The favorable antioxidant and antimicrobial activities of lignin have been shown to promote wound healing.However,the accumulation of lignin in high concentrations in the body brings about varying degrees of biotoxicity.Herein,a controlled/sustained release polyvinyl alco-hol/chitosan/sulfonated lignin hydrogel(PVA-CS-L)integrated mechanical strengthening and bioactivities of lignin was developed.The lignin-induced non-covalent bond network(van der Waals force,hydrogen and electrostatic interactions)promoted energy dissipation when the hy-drogel was subjected to stretching and compression.This endowed the PVA-CS-L hydrogel with improved tensile(∼36 kPa)and compressive strength(∼900 kPa),as well as compressive tough-ness(∼9.0 MJ/m^(3)),which were superior to the polyvinyl alcohol/chitosan hydrogel(PVA-CS)(31 kPa,680 kPa,and 7.5 MJ/m^(3),respectively).The construction of electrostatic interaction could not only slow down the sudden release of lignin but also make the hydrogel exhibit a good pH-sensitive behavior of controlled-release lignin.Also,the developed hydrogel had good biocom-patibility and the released lignin had reactive oxygen species scavenging as well as inhibitory activity against Staphylococcus aureus.Finally,preliminary evaluation of drug delivery reveals that the presence of lignin enabled the hydrogel to exhibit longer-lasting controlled/sustained epigallocatechin gallate release properties.Such lignin-based controlled/sustained release hydro-gel that integrates the molecular structure and biological difunctional features of lignin gives new insight into cost-effective,easy-to-operate manufacturing of load-bearing and bioactive materials.
Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can react in various chemical reactions and serve as a raw material in various processes to obtain multiple products.These characteristics make lignin suitable for synthesizing products from natural raw materials,replacing fossil ones.Due to a high aromatic variety and complex structural arrangement,lignin isolation and fractionation are still challenging.The aim and novelty of this work was the modification of severity and enzymatic hydrolysis proce-dure on an industrial pre-treatment to improve by-products of birch processing as a raw material for the potential production of different products.Lignin from birch wood enzymatic hydrolysis was obtained and marked accord-ingly:HS(high severity),MS(medium severity),and LS(low severity)lignin.Samples were characterized by ash content,analytical pyrolysis,solubility,and viscosity.HS lignin was characterized by a relatively high carbohy-drate content(16%)and lower lignin content(77%).Meanwhile,LS lignin showed increased lignin content(83%)and reduced carbohydrate content(9%).It can be concluded that the delignification process greatly influ-ences the properties of the obtained lignin.HS lignin resulted in a lower polydispersity index(PDI)and more condensed structure,while LS lignin showed a higher PDI but a lower content of carbohydrates.Therefore,look-ing for a golden middle way is necessary whilefinding the conditions according to the usefield.
With the development of electronics and portable devices,there is a significant drive to develop electrode materials for supercapacitors that are lightweight,economical,and provide high energy and power densities.Lignin-based porous carbons have recently been extensively studied for en-ergy storage applications because of their characteristics of large specific surface area,easy doping,and high conductivity.Significant progress in the synthesis of porous carbons derived from lignin,using different strategies for their preparation and modification with heteroatoms,metal oxides,met-al sulfides,and conductive polymers is considered and their electrochemical performances and ion storage mechanisms are discussed.Considerable fo-cus is directed towards the challenges encountered in using lignin-based por-ous carbons and the ways to optimize specific capacity and energy density for supercapacitor applications.Finally,the limitations of existing technolo-gies and research directions for improving the performance of lignin-based carbons are discussed.
With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has surged.In this work,a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres(HLNPs)-intercalated two-dimensional transition metal carbide(Ti_(3)C_(2)T_(x) MXene)for fabricating highly stretchable and durable supercapacitors.By depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient,a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene lamella.Moreover,the micro-chamber architecture of thin-walled lignin nanospheres effectively extended the contact area between lignin and MXene to improve ion and electron accessibility,thus better utilizing the pseudocapacitive property of lignin.All these strategies effectively enhanced the capacitive performance of the electrodes.In addition,HLNPs,which acted as a protective phase for MXene layer,enhanced mechanical properties of the wrinkled stretchable electrodes by releasing stress through slip and deformation during the stretch-release cycling and greatly improved the structural integrity and capacitive stability of the electrodes.Flexible electrodes and symmetric flexible all-solid-state supercapacitors capable of enduring 600%uniaxial tensile strain were developed with high specific capacitances of 1273 mF cm^(−2)(241 F g^(−1))and 514 mF cm^(−2)(95 F g^(−1)),respectively.Moreover,their capacitances were well preserved after 1000 times of 600%stretch-release cycling.This study showcased new possibilities of incorporating biobased lignin nanospheres in energy storage devices to fabricate stretchable devices leveraging synergies among various two-dimensional nanomaterials.
Population size plays a crucial role in determining wheat yields.Altered carbohydrate accumulation resulting from increased competition between populations and individuals leads to poor-quality stems.The sowing date can mitigate competition in densely planted populations.However,the underlying mechanism by which it confers resistance to wheat lodging remains elusive.In this study,Zimai 28(lodging-sensitive variety)and Shannong 28(lodging-resistant variety)were used with three sowing treatments on October 22(S1),October 28(S2),and November 3(S3).The sowing rate was adjusted to ensure adequate population size and consistency in the overwintering populations across sowing dates(300 plant m2 for S1,375 plant m2 for S2,and 525 plant m2 for S3).The lodging resistance in winter wheat was increased by delayed sowing and increased sowing rate,which led to a reduction in tiller numbers and fostered primary stem development.A reduction in the overwinter cumulative temperature from 500 to 450C,coupled with an elevation in sowing rates from 300 to 375 plant m2(transition from S1 to S2),corresponded with a notable increase in structural carbohydrates(lignin,cellulose,hemicellulose,and pectin)by 175.07 mg g1.Additionally,there was a moderate increase in non-structural carbohydrates,including soluble sugars and starch,by 15.54 mg g1.Delayed sowing and increased sowing rate elevated the precursor contents of lignin synthesis.Enhanced metabolic activity of related pathways ultimately increased dimer/trimer content.In summary,this study highlights the pivotal role of lignin metabolites and cross-linked structures in determining the stem stiffness breaking strength.
Chunhui LiHaixing CuiMin JinShufang SunJiayu WangYongli LuoYong LiZhenlin Wang
Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in broad-spectrum(UVA and UVB)sunscreens.It could be partially and selectively acetylated in a simple,fast,and more reliable process.In this work,a composite film was prepared with UV-resistant properties through a casting method.Bio-based cellulose acetate(CA)was employed as a major matrix while nano-acetylated kraft lignin(AL-NPs)was used as filler during synthesizing UV-shielding films loaded with various amounts(1–5 wt.%)of AL-NPs.Kraft lignin was acetylated through a simple and fast microwave-assisted process using acetic acid as a solvent and acetylating agent.The physicochemical and morphological characteristics of the prepared films were evaluated using different methods,including scanning electron microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),X-ray diffraction analysis(XRD),mechanical testing and contact angle measurement.The UV-Vis spectroscopy optical investigation of the prepared films revealed that AL-NPs in the CA matrix showed strong UV absorption.This feature demonstrated the effectiveness of our research in developing UV-resistant bio-based polymer films.Hence,the prepared films can be considered as successful candidates to be applied in packaging applications.
[Objectives]This study was conducted to investigate the effects of lignin-based fully biodegradable plastic film on the growth and quality of lettuce under open-field cultivation conditions.[Methods]In this experiment,compared with bare soil,a polyethylene plastic film(PE)treatment and two lignin-based fully biodegradable plastic film treatments(LBF-0.01 and LBF-0.008)with different thicknesses were set to study the effects on the growth and quality of lettuce.[Results]During autumn cultivation in Shanghai,the thermal insulation performance and yield-increasing effect of the two degradable plastic films were consistent with those of PE film,and effectively met lettuce growth requirements,but treatment LBF-0.01was better than treatment LBF-0.008.Moreover,lignin-based fully biodegradable plastic film could significantly increase the contents of Vc,soluble sugar and carotenoids in lettuce,and treatment LBF-0.008 showed the best effect.It could be seen that under the experimental conditions,the two kinds of lignin-based biodegradable plastic films with different thicknesses could be applied to the cultivation of lettuce in the open field in Shanghai in autumn,and LBF-0.01 had the best effect of increasing temperature and increasing yield,while LBF-0.008 had the best effect of improving quality.[Conclusions]This study provides theoretical basis and technical support for the further application of lignin-based fully biodegradable plastic film.
Plants mount induced resistance and adult-plant resistance against different pathogens throughout the whole growth period.Rice production faces threats from multiple major diseases,including rice blast,sheath blight,and bacterial leaf blight.Here,we report that the miR172a–SNB–MYB30 module regulates both induced and adult-plant resistance to these three major diseases via lignification in rice.Mechanistically,pathogen infections induce the expression of miR172a,which downregulates the transcription factor SNB to release its suppression of MYB30,leading to an increase in lignin biosynthesis and disease resistance throughout the whole growth period.Moreover,expression levels of miR172a and MYB30 gradually increase and are consistently correlated with lignin contents and disease resistance during rice development,reaching a peak at full maturity,whereas SNB RNA levels are negatively correlated with lignin contents and disease resistance,indicating the involvement of the miR172a–SNB–MYB30 module in adult-plant resistance.The functional domain of SNB protein and its binding sites in the MYB30 promoter are highly conserved among more than 4000 rice accessions,while abnormal expression of miR172a,SNB,or MYB30 compromises yield traits,suggesting artificial selection of the miR172a–SNB–MYB30 module during rice domestication.Taken together,these results reveal a novel role for a conserved miRNA-regulated module that contributes significantly to induced and adult-plant resistance against multiple pathogens by increasing lignin accumulation,deepening our understanding of broad-spectrum resistance and adult-plant resistance.
