Viscoelastic Response in Hydrous Polymers: The Role of Hydrogen Bonds and Microstructure

Water responsive polymers represent a remarkable group of soft materials, acting as a laboratory for diverse water responsive physical phenomena and cutting-edge biology–electronics interfaces. We report on peculiarly distinctive viscoelastic behaviors of the biobased water responsive polymer cellulose 10-undecenoyl ester, while biobased regenerated cellulose displays stronger hydroplastic behaviors. We discovered a novel hydrous deformation mechanism involving the stretching of hydrogen bonds mediated by hydroxyl groups and water molecules, serving as a crucial factor in accommodating deformations. In parallel, the microstructure of cellulose 10-undecenoyl ester with unique coexisting nanoparticles and a continuous phase of entangled chains is mechanically resilient in the anhydrous state but enhances structural stiffness in the hydrous state. This variation arises from a different hydration level within the hydrous microstructure. Such a fundamental discovery offers valuable insights into the connection between the microscopic physical properties that can be influenced by water and the corresponding viscoelastic responses, extending its applicability to a wide range of hygroscopic materials

Dual Regulation of Sulfonated Lignin to Prevent and Treat Type 2 Diabetes Mellitus

With the rapid increase of diabetes cases in the world, there is an increasing demand for slowing down and managing diabetes and its effects. It is considered that a viable prophylactic treatment for type 2 diabetes mellitus (T2DM) is to reduce carbohydrate digestibility by controlling the activities of α-amylase and α-glucosidase to control postprandial hyperglycemia and promote the growth of intestinal beneficial bacteria. In this work, the effects of sulfonated lignin with different sulfonation degrees (0.8 mmol/g, SL1; 2.9 mmol/g, SL2) on the inhibition of α-amylase and α-glucosidase and the proliferation of intestinal beneficial bacteria in vitro were investigated. The results showed that both SL1 and SL2 can inhibit the activity of α-amylase and α-glucosidase. The inhibition capacity (IC50, 32.35 μg/mL) of SL2 with a low concentration (0–0.5 mg/mL) to α-amylase was close to that of acarbose to α-amylase (IC50, 27.33 μg/mL). Compared with the control groups, the bacterial cell concentrations of Bifidobacteria adolescentis and Lactobacillus acidophilus cultured with SL1 and SL2 increased in varying degrees (8–36%), and the produced short-chain fatty acids were about 1.2 times higher. This work demonstrates the prospect of sulfonated lignin as a prebiotic for the prevention and treatment of T2DM, which provides new insights for opening up a brand new field of lignin

MOESM2 of A sustainable process for procuring biologically active fractions of high-purity xylooligosaccharides and water-soluble lignin from Moso bamboo prehydrolyzate

Additional file 2: Fig. S1. Main structures in the XOS and S-L preparations

Characterization and Application of Lignin–Carbohydrate Complexes from Lignocellulosic Materials as Antioxidants for Scavenging <i>In Vitro</i> and <i>In Vivo</i> Reactive Oxygen Species

Lignin–carbohydrate complexes (LCCs) have shown antioxidant ability to scavenge the individual free radicals in vitro, while little work has been carried out to show if the LCCs can efficiently scavenge the intracellular and endogenous reactive oxygen species (ROS), which are the multiple radicals derived from the reduction of molecular oxygen during the metabolism process. In this work, carbohydrate-rich LCCs from bamboo (LCCs–B-B) and poplar (LCCs–B-P) were isolated according to the classical method, and their antioxidant activities were evaluated by scavenging intracellular ROS in RAW 264.7 cells in vitro and endogenous ROS in zebrafish in vivo. Results from composition analysis show that both LCC preparations possess similar contents of carbohydrate (52.2% and 51.2%) and lignin (44.1% and 47.8%). However, NMR analysis revealed that the LCCs–B-B contain 16.1/100C9 LCCs linkages, higher than that in LCCs–B-P (12.3/100C9). Antioxidant assays indicated that LCCs–B-B exhibited better antioxidant activities for scavenging the individual free radicals. At the cellular and animal model levels, LCCs–B-B also outperformed the performance of LCCs–B-P in scavenging the endogenous ROS in H2O2-stimulated RAW 264.7 cells in vitro and zebrafish in vivo, which may be due to its better ability to prevent the reduction of antioxidant enzyme activity (superoxide dismutase and glutathione peroxidase) in oxidative stress

MOESM1 of New strategy to elucidate the positive effects of extractable lignin on enzymatic hydrolysis by quartz crystal microbalance with dissipation

Additional file 1: Table S1. Recovery/removal of all components in ethanol-pretreated materials

MOESM1 of A sustainable process for procuring biologically active fractions of high-purity xylooligosaccharides and water-soluble lignin from Moso bamboo prehydrolyzate

Additional file 1: Table S1. Assignment signals of substructure and LCCs linkages in the 2D HSQC spectra of the XOS and S-L preparations

Integrated Nondestructive Spectroscopic Technology to Reveal the Influence Mechanism of Lignins from Pretreated Corn Stover on Cellulose Saccharification

The changes in the structure of lignin during the pretreatment processes of biomass can affect its subsequent enzymatic hydrolysis efficiency. To explore the influence mechanism of dilute acid and hydrothermal pretreatment of corn stover lignin on cellulose saccharification, an integrated nondestructive spectral technology with fluorescence spectroscopy, surface plasmon resonance, and atomic force microscopy was performed. It showed that the surface lignins on the corn stover with dilute acid pretreatment at 190 °C (DA190-SL) and hydrothermal pretreatment at 190 °C (HP190-SL) possessed enhancement (from 76.95 to 80.09%) and inhibition (from 76.95 to 61.91%) for the enzymatic digestibility of Avicel, respectively. Nondestructive spectroscopic analysis indicated that HP190-SL adsorbed onto cellulase is mainly driven by hydrogen bonding and van der Waals forces, while the DA190-SL-enzyme system was mainly driven by hydrophobic interactions. The association affinity of DA190-SL combined with cellulase was higher than that of HP190-SL. The binding force of the HP190-SL-enzyme (0.16 nN) is lower than that of the DA190-SL-enzyme (0.75 nN), which leads to a higher propensity for dissociation of HP190-SL from cellulase after binding. This study aims to establish a theoretical basis for regulating the enzymatic performance during the hydrothermal and dilute acid pretreatment of corn stover at the molecular level

Direct Extraction of Uniform Lignin Microspheres from Bamboo Using a Polyol-Based Deep Eutectic Solvent

Conventional preparation of lignin micro-/nano-particles (LMNPs) often needs multiple steps accompanied by high cost, low efficiency, and low yield. Herein, this study established a polyhydric alcohol-based deep eutectic solvent (PA-DES) fractionation for direct LMNP assembly from raw lignocellulose. The results indicated that lignin was significantly extracted by 41.55–70.33% depending on the PA-DES varieties. With lignin removal, the substrate showed high glucan enzymatic saccharification from 70.44 to 100%. Specially, over 90% lignin could be recovered in each PA-DES, and the obtained LMNPs showed quite uniform spherical morphology with a tunable size of 550–3254 nm and narrow polydispersity index (PDI) of 0.295–0.398. The proposed DES showed a near theoretical recovery yield, which still featured excellent fractionation performance even after three cycles of reuse. The findings highlight the simultaneous utilization of cellulose and lignin in a one-pot biomass fractionation under mild conditions with sugars and LMNPs as the coproducts

Polydopamine-Reinforced Hemicellulose-Based Multifunctional Flexible Hydrogels for Human Movement Sensing and Self-Powered Transdermal Drug Delivery

The preparation of bio-based hydrogels with excellent mechanical properties, stable electrochemical properties, and self-adhesive properties remains a challenge. In this study, nano-polydopamine-reinforced hemicellulose-based hydrogels with typical multistage pore structures were prepared. The nanocomposite hydrogels exhibit stable mechanical properties and show no significant crushing phenomenon after 1000 cycles of cyclic compression. Its ultimate tensile strain was 101%, which is significantly higher than that of native skin. The shear adhesion strength of the hydrogel to skin tissue reaches 7.52 kPa, which is better than fibrin glue (Greenplast) (5 kPa), and the excellent adhesion property prolongs the service time of the hydrogel in biomedicine applications. The impedance of the hydrogel was reduced and the electrical conductivity was increased with the addition of nano-polydopamine. The prepared nanocomposite hydrogel can detect various body movements (even throat vibrations) in real time as a motion sensor while being able to rapidly load cationic drugs and facilitate transdermal introduction of electrically stimulated drug ions as a drug patch. It provides theoretical support for the fabrication of hemicellulose-based hydrogels with excellent properties through molecular design and nanoparticle reinforcement. This has important implications for the development of next-generation flexible materials suitable for health monitoring and self-administration

Antitumor Effects of Carrier-Free Functionalized Lignin Materials on Human Hepatocellular Carcinoma (HepG2) Cells

Lignin, as an abundant aromatic biopolymer in plants, has great potential for medical applications due to its active sites, antioxidant activity, low biotoxicity, and good biocompatibility. In this work, a simple and ecofriendly approach for lignin fractionation and modification was developed to improve the antitumor activity of lignin. The lignin fraction KL-3 obtained by the lignin gradient acid precipitation at pH = 9–13 showed good cytotoxicity. Furthermore, the cell-feeding lignin after additional structural modifications such as demethylation (DKL-3), sulfonation (SL-3), and demethylsulfonation (DSKL-3) could exhibit higher glutathione responsiveness in the tumor microenvironment, resulting in reactive oxygen species accumulation and mitochondrial damage and eventually leading to apoptosis in HepG2 cells with minimal damage to normal cells. The IC50 values for KL-3, SL-3, and DSKL-3 were 0.71, 0.57, and 0.41 mg/mL, respectively, which were superior to those of other biomass extractives or unmodified lignin. Importantly, in vivo experiments conducted in nude mouse models demonstrated good biosafety and effective tumor destruction. This work provides a promising example of constructing carrier-free functionalized lignin antitumor materials with different structures for inhibiting the growth of human hepatocellular carcinoma (HepG2) cells, which is expected to improve cancer therapy outcomes