Antibacterial mechanism of lignin and lignin-based antimicrobial materials in different fields

Biocides as drivers of antibiotic resistance: A critical review of environmental implications and public health risks

The widespread and indiscriminate use of biocides poses significant threats to global health, socioeconomic development, and environmental sustainability by accelerating antibiotic resistance. Bacterial resistance development is highly complex and influenced significantly by environmental factors. Increased biocide usage in households, agriculture, livestock farming, industrial settings, and hospitals produces persistent chemical residues that pollute soil and aquatic environments. Such contaminants contribute to the selection and proliferation of resistant bacteria and antimicrobial resistance genes (ARGs), facilitating their dissemination among humans, animals, and ecosystems. In this review, we conduct a critical assessment of four significant issues pertaining to this topic. Specifically, (i) the role of biocides in exerting selective pressure within the environmental resistome, thereby promoting the proliferation of resistant microbial populations and contributing to the global spread of antimicrobial resistance genes (ARGs); (ii) the role of biocides in triggering transient phenotypic adaptations in bacteria, including efflux pump overexpression, membrane alterations, and reduced porin expression, which often result in cross-resistance to multiple antibiotics; (iii) the capacity of biocides to disrupt bacteria and make the genetic content accessible, releasing DNA into the environment that remains intact under certain conditions, facilitating horizontal gene transfer and the spread of resistance determinants; (iv) the capacity of biocides to disrupt bacterial cells, releasing intact DNA into the environment and enhancing horizontal gene transfer of resistance determinants; and (iv) the selective interactions between biocides and bacterial biofilms in the environment, strengthening biofilm cohesion, inducing resistance mechanisms, and creating reservoirs for resistant microorganisms and ARG dissemination. Collectively, this review highlights the critical environmental and public health implications of biocide use, emphasizing an urgent need for strategic interventions to mitigate their role in antibiotic resistance proliferation.

Optimizing SiO2 Nanoparticle Structures to Enhance Drought Resistance in Tomato (Solanum lycopersicum L.): Insights into Nanoparticle Dissolution and Plant Stress Response

Drought stress significantly limits crop productivity and poses a critical threat to global food security. Silica nanoparticles (SiO2NPs) have shown a potential to mitigate drought stress, but the role of the nanostructure on overall efficacy remains unclear. This study evaluated solid (SSiO2NPs), porous (PSiO2NPs), and hollow (HSiO2NPs) SiO2NPs for their effects on drought-stressed tomatoes (Solanum lycopersicum L.). Silicic acid release rates followed the order: HSiO2NPs > PSiO2NPs > SSiO2NPs > Bulk-SiO2. Compared to untreated controls, foliar application of PSiO2NPs and HSiO2NPs under drought stress significantly improved shoot Si concentrations and plants' dry weight. These treatments also enhanced antioxidant enzyme activities (catalase, peroxidase, and superoxide dismutase) and phytohormone-targeted metabolome levels (jasmonic acid, salicylic acid, and auxin), contributing to greater drought tolerance. Conversely, SSiO2NPs, silicic acid, and Bulk-SiO2 had minimal impact on plant dry weight or physiological responses. These results highlight the importance of nanoparticles architecture in alleviating drought stress and promoting sustainable agriculture.

Lignin micro/nanoparticles from alternative biomass sources for neutral-pH Pickering emulsions and quercetin encapsulation

Conventional Pickering emulsions (PEs) stabilizers are often petrochemical-based, raising concerns about bioincompatibility and adverse reactions. Using sustainable biomass, such as pruning residues, offers potential for natural PEs stabilizers development. This study explores the use of avocado pruning lignin (APL), alongside various commercial lignins, to produce natural stabilizers for neutral-pH PE. The effect of lignin chemical and structural composition to produce lignin nanoparticles (NP) and microparticles (MP) was studied. APL exhibited high carbohydrate content, contributing to excellent surface tension reduction and enhanced antimicrobial properties. However the presence of carbohydrates compromised APL solubility in acetone:water mixtures, hindering the nanoprecipitation process via the solvent exchange method. A washing step, consisting in the removal of water-soluble fraction of APL (APLWEF) improved this process. Both lignin NPs and MPs demonstrated effective stabilization of neutral-pH PEs, maintaining stability for up to 27 days with minimal changes in creaming index (CI). Quercetin encapsulation efficiency (EE) in all lignin types exceeded 90 %, except for APLWEF, which showed an EE around 78 %. The antioxidant activity in emulsions incorporating quercetin was particularly high, with kraft lignin sample maintaining an activity level of 0.93 mg of Trolox equivalents per g of emulsion at day 10, exhibiting minimal change from day 0.

Sickle Cell Disease and Antimicrobial Resistance: A Systematic Review and Meta-Analysis

Background/Objectives: Antimicrobial resistance (AMR) is increasingly rising due to antimicrobial overuse and misuse. In sickle cell disease (SCD) care, frequent antibiotic use drives the rapid emergence of AMR, threatening treatment options and patient lives. This systematic review synthesizes data on AMR with regard to SCD patients for the first time. Methods: A comprehensive database search for articles published in English was conducted in PubMed, Scopus, ScienceDirect, and Web of Science, with no restriction set for the year of publication. The DerSimonian-Laird method was applied to derive the pooled prevalence, while the Mantel-Haenszel method was used to calculate the pooled odds ratio. Results: A total of 18 eligible studies covering 3220 SCD patients published between 1996 and 2024 were included in this review. The common bacterial pathogens reported in the included studies were Streptococcus pneumoniae (10 studies), Staphylococcus aureus (10 studies), and Escherichia coli (4 studies). For S. aureus, the pooled resistance was highest for penicillins (ampicillin = 100%; penicillin = 93.64%; and amoxicillin = 77.82%) followed by cefuroxime (51.23%). The pooled prevalence of methicillin-resistant S. aureus (MRSA) was 19.30%. SCD patients had 2.89 and 2.47 times higher odds of being colonized or infected with penicillin-resistant and erythromycin-resistant S. aureus strains, respectively. For S. pneumoniae, resistance prevalence was highest for co-trimoxazole (81.1%), followed by penicillin (47.08%). The pooled prevalence of multidrug-resistant (MDR) S. pneumoniae isolates was 32.12%. The majority of the studies included (n = 14, 77.8%) were of moderate quality according to the modified STROBE checklist. Conclusions: This review reveals a high prevalence of AMR with regard to SCD patients. SCD patients have an increased risk of resistance to penicillin and co-trimoxazole across several bacterial pathogens. The limited geographical distribution of the included studies underscores the urgent need for expanded AMR research on the subject, especially in regions with high SCD burden.

Modification of walnut shell lignin nanoparticles through deep eutectic solvent for application in active food packaging films

The depletion and polluting nature of fossil fuels, coupled with the threat to human health posed by microplastics generated from plastic packaging, have underscored the significance of renewable resources in addressing environmental degradation. Among these, biomass has emerged as a prominent contender. The complex molecular structure of lignocellulose and limitations of conventional pretreatments hinder its efficient utilization. To address this, a ternary deep eutectic solvent (DES) was developed to extract bioactive lignin nanoparticles (LNPs) from walnut shells. Employing a continuous processing platform, 56.84 % of the lignin was converted into LNPs via DES and anti-solvent precipitation. Ethylene glycol in the DES preserved lignin's side-chain functionality, yielding LNPs with a ζ-potential of -28.29 mV, a particle size of 203.48 nm, and superior antioxidant activity compared to LNPs prepared by traditional DES. Electrostatic and non-covalent interactions between LNPs and ε-polylysine (ε-PL) within a polyvinyl alcohol (PVA) matrix produced a composite film with a tensile strength of 33.32 MPa, 90 % UV-blocking efficiency, and 60 % microbial growth inhibition. When applied to fresh walnut packaging, the film's gradual release of LNPs suppressed mold proliferation via phenolic hydroxyl groups, reduced oxidative degradation of nutrients, and extended shelf life. This study introduces a scalable, circular approach to repurposing agricultural waste into biodegradable active packaging, aligning lignin valorization with sustainable food preservation strategies.

Advancements in Antimicrobial Textiles: Fabrication, Mechanisms of Action, and Applications

Within the past decade, much attention has been drawn to antimicrobial textiles due to their vast potential for reducing the spread of infectious diseases and improving hygiene standards in various environments. This review paper discusses recent studies on preparation methods, modes of action, effectiveness against different microorganisms, and applications of antimicrobial textiles in diverse industries. It examines further challenges, including durability, environmental impact, and regulatory considerations, and looks at prospects for developing and integrating these novel materials. This paper intends to provide a broad-based understanding of state-of-the-art technologies and emerging trends in antimicrobial textiles by integrating existing knowledge and highlighting recent advances in this field that contribute much to improved public health and safety.

Cellulose and lignin nanoparticles from an Ayurvedic waste stream for essential oil-based active packaging to extend shelf life of strawberries

Cellulose and lignin nanoparticles (NCP and LNP) were successfully extracted from Dashamoola spent material (DSM), a residue from an Ayurvedic decoction. NCP had a particle size of 493.6 nm and a zeta potential of -30.9 mV, indicating good colloidal stability. FTIR confirmed the removal of non-cellulosic components, while TGA demonstrated thermal stability, with major degradation between 260 °C and 350 °C. A semi-crystalline structure of nanocellulose was indicated via XRD analysis. Oil-in-water emulsions of tea tree oil (TTO) were prepared using NCP (C at 4 %), LNP (L at 4 %), and a combination blend (2 % each of C and L in CL_TTO), with 16 % TTO, all in w/v. Among these, CL_TTO emulsions had the smallest particle size and highest stability. PVOH-based films, prepared with a 4 % w/v mixture of CL_TTO emulsion, PVOH, and glycerol, demonstrated improved tensile strength, Young's modulus, water vapour barrier properties, and water repellence. These films blocked 95 % UV transmittance, providing appreciable protection to light-sensitive products. PVOH-CL_TTO films also exhibited strong antioxidant activity (85 % DPPH scavenging) and antimicrobial property against E. coli. These films extended the shelf life of strawberries by preserving lightness, firmness, and pH for 14 days under chilling (4 °C). These findings highlight the potential of NCP and LNP obtained from DSM for producing sustainable active packaging which would valorizing Ayurvedic waste stream.

Shading stress promotes lignin biosynthesis in soybean seed coat and consequently extends seed longevity

The macromolecular components of the seed coat, particularly lignin, play a critical role in regulating seed viability. In the maize-soybean intercropping (MSI) system, shading stress was reported to enhance the viability of soybean seeds. However, the specific role of seed coat lignin in this process remains poorly understood. In this study, we demonstrated that soybean seed coats derived from the MSI system exhibit significantly higher lignin content and mechanical resistance compared to those from the sole cropping systems. Further investigations with artificial shading treatments revealed a substantial impact on the accumulation of phenylpropanoids in soybean seeds. Notably, shading applied during the reproductive stage resulted in decreased levels of anthocyanins, proanthocyanidins, and isoflavones, while simultaneously increasing lignin content. Moreover, both the mechanical resistance of the seed coats and the seeds' longevity under deteriorative conditions improved significantly compared to the normal light control. Gene expression and metabolomics analyses indicated that shading stress promotes the expression of key genes involved in lignin biosynthesis within the soybean seed coats, increasing the amount of several intermediate metabolites. Taken together, these findings reveal that shading stress in the MSI system promotes the biosynthesis and accumulation of lignin in soybean seed coats and thereby regulating seed longevity.

Innovative antimicrobial lignins: Extraction and characterization for advanced hydrogel applications

The antioxidant and antimicrobial activities of lignin are often emphasized; however, not every type exhibits these properties. In this work, water-soluble fractions of alkali lignin (AL), poly-(caffeyl alcohol) lignin (PCFA), pyrolytic lignin (PL) and grape seed lignin (GSL) were prepared. The original and water-soluble lignin fractions were comprehensively characterized using high-resolution 2D NMR spectroscopy. Notably, water-soluble fractions of PCFA, PL and GSL lignins exhibited 3.6 to 3.9 higher antioxidant activities than the original lignins despite having a phenolic content of approximately 12 % to 55 % lower. Additionally, these fractions demonstrated antimicrobial activities against Micrococcus luteus, Serratia marcescens and Escherichia coli. The potential of water-soluble lignin fractions as active modifiers for physically crosslinked hydrogels was also investigated. Specifically, PL/F lignin served as an antioxidant and antimicrobial agent for modifying carrageenan without disrupting its viscoelastic and swelling behaviour. Carrageenan hydrogels with 6 % PL/F lignin showed an antioxidant activity of 219.6 mg TE g-1 hydrogel and reduction rates of 43.9 % against M. luteus, 31.6 % against S. marcescens and 20.6 % against E. coli.

Characterization of hemp (Cannabis sativa L.) raw bast fibers of monoecious versus dioecious cultivars from flowering to senescence: FTIR of lignocelluloses and extract bioactivities

Hemp is a multipurpose crop. Due to the revived interest in sustainable crops, hemp cultivation has increased in recent years. Both dioecious and monoecious hemp varieties are cultivated, yet few studies provide a comparative characterization. Monoecious cannabis plants are more uniform and economically efficient, being a whole-plant harvesting type. The aim of this research was to provide a comparative characterization of monoecious versus dioecious hemp bast fibers. There was conducted a microscopic analysis that showed their localization, the FTIR characterization of raw lignocellulosic fibers and extract bioactivity assays (antioxidant and microbiologic). Results indicated that FTIR absorbance ratios of peaks 1427/897 cm-1, 1373-1375/667 cm-1, and1373/2905-2910 cm-1 are relevant for hemp fibers parameters. A significant positive correlation was found between total phenolic content and antioxidant activity (r = 0.69*, r = 0.56*). Analysis of raw bast fibers extract indicated that the monoecious cultivar in the senescence phenophases had highest total phenolic content, and was more effective against all tested pathogenic bacterial strains. Both monoecious cultivar and male plants of the dioecious cultivar had higher total phenolic content than female plants of the dioecious cultivar, although at different phenophases. The male plants in the technological maturity phenophases presented the highest total phenolic content. Lower antioxidant activity was registered by female plants of the dioecious cultivar, which also showed lower total phenolic content, and the extract had no effect against Listeria monocytogenes, regardless of harvest time. The findings thus point to monoecious cultivars as having potential relevance in applications requiring enhanced bioactive properties, besides being advantageous for large-scale cultivation for fibers and seeds due to the economic efficiency.

Fabrication of lignin nanoparticles with adjustable size, antioxidant, antibacterial, and hydrophobic properties by a two-step fractionation

Lignin nanoparticles (LNPs) are gaining attention for their renewability and environmental friendliness in advanced nanomaterials. To establish a new sustainable value chain, it is vital to fully utilize lignin resources and thoroughly examine the effects of LNPs size and structure on performance. Herein, a two-step fractionation scheme is engineered via combining sequential organic solvent fractionation and acid precipitation methods to obtain four lignin fractions (denoted as F1, F2, F3, and F4) with low heterogeneity, suitable hydroxyl content and the syringyl (S)/guaiacyl (G) ratio for LNPs fabrication. Up to 88.7 % of alkali lignin was collected to prepare LNPs, and the LNPs showed controllable sizes (100-500 nm, denoted as F1-LNP, F2-LNP, F3-LNP, and F4-LNP). The size gradually decreased from F1-LNP to F4-LNP with increasing specific surface area of LNPs, contributing to superior antibacterial and antioxidant properties. Notably, a higher S/G ratio with enriched p-hydroxyphenyl (H) units resulted in a smaller size of LNPs, possibly resulting from the greater attraction and larger binding energy between S-S and H-H than G-G. This work gives insights into the full utilization of technical lignin to nano-particles to meet specific performance requirements, which will particularly broaden the commercialization and high-value utilization of lignin.

A review on bioactivity, plant safety, and metal-reducing potential of lignin, its micro/nanostructures, and composites

Modern science focuses on sustainability-oriented innovation. Structurally sophisticated lignin is a sustainable alternative to non-renewable resources. Over the last several years, a tremendous scientific effort has been made to innovate lignin-based sustainable materials for numerous advanced applications. The lignin's phenolic, methoxyl and aliphatic hydroxyl functional groups are biologically and chemically active, making it conducive to developing state-of-the-art biomedicine, food packaging, crop protection, and catalyst materials. The biocidal effect of lignin rests on the phenolic compounds, specifically the double bond in α, β positions of the side chain, and a methyl group in the γ position. Also, depending on the biomass source and the pulping method, lignins possess different biocidal and antioxidant properties. The abundant hydroxyl groups in lignin are metal reductants and possess capping ability for the nanoparticles (NPs). This review focused on lignin's bioactivity mechanism, including antimicrobial efficacy and antioxidant properties. Lignin-based micro/nanocomposites and their application on food packaging, plant protection, and growth will also be explored. We will also review the application of lignin as a reducing and capping agent for the synthesis of metal NPs.

NaOH/urea aqueous solution facilitates spectroscopic quantitation of lignin in corn stalk

A facile spectrometric determination of lignin in corn straw was constructed through dissolving the lignin-carbohydrate complex in aqueous solution at room temperature, where NaOH/urea was induced to prepare a transparent aqueous solution of carbohydrate-linked lignin for quantification at 298 nm without any interference from the carbohydrate.

Advancements in Lignin Valorization for Energy Storage Applications: Sustainable Technologies for Lignin Extraction and Hydrothermal Carbonization

The conversion of industrial waste lignin into sustainable carbon materials is an essential step towards reducing dependency on fossil fuels and mitigating environmental impacts. This review explores various aspects of lignin utilization, with particular focus on the extraction of lignin and the application of lignin-derived carbon materials in energy storge applications. The review explores advanced chemical methods to improve the efficiency of biomass conversion, detailing emerging technologies for lignin extraction from various biomasses using innovative solvents and techniques, such as Ionic Liquids and Deep Eutectic Solvents (DESs). Additionally, it discusses the parameters that impact the hydrothermal carbonization (HTC) process. The produced hydrochar shows potential for use as optimized precursors for energy storage applications. This review also considers the implications of these technologies for environmental sustainability and the circular economy, suggesting future research directions to enhance and scale these processes for global impact. This comprehensive analysis highlights the critical role of advanced biomass conversion technologies in achieving sustainability and outlines pathways for future lignin-based carbon materials innovations.

Parallel Detection of the Unamplified Carbapenem Resistance Genes blaNDM-1 and blaOXA-1 Using a Plasmonic Nano-Biosensor with a Field-Portable DNA Extraction Method

Antimicrobial resistance (AMR) is a rapidly growing global concern resulting from the overuse of antibiotics in agricultural and clinical settings. The challenge is exacerbated by the lack of rapid surveillance for resistant bacteria in clinical, environmental, and food supply settings. The increasing resistance to carbapenems, an important sub-class of beta-lactam antibiotics, is a major concern in the healthcare community. Carbapenem resistance (CR) has been found in the environment and food supply chain, where it has the potential to spread to pathogens, animals, and humans through direct or indirect contact. Rapid detection for preventative and control measures should be developed. This study utilized a gold nanoparticle-based plasmonic biosensor for the parallel detection of the CR genes blaNDM-1 and blaOXA-1. To explore the field portability, DNA was extracted using two methods: a commercial extraction kit and a boiling method. The results were compared between the two methods using a spectrophotometer and a cellphone application for RGB values to quantify the visual results. The results showed that the boiling method of extraction was more effective than extraction with a commercial kit for this analysis. The parallel detection of unamplified genes extracted via the boiling method is novel. When combined with other portable testing equipment, the approach has the potential to be an inexpensive, rapid, and simple on-site CR gene detection protocol.

Lignin and copper nanocomposite coating for antibacterial mask

Lignin is a natural phenolic polymer characterized with renewable, sustainable and biocompatible, but yet remain underutilized. In the post-pandemic era, people are conventionally reusing mask but without any disinfections to prevent infection of virus in public places, which could lead to accumulation of bacteria and secondary infections. The development of antibacterial mask from lignin would simultaneously address the hygiene issues of used mask due to microbe accumulation and provide novel approach for lignin valorization. Herein, lignin/copper nanoparticle with excellent water dispersibility, antibacterial activity, and non-cytotoxicity was synthesized by in situ reduction of copper ions in lignin nanoparticles. The structure of lignin/copper nanoparticle, and antibacterial performance of the mask were thoroughly explored to understand the key factors to tune the process. Antibacterial mask was then prepared by simple dip coating of the lignin/copper nanocomposite onto the middle layer of a mask, which could effectively prevent the penetration of bacteria from the outer layer into the inner layer. The results of this study provide a feasible approach to prepare antibacterial mask using plant-derived, sustainable, and cheap raw material, namely lignin, which facilitate the high value valorization of lignin.

Drug-loaded Fe3O4/lignin nanoparticles to treat bacterial infections

Lignin is a biopolymer employed for various biomedical applications. Nevertheless, the drug loading and release mechanism of Fe3O4 nanoparticles with surface functionalization by lignin has yet to be described. Hence, this study functionalizes Fe3O4 nanoparticles surface with lignin (Fe3O4/Lig) for ciprofloxacin delivery and examines its adsorption-release mechanisms. The presence of lignin and ciprofloxacin on Fe3O4 nanoparticles were verified using FT-IR that shows distinct peaks for each functional group of lignin and ciprofloxacin. The study has proved selective adsorption of ciprofloxacin ions via electrostatic interactions. The optimal adsorption efficiency in the examined region was 65 %, with a capacity of 9.55 mg/g. Drug release efficiency was evaluated in buffer at pH 7.4 and pH 1.2-6.8, yielding ∼66 % and ∼100 %, respectively. The release profile fits Peppas's model, which uses a diffusion and disintegration mechanism. Furthermore, the HET-CAM model study presented that the substance does not irritate the cell membranes of the egg, indicating that it is safe for mucosa and tissues. The IC50 value for antibacterial activity against Gram-negative Salmonella enterica and Escherichia coli was 10.00 ± 0.76 μg/mL and 1.87 ± 0.06 μg/mL, respectively. In summary, the study effectively prepared Fe3O4/Lig-CIP nanoparticles, as well as remained antibacterial properties against both Gram (+) and Gram (-) microorganisms.

Lignin-Based Coatings: A Sustainable Approach to Produce Antibacterial Textiles

The growing interest in developing antibacterial textiles using natural functional agents is largely driven by their sustainable and eco-friendly attributes. Lignin, a highly available biopolymer with a polyphenolic structure, has drawn attention due to its potential as a bioactive antibacterial agent. However, its inherent heterogeneity poses challenges, particularly regarding its antibacterial efficacy. In this study, unmodified kraft lignin sourced directly from the paper industry was applied to cotton and polyester fabrics, using a knife-coating technique with varying concentrations (0%, 5%, 10%, 20%, and 30% w/v), to assess its potential as an antibacterial coating. The lignin-coated fabrics demonstrated hydrophobic properties, with water contact angles reaching up to 110.3° and 112.6°, for polyester and cotton fabrics, respectively, alongside significantly reduced air permeability and water vapor permeability indexes, regardless of lignin concentration. Antibacterial evaluations also revealed that lignin-based coatings, with at least 10% w/v concentration, allowed cotton fabrics with a bacterial reduction surpassing 96%, according to ASTM E2149-2013, particularly for Gram-positive S. aureus, highlighting the potential of lignin as an antibacterial agent. Despite their limited resistance to domestic washing, the lignin-coated fabrics demonstrated exceptional stability under hot-pressing conditions. Therefore, this stability, combined with the hydrophobic and antibacterial properties observed, particularly on coated cotton fabrics, highlights the potential application of lignin-based coatings for the development of antibacterial and water-repellent textiles, with these coatings being particularly suited for single-use applications or scenarios where washing resistance is not a requirement. This approach offers a sustainable and efficient method for producing functional textiles while enabling value-added utilization of lignin, showcasing its potential as an eco-friendly solution in textile functionalization.

GhRac9 improves cotton resistance to Verticillium dahliae via regulating ROS production and lignin content

Rac/Rop proteins, a kind of unique small GTPases in plants, play crucial roles in plant growth and development and in response to abiotic and biotic stresses. However, it is poorly understood whether cotton Rac/Rop protein genes are involved in mediating cotton resistance to Verticillium dahliae. Here, we focused on the function and mechanism of cotton Rac/Rop gene GhRac9 in the defense response to Verticillium dahliae infection. The expression level of GhRac9 peaked at 24 h after V. dahliae infection and remained consistently elevated from 24 to 48 h upon SA treatment. Furthermore, silencing GhRac9 using VIGS (Virus-induced gene silence) method attenuated cotton defense response to V. dahliae by reducing ROS (Reactive Oxygen Species) burst, peroxidase activity and lignin content in cotton plants. On the contrary, heterologous overexpression of GhRac9 enhanced Arabidopsis resistance to V. dahliae and significantly increased ROS production in Arabidopsis plants. Furthemore, transient overexpressing of GhRac9 significantly enhanced ROS burst and POD activity in cotton plants. In addition, GhRac9 positively regulated the expression levels of the genes related to SA signaling pathway in cotton plants. In conclusion, GhRac9 functioned as a positive regulator in the cotton defense response to V. dahliae, which provided important insights for breeding new cotton varieties resistant to V. dahliae.

Lignin-based flame retardants chelated with Fe3+: Facilitating the development of flame retardant, UV resistant and antibacterial properties polyvinyl alcohol composites

To overcome the problems of inflammability, poor UV resistance and susceptible to bacterial growth of polyvinyl alcohol (PVA), a new lignin-based PVA composite (PVA/PLig-Fe) was prepared. Compared to PVA, the limiting oxygen index (LOI) of PVA/PLig-Fe was increased by 64.8 %. The peak heat release rate (PHRR) and total heat release (THR) were reduced from 247.40 kW/m2 and 8.26 MJ/m2 of pure PVA to 151.70 kW/m2 and 6.95 MJ/m2, respectively. In addition, the total smoke production (TSP) of the modified sample was reduced from 3.11 m2 to 1.87 m2 compared with PVA. Notably, the elongation at break and tensile strength of PVA/PLig-Fe increased from 188 % and 35 MPa to 247 % and 53 MPa, and its transmittance of UVA (TUVA) and transmittance of UVB (TUVB) were reduced to 0.54 % and 0.59 %, respectively. Besides, the treated samples demonstrated 99.95 % and 99.90 % antibacterial activity against E. coli and S. aureus, respectively. The present research provides a feasible approach for the development of flame retardant, enhanced mechanical properties, UV resistant, and antibacterial PVA composites as a promising application in packaging.

Is Kraft Pulping the Future of Biorefineries? A Perspective on the Sustainability of Lignocellulosic Product Development

By reflecting on the history and environmental impact of conventional biorefining, such as kraft pulping, we aim to explore important questions about how natural polymers can be more sustainably sourced to develop bio-products and reduce reliance on plastics. Since the Industrial Revolution, chemical pulping processes have enabled the mass production of cellulosic products from woody biomass. Kraft pulping, which dominates within modern pulp and paper mills, has significantly contributed to environmental pollution and carbon emissions due to sulfurous byproducts and its high water and energy consumption. While chemical pulping technologies have advanced over time, with improvements aimed at enhancing sustainability and economic feasibility, conventional biorefineries still face challenges related to biomass conversion efficiency and environmental impact. For example, efforts to fully utilize wood resources, such as isolating lignin from black liquor, have made limited progress. This perspective provides a thoughtful examination of the growth of chemical pulping, particularly the kraft process, in the production of consumer goods and its environmental consequences. It also presents key insights into the bottlenecks in developing truly sustainable biomass conversion technologies and explores potential alternatives to traditional chemical pulping.

Exploring the relationship between lignin structure and antioxidant property using lignin model compounds

Lignin has a natural polyphenol structure that is expected to replace chemically synthesized antioxidants as a native antioxidant with biodegradable and convenient source characteristics. However, the improvement of the antioxidant property of lignin and its application as an antioxidant are still somewhat limited due to the lack of understanding of the relationship between specific lignin structures and antioxidant property. Therefore, the study of the relationship between lignin structure and antioxidant property is crucial to realize the high-quality application of lignin. In this experiment, the scavenging ability of free 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radicals was determined for different grades of acetylated tannins, typical lignin model compounds and different structural units of milled wood lignin to investigate the relationship between lignin structure and antioxidant property. Based on the experimental results, some structure-activity relationships were proposed and the mechanism of the antioxidant property of lignin was discussed. The number of phenolic hydroxyl groups was linearly and positively correlated with antioxidant property, and the scavenging of DPPH radicals increased significantly with the increase in the number of methoxy groups in the model compounds. Moreover, aldehyde and carboxyl groups had a negative effect on the antioxidant property of lignin, while methoxy, alkyl and alcohol hydroxyl groups played a positive role. The guaiacyl (G) and syringyl (S) units favored the antioxidant property, so the difference in the content of structural units in lignin under certain conditions of phenolic hydroxyl content also affected the antioxidant property. Therefore, the antioxidant property of aspen milled lignin was higher than that of other milled lignin from different wood species. Finally, the mechanism of DPPH free radical scavenging by lignin was revealed to better understand the relationship between lignin structure and antioxidant property.

Capability lignin from Acacia crassicarpa black liquor as an environmentally benign antibacterial agent to produce antibacterial and hydrophobic textiles

Recently, the growing health awareness of society on the utilization of fabrics has led to an increasing demand for natural-based antibacterial textiles. Lignin, a generous polyphenol compound in nature, is capable of preventing bacterial growth; in particular, it dwells bacteria closely together on human skin, such as Staphylococcus epidermidis, Bacillus subtilis, Propionibacterium acnes, and Staphylococcus aureus. However, the antibacterial properties of lignin are limited by factors such as the lignin concentration, source, and type of bacteria. This study aimed to evaluate the potency of lignin as an antibacterial agent for textiles. Moreover, the thermal properties and wettability of the textile after lignin coating were also investigated. This study showed that lignin isolation methods significantly contributed to the inhibition of bacterial growth in the clear zone diameter. In addition, the lignin structure, lignin concentration, and type of bacteria had notably different antibacterial effects. SEM images showed that lignin was successfully coated on the fiber, and the antibacterial textile was successfully fabricated with clear zones in the range of 0.1-0.5 cm against four different bacteria. Lignin did not significantly improve the thermal stability of the textile, as proven by the TGA results. After the HDTMS coating by dispersion method, the wettability of the lignin-textile improved to that of the hydrophobic material, with a contact angle greater than 119.05° with excellent antibacterial properties (clear zone of 0.1-0.43 cm).

Electrospun lignin-loaded artificial periosteum for bone regeneration and elimination of bacteria

Recently, the non-negligible role of the periosteum in bone repair has attracted the attention of researchers. In this study, poly(ε-caprolactone) (PCL)/lignin nano-fibrous membranes prepared by electrospinning are proposed as an artificial periosteum. Both in vitro and in vivo studies confirmed that PCL/lignin membranes have a pro-osteogenic effect. This effect was dependent on the lignin concentration, and there was an optimal concentration at which the membrane possessed the highest osteogenesis-potentiating activity among those tested in this study. In addition, the PCL/lignin membranes exhibited promising antibacterial properties against both E. coli and S. aureus, with high lignin concentrations corresponding to high-bactericidal activity. The prepared PCL/lignin membranes displayed promising osteogenic and antibacterial properties. With satisfactory hydrophilicity and mechanical properties, they hold great potential in serving as an artificial periosteum for bone tissue repair. This study provides both theoretical and laboratory evidence for the application of the renewable resource lignin in the repair of the periosteum and bone injuries.

Graphene oxide, starch, and kraft lignin bio-nanocomposite controlled-release phosphorus fertilizer: Effect on P management and maize growth

This study focuses on the synthesis and practical application of bio-nanocomposite films made from a mixture of starch (ST) and Kraft lignin (KL) with graphene oxide (GO) nanoparticles. FTIR, XRD, Raman, SEM, and TEM analysis confirmed the synthesis's success of GO. The bio-nanocomposites were used as advanced coatings for triple superphosphate (TSP) fertilizers, and their implications for maize (Zea mays L.) plant growth were examined. Incorporating GO into the composite matrix is a significant accomplishment of this study, as demonstrated by the noticeable changes observed in the FTIR spectra, indicating consequent structural changes. Morphological analyses conducted by SEM reveal changes in the surface characteristics of the ST/KL films, providing essential information about the structural details of the bio-nanocomposite. The utilization of precision-coated TSP fertilizers leads to a significant enhancement in mechanical strength, as demonstrated by the improved crush resistance. Furthermore, these formulations guarantee a gradual release of phosphorus, showcasing their potential for efficient nutrient management in agricultural settings. The study examines the practical application of coated TSP fertilizers in agriculture and their positive effects on various growth parameters of Maize (Zea mays L.) plants. Using these fertilizers promotes sustainable and efficient agricultural practices, contributing to developing innovative agrochemical solutions.

Lignin: An Adaptable Biodegradable Polymer Used in Different Formulation Processes

INTRODUCTION

LIG is a biopolymer found in vascular plant cell walls that is created by networks of hydroxylated and methoxylated phenylpropane that are randomly crosslinked. Plant cell walls contain LIG, a biopolymer with significant potential for usage in modern industrial and pharmaceutical applications. It is a renewable raw resource. The plant is mechanically protected by this substance, which may increase its durability. Because it has antibacterial and antioxidant qualities, LIG also shields plants from biological and chemical challenges from the outside world. Researchers have done a great deal of work to create new materials and substances based on LIG. Numerous applications, including those involving antibacterial agents, antioxidant additives, UV protection agents, hydrogel-forming molecules, nanoparticles, and solid dosage forms, have been made with this biopolymer.

METHODS

For this review, a consistent literature screening using the Pubmed database from 2019-2024 has been performed.

RESULTS

The results showed that there is an increase in interest in lignin as an adaptable biomolecule. The most recent studies are focused on the biosynthesis and antimicrobial properties of lignin-derived molecules. Also, the use of lignin in conjunction with nanostructures is actively explored.

CONCLUSIONS

Overall, lignin is a versatile molecule with multiple uses in industry and medical science.

Conversion of Lignin to Nitrogenous Chemicals and Functional Materials

Lignin has long been regarded as waste, readily separated and discarded from the pulp and paper industry. However, as the most abundant aromatic renewable biopolymer in nature, lignin can replace petroleum resources to prepare chemicals containing benzene rings. Therefore, the high-value transformation of lignin has attracted the interest of both academia and industry. Nitrogen-containing compounds and functionalized materials are a class of compounds that have wide applications in chemistry, materials science, energy storage, and other fields. Converting lignin into nitrogenous chemicals and materials is a high-value utilization pathway. Currently, there is a large amount of literature exploring the conversion of lignin. However, a comprehensive review of the transformation of lignin to nitrogenous compounds is lacking. The research progress of lignin conversion to nitrogenous chemicals and functional materials is reviewed in this article. This article provides an overview of the chemical structure and types of industrial lignin, methods of lignin modification, as well as nitrogen-containing chemicals and functional materials prepared from various types of lignin, including their applications in wastewater treatment, slow-release fertilizer, adhesive, coating, and biomedical fields. In addition, the challenges and limitations of nitrogenous lignin-based materials encountered during the development of applications are also discussed. It is believed that this review will act as a key reference and inspiration for researchers in the biomass and material field.

Synthesis and Antibacterial Properties of Novel Quaternary Ammonium Lignins

The ongoing demand for effective antimicrobial materials persists, and lignin emerges as a promising natural antibacterial material with renewable properties. The adaptability of lignin to various chemical modifications offers avenues to enhance its antimicrobial activity. Here, we employed chloromethylation and subsequent functionalization with variable tertiary N-alkyl dimethyl amines to produce C6-C18 quaternary ammonium lignins (QALs) from hardwood (aspen), softwood (pine), and grass (barley straw). Successful synthesis of QALs was confirmed through NMR and FTIR analysis results along with an increase in the surface ζ-potential. Antibacterial activity of QALs against clinical strains of Klebsiella pneumoniae and methicillin-resistant Staphylococcus aureus was assessed using minimal bactericidal concentration (MBC) assay and agar growth inhibition zone (ZOI) test. The antibacterial activity of QALs was found to be higher than that of the unmodified lignins. QALs with longer alkyl chains demonstrated an MBC of 0.012 mg/L against K. pneumoniae already after 1 h of exposure with similar effect size reached after 24 h for S. aureus. For all the lignins, an increase in alkyl chain length resulted in an increase in their bactericidal activity. MBC values of C14-C18 QALs were consistently lower than the MBC values of QALs with shorter alkyl chains. Besides the alkyl chain length, MBC values of barley and pine QALs were negatively correlated with the surface ζ-potential. While alkyl chain length was one of the key properties affecting the MBC values in a liquid-based test, the agar-based ZOI test demonstrated an antibacterial optimum of QALs at C12-C14, likely due to limited diffusion of QALs with longer alkyl chains in a semisolid medium.

Polystyrene nanoplastics induce cell type-dependent secondary wall reinforcement in rice (Oryza sativa) roots and reduce root hydraulic conductivity

Nanoplastics (NPs) have been demonstrated the ability to penetrate plant roots and cause stress. However, the extent of NPs penetration into various root tissues and the corresponding plant defense mechanisms remain unclear. This study examined the penetration and accumulation patterns of polystyrene nanoplastics (PS-NPs) in different cell types within rice roots, and explored how the roots quickly modify their cell wall structure in response. The findings showed that fully developed sclerenchyma cells in rice roots effectively prevented the invasion of PS-NPs. Meanwhile, PS-NPs triggered the accumulation of lignin and suberin in specific cells such as the exodermis, sclerenchyma, and xylem vessels. PS-NPs at a concentration of 50 mg L-1 increased cell wall thickness by 18.6 %, 21.1 %, and 22.4 % in epidermis, exodermis, and sclerenchyma cells, respectively, and decreased root hydraulic conductivity by 14.8 %. qPCR analysis revealed that PS-NPs influenced the cell wall synthesis pathway, promoting the deposition of lignin and suberin monomers on the secondary wall through the up-regulation of genes such as OsLAC and OsABCG. These results demonstrate that PS-NPs can induce cell type-specific strengthening of secondary walls and barrier formation in rice roots, suggesting the potential role of plant secondary wall development in mitigating NPs contamination risks in crops.

Tough Supramolecular Hydrogels Crafted via Lignin-Induced Self-Assembly

Supramolecular hydrogels are typically assembled through weak non-covalent interactions, posing a significant challenge in achieving ultra strength. Developing a higher strength based on molecular/nanoscale engineering concepts is a potential improvement strategy. Herein, a super-tough supramolecular hydrogel is assembled by gradually diffusing lignosulfonate sodium (LS) into a polyvinyl alcohol (PVA) solution. Both simulations and analytical results indicate that the assembly and subsequent enhancement of the crosslinked network are primarily attributed to LS-induced formation and gradual densification of strong crystalline domains within the hydrogel. The optimized hydrogel exhibits impressive mechanical properties with tensile strength of ≈20 MPa, Young's modulus of ≈14 MPa, and toughness of ≈50 MJ m⁻3, making it the strongest lignin-PVA/polymer hydrogel known so far. Moreover, LS provides the supramolecular hydrogel with excellent low-temperature stability (<-60 °C), antibacterial, and UV-blocking capability (≈100%). Interestingly, the diffusion ability of LS is demonstrated for self-restructuring damaged supramolecular hydrogel, achieving 3D patterning on hydrogel surfaces, and enhancing the local strength of the freeze-thaw PVA hydrogel. The goal is to foster a versatile hydrogel platform by combining eco-friendly LS with biocompatible PVA, paving the way for innovation and interdisciplinarity in biomedicine, engineering materials, and forestry science.

Exploitation of functionalized green nanomaterials for plant disease management

A crucial determining factor in agricultural productivity is biotic stress. In addition, supply of quality food to the ever-increasing world's population has raised the food demand tremendously. Therefore, enhanced agricultural crop productivity is the only option to mitigate these concerns. It ultimately demanded the often and indiscriminate use of synthetic agrochemicals such as chemical fertilizers, pesticides, insecticides, herbicides, etc. for the management of various biotic stresses including a variety of plant pathogens. However, the food chain and biosphere are severely impacted due to the use of such harmful agrochemicals and their byproducts. Hence, it is need of hour to search for novel, effective and ecofriendly approaches for the management of biotic stresses in crop plants. Particularly, in plant disease management, efforts are being made to take advantage of newly emerged science i.e. nanotechnology for the creation of inorganic nanoparticles (NPs) such as metallic, oxide, sulphide, etc. through different routes and their application in plant disease management. Among these, green nanomaterials which are synthesized using environmentally friendly methods and materials reported to possess unique properties (such as high surface area, adjustable size and shape, and specific functionalities) making them ideal candidates for targeted disease control. Nanotechnology can stop crop losses by managing specific diseases from soil, plants, and hydroponic systems. This review mainly focuses on the application of biologically produced green NPs in the treatment of plant diseases caused due to bacteria, viruses, and fungi. The utilization of green synthesis of NPs in the creation of intelligent targeted pesticide and biomolecule control delivery systems, for disease management is considered environmentally friendly due to its pursuit of less hazardous, sustainable, and environmentally friendly methods.

The Synergetic Reduction of the Condensation Degree of Dissolved Lignin (DL) during the Refining Process of Wheat Straw Biomass Based on the MA/O3 System

Lignin, a natural pol2ymer with a complex structure that is difficult to separate, is prone to C-C bond condensation during the separation process. To reduce the condensation of lignin, here, a novel method is proposed for separating the components by using a combination of maleic acid (MA)/ozone (O3) to co-treat wheat straw. The removal of lignin, glucan, and xylan was 38.07 ± 0.2%, 31.44 ± 0.1%, and 71.98 ± 0.1%, respectively, under the conditions of ball-milling of wheat straw for 6 h, reaction temperature of 60 °C, and O3 holding time of 9 min. Lignin-rich solutions were collected to extract the dissolved lignin (DL) after washing the treated samples. The DL obtained under MA/O3 conditions had a carboxyl group (-COOH) content of 2.96 mmol/g. The carboxyl group of MA underwent esterification with the hydroxyl group (-OH) at the γ position of lignin and O3 reacted on the positions of the lignin side chain or the phenolic ring, resulting in a break in the side chain and the opening of the phenolic ring to introduce the carboxyl group. The 2D-HSQC-NMR results revealed that the phenolic ring-opening reaction of lignin in the presence of O3 was essentially free of β-β and β-5 condensation bonds.

Preparation of Vitamin-g-Lignin Nanohybrids with Excellent Biological Activity and Fluorescence Performance

As a natural renewable biomacromolecule, lignin has some inherently interesting properties such as fluorescence, antioxidation, and antibacterial performance. However, the unsatisfactory fluorescence and biological activities have greatly limited their value-added and large-scale applications. In this work, lignin nanoparticles (LNPs) grafted with vitamin B1 hybrid nanoparticles (LEVs) were obtained by using ethylenediamine and different contents of vitamin B1 through a simple hydrothermal method. The chemical structure, fluorescence properties, and bioactivity were characterized to assess the effects of ethylenediamine and vitamin B1 on the properties of LEVs. It was found that the fluorescence performance of synthesized LEV particles was improved with the increase in the amount of vitamin B1. The free radical scavenging rate (RSA, %) increased to 97.8%, while the antibacterial rates reached up to 99.9%. The antibacterial activity of LEV involved multiple combined mechanisms. The introduction of imine, amide groups, and positively charged VB1 of LEV will make it easier to interact with the negatively charged bacterial phospholipid membranes and cause bacterial lysis and death. Then, the PVA/LEV hydrogel composites were prepared by the freezing-thawing method, and the results showed that PVA/LEV hydrogels had more comprehensive performance such as improved mechanical properties and antioxidant and antibacterial activities, resulting in its great potential to be used as an efficient biomedical material.

Fabrication of lignocellulose/liquid metal-based conductive eutectic hydrogel composite for strain sensors

High conductive and freeze-resistant hydrogels with adhesion function are ideal candidates for soft electronic devices. However, it remains a challenge to design appropriate conductive nanofillers to endow hydrogels with all these characteristics. Liquid metal (LM) exhibits exceptional electrical conductivity and convenient processability, rendering it a highly promising contender. Cellulose nanofibrils (CNFs) were employed as the interfacial stabilizer in synthesizing stable CNFs encapsulated LM solutions. Then the lignin was further coated on the surface of CNFs-LM (LCL) to prepare lignin-coated hybrid hydrogels. The obtained LCL displayed outstanding water-dispersible stability and were promising conductive nanofillers for hydrogels. During the fabrication of poly N-(hydroxymethyl) acrylamide (PHA) hydrogels, the LM was dispersed into LM particles with smaller sizes, leading to highly conductive LCL-PHA hydrogels (0.38 S·m-1). The prepared LCL-PHA hydrogels exhibited exceptional mechanical properties, including a strain at a break of 134.6 %, stress at a break of 22.7 Kpa, and a toughness of 16.3 KJ·m-3. Additionally, the LCL-PHA hydrogels demonstrated favorable electrical conductivity and adhesion. Notably, even after being subjected to freezing at -20 °C for 24 h, they remained suitable for effective real-time monitoring of all types of human activities, demonstrating superior environmental stability.

Natural lignocellulosic biomass structure inspired CNF/Lignin/PBAT composite film with thermoplastic, antibacterial and UV-blocking abilities

The development of a thermoplastic, biodegradable composite material to replace conventional polymers derived from petroleum was the main area of concentration. Herein, a method for preparing antibacterial, UV-blocking and degradable CNF/Lignin/PBAT composite films (CLP) using cellulose nanofibrils (CNF), lignin, and Poly (butylene adipate-terephthalate) (PBAT) as raw materials by solution casting method was described. With the adding of PBAT, the thermal stability, thermoplastic, mechanical properties were enhanced by improving the compatibility between components. The maximum tensile strength of CLP could reach 189.72 MPa, which increased 25.5 % compared to CNF/Lignin film. The average initial decomposition temperature could reach 321 °C, which was much higher than that of CNF and lignin. At the same time, its good heat-sealing performance made it suitable for practical use. Meanwhile, the composite films had excellent UV resistance and could block over 95 % of UV light. The antibacterial results indicated that the films had a good inhibitory effect on E. coli and S. aureus, with a maximum inhibitory ring diameter of 5.56 and 6.36 mm. In addition, the composite film also had excellent barrier capability to liquid and gas. The prepared film had potential to produce flexible packing, industrial compositing and biomedical fields.

Treating waste with waste: Lignin acting as both an effective bactericide and passivator to prevent acid mine drainage formation at the source

Acid mine drainage (AMD) induced by pyrite oxidation is a notorious and serious environmental problem, but the management of AMD in an economical and environmentally friendly way remains challenging. Here, lignin, a natural polymer and abundant waste, was employed as both a bactericide and passivator to prevent AMD formation. The addition of lignin to a mimic AMD formation system inoculated with Acidithiobacillus ferrooxidans at a lignin-to-pyrite weight ratio of 2.5: 10 reduced the combined abiotic and biotic oxidation of pyrite by 68.4 % (based on released SO42-). Morphological characterization of Acidithiobacillus ferrooxidans revealed that lignin could act on the cell surface and impair the cell integrity, disrupting its normal growth and preventing biotic oxidation of pyrite accordingly. Moreover, lignin can be used alone as a passivator to form a coating on the pyrite surface, reducing abiotic oxidation by 71.7 % (based on released SO42-). Through multiple technique analysis, it was proposed that the functional groups on lignin may coordinate with iron ions on pyrite, promoting its deposition on the surface. In addition, the inherent antioxidant activity of lignin may also be actively involved in the abatement of pyrite oxidation via the reduction of iron. Overall, this study offered a "treating waste with waste" strategy for preventing AMD formation at the source and opened a new avenue for the management of AMD.

Solvent-Induced Lignin Conformation Changes Affect Synthesis and Antibacterial Performance of Silver Nanoparticle

The emergence of antibiotic-resistant bacteria necessitates the development of novel, sustainable, and biocompatible antibacterial agents. This study addresses cytotoxicity and environmental concerns associated with traditional silver nanoparticles (AgNPs) by exploring lignin, a readily available and renewable biopolymer, as a platform for AgNPs. We present a novel one-pot synthesis method for lignin-based AgNPs (AgNPs@AL) nanocomposites, achieving rapid synthesis within 5 min. This method utilizes various organic solvents, demonstrating remarkable adaptability to a wide range of lignin-dissolving systems. Characterization reveals uniform AgNP size distribution and morphology influenced by the chosen solvent. This adaptability suggests the potential for incorporating lignin-loaded antibacterial drugs alongside AgNPs, enabling combined therapy in a single nanocomposite. Antibacterial assays demonstrate exceptional efficacy against both Gram-negative and Gram-positive bacteria, with gamma-valerolactone (GVL)-assisted synthesized AgNPs exhibiting the most potent effect. Mechanistic studies suggest a combination of factors contributes to the antibacterial activity, including direct membrane damage caused by AgNPs and sustained silver ion release, ultimately leading to bacterial cell death. This work presents a straightforward, adaptable, and rapid approach for synthesizing biocompatible AgNPs@AL nanocomposites with outstanding antibacterial activity. These findings offer a promising and sustainable alternative to traditional antibiotics, contributing to the fight against antibiotic resistance while minimizing environmental impact.

Amphiphilic nanofibrillated cellulose/polyurethane composites with antibacterial, antifouling and self-healing properties for potential catheter applications

This study focuses on enhancing interventional medical devices, specifically catheters, using a novel composite material. Challenges like corrosion and contamination in vivo, often caused by body fluids' pH, bacteria, and proteins, lead to mechanical damage, bacterial colonization, and biofilm formation on devices like catheters. The objective of this study was to prepare a versatile composite (HFs) by designing polyurethanes (HPU) with an ionic chain extender (HIID) and blending them with amphiphilic nanofibrillated cellulose (Am-CNF). The composite leverages dynamic interactions such as hydrogen bonding and electrostatic forces, as evidenced by Molecular Mechanics (MM) calculations. The H4F0.75 composite exhibited exceptional properties: 99 % length recovery post 600 stretching cycles at 100 % strain, rapid self-healing in artificial urine, high bactericidal activity, and excellent cell viability. Moreover, mechanical aging tests and UV-vis spectral analysis confirmed the material's durability and safety. These findings suggest that the HFs composite holds significant promise for improving catheters' performance in medical applications.

Evaluating the mechanism of soybean meal protein for boosting the laccase-catalyzed of thymol onto lignosulfonate via restraining non-specific adsorption

The control of laccase-catalyzed efficiency often relies on the utilization of modifying enzyme molecules and shielding agents. However, their elevated costs or carcinogenicity led to the inability for large-scale application. To address this concern, we found that a low-cost protein from soybean meal can reduce lignin's ineffective adsorption onto enzymes for improving the efficiency of thymol grafting to lignosulfonate. The results demonstrated that by adding 0.5 mg/mL of additional soybean meal protein, the thymol reaction ratio of the modified lignosulfonate (L-0.5 S) significantly boosted from 18.1 % to 35.0 %, with the minimal inhibitory concentrations of the L-0.5 S against Aspergillus niger dramatically improved from 12.5 mg/mL to 3.1 mg/mL. Multiple characterization methods were employed to better understand the benefit of the modification under the addition of the soybean meal protein. The CO and R1-O group content increased from 20.5 % to 37.8 % and from 65.1 % to 75.5 %, respectively. The proposed potential reaction mechanism was further substantiated by the physicochemical properties. The incorporation of soybean meal effectively mitigated the non-specific adsorption of lignosulfonate, resulting in a reduction of the surface area of lignin from 235.0 to 139.2 m2/g. The utilization of soybean meal as a cost-effective and efficient shielding agent significantly enhanced the efficiency of subsequent enzyme catalysis. Consequently, the application of soybean meal in commercial enzyme catalysis holds considerable appeal and amplifies the relevance of this study in preservative industries.

Hydrogels based on lignin extracted from cashew apple bagasse and its application in antimicrobial wound dressings

Hydrogels are versatile materials with a three-dimensional network structure that can retain water and release bioactive compounds. They have found applications in various fields, including agriculture, biomaterial synthesis, and pharmaceuticals. Incorporating natural antimicrobial compounds into hydrogels is a promising approach to developing non-toxic biomedical materials, particularly for wound healing dressings. It was evaluated the extraction and use of cashew apple bagasse lignin (CAB-Lig) due to its healing, anti-inflammatory, and antimicrobial properties for producing a hydrogel-based bandage. The extraction process involved acid and alkali treatments followed by precipitation. The antimicrobial potential of CAB-Lig was evaluated at different concentrations for formulating hydrogels. Hydrogels containing 0.1 % and 3 % lignin showed high swelling and liquid retention abilities. The 3 % lignin hydrogel exhibited effectiveness against Escherichia coli and Staphylococcus aureus. Incorporating CAB-Lig into the hydrogel structure improved its mechanical properties, making it more suitable for application as a bandage. Moreover, the extracted lignin showed low toxicity, indicating its safe use. A bandage was formulated by combining the CAB-Lig-based hydrogel with polyester, which possessed antimicrobial properties and demonstrated biocompatibility (L929 and HaCat cells). The results confirmed the potential of CAB-Lig for synthesizing hydrogels and dressings with antimicrobial properties, offering a sustainable solution for utilizing lignocellulosic biomass.

Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties

This study reports on the two-step manufacturing process of a filtration media obtained by first electrospinning a layer of polycaprolactone (PCL) non-woven fibers onto a paper filter backing and subsequently coating it by electrospraying with a second layer made of pure acidolysis lignin. The manufacturing of pure lignin coatings by solution electrospraying represents a novel development that requires fine control of the underlying electrodynamic processing. The effect of increasing deposition time on the lignin coating was investigated for electrospray time from 2.5 min to 120 min. Microstructural and physical characterization included SEM, surface roughness analysis, porosity tests, permeability tests by a Gurley densometer, ATR-FTIR analysis, and contact angle measurements vs. both water and oil. The results indicate that, from a functional viewpoint, such a natural coating endowed the membrane with an amphiphilic behavior that enabled modulating the nature of the bare PCL non-woven substrate. Accordingly, the intrinsic hydrophobic behavior of bare PCL electrospun fibers could be reduced, with a marked decrease already for a thin coating of less than 50 nm. Instead, the wettability of PCL vs. apolar liquids was altered in a less predictable manner, i.e., producing an initial increase of the oil contact angles (OCA) for thin lignin coating, followed by a steady decrease in OCA for higher densities of deposited lignin. To highlight the effect of the lignin type on the results, two grades of oak (AL-OA) of the Quercus cerris L. species and eucalyptus (AL-EU) of the Eucalyptus camaldulensis Dehnh species were compared throughout the investigation. All grades of lignin yielded coatings with measurable antibacterial properties, which were investigated against Staphylococcus aureus and Escherichia coli, yielding superior results for AL-EU. Remarkably, the lignin coatings did not change overall porosity but smoothed the surface roughness and allowed modulating air permeability, which is relevant for filtration applications. The findings are relevant for applications of this abundant biopolymer not only for filtration but also in biotechnology, health, packaging, and circular economy applications in general, where the reuse of such natural byproducts also brings a fundamental demanufacturing advantage.