investigations, especially with the X-ray crystallographic analysis of the iodine-loaded sample, allowed the direct visualization of the iodine binding modes at the molecular level. A network of multiple non-covalent interactions including hydrogen bonds, halogen bonds, anion···π interactions, electrostatic interaction between polyiodides and the hexacationic skeleton of the cage are found responsible for the observed high iodine capture performance. Our results may provide an alternative strategy to design efficient iodine adsorbents.

A novel Ag3L2 coordination cage derived from a tripodal oxazoline ligand: synthesis, structure and catalysis

Coordination cages have attracted considerable attention recently due to the well-defined cavities and varied potential applications in different fields. In this work, a new tripodal oxazoline-based ligand with C3 symmetry, tris(4-(4,5-dihydrooxazol-2-yl)phenyl)amine (TOPA), was synthesized and employed to constitute coordination cage compounds. By the reaction of TOPA and AgPF6 at room temperature, a novel M3L2-type crystalline coordination cage complex was obtained with the formula of {[Ag3(TOPA)2]·(PF6)3}(1). In this complex, the adjacent two ligands coordinated with three Ag+ ions to form a coordination cage and these cages further generate the three-dimensional (3D) supramolecular networks through noncovalent interactions including hydrogen bond, C-H…π and F…Ag interactions. Moreover, cage complex 1 exhibited good catalytic performance in the cyclopropanation of styrene with methyl 2-diazo-2-(4-methoxyphenyl)acetate.

Spectroscopic study of solvent effects on the electronic absorption spectra of morpholine and its complexes

The electronic absorption spectra of morpholine and its five morpholine complexes have been studied in different solvents of various polarities. The regression and correlation coefficients have been calculated with the SPSS program. Solvation energy relationships were deduced from spectral shifts and correlated with solvent parameters α (solvent hydrogen bond donor acidity), β (solvent hydrogen bond acceptor basicity), and π* (dipolarity/polarizability). The percentage contributions of the calculated solvatochromic parameters show that classic solvation effects play a major role in explaining the spectral shifts in all investigated complexes. The blue shift of [Fe(MOR)3Cl3]·4H2O, [Ni(MOR)4Cl2]·4H2O, and [Cu(MOR)4Cl2]·6H2O complexes is due to the formation of hydrogen bonds, which suggests the stabilization of the ground electronic state compared with the excited state. [CuNi(MOR)2Cl4]·4H2O and [CuZn(MOR)3Cl4]·2H2O are mixed metal complexes that suffer a red shift due to the solute-solvent interactions, which causes stabilization of the excited solute state with increasing solvent polarity. The bands are affected by specific solute-solvent interactions including hydrogen bond donor ability (acidity) and hydrogen bond acceptor ability (basicity) and nonspecific solute-solvent interactions including electromagnetic interaction between the dipole moments of solute and polar solvents.

Interactions between Paracetamol and Formaldehyde: Theoretical Investigation and Topological Analysis.

In this work, noncovalent interactions including hydrogen bonds, C···C, N···O, and van der Waals forces between paracetamol and formaldehyde were investigated using the second-order perturbation theory MP2 in conjunction with the correlation consistent basis sets (aug-cc-pVDZ and aug-cc-pVTZ). Two molecular conformations of paracetamol were considered. Seven equilibrium geometries of dimers were found from the result of the interactions with formaldehyde for each conformation of paracetamol. Interaction energies of complexes with both ZPE and BSSE corrections range from -7.0 to -21.7 kJ mol-1. Topological parameters (such as electron density, its Laplacian, and local electron energy density at the bond critical points) of the bonds from atoms in molecules theory were analyzed in detail. The natural bond orbital analysis showed that the stability of complexes was controlled by noncovalent interactions including O-H···O, N-H···O, C-H···O, C-H···N, C-H···H-C, C···C, and N···O. The red- and blue-shifted hydrogen bonds could both be observed in these complexes. The properties of these interactions were also further examined in water using a polarized continuum model. In water, the stability of the complex was slightly reduced as compared to that in the gas phase.

Methanesulfonic acid and iodous acid nucleation: a novel mechanism for marine aerosols.

By seeding clouds, new particle formation (NPF) has a substantial impact on radiation balance, bio-geochemical cycles and global climate. Over oceans, both methanesulfonic acid (CH3S(O)2OH, MSA) and iodous acid (HIO2) have been reported to be closely associated with NPF events; however, much less is known about whether they can jointly nucleate to form nanoclusters. Hence, quantum chemical calculations and Atmospheric Cluster Dynamics Code (ACDC) simulations were performed to investigate the novel mechanism of MSA-HIO2 binary nucleation. The results indicate that MSA and HIO2 can form stable clusters via multiple interactions including hydrogen bonds, halogen bonds, and electrostatic forces between ion pairs after proton transfer, which are more diverse than those in MSA-iodic acid (HIO3) and MSA-dimethylamine (DMA) clusters. Interestingly, HIO2 can be protonated by MSA exhibiting base-like behavior, but it differs from base nucleation precursors by self-nucleation rather than solely binding to MSA. Due to the greater stability of MSA-HIO2 clusters, the formation rate of MSA-HIO2 clusters can be even higher than that of MSA-DMA clusters, suggesting that MSA-HIO2 nucleation is a non-negligible source of marine NPF. This work proposes a novel mechanism of MSA-HIO2 binary nucleation for marine aerosols and provides deeper insights into the distinctive nucleation characteristics of HIO2, which can help in constructing a more comprehensive sulfur- and iodine-bearing nucleation model for marine NPF.

Bioinspired fabrication of self-recovery, adhesive, and flexible conductive hydrogel sensor driven by dynamic borate ester bonds and tannic acid-mediated noncovalent network

Conductive polymer hydrogels have received enormous attention because of their promising applications in healthcare monitoring, soft robots, and wearable electronics. Development of hydrogel sensor with strong mechanical properties, excellent sensing capabilities, self-healing and adhesive properties is highly desirable and still remains a critical challenge. Herein, we report a borax crosslinked flexible hydrogel based on polyvinyl alcohol (PVA), sodium alginate (SA), and tannic acid (TA) modify barium titanate (BT) nanoparticles (T@BT) via a facile one-pot method. The crosslinking network was formed by dynamic reversible borate ester bond and TA-enabled interactions including hydrogen bonds and coordination bonds, which endowed the hydrogel with excellent self-healing and mechanical properties. Meanwhile, the combination of functional catechol groups in TA with the significantly improved cohesion of the hydrogel enabled the hydrogel to exhibit strong and residue-free adhesion to a variety of inorganic and organic materials. The adhesion strength to wood was up to 67.5 kPa. Furthermore, the addition of the T@BT not only rendered the hydrogel highly conductive (1.91 S/m) and sensitive for sensing, but also synergistically enhanced the toughness (587.1 KJ/m3) of the hydrogel. This work provides new ideas for the preparation of multifunctional conductive hydrogels.

Insight into the structural basis of the dual inhibitory mode of Lima bean (Phaseolus lunatus) serine protease inhibitor.

Bovine pancreatic trypsin was crystallized, in-complex with Lima bean trypsin inhibitor (LBTI) (Phaseolus lunatus L.), in the form of a ternary complex. LBTI is a Bowman-Birk-type bifunctional serine protease inhibitor, which has two independent inhibitory loops. Both of the loops can inhibit trypsin, however, only the hydrophobic loop is specific for inhibiting chymotrypsin. The structure of trypsin incomplex with the LBTI has been solved and refined at 2.25 Å resolution, in the space group P41, with Rwork /Rfree values of 18.1/23.3. The two binding sites of LBTI differ in only two amino acids. Lysine and leucine are the key residues of the two different binding loops positioned at the P1, and involved in binding the S1 binding site of trypsin. The asymmetric unit cell contains two molecules of trypsin and one molecule of LBTI. The key interactions include hydrogen bonds between LBTI and active site residues of trypsin. The 3D structure of the enzyme-inhibitor complex provided details insight into the trypsin inhibition by LBTI. To the best of our knowledge, this is the first report on the structure of trypsin incomplex with LBTI.

Efficient Control of the Formation of Pillar[5]arene-based Supramolecular Polymers

• Background: The design and preparation of functional pillar[n]arene-based supramolecular polymers have attracted extensive attention due to their wide range of applications. • Objective and Method: Based on the strategy of synergistic effects of non-covalent interactions including hydrogen bonds and host-guest interaction, an amphiphilic pillar[5]arene 1 with two terminated acid chains was designed, and its self-assembly properties were investigated by 1HNMR, TEM, SEM and UV-Vis. • Results: The pillar[5]arene 1 can form a self-inclusion complex, whose carboxyl groups are locked on the surface of cavity at low concentration (<4.5 mM) in chloroform. Interestingly, when competitive guest dihaloalkanes such as α,ω-diiodobutane (DIB), α,ω-dibromobutane (DBB) and α,ω-dichlorobutane (DCB), were added, supramolecular polymers were immediately obtained and precipitated. Their critical precipitation concentration (CPC) were calculated as 1 mM, 3 mM and 5 mM for DIB, DBB and DCB, respectively. Moreover, tuning the solvent, concentration and guests can reversibly control their polymerization. • Conclusion: This study provided an efficient method for the preparation of pillar[5]arene-based supramolecular polymers, which have potential application for the separation or purification of the dihaloalkanes.

Identification of secondary metabolites from Crescentia cujete as promising antibacterial therapeutics targeting type 2A topoisomerases through molecular dynamics simulation

The potential of fluoroquinolones as remarkable antibacterial agents evolved from their ability to generate ‘poison’ complexes between type IIA topoisomerases [topo2As (DNA gyrases and topoisomerases IV)] and DNA. However, the overuse of fluoroquinolones coupled with chromosomal mutations in topo2As has increased incidence of resistance and consequently undermined the application of the currently available fluoroquinolones in clinical practice. In this study, the molecular mechanism of interaction between the secondary metabolites of Crescentia cujete (an underutilized plant with proven anti-bacterial activity) and topo2As was investigated using computational methods. Through molecular docking, the top five compounds with the best affinity for each topo2A were identified and subjected to molecular dynamics simulation over a period of 100 ns. The results revealed that the identified compounds had higher binding energy values than the reference standards against the topo2As except for topoisomerase IV ParC, and this was consistent with the results of the structural stability and compactness of the resulting complexes. Specifically, cistanoside D (−49.18 kcal/mol), chlorogenic acid (−55.55 kcal/mol), xylocaine (−33.08 kcal/mol), and naringenin (−35.48 kcal/mol) had the best affinity for DNA gyrase A, DNA gyrase B, topoisomerase IV ParC, and topoisomerase IV ParE, respectively. Of the constituents of C. cujete evaluated, only apigenin and luteolin had affinity for all the four targets. These observations are indicative of the identified compounds as potential inhibitors of topo2As as evidenced from the molecular interactions including hydrogen bonds established with the active site amino acids of the respective targets. This is the first in silico report on the antibacterial effect of C. cujete and the findings would guide structural modification of the identified compounds as novel inhibitors of topo2As for further in vitro and in vivo assessments.

Efficient separation of methanol/dimethyl carbonate mixtures by UiO-66 MOF incorporated chitosan mixed-matrix membrane

Pervaporation shows great potential in separation of organic-organic mixtures that are widely involved in chemical and petrochemical industries, while the separation performance of polymeric membranes is undesirable for practical application. In this work, we incorporated UiO-66 (ZrCl4) metal-organic frameworks (MOFs) into chitosan (CS) membrane to separate methanol-dimethyl carbonate (DMC) mixtures. ZrOCl2·8H2O or ZrCl4 was selected as metal precursor to synthesize UiO-66, which aimed to investigate the structural defect of UiO-66 for the separation performance of mixed matrix membranes (MMMs). BET, 1H NMR and low-angle XRD characterizations indicated that UiO-66 (ZrCl4) with appropriate pore size is more suitable for preferentially permeate methanol over DMC. IR, dielectric relaxation and DSC characterizations combined with molecular simulations revealed the ideal interfacial morphology of UiO-66/CS MMMs was owing to the favorable molecular interactions including hydrogen bond interaction and van der Waals interaction. Pervaporation separation of methanol-DMC mixtures demonstrated that UiO-66 (ZrCl4) nanofillers can simultaneously enhance the permeation flux and separation factor of CS membrane. The optimized 10 wt% UiO-66 (ZrCl4)/CS MMM exhibited total flux and methanol/DMC separation factor of 355 g/m2h and 337 for 10 wt% methanol-DMC mixtures at 50 °C, which were 3.4-fold and 25-fold higher than that of the pure CS membrane, respectively, and outperformed the state-of-the-arts polymer-based membranes.

Ultrastretchable, Adhesive, and Antibacterial Hydrogel with Robust Spinnability for Manufacturing Strong Hydrogel Micro/Nanofibers.

The ultrastretchable (over 12400%) hydrogel with long-lasting adhesion, strong antibacterial activity, and robust spinnability is developed based on the oxidative decarboxylation and quinone-catechol reversible redox reaction induced by Ag-lignin nanoparticles in a precursor solution containing citric acid (CA), acrylic acid (AA), and poly (acrylamide-co-acrylic acid) (P(AAm-co-AA)). With massive reversible interactions including hydrogen bonds and electrostatic forces, such hydrogel exhibits promising injectability and is facilely spun via manual drawing, draw-spinning, and electrospinning for manufacturing strong hydrogel micro/nanofibers. The resulting fibers exhibit excellent mechanical properties, including tensile stress of 422.0MPa, strain of 86.5%, Young's modulus of 8.7GPa, and toughness of 281.6MJ m-3 . The hydrogel microfibers obtained from a house-built spinner are scaled-up fabricated while retaining promising mechanical properties, as evidenced by lifting a load (317.2g) using the spun fibers of ≈33000 times lighter weight (9.5mg), indicating their great potentials in the applications such as net and safety cord which require robust mechanical properties. Moreover, assisted by a commercial electrospinning machine, nanosized hydrogel fibers are facilely spun on personal protective equipment such as a mask to offer an antiseptic coating with near 100% killing efficiency against airborne bacteria aerosols, demonstrating the capability of spun hydrogel fibers on disinfection-related applications.

Highly stretchable, compressible, adhesive hydrogels with double network

In this work, a double network bovine serum albumin-polyacrylamide (BSA-PAM) adhesive hydrogel was fabricated, in which combination of physical interactions including hydrogen bonds and chain entanglements, and chemical covalent photo-crosslinking. The BSA-PAM hydrogel exhibited excellent mechanical and adhesive properties. The composite hydrogel not only demonstrated excellent tensile properties (maximum force elongation 1552%~2037%), but also displayed extremely high fatigue resistance even when subjected to compress strains of up to 85%. More importantly, the BSA-PAM hydrogel showed excellent adhesiveness to various substrates (90 kPa~150 kPa for glass and 9.74 kPa~35.09 kPa for pigskin). This work provided a facile way of fabricating tough, stretchable and adhesive BSA-PAM hydrogels.

Gelling properties of silver carp surimi incorporated with konjac glucomannan: Effects of deacetylation degree

Effects of konjac glucomannan (KGM) with different deacetylation degrees on silver carp surimi gel properties were studied. As deacetylation degree increased, viscosity, solubility, and water absorption capability of KGM decreased gradually while particle size increased. The gel strength of surimi gel increased with the KGM deacetylation degree up to 50.72% and then significantly decreased. The maximum gel strength was 3.26 times higher than that of surimi gel with native KGM. The relaxation time of immobilized water decreased from 108.22 to 104.70 ms and then increased up to 110.92 ms with the deacetylation degree, while the proportion of the immobilized water increased from 92.74 to 98.59% and then decreased to 97.46%. Water distribution became less uniform as the deacetylation degree exceeded 50.72%. Surimi gel with KGM of a higher deacetylation degree formed a denser microstructure along with a higher dimensional fraction value. However, the microstructure was disrupted and the dimensional fraction value decreased as the deacetylation degree exceeded 50.72%. Chemical interactions including hydrogen bonds, hydrophobic interactions, and cross-linking extent increased with the KGM deacetylation degree up to 50.72% and then gradually decreased. The results suggest that KGM with a deacetylation degree of 50.72% is the most suitable for surimi products.

Flexible Lignin-based hydrogels with Self-healing and adhesive ability driven by noncovalent interactions

Flexible and adhesive hydrogels with self-healing abilities have great potential in various fields. In the present study, a new type of self-healing and adhesive hydrogel driven by noncovalent interactions including hydrogen bonds and hydrophobic interactions was readily constructed by mixing lignosulfonate (LS) and polyvinylpyrrolidone (PVP) in water. When the pH value was adjusted to neutral, LS aggregated to form rigid noncovalent junctions and PVP associated with these domains to form a flexible network. A series of hydrogels were obtained by altering the concentrations of LS and PVP. Owing to the unique structure and dynamic and reversible characteristics of the gelation mechanism, the hydrogel exhibited good toughness, and self-healing ability. The abundant active groups and improved cohesion endowed the LS/PVP composite (LPC) hydrogel with good adhesive ability to various substrates. In addition, the LPC hydrogel exhibited excellent biocompatibility. Collectively, these advanced properties allowed the hydrogel to be successfully applied as a hemostatic agent to treat organ injuries. This work provides a new platform for multifunctional lignin-based hydrogel which could be applied in biomaterials.

Strong and elastic pea protein hydrogels formed through pH-shifting method

Pea protein has attracted attentions as an alternative for soy protein, but its weaker gelling properties has limited its applications in food formulations. This research reports a heat-induced strong and elastic gel from pea protein isolate (PPI) pre-treated by a modified pH-shifting method. The scanning electron microscopy (SEM) observation and rheological measurement revealed that the formation of three-dimensional (3D) coagulum for pea protein at pH 12 by extending the alkali holding time (1, 24 and 48 h) and such coagulum maintained their structure when adjusting pH back to neutral. Further heating the pH-shifted PPI suspension at 92 °C led to gels of densely cross-linked polymer-like network with thin connective walls and pore size of 1–2 μm. Such uniform polymer-like gel network microstructure obtained in this work might be related to a high level of pea protein unfolding during pH-shifting treatment, which made the protein chain flexible and created more active sites to promote molecular interactions including hydrogen bonds and hydrophobic interactions when the protein was neutralized and heated. Notably the gel mechanical strength was dramatically increased to 21 kPa, accompanied by excellent elasticity and water holding capacity (>95%). The modified method of pH-shifting process has provided a new approach for preparation of pea protein gels with superior strength, thus may enable wider applications of pea protein applications in food formulations where gelling and texturization functions are required.