Cellulosic Materials Research Articles

Characterization of MSC Growth, Differentiation, and EV Production in CNF Hydrogels Under Static and Dynamic Cultures in Hypoxic and Normoxic Conditions.

Mesenchymal stem cells (MSCs) hold immense therapeutic potential due to their regenerative and immunomodulatory properties. However, to utilize this potential, it is crucial to optimize their in vitro cultivation conditions. Three-dimensional (3D) culture methods using cell-laden hydrogels aim to mimic the physiological microenvironment in vitro, thus preserving MSC biological functionalities. Cellulosic hydrogels are particularly promising due to their biocompatibility, sustainability, and tunability in terms of chemical, morphological, and mechanical properties. This study investigated the impact of (1) two physical crosslinking scenarios for hydrogels derived from anionic cellulose nanofibers (to-CNF) used to encapsulate adipose-derived MSCs (adMSCs) and (2) physiological culture conditions on the in vitro proliferation, differentiation, and extracellular vesicle (EV) production of these adMSCs. The results revealed that additional Ca2+-mediated crosslinking, intended to complement the self-assembly and gelation of aqueous to-CNF in the adMSC cultivation medium, adversely affected both the mechanical properties of the hydrogel spheres and the growth of the encapsulated cells. However, cultivation under dynamic and hypoxic conditions significantly improved the proliferation and differentiation of the encapsulated adMSCs. Furthermore, it was demonstrated that the adMSCs in the CNF hydrogel spheres exhibited potential for scalable EV production with potent immunosuppressive capacities in a bioreactor system. These findings underscore the importance of physiological culture conditions and the suitability of cellulosic materials for enhancing the therapeutic potential of MSCs. Overall, this study provides valuable insights for optimizing the in vitro cultivation of MSCs for various applications, including tissue engineering, drug testing, and EV-based therapies.

Biotechnology in Food Packaging Using Bacterial Cellulose.

Food packaging, which is typically made of paper/cardboard, glass, metal, and plastic, is essential for protecting and preserving food. However, the impact of conventional food packaging and especially the predominant use of plastics, due to their versatility and low cost, bring serious environmental and health problems such as pollution by micro and nanoplastics. In response to these challenges, biotechnology emerges as a new way for improving packaging by providing biopolymers as sustainable alternatives. In this context, bacterial cellulose (BC), a biodegradable and biocompatible material produced by bacteria, stands out for its mechanical resistance, food preservation capacity, and rapid degradation and is a promising solution for replacing plastics. However, despite its advantages, large-scale application still encounters technical and economic challenges. These include high costs compared to when conventional materials are used, difficulties in standardizing membrane production through microbial methods, and challenges in optimizing cultivation and production processes, so further studies are necessary to ensure food safety and industrial viability. Thus, this review provides an overview of the impacts of conventional packaging. It discusses the development of biodegradable packaging, highlighting BC as a promising biopolymer. Additionally, it explores biotechnological techniques for the development of innovative packaging through structural modifications of BC, as well as ways to optimize its production process. The study also emphasizes the importance of these solutions in promoting a circular economy within the food industry and reducing its environmental impact.

Functionalization of cellulose nanocrystals with a potent antimalarial compound: Synthesis, characterization, and biological studies

Cellulosic materials, such as cellulose nanocrystals (CNCs), are biocompatible, biodegradable and have unique and fascinating biomedical applications. Calxinin (CXN), a potent multistage antimalarial compound was functionalised with CNCs to improve biocompatibility and enhance the bioactivity of the resulting CNC-CXN nano-conjugate. Elemental analysis, powder X-ray, SEM, AFM, Infrared, and solid-state NMR spectroscopic techniques confirmed the composition of novel CNC-CXN nano-conjugate. Next, CNC-CXN nano-conjugate did not exhibit apparent cytotoxic effects on the sensitive Vero E6 cell line up to a concentration of 4.66 μg/μl. The CNC-CXN nano-conjugate was also evaluated for its preliminary efficacy on Plasmodium falciparum (3D7) malaria parasite and showed a 50 % inhibitory concentration value of 0.02 μg/μl. Overall, the selectivity index (SI) of the CNC-CXN nano-conjugate significantly improved to 233, indicating its suitability for further validation studies in animal models.

One pot gamma radiation mediated interfacial engineering of P-N synergistic flame retardant and antibacterial cellulose fabric: novel fabrics for future applications

The work describes an ionizing radiation mediated, toxic solvent free interfacial engineering of a novel Phosphorus-Nitrogen functionalized bifunctional cotton cellulose fabric (BCF) endowed with flame retardant (FR) and antibacterial properties. Monomers bis[2-(methacryloyloxy)ethyl] phosphate (B2MEP) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MAETC) in different proportions were co-grafted onto cellulose fabric via 60Co radiation mediated Simultaneous Irradiation Grafting Process (SIGP) to incorporate Phosphorus and Nitrogen functionalities. Effects of radiation dose, monomer concentration on the grafting yield (GY) were investigated and samples were characterized using TGA, ATR-FTIR, XRD, SEM–EDX, EDXRF, CHN Elemental Analysis and XPS analytical techniques. Limiting oxygen index (IS:13501/ASTM D 2863) and vertical flammability tests (IS11871-1986) were conducted to establish the halogen free, P-N synergistic FR properties of the fabric. All the co-grafted samples were observed to possess LOI values in excess of 30%, while BCF (1:2) (GY = ~ 44%) demonstrated LOI of 32% with the least char length of 74 mm in the vertical flammability tests. Tear strength studies were carried out as per ASTMD 1424-09. Antibacterial assay revealed that the fabric possessed activity against both gram positive (S. aureus) and gram negative (E. coli) organisms, with BCF (1:4) (GY = ~ 48%) demonstrating complete killing of ~ 5 log cycles for both microorganisms in 24 h. BCF retained its FR and antibacterial properties even after multiple washing cycles. With its bonafide green credentials, durability and unique properties, multifunctional BCF fabric prepared under optimized conditions of P/N ratio > 1.7 and GY ~ 45% can be a potential candidate for future applications.

Controlling the rheology of cellulose dissolved in 4–methylmorpholine N–oxide and tensile properties of precipitated cellulose films via mixture design

AbstractProperties which control the mechanical performance of regenerated or precipitated cellulose films are currently not well-known and a mechanistic understanding of the underlying phenomena should be established. Solution rheology is a crucial property for casting films and spinning fibres in terms of process runnability, and it can have a considerable effect on the mechanical properties of the prepared cellulose products. We hypothesized that the viscosity of cellulose dissolved in 4-methylmorpholine N-oxide (NMMO) and the mechanical properties of precipitated cellulose films could potentially be improved by controlling the molecular weight distribution of cellulose pulp, taking inspiration from traditional plastic industry. We evaluated the effects of pulp blends on the viscoelastic properties of dissolved cellulose-NMMO dopes and used the dopes to prepare cellulose films and determined their mechanical properties. Lastly, we employed the determined dope and film characteristics to build linear regression models for predicting dope rheology and mechanical performance of films. Mixture films with 2:1 and 1:2 ratios of pulps with both medium and high degree of polymerization showed in average 36% and 46% higher toughness than their unimodal versions. The model results demonstrated that film performance could be tailored by changing the pulp composition. These findings play an important role in optimizing the future processability of dissolved cellulose dopes for producing bio-based cellulose materials and could bring us a step closer to traditional plastic polymer disciplines by tailoring their performance based on pulp properties. Graphic abstract

Synthesis of bioplastics and the effects of additives on the mechanical, thermal and biodegradable properties

The mounting global concern over the environmental consequences of petroleum-based plastics has prompted significant research into sustainable alternatives, with bioplastics emerging as a forerunning solution. This systematic review elucidates the multifaceted synthesis processes of bioplastics, which are derived from renewable sources such as plant starches, cellulose, and waste materials. The synthesis encompasses stages from raw material selection, pre-treatment, to the incorporation of various additives, with the aim to achieve specific properties in the resultant bioplastics. A substantial focus of this review lies in comprehensively understanding the role of additives, which serve as the pivotal agents in tailoring the mechanical and thermal characteristics of bioplastics. Additives, including cross-linking agents, plasticizers, fillers, compatibilizers, and reinforcement agents, are critically examined for their influence on attributes such as tensile strength, flexibility, thermal stability, and biodegradability. Factors such as intermolecular interactions, hydrogen bonding, and moisture content, play a determining role towards the resultant properties. The prospects for bioplastics are rapidly expanding, signalling a transformative shift in various applications ranging from eco-friendly packaging to advanced biomedical devices. This article serves as a comprehensive guide to both researchers and industry stakeholders, providing deep insights into the synthesis of bioplastics and the transformative role additives play in their functional properties.

Applying Subcritical Water Extraction to Obtain Bioactive Compounds and Cellulose Fibers from Brewer Spent Grains

Of the three types of waste generated in beer processing, brewer’s spent grain (BSG) is the most abundant and has a high potential for valorization. In this work, defatted BSG (DB) was subjected to an extraction process with subcritical water at different temperatures to obtain extracts rich in phenols and the cellulosic fractions, which were also purified by using hydrogen peroxide (H2O2). The results showed that the dry extracts obtained at 170 °C were richer in phenolics (24 mg Gallic Acid Equivalent (GAE) g−1 DB), but with lower antioxidant capacity (71 mg DB·mg−1 2,2-diphenyl-1-pikryl-hydrazyl). This extract also showed the highest antibacterial potential against L. innocua (80 mg·mL−1) and E. coli (140 mg·mL−1) than those obtained at lower temperatures. The purification of cellulose from the treated residues, using hydrogen peroxide, revealed that DB is a limited source of cellulose material since the bleached fractions showed low yields (20–25%) and low cellulose purity (42–71%), even after four bleaching cycles (1 h) at pH 12 and 8% H2O2. Despite this, the subcritical water extraction method highlights the potential of a simple process as a technological option to convert underutilized side streams like beer bagasse into added-value, potential ingredients for innovative food and pharmaceutical applications.

Isolation and Characterization of Nanocellulose from Polypodiophyta Fern Using Chemo-Mechanical Method.

Nanocellulose is considered a promising and sustainable biomaterial, with excellent properties of biorenewability with improved mechanical properties. As a unique natural biopolymer, it has been applied to many different industries, where efficient and environmentally friendly productions are in demand. For the first time, ferns from the class Polypodiopsida were used for the isolation of cellulose fibers, which was performed using a chemo-mechanical method. As chemical treatment plays a crucial role in the isolation of nanocellulose, it affects the efficiency of the extraction process, as well as the properties of the resulting nanocellulose. Therefore, mechanical fibrillation was performed via grinding, while the chemical process consisted of three different treatments: alkali treatment, bleaching, and acid hydrolysis. In three different experiments, each treatment was separately prolonged to investigate the differing properties of isolated nanocellulose. Structural analysis and morphological analysis were investigated by SEM, EDS, FT-IR, and DLS. The thermal stability of cellulose fibers was investigated by TGA/DSC. The morphology of obtained nanocellulose was confirmed via SEM analysis for all samples, with particles ranging from 20 nm up to 600 nm, while the most consistent sizes were observed for NC3, ranging from 20 to 60 nm. FT-IR spectra showed prominent absorption peaks corresponding to cellulose, as well as the absence of absorption peaks, corresponding to lignin and hemicellulose. The EDS confirmed the elemental purity of nanocellulose, while TGA/DSC indicated higher thermal stability of nanocellulose, compared to untreated fern, which started to degrade earlier than nanocellulose. Such characteristics with unique properties make nanocellulose a versatile biomaterial for the industrial production of cellulosic materials.

Progress in Biopolymer Coatings for Achieving Sustainable Paper and Paperboard Packaging for Food Applications: A Brief Review

ABSTRACTPaper and paperboard are cellulosic materials used to manufacture food packaging. However, their low resistance to water and fat, as well as their poor barrier properties have limited their packaging applications as food contact materials. The current review analyses the use of biopolymeric coatings as an alternative to improve surface and barrier properties in paper and paperboard with focus in food sector application. Advances in coated paper (board) can be classified into three groups: (1) coatings manufactured with a single biopolymer; (2) coatings manufactured with composite biopolymers; and (3) biopolymeric coatings incorporated with bioactive molecules or nanoparticles. The use of a single or composite biopolymer coating improved the mechanical, barrier properties, and grease resistance. In contrast, the use of chemical compounds and nanoparticles has imparted active properties (antibacterial and ethylene scavengers) in the resulting coating paper (board). The water vapour transmission rate has been reduced with the use of biopolymeric coatings. Future studies should focus on applying coated paper (board) in foods with a special interest in food self‐life, migration, and toxicity.

Graphenic materials prepared from magnesium ions doping cellulose and its application in electrochemical detection of adenine and guanine

Graphenic materials of high quality are in high-demand. In this study, a method is proposed for the synthesis of graphenic materials by the pyrolysis of cellulose materials. Cellulose materials were oxidized and doped with magnesium prior to pyrolysis, which improved the graphitization efficiency significantly. The obtained graphenic materials, exhibiting a well-developed porous structure, high specific surface area, were employed for the fabrication of a composite electrode. The composite electrode was employed for the simultaneously detection of adenine (AE) and guanine (GA) with excellent performance in the electrocatalytic oxidation response. Various electrochemical tests were carried out to optimized the detection of AE and GA. Under the optimized conditions, the simultaneous quantification of GA and AE is achieved from 1 – 100 μM with detection limits from 0.4 – 0.6 μM. This study offers a promising alternative for the synthesis of graphenic materials of high quality.

Carboxylated celluloses as effective stabilizers for super-stable Pickering emulsions: Effects of different carboxyl moieties and particle morphologies on performance

Carboxyl functionalization of cellulose could enhance its stabilizing ability in Pickering emulsions, though the influences of different carboxylation methods remain largely unknown. In order to fill in this knowledge gap, three typical carboxylated cellulosic materials, TEMPO-oxidized cellulose nanofibrils (TCN), carboxymethylated cellulose nanofibrils (CM-CN) and carboxymethyl cellulose (CMC), have been investigated to stabilize Pickering emulsions. There is a common feature among the three carboxylated cellulosic materials that they were all adsorbed at oil-water interface to form an elastic cellulose particle shell around oil droplets. However, the networks formed in the aqueous phase were quite different. For both TCN and CM-CN, the physical entanglement of the fibers and the interactions between fibers, mainly intramolecular hydrogen bonds, led to strong networks in the aqueous phase, thus contributing to good stability of Pickering emulsions. In contrary, the interaction between the suspended CMC particles was limited, which could not drive them to form a continuous network in the aqueous phase, so that CMC was least effective to stabilize oil droplets as indicated by the clearly observed phase separation even in the freshly prepared Pickering emulsions. Specifically, CM-CN with a larger aspect ratio (length of 499 ± 306 nm and diameter of 7 ± 2 nm), excellent thermal stability and comparatively high three phase contact angle (78.4°) was an effective stabilizer to prepare a super-stable Pickering emulsion, which had best emulsifying index (100%) even after 30-day of storage. This study demonstrated that different carboxyl functionalization would lead to different properties of cellulose, thus affecting their performance in stabilizing Pickering emulsions.

Characteristics of bast fibers derived from the bark of three paper-mulberry cultivars in Korea

Bast fiber from paper-mulberry (Broussonetia papyrifera) has long been utilized for handmade paper in Asia, serving as a prominent non-wood cellulose material. When restoring paper cultural assets, selecting a similar paper to the original ensures longevity and prevents deterioration issues like warping or tearing. The production of handmade paper involves several processes, including refining, steaming, and bleaching of raw materials. Once formed into sheets, the physical properties of the paper are dictated by these materials and remain unchanged unless the paper is newly made. Handmade paper production is labor-intensive and time-consuming, emphasizing the need for careful raw material selection to match desired characteristics. This study evaluated the dendrological, morphological, anatomical, and chemical compositions of three paper-mulberry wood types cultivated in Korea and inferred their suitability as pulp for papermaking or repair of archival paper specimens. Paper-mulberry wood showed differences in fiber length according to molecular phylogenetic characteristics, but there were no differences in anatomical characteristics owing to the immaturity of the wood. This study investigated the characteristics of the bast fibers from the bark of paper-mulberry trees with different genetic traits to identify favorable factors likely to affect the pulp and papermaking process and paper quality.

Comparative In Vivo Biocompatibility of Cellulose-Derived and Synthetic Meshes in Subcutaneous Transplantation Models.

Despite the increasing interest in cellulose-derived materials in biomedical research, there remains a significant gap in comprehensive in vivo analyses of cellulosic materials obtained from various sources and processing methods. To explore durable alternatives to synthetic medical meshes, we evaluated the in vivo biocompatibility of bacterial nanocellulose, regenerated cellulose, and cellulose nanofibrils in a subcutaneous transplantation model, alongside incumbent polypropylene and polydioxanone. Notably, this study demonstrates the in vivo biocompatibility of regenerated cellulose obtained through alkali dissolution and subsequent regeneration. All cellulose-derived implants triggered the expected foreign body response in the host tissue, characterized predominantly by macrophages and foreign body giant cells. Porous materials promoted cell ingrowth and biointegration. Our results highlight the potential of bacterial nanocellulose and regenerated cellulose as safe alternatives to commercial polypropylene meshes. However, the in vivo fragmentation observed for cellulose nanofibril meshes suggests the need for measures to optimize their processing and preparation.

Ultrafast surface esterification of cellulosic materials in aqueous media at room temperature

Ultrafast surface esterification of cellulosic materials in aqueous media at room temperature

Design of experiments investigation into the production of all cellulose composites using regenerated cellulosic textiles

All cellulose composites (ACCs) can be produced from native and man-made cellulosic fibres; use of the latter provides an additional application for waste-derived regenerated fibers. ACCs were prepared using an ionic liquid dissolution method, utilizing a regenerated cellulose (Tencel) textile, with and without an interleaf cellulosic film. A design of experiments methodology was applied to explore process-property relationships; concentration of the ionic liquid and the processing time and temperature were investigated. It was found that the film remained in-between the textile layers, rather than penetrating the fiber assembly, in contrast to our previous work on cotton-based ACCs. This is due to the structural differences between Tencel and cotton fabric. A multi-response optimization was conducted through a central composite face centered strategy, which captured the film system more strongly. Optimized processing conditions were identified, yielding a Young’s modulus and strain-to-failure of 5.3 GPa and 3.5% respectively, validated through in-lab samples.

Enhancing the Mechanical Properties of Regenerated Cellulose through High-Temperature Pre-Gelation

This paper investigates the effects of pre-gelation on cellulose dissolved in LiCl/DMAc solutions to enhance the properties of regenerated cellulose materials. This study focuses on characterizing the crystallinity, molecular orientation, and mechanical performance of cellulose fibers and hydrogels prepared with and without pre-gelation treatment. X-ray diffraction (XRD) analysis reveals that crystallinity improvement from 55% in untreated fibers to 59% in fibers pre-gelled for 3 and 7 days, indicating a more ordered arrangement of cellulose chains post-regeneration. Additionally, XRD patterns show improved chain alignment in pre-gelled fibers, as indicated by reduced full width at half the maximum of Azimuthal scans. Mechanical testing demonstrates a 30% increase in tensile strength and a doubling of the compression modulus for pre-gelled fibers compared to untreated fibers. These findings underscore the role of pre-gelation in optimizing cellulose material properties for applications ranging from advanced textiles to biomaterials and sustainable packaging. Future research directions include further exploration of the structural and functional benefits of pre-gelation in cellulose processing and its broader implications in material science and engineering.

From Cellulose Solutions to Aerogels and Xerogels: Controlling Properties for Drug Delivery.

A cheap and easy-to-recycle solvent, namely, aqueous NaOH with no additives, was used to dissolve cellulose and make cross-linker-free materials with varying porosity, testing them as drug delivery devices. Cellulose solutions were gelled, coagulated in a nonsolvent (water, ethanol), and dried either using supercritical CO2 (aerogels) or low-vacuum evaporation (named "xerogels"). Aerogels had densities of around 0.1 g/cm3 and specific surface areas (SSAs) of 200-400 m2/g. A significant influence of the first nonsolvent and drying mode on material properties was recorded: when the first nonsolvent was ethanol and low-vacuum drying was performed from ethanol, aerogel-like xerogels were obtained with densities of around 0.2 g/cm3 and SSAs of 200-260 m2/g. Other conditions (under evaporative drying) resulted in cellulose with much lower porosity and SSA. All materials were evaluated as drug delivery devices in simulated gastrointestinal fluids; theophylline was used as a model drug. Materials of high porosity exhibited shrinking and rapid drug release, whereas denser materials swelled and showed slower release. Two release mechanisms were suggested: diffusion through aqueous media in pores and diffusion through swollen pore walls. The results demonstrate a large spectrum of options for tuning the properties of porous cellulose materials for drug release applications.

Cotton Fabric Coating by Cationic Starches to Aim for Salt‐Free Reactive Dyeing

AbstractCationic starch (CatS) coating of cellulose fabrics enables salt‐free reactive dyeing. However, the relation of the degree of substitution and CatS concentration in the dyeing procedure are open issues. Accordingly, three cationic starches of increasing degree of substitution were used at different concentrations for the coating of cotton fabrics. Fabrics were evaluated for stiffness, dye uptake, dye exhaustion, wash fastness and nitrogen content.With an increasing degree of substitution coating solutions become more viscous, resulting in increased wet pick‐up and less stiff coated fabrics. These fabrics show increasing dye absorption and color generation. Due to the molecular size of the cationic starch, yarn/fiber ring dyeing is supposed present. Specifically, color generation can be adjusted by initial cationic starch coating concentration. Above 5 % CatS concentration ceases to have an increasing coloration effect. Pre‐treating a cellulose fabric with approximately 2.2 % CatS (Ds=0.7) enables similar coloration to a standard reactive dyeing protocol. Light fastness is reduced by 1–1.5 compared to salt‐based reactive dyeing. Rub fastness decreases by 1–2 only for higher substituted cationic starches (Ds=0.7). Nitrogen analysis reveals that a share of the CatS elutes off the fabrics into the dye bath.

Hydrothermal extraction of microcrystalline cellulose from post-consumer indigo denim fabrics and evaluation of its UV blocking property

Abstract Waste cotton clothes, including post-consumer denim fabrics, are abundant biopolymer sources due to their high cellulose content. These waste materials commonly end up in landfills, posing health and environmental concerns and losing valuable cellulosic materials. To address these, this study aims to extract and characterize microcrystalline cellulose (MCC) from post-consumer indigo denim fabrics using a one-step hydrothermal method and evaluate its UV-blocking properties. FTIR and TGA analysis of raw and bleached denim confirmed the presence and purity of cotton cellulose and the indigo dye. Extracted MCC yielded 70-84%, with a degree of polymerization (DP) of 281-299. XRD analysis of the MCC showed a cellulose Type I structure. FTIR suggests the removal of amorphous phases of cellulose, leaving the crystalline structure. SEM meanwhile revealed rod-shaped and rough-surfaced MCC particles with diameters of 10-20 μm and lengths of 45-60 μm. Both FTIR and SEM indicated the retention of indigo dye on MCC surface. Increased acid hydrolysis time led to smaller particle sizes and higher degree of crystallinity (CrI). Indigo PVA-MCC films showed good transparency and effective UV blocking. These results indicate the successful conversion of denim to MCC via the hydrothermal method and the stability of indigo dye in the cellulose matrix.

Cellulose, cellulose nanofibers, and cellulose acetate from Butia fruits (Butia odorata): Chemical, morphological, structural, and thermal properties

Cellulose possesses numerous advantageous properties and is a precursor to compounds and derivatives. The objective of this study was to isolate and characterize cellulose from Butia fruits and simultaneously produce cellulose nanofibers and cellulose acetate from the isolated cellulose. Cellulose extraction was performed using a combination of alkaline and bleaching treatments, while the production of cellulose nanofibers and cellulose acetate was achieved through acid hydrolysis and acetylation, respectively. The materials were characterized by their chemical composition, size distribution, zeta potential, morphology, relative crystallinity (XRD), functional groups (FTIR), molecular structure (NMR), and thermal stability (TGA). The Butia crude fibers presented 49.4 % cellulose, 4.5 % hemicellulose, 25.4 % lignin, and 1.3 % ash. The cellulose nanofibers presented an average diameter ranging from 13.7 to 93.1 nm and exhibited a high degree of crystallinity (63.3 %). FTIR, XRD, 13C, and 1H NMR analyses confirmed that the isolation processes effectively removed amorphous regions from the cellulose nanofibers and confirmed the cellulose acetylation process. As demonstrated, cellulosic materials derived from Butia fruit exhibit promise for various applications, including their potential use as reinforcing agents in polymer matrices, due to their high extraction yield, thermal properties, and crystallinity.