Search Results (551)

CO₂ laser processing has emerged as an efficient dry-finishing technique capable of inducing controlled chemical and morphological transformations in cotton and denim textiles. The strong mid-infrared absorption of cellulose enables localised photothermal heating, leading to selective dye decomposition, surface oxidation, and micro-scale ablation while largely preserving the bulk fabric structure. These laser-driven mechanisms modify colour, surface chemistry, and topography in a predictable, parameter-dependent manner. Low-fluence conditions predominantly produce uniform fading through fragmentation and oxidation of indigo dye; in comparison, moderate thermal loads promote the formation of carbonyl and carboxyl groups that increase surface energy and enhance wettability. Higher fluence regimes generate micro-textured regions with increased roughness and anchoring capacity, enabling improved adhesion of dyes, coatings, and nanoparticles. Compared with conventional wet processes, CO₂ laser treatment eliminates chemical effluents, strongly reduces water consumption and supports digitally controlled, Industry 4.0-compatible manufacturing workflows. Despite its advantages, challenges remain in standardising processing parameters, quantifying oxidation depth, modelling thermal behaviour, and assessing the long-term stability of functionalised surfaces under real usage conditions. In this review, we consolidate current knowledge on the mechanistic pathways, processing windows, and functional potential of CO₂ laser-modified cotton substrates. By integrating findings from recent studies and identifying critical research gaps, the review supports the development of predictable, scalable, and sustainable laser-based cotton textile processing technologies. Full article

Stimuli-responsive materials based on renewable biopolymers are highly attractive for developing sustainable chemical sensors. Here, two spiropyran derivatives (SP1 and SP2) were synthesized and covalently grafted onto cellulose, yielding the functional materials Cel-SP1 and Cel-SP2. Cellulose was selected as a biocompatible, biodegradable, and renewable support able to provide a stable, hydrogen-bond-rich microenvironment for chromic responses. Raman spectroscopy confirmed successful esterification, while SEM-EDS analyses revealed preserved cellulose morphology and the incorporation of nitrogen-rich spiropyran moieties. Both materials exhibited pronounced solvatochromic and pH-dependent behaviors in the solid state. Diffuse reflectance measurements revealed distinct bathochromic or hypsochromic shifts depending on solvent polarity and specific solute–matrix interactions, with DMF and DMSO producing the strongest responses. Under acidic vapors, both materials generated new absorption bands consistent with the formation of protonated merocyanine species, whereas basic vapors promoted partial or full reversion to the spiropyran form. Cel-SP1 and Cel-SP2 also displayed solvent- and pH-dependent luminescence, with Cel-SP2 showing a markedly higher sensitivity to protonation. Prototype solvent strips and acid/base vapor indicators demonstrated fast, naked-eye, reversible chromic transitions. These results highlight spiropyran-modified cellulose as an effective, renewable platform for dual solvent and acid/base vapor sensing. Full article

Background: Zn is an essential mineral nutrient for human health. Its deficiency may result not only from insufficient intake but also from impaired absorption. Dietary components released from the food matrix during digestion can interact in ways that either enhance or inhibit mineral bioavailability. Objectives: The primary aim of this study was to evaluate the bioaccessibility of Zn from dietary supplements, particularly in the context of diet type, chemical form, and pharmaceutical formulation effects. Methods: The experiment was conducted using an in vitro gastrointestinal digestion model with cellulose dialysis membranes. Zn content after digestion was determined using flame atomic absorption spectrometry (F-AAS). The method employed had been previously developed and validated for use in determining the bioaccessibility of mineral nutrients. Results: The bioaccessibility of Zn from the standard, basic, and high-fiber diets was 19.43, 16.18, and 8.12%, respectively. In the presence of a standard diet, the bioaccessibility of Zn from dietary supplements was within the range 1.77–36.09%, in the presence of a basic diet, 1.05–35.86%; and in the presence of a high-fiber diet, 1.37–35.94%. The highest values were observed for zinc picolinate, whereas the lowest were determined for zinc oxide. Conclusions: A high-fiber diet significantly reduced Zn bioaccessibility. Bioaccessibility is also strongly dependent on the chemical form of zinc. Full article

Research indicates that TRF improves mammalian metabolism and health via the microbiota–gut–brain axis. Previous studies showed that TRF promotes pig growth, but the intestinal mechanisms remain unclear. This study explored the impact of TRF on pig intestinal functions. Twelve male pigs were split into ad libitum feeding (FA) and TRF groups. FA pigs had free access to feed, whereas TRF pigs were fed during 07:00–08:00, 12:00–13:00, and 17:00–18:00. TRF enhanced crude protein digestibility by 18.9% (p = 0.045) and increased pancreatic chymotrypsin and lipase activities, while reducing ileal amylase, sucrase, and lipase activities. Transcriptomic analysis identified 1339 differentially expressed genes (DEGs) in the jejunum and 268 in the colon, indicating segment-specific responses. Jejunal DEGs were associated with protein digestion and absorption (e.g., SLC1A1, SLC38A2, XPNPEP2), extracellular matrix–receptor interaction, and PI3K-Akt signaling, while colonic DEGs were linked to starch and sucrose metabolism and circadian entrainment. Importantly, TRF decreased colonic starch by 24% (p = 0.02) and cellulose by 18% (p = 0.04), with low impact on nitrogenous substrates. These results suggest that TRF improves protein absorption in the upper intestine and carbohydrate metabolism in the lower intestine, providing insights for refining TRF strategies in precision nutrition. Full article

The inhibitory effects of natural cellulose (NC), microcrystalline cellulose (MC), and soluble fiber dextrin (SC) on amylase activity have been established; however, the underlying mechanisms remain poorly understood. This study employed fluorescence spectroscopy and fluorescence thermodynamics to investigate the quenching parameters, thermodynamic properties, and quenching mechanisms of cellulose interactions with α-amylase and amyloglucosidase. Structural alterations in both enzymes were examined using synchronous fluorescence and UV–visible absorption spectroscopy. The results indicated that NC, MC, and SC primarily induced static quenching of fluorophores in α-amylase and amyloglucosidase. When addition of SC reached 3%, SC reduced the fluorescence intensity of tyrosine and tryptophan residues in α-amylase by 70.9% and 86.8%, and in amyloglucosidase by 43.7% and 46.5%, respectively. Increasing SC levels also decreased hydrophobicity around tyrosine and tryptophan in α-amylase. These findings provide insights into designing cellulose-based amylase inhibitors through structural modulation for developing low-glycemic index (GI) foods. Full article

The effects of pectin extraction, cellulose purification, and sonication on the juice extraction residue from grapefruit were investigated. Pectin extraction using pressurized carbon dioxide (pCO₂) in a sodium oxalate solution (U-OX) lowered the cellulose content and increased the hemicellulose and lignin contents, whereas pectin extraction in deionized water (U-DW) did not affect these contents. Pectin extraction and cellulose purification induced hydrolysis and removal of non-crystalline cellulose regions. The sonication of the purified cellulose samples formed fiber-like structures with widths of <100 nm on their surfaces. The cellulose purification process increased the surface charge and formed a gel-like structure with increased hardness, adhesiveness, and film structure. These processes enhance the absorption of amphiphilic dyes, although to a lesser extent than that of the untreated juice extraction residue (UJR) after sonication. Before sonication, UJR adsorbed cationic dyes, whereas after, UJR adsorbed both polar and nonpolar dyes. These results suggest that juice residue could be used as a biomaterial with diverse potential applications. Full article

Climate change and the impacts related to nonbiodegradable synthetic materials highlight the need for sustainable alternatives. Biopolymers from renewable sources show great potential for producing hydrogels, which are three-dimensionally crosslinked materials with high water absorption. In this work, super-absorbent biodegradable hydrogels were produced via single-step reactive extrusion using mixtures of starch, gelatin, cellulose, and xanthan gum, with glycerol as a plasticizer, and citric acid as a crosslinking agent. Pelleted hydrogels were obtained with water absorption between 290% and 363%. Reactive extrusion promoted the formation of new ester and amide bonds, confirmed by FT-IR. Citric acid was effective as a crosslinker, and higher citric acid content (3%) produced samples with greater swelling, supported by the porous internal structure observed. Preliminary agricultural tests showed that the formulation with the highest citric acid content, when added to soil at 5%, significantly increased water-holding capacity and resulted in the highest germination rate of maize seeds. Overall, the extrusion process proved efficient, scalable, and environmentally friendly for producing biodegradable hydrogels for agricultural applications. Full article

Produced from the parenchymatous tissue of the stem pith of Tetrapanax papyrifer, the material known as pith paper served as a distinctive support medium for Chinese export paintings during the 19th and early 20th centuries. Today, it is commonly found in collections worldwide. Due to its inherently fragile structure, conservation interventions are often necessary. However, the material’s chemical composition and deterioration mechanisms remain poorly understood, which not only complicates treatment decisions but also undermines preventive conservation efforts. This study presents a systematic investigation into the anatomical structure and ageing behaviour of pith paper using a multi-analytical approach. Optical and scanning electron microscopy revealed a preserved honeycomb-like cellular architecture composed of thin-walled, entirely of non-lignified parenchyma cells, which contributes to the material’s mechanical fragility. Artificial ageing experiments showed a significant loss of flexibility, increased yellowing, and a decline in pH with ageing time. Infrared spectroscopy identified molecular changes consistent with cellulose chain scission, with decreases in O–H and C–O–C absorptions revealing acid-hydrolysis-driven breakdown, while colourimetry pointed to the formation of chromophoric degradation products. These findings offer a foundational understanding of pith paper’s vulnerabilities and provide essential insights for the development of informed conservation and storage strategies. Full article

This study explores the production of composites based on polylactic acid (PLA) reinforced with microcrystalline cellulose (MCC), using Additive Manufacturing technology via LCD. Polylactic acid, being biodegradable and possessing good mechanical properties, was combined with microcrystalline cellulose, which has a high modulus of elasticity, aiming to further improve its performance. Composites with different microcrystalline cellulose contents (1, 3, 5, and 10%) were obtained and compared to pure PLA. Characterization involved thermal, mechanical, morphological, and structural tests. The results showed that the addition of microcrystalline cellulose increases hardness, tensile strength, and modulus of elasticity. Scanning electron microscopy revealed more heterogeneous fracture surfaces in the composites compared to pure polylactic acid. Thermal stability varies according to the microcrystalline cellulose content, with increased degradation observed in some samples, reaching 1%. Increased water absorption was also detected with increasing microcrystalline cellulose concentration, indicating potential limitations in humid environments. The incorporation of microcrystalline cellulose, especially at moderate concentrations such as 3%, proved to be an effective strategy for improving the mechanical properties of polylactic acid. Full article

In recent years, the sustained and even increasing interest in the development and application of novel composite materials based on the polysaccharide bacterial cellulose (BC) has been driven by the accumulation of experimental data and the emergence of analytical reviews that narratively summarize these findings. This review presents a comparative and critical analysis of various approaches to the fabrication of BC-based composites. Among them, in situ biosynthesis is highlighted as the most promising strategy. In this approach, different additives are introduced directly into the culture medium of BC-producing microorganisms, enabling the formation of materials with different mechanical and physicochemical properties. Such a method also allows imparting to the composites a range of properties that BC itself does not possess, including antibacterial and enzymatic activity, as well as electrical conductivity. During the so-called “cell weaving” stage, performed by BC-producing microorganisms, diverse substances and microorganisms can be incorporated into the cultivation medium. By varying the concentrations of the introduced compounds, their ratios to the synthesized BC, and by employing different BC-producing strains and substrates, it becomes possible to regulate the characteristics of the resulting composites. Special attention is given to the role of various polysaccharides that are either introduced into the medium during BC biosynthesis or co-synthesized alongside BC within the same environment. Depending on the mode of incorporation of these additional polysaccharides, the resulting materials demonstrate variations in Young’s modulus and tensile strength. Nevertheless, they almost invariably exhibit a decreased degree of BC crystallinity within the composite structure and an enhanced water absorption capacity compared to the pure polymer. Full article

This study investigates the long-term service effects on Chinese fir (Cunninghamia lanceolata) components from ancient timber buildings in southern China. Anisotropic mechanical tests were performed to examine the evolution of mechanical properties from the perspectives of moisture absorption behavior, chemical composition, and microstructural characteristics. The results show that, after approximately 217 ± 12 years (Lvb specimens) and 481 ± 23 years (Xuc specimens) of service, the longitudinal compressive strength and corresponding elastic modulus of Chinese fir increased by about 11% and 15% and 33% and 71%, respectively, compared with fresh timber. The bending strength of the Lvb sample exhibited a slight reduction (approximately 6%), whereas the Xuc specimens showed the highest increase (33%). This difference is mainly attributed to long-term bending loads that caused structural damage in the Lvb beam specimens. In contrast, changes in lateral mechanical properties were negligible. Chemical composition analysis revealed an increase in extractive content and a reduction in cellulose and hemicellulose, leading to a notable rise in crystallinity. Scanning electron microscopy (SEM) observations further showed interlayer separation, wrinkling, and local collapse of the cell walls, suggesting significant cell wall densification. Overall, the evolution of mechanical properties is governed by the combined effects of increased crystallinity and microstructural densification, which together enhance the longitudinal and bending performance of aged timber with increasing service time. The findings provide a scientific basis for evaluating the performance and structural safety of aged timber components in the conservation of ancient timber buildings. Full article

Paper plays an important role in the packaging industry due to its low cost, light weight, recyclability and biodegradability. However, the use of paper as a packaging material is severely limited due to its hydrophilicity caused by the hydroxyl groups of cellulose. This study reports a simple preparation of highly hydrophobic kraft paper by a one-step dip coating method using [3-(2,2,3,3-tetrafluoropropoxy)propyl]silsesquioxane, {3-[(2,2,3,3,4,4,5,5-octafluoropentyl)oxy]propyl}silsesquioxane or {3-[(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl)oxy]propyl}silsesquioxane as hydrophobic agents. As a result of modification of kraft paper, a stable covalently bonded coating is formed on its surface. The coated kraft paper has demonstrated (1) high water resistance (the water contact angle (WCA) values were 124–141°, and the water absorption and the water vapor permeability (WVP) rates were significantly decreased), (2) excellent resistance to aggressive environments and temperature, (3) enhanced mechanical properties (tensile strength increased from 46.8 to 70.8 MPa), and (4) high wear resistance, as confirmed by sandpaper abrasion, bending, and finger-wipe tests. It was shown that the maximum contact angle values were achieved for kraft paper modified with a 5% polymer solution. The results of this study have great potential, given the simplicity of the modification method, for use in the production of paper-based packaging materials with water-repellent, enhanced mechanical and moisture-protective properties. Full article

Obesity and type 2 diabetes are closely linked and often referred to as diabesity. Therapies of diabesity include improving intestinal health and reducing intake of fat and sugars. Diagnosis of diabesity-related metabolic disorders would involve monitoring of glucose and other factors. Nanocellulose, also known as cellulose nanomaterials, is emerging as a potential material for various applications. It has unique properties, such as high surface area, biodegradable, biocompatibility and tunable surface chemistry. In this review, we initially provided a brief description of differently produced nanocellulose and their potential applications in different areas, including therapeutics and diagnostics, by focusing on obesity and diabetes. Then, the uptake, absorption, distribution, metabolism and excretion of nanocellulose were discussed. Further, the mechanisms of nanocellulose in modulating diabesity were summarized by emphasizing the role of gut microbiota. Finally, we discussed gut microbiota-related health effects of nanocellulose, both beneficial and detrimental. It was found that the interactions between nanocellulose and gut were complex, with alterations of microbial composition, metabolic activity, and the immune functions both locally and systemically. There seemed to be many beneficial changes following short-term exposure to nanocellulose (e.g., increased beneficial bacteria and decreased pathogenic ones); however, some of these effects were no longer seen after long-term consumption. Importantly, long-term nanocellulose consumption may be associated with certain detrimental health effects, e.g., malnutrition and its associated neurotoxicity, although additional studies are needed to substantiate such health implications. This information is critical for developing safe and effective nanocellulose derivatives that can be applied in food and medicine as well as to harness the benefits of the gut microbiota. Full article

Despite extensive use of polyvinylpyrrolidone (PVP)–polyethylene glycol (PEG) hydrogels in biomedical adhesives, a systematic understanding of how water content governs their rheological and adhesive performance remains lacking—particularly under variable humidity. This work addresses this gap by introducing 3–12 wt% hydroxypropyl cellulose (HPC) as a non-covalent crosslinker into a PVP/PEG gel (2/1 wt/wt) to tune its moisture uptake and stabilize viscoelasticity, thereby enabling robust, humidity-adaptive adhesion. Analysis of water content in hydrogels across a relative humidity range of 3% to 100% revealed that HPC restricts their water absorption capacity, thereby enhancing their tolerance to high-humidity conditions. The adhesive and rheological properties of the hydrogels were investigated as functions of HPC and water concentrations. With an increase in the HPC content, the adhesive properties of the initial low-water hydrogels decreased. However, high humidity strongly affected the hydrogels’ adhesive and rheological properties. The water content for hydrogels to maintain their adhesive properties was about 7–16%, depending on the hydrogel composition. This range corresponds to relative air humidity of 45–80%, tending to shift towards more moisture conditions under the effect of HPC. Thus, HPC enables PVP/PEG adhesives to operate over a broader range of relative humidities and in contact with wet skin when used in medicine as matrices for transdermal therapeutic systems, wound dressings, and flexible electrodes. Full article

Bone fractures are a serious health problem worldwide, and up to 10% of emergency department visits are related to such injuries. The development of effective materials for bone repair remains an urgent need of modern medicine. The aim of this study was to develop new scaffolds based on biopolymers (methyl cellulose and hydroxyethyl cellulose) modified with carbonate nanoparticles (CaCO₃, MgCO₃, ZnCO₃, MnCO₃, CuCO₃) for potential applications in bone tissue engineering. FTIR spectroscopy confirmed the successful formation of stable composite structures: characteristic absorption bands of the functional groups of the molecules that make up the scaffold, as well as specific fluctuations in metal-oxygen bonds (Ca–O, Zn–O, Cu–O), were revealed. Stability tests revealed the most stable samples when changing the pH and the ionic strength of the solution. The developed scaffold matrices had a high porosity in the range from 93.3% to 98.0%, and their moisture absorption capacity ranged from 858% to 1402%. Specific gravity measurements ranged from 0.050 g/cm³ to 0.067 g/cm³, indicating optimal material density for potential biomedical applications. Biological evaluation demonstrated different cytotoxic effects depending on the type of nanoparticles. Thus, matrices with minimal toxicity and promising biocompatibility (modified CaCO₃), as well as with significant toxic effects (modified ZnCO₃ and CuCO₃) were found. As a result, it was found that CaCO₃-modified scaffolds have the most favorable combination of structural, physical, and biological properties for potential applications in bone tissue engineering. The developed innovative materials are porous scaffolds in which nanoparticles of carbonates of osteotropic elements are embedded, which presumably contribute to the acceleration of bone tissue regeneration. However, this study provides encouraging preliminary data, and further in-depth biological and functional studies are needed to fully confirm the osteogenic potential and regenerative efficacy of the scaffolds. Full article