Lignin-facilitated growth of Ag/CuNPs on surface-activated polyacryloamidoxime nanofibers for superior antibacterial activity with improved biocompatibility

Lignin micro-nanospheres loaded with silver nanoparticles for excellent antibacterial activity

Silver nanoparticles (AgNPs) have been widely studied for their tunable structural properties and broad-spectrum antibacterial properties. However, AgNPs are easy to accumulate and unstable. Herein, lignin micro-nanospheres (LMNs) loaded with silver nanoparticles were prepared by chemical reduction method. The AgNPs/LMNs composite manifested good stability and dispersibility to AgNPs. The total release content of Ag/Ag+ was only 0.13 % within 12 h and only 2.25 % within 24 h due to the self-antibacterial properties and high surface activity of LMNs. The AgNPs/LMNs showed excellent inhibition and killing effects on both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) within 24 h, with the minimum bactericidal concentrations (MBC) of 5 and 2.5 μg/mL, respectively. After collaborative photothermal-assisted treatment, the MBC was reduced to 2.5 and 1.25 μg/mL, respectively. Compared to the same type of AgNPs composite, the concentration of antibacterial components required using the method was reduced by >90 %. The AgNPs in the AgNPs/LMNs caused direct damage to the bacterial cell membrane by generating reactive oxygen species and releasing silver ions, thus achieving an antibacterial effect. This provides an effective strategy for the development of new antibacterial materials.

Advances in Bacterial Cellulose-Based Scaffolds for Tissue Engineering: Review

Bacterial cellulose (BC) has emerged as a highly versatile and promising biomaterial in tissue engineering, with potential applications across skin, bone, cartilage, and vascular regeneration. Its exceptional properties like high mechanical strength, superior biocompatibility, excellent moisture retention, and inherent ability to support cell adhesion and proliferation, make BC particularly effective for wound healing and skin regeneration. These attributes accelerate tissue repair and foster new tissue formation, highlighting its value in skin-related applications. Additionally, BC's capacity to support osteogenic differentiation, combined with its mechanical robustness, positions it as a strong candidate for bone tissue engineering, facilitating regeneration and repair. Recent advancements have emphasized the development of BC-based hybrid scaffolds to enhance tissue-specific functionalities, including vascularization and cartilage regeneration. These innovations aim to address the complex requirements of various tissue engineering applications. However, challenges remain, particularly regarding the scalability of BC production, cost-effectiveness, and the long-term stability of BC-based scaffolds. Such barriers continue to limit its broader clinical adoption. This review critically examines the synthesis methods, intrinsic properties, and recent innovations in the design of BC-based scaffolds, offering insights into their potential to revolutionize regenerative medicine. Furthermore, it addresses the key challenges and limitations that must be overcome to enable the clinical integration of BC. By addressing these limitations, BC could play a transformative role in advancing tissue engineering and regenerative therapies, bridging the gap between laboratory research and clinical application.

Lignin-Based Functional Materials in Agricultural Application: A Review

The demand for biodegradable, sustainable, and eco-friendly alternatives is growing in crop production and protection, which forces an urgent need for society to shift toward more sustainable agricultural development. In recent years, the development and research of lignin-based functional materials have gained increasing attention and impetus, and their use has become more widespread in sustainable agriculture. This review covers the latest research on the potential applications of lignin-based functional materials in plant protectants, sensors for pollutant detection, toxic element removal in soil and water, enzyme immobilization, plant growth regulators/biostimulants, hydrogels, and mulching films. Finally, future challenges and perspectives of lignin-based functional materials are discussed to provide a new strategy for the promotion of sustainable agriculture.

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.

Copper-Based Nanozymes: Potential Therapies for Infectious Wounds

Bacterial infections are a significant obstacle to the healing of acute and chronic wounds, such as diabetic ulcers and burn injuries. Traditional antibiotics are the primary treatment for bacterial infections, but they present issues such as antibiotic resistance, limited efficacy, and potential side effects. This challenge leads to the exploration of nanozymes as alternative therapeutic agents. Nanozymes are nanomaterials with enzyme-like activities. Owing to their low production costs, high stability, scalability, and multifunctionality, nanozymes have emerged as a prominent focus in antimicrobial research. Among various types of nanozymes, metal-based nanozymes offer several benefits, including broad-spectrum antimicrobial activity and robust catalytic properties. Specifically, copper-based nanozymes (CuNZs) have shown considerable potential in promoting wound healing. They exhibit strong antimicrobial effects, reduce inflammation, and enhance tissue regeneration, making them highly advantageous for use in wound care. This review describes the dual functions of CuNZs in combating infection and facilitating wound repair. Recent advancements in the design and synthesis of CuNZs, evaluating their antimicrobial efficacy, healing promotion, and biosafety both in vitro and in vivo on the basis of their core components, are critically important.

Anti-inflammatory and anti-oxidative electrospun nanofiber membrane promotes diabetic wound healing via macrophage modulation

BACKGROUND

In the inflammatory milieu of diabetic chronic wounds, macrophages undergo substantial metabolic reprogramming and play a pivotal role in orchestrating immune responses. Itaconic acid, primarily synthesized by inflammatory macrophages as a byproduct in the tricarboxylic acid cycle, has recently gained increasing attention as an immunomodulator. This study aims to assess the immunomodulatory capacity of an itaconic acid derivative, 4-Octyl itaconate (OI), which was covalently conjugated to electrospun nanofibers and investigated through in vitro studies and a full-thickness wound model of diabetic mice.

RESULTS

OI was feasibly conjugated onto chitosan (CS), which was then grafted to electrospun polycaprolactone/gelatin (PG) nanofibers to obtain P/G-CS-OI membranes. The P/G-CS-OI membrane exhibited good mechanical strength, compliance, and biocompatibility. In addition, the sustained OI release endowed the nanofiber membrane with great antioxidative and anti-inflammatory activities as revealed in in vitro and in vivo studies. Specifically, the P/G-CS-OI membrane activated nuclear factor-erythroid-2-related factor 2 (NRF2) by alkylating Kelch-like ECH-associated protein 1 (KEAP1). This antioxidative response modulates macrophage polarization, leading to mitigated inflammatory responses, enhanced angiogenesis, and recovered re-epithelization, finally contributing to improved healing of mouse diabetic wounds.

CONCLUSIONS

The P/G-CS-OI nanofiber membrane shows good capacity in macrophage modulation and might be promising for diabetic chronic wound treatment.

"Micro-to-nano": Reengineering of jute for constructing cellulose nanofibers as a next-generation biomaterial

Micro-to-nano transformation can make a material unique. This research uses jute microfiber to extract Holo and Alpha forms of cellulose, which are later attempted to electrospun into superfine nanofibers (NFs). Initial investigation of morphological, physicochemical, crystallographic, and thermal properties confirmed successful synthesis of Holo and Alpha-cellulose (H/A-cellulose). Afterwards, the electrospinnable concentration of H/A-cellulose was optimized and their bead-free ultrafine NFs in the range of 109-145 nm were fabricated. FTIR analysis confirmed the source composition in Holo and Alpha CNF with the partial formation of trifluoroacetyl esters. Alpha CNF exhibited better structural integrity despite the crystallinity and thermal stability deteriorated in both Holo and Alpha CNF. Both Holo and Alpha CNF exhibited adequate mechanical performance and liquid uptake properties. Alpha CNF showed better morphological stability in organic solvents and slower biodegradation than Holo CNF. Subsequent investigation revealed that both Holo and Alpha CNF didn't exhibit cytotoxic effects on COS-7 cells and above 90 % of cells were viable in contact with both CNF. Significant proliferation and attachment of COS-7 cells were noticed within 7 days of incubation with the prepared CNF. Our findings revealed that jute-extracted cellulose can be a viable and potential source for constructing cellulose-based advanced nano-biomaterials.

Breakthrough Curve Modeling and Analysis for Lysozyme Adsorption by Tris(hydroxymethyl)aminomethane Affinity Nanofiber Membrane

In this study, a polyacrylonitrile nanofiber membrane was first hydrolyzed and then functionalized with tris(hydroxymethyl)aminomethane (P-Tris), then used as an affinity nanofiber membrane for lysozyme adsorption in membrane chromatography. The dynamic adsorption behavior of lysozyme was investigated in a flow system under various operating parameters, including adsorption pHs, initial feed lysozyme concentration, loading flow rate, and the number of stacked membrane layers. Four different kinetic models, pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion kinetic models, were applied to experimental data from breakthrough curves of lysozyme. The results showed that the dynamic adsorption results were fitted well with the pseudo-second-order kinetic model. The breakthrough curve experimental results show significant differences in the breakthrough time, the dynamic binding capacity, the length of the mass transfer zone, and the utilization rate of the membrane bed under different operating parameters. Four dynamic adsorption models (i.e., Bohart-Adams, Thomas, Yoon-Nelson, and BDST models) were used to analyze the breakthrough curve characteristics of the dynamic adsorption experiments. Among them, the Yoon-Nelson model was the best model to fit the breakthrough curve. However, some of the theoretical results based on the Thomas and Bohart-Adams model analyses of the breakthrough curve fit well with the experimental data, with an error percentage of <5%. The Bohart-Adams model has the largest difference from the experimental results; hence it is not suitable for breakthrough curve analysis. These results significantly impact dynamic kinetics studies and breakthrough curve characteristic analysis in membrane bed chromatography.