Cellulose Nanostructures Research Articles

Effects of Anchovy, Mussel, and Shrimp Powders on the Flame Retardancy of Bacterial Cellulose

ABSTRACT This study aims to fabricate bacterial cellulose with improved flame retardancy by applying anchovy, mussel, and shrimp powders. The elemental analysis confirmed that raw marine powders contained nitrogen and sulfur elements which could play important roles in enhancing the flame retardancy of bacterial cellulose. Thermogravimetric analysis revealed the improved thermal stability of bacterial cellulose following entrapping and crosslinking of the marine powders. The fabricated bacterial celluloses with marine powders had similar levels of flame retardancy as that of bacterial cellulose treated with a commercial flame-retardant, sodium metasilicate nonahydrate, which was confirmed by the vertical flammability test and limiting oxygen index. The char morphology analysis revealed intumescent char on the surface of the samples, confirming the effect of marine powders on the flame retardancy of bacterial cellulose. Moreover, the marine powders were entrapped and crosslinked with bacterial cellulose nanostructures, and the chemical and crystalline structures of bacterial cellulose were retained. This study proposes an efficient method to improve the flame retardancy of bacterial cellulose by introducing marine powders via the combined entrapment and crosslinking method.

Cardamom Pickering emulsions stabilized by cellulose nanostructures as disinfection agents against bacteria and SARS-CoV-2

This study introduces a new disinfectant agent utilizing cardamom essential oil stabilized by cellulose nanomaterials (CN). The Pickering emulsion technique prevented oil degradation and extended its storage duration. Cellulose nanocrystals (CNC) or cellulose nanofibers (CNF) were utilized as stabilizers, and the emulsions were evaluated for surface tension, rheology, morphology, antimicrobial and antiviral activity against S. enterica, S. aureus, P. aeruginosa, E. coli, and SARS-CoV-2. Surface tension measurements indicated an electrostatic stabilization mechanism in CNC emulsions, exhibiting fluid behavior confirmed by rheological tests. On the other hand, CNF emulsions displayed drop packaging, characteristic of shear-thinning behavior, as confirmed by the Ostwald-de-Waele model. The emulsions exhibited antibacterial activity against S. aureus and P. aeruginosa, particularly the CNC samples, suggesting that nanocellulose alters the regulation of oil migration into the medium. Testing against SARS-CoV-2 revealed that cardamom essential oil required 30 min of contact for viral protein denaturation, while CNC and CNF emulsions took 60 and 50 min, respectively. This indicates that CN acts as an encapsulating agent, prolonging the oil’s release time and necessitating longer contact periods with the virus. These findings demonstrate the potential of these emulsions in developing new antimicrobial and antiviral products.

Removal of Cr(VI) using thiol-modified cellulose nanostructure for water sustainability: detailed adsorption study

Removal of Cr(VI) using thiol-modified cellulose nanostructure for water sustainability: detailed adsorption study

Nonlinear viscoelasticity of Melaleuca alternifolia essential oil Pickering emulsion stabilized with cellulose nanofibrils

Pickering emulsions are suitable technological approaches to stabilize the bioactive compounds of essential oils (EOs) with economic interests for the pharmaceutical, cosmetic and food industries using atoxic and renewable stabilizers, such as cellulose nanostructures. The Melaleuca alternifolia essential oil (MaEO) is recognized for its pronounced antimicrobial performance, which has attracted your interest in developing eco-friendly antiseptic products. In this contribution, we report the nonlinear viscoelasticity behavior of MaEO-in-water Pickering emulsions stabilized by cellulose nanofibrils (CNF) using Large Amplitude Oscillatory Shear (LAOS) tests. The rheological characterizations by Fourier Transform (FT) rheology spectroscopy and Lissajous plots enabled the correlation of the viscous and elastic behaviors with the physical processes involving the deformation of the emulsion. Also, the internal structure of the emulsion was elucidated by fluorescence optical microscopy. Several findings relative to the effects of the shear deformation amplitude over the nonlinear viscoelasticity of the emulsified system are reported here, which are essential to the industrial processes used to develop technological products.

Cellulose nanofibers, nanocrystals, and bacterial nanocellulose: Fabrication, characterization, and their most recent applications

AbstractIn nature, cellulose is present in fibrillar structures with alternative crystalline and amorphous fragments. The application of various chemical treatments (acid hydrolysis, enzymolysis, and oxidation) could lead to the extraction and purification of crystalline compartments in the form of cellulose nanocrystals. On the other hand, applying harsh mechanical treatments (milling, ultrasonication, high‐pressure processing, grinding, microfluidization, etc.) could result in the degradation of cellulose macrostructures into nano‐fibrillated segments without depletion of the amorphous fractions. These structures are called cellulose nanofibers. Bacterial nanocelluloses (BNCs) are another nanostructure of cellulose that is generated through the bottom–up technique. BNCs are the purest forms of cellulose nanostructures (CNSs). Hitherto, various spectroscopy and microscopy characterization techniques have been developed for in‐depth investigation of CNSs. The valuable information obtained via such instrumental techniques has opened windows on new horizons for the application of CNSs in novel realms. Nowadays, CNSs have found a seat in biomedical, packaging, emulsification, water filtration, and textile applications. In this review, after describing various forms of CNSs and their fabrication methods, the most recent techniques that have been utilized for the characterization of these structures plus their current application in different realms are comprehensively overviewed.

Determination of Lorazepam and Diazepam Using Modified Nanocrystalline Cellulose for Ultrasonic-Assisted Dispersive Solid Phase Microextraction (UA-DSPME) and Gas Chromatography-Mass Spectrometry (GC-MS)

A rapid and effective method utilizing ultrasonic assisted-dispersive solid-phase microextraction coupled with gas chromatography/mass spectrometry (GC/MS) was developed for the determination of lorazepam and diazepam in biological and aqueous samples. A modified nanocrystalline cellulose-based sorbent was prepared and applied for the microextraction of the analytes. The extraction efficiency of the sorbents prepared using self-assembled N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, including cellulose nanostructure and modified nanocrystalline cellulose, was compared. The modified cellulose nanostructure was characterized using thermogravimetric analysis (TGA), energy dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FTIR). Additionally, the study investigated the effects of relevant factors on the extraction/desorption performance, including extraction time, ionic strength, and the type and volume of the desorption solvent. The method achieved limits of detection of 1 ng mL−1 and 3 ng mL−1 and quantification limits of 4 ng mL−1 and 10 ng mL−1 for lorazepam and diazepam, respectively. Furthermore, the developed method demonstrated good repeatability with relative standard deviations of 4% and 6% (n = 5) for the spiked analyte aqueous solutions at 50 ng mL−1. The method also exhibited high linearity (R > 0.9996) in the range from 10 to 1000 ng mL−1.

Nanocellulose-based porous materials: Regulation and pathway to commercialization in regenerative medicine.

We review the recent progress that have led to the development of porous materials based on cellulose nanostructures found in plants and other resources. In light of the properties that emerge from the chemistry, shape and structural control, we discuss some of the most promising uses of a plant-based material, nanocellulose, in regenerative medicine. Following a brief discussion about the fundamental aspects of self-assembly of nanocellulose precursors, we review the key strategies needed for material synthesis and to adjust the architecture of the materials (using three-dimensional printing, freeze-casted porous materials, and electrospinning) according to their uses in tissue engineering, artificial organs, controlled drug delivery and wound healing systems, among others. For this purpose, we map the structure-property-function relationships of nanocellulose-based porous materials and examine the course of actions that are required to translate innovation from the laboratory to industry. Such efforts require attention to regulatory aspects and market pull. Finally, the key challenges and opportunities in this nascent field are critically reviewed.

Postbiotics in active food packaging: The contribution of cellulose nanocomposites

The food and pharmaceutical industries have developed innovative products containing probiotics, prebiotics, and synbiotics. According to International Scientific Association of Probiotics and Prebiotics (ISAPP), 'postbiotics' are preparations of inanimate microorganisms and/or their components which have host health benefits. Postbiotic preparations contain short-chain fatty acids, exopolysaccharides, vitamins, enzymes, bacteriocins, and theic acid. Various postbiotics improve human and animal health. In addition, there is evidence of their action as a food bio-preservative. Food packaging is important in food products protection from environmental damage and microbial contamination. Natural active agents are proxy to chemical agents in food packaing, attributed to consumer demand and awareness. Natural biopolymers have become the subject of much interest as they reduce environmental problems due to their abundance, biocompatibility, biodegradability, chemical stability and non-toxicity. Cellulose nanostructures with physicochemical and antibacterial properties have been widely studied for diverse applications, including food packaging to extend the shelf life of packaged food products. In this context, the present review proposes to provide a thorough discussion on production technologies, characterization, biological activities and possible applications of postbiotics in active food packaging based on cellulose nanocomposites.

Potential of Nanocellulose as a Dietary Fiber Isolated from Brewer's Spent Grain.

Steady growth in beer production is increasing the number of by-products named brewers' spent grain. Such by-products are a source of several components, where cellulose is usually present in high amounts. The aim of this study was to develop a protocol to obtain a mix of cellulose microfibers with an average diameter of 8-12 µm and cellulose nanoplatelets with an average thickness of 100 nm, which has several applications in the food industry. The process comprised one alkaline treatment followed by acid hydrolysis, giving a new mix of micro and nanocellulose. This mix was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and laser scanning microscopy corroborating the presence and measurements of the cellulose nanostructure, showing an aspect ratio of up to 500. Finally, we demonstrated that the administration of this new type of nanocellulose allowed us to control the weight of mice (feed intake), showing a significant percentage of weight reduction (4.96%) after 15 days compared with their initial weight, indicating the possibility of using this material as a dietary fiber.

Design of Innovative Biocompatible Cellulose Nanostructures for the Delivery and Sustained Release of Curcumin

Poor aqueous solubility, stability and bioavailability of interesting bioactive compounds is a challenge in the development of bioactive formulations. Cellulose nanostructures are promising and sustainable carriers with unique features that may be used in enabling delivery strategies. In this work, cellulose nanocrystals (CNC) and cellulose nanofibers were investigated as carriers for the delivery of curcumin, a model liposoluble compound. Nanocellulose modification with the surfactant cetyltrimethylammonium bromide (CTAB), tannic acid and decylamine (TADA), and by TEMPO-mediated oxidation were also tested and compared. The carrier materials were characterized in terms of structural properties and surface charge, while the delivery systems were evaluated for their encapsulation and release properties. The release profile was assessed in conditions that mimic the gastric and intestinal fluids, and cytotoxicity studies were performed in intestinal cells to confirm safe application. Modification with CTAB and TADA resulted in high curcumin encapsulation efficiencies of 90 and 99%, respectively. While no curcumin was released from TADA-modified nanocellulose in simulated gastrointestinal conditions, CNC-CTAB allowed for a curcumin-sustained release of ca. 50% over 8 h. Furthermore, the CNC-CTAB delivery system showed no cytotoxic effects on Caco-2 intestinal cells up to 0.125 g/L, meaning that up to this concentration the system is safe to use. Overall, the use of the delivery systems allowed for the reduction in the cytotoxicity associated with higher curcumin concentrations, highlighting the potential of nanocellulose encapsulation systems.

Structure and properties of nitrocellulose: approaching 200 years of research.

This review brings together almost 200 years of fragmented research on the structure of nitrocellulose to give an overview that covers production to application in composite materials. As a mouldable plastic, energetic rocket propellant and biomolecular binding membrane, nitrocellulose still finds widespread practical application today despite the inception of synthetic plastics. The influence of different cellulose source materials affects the structure and properties of nitrocellulose in ways that are not fully understood, and so this review brings together relatively recent developments in the understanding of cellulose nanostructures to highlight where the gaps in understanding now reside. The influence of nitration conditions on the material properties of nitrocellulose is described, together with the proposed mechanisms and equilibria associated with these synthetic routes. The reported crystal structures of nitrocellulose are also reviewed, and the confirmed structural features are separated from those yet to be proven. We also consider how nitrocellulose interacts with other compounds, to help explain the distinct properties of its composite materials. This review points to further work that is required to obtain well founded structural models of nitrocellulose, while highlighting opportunities to control and direct its structure to improve its material properties.

Organized mineralized cellulose nanostructures for biomedical applications.

Cellulose is the most abundant naturally-occurring polymer, and possesses a one-dimensional (1D) anisotropic crystalline nanostructure with outstanding mechanical robustness, biocompatibility, renewability and rich surface chemistry in the form of nanocellulose in nature. Such features make cellulose an ideal bio-template for directing the bio-inspired mineralization of inorganic components into hierarchical nanostructures that are promising in biomedical applications. In this review, we will summarize the chemistry and nanostructure characteristics of cellulose and discuss how these favorable characteristics regulate the bio-inspired mineralization process for manufacturing the desired nanostructured bio-composites. We will focus on uncovering the design and manipulation principles of local chemical compositions/constituents and structural arrangement, distribution, dimensions, nanoconfinement and alignment of bio-inspired mineralization over multiple length-scales. In the end, we will underline how these cellulose biomineralized composites benefit biomedical applications. It is expected that this deep understanding of design and fabrication principles will enable construction of outstanding structural and functional cellulose/inorganic composites for more challenging biomedical applications.

Elaboration, Characterization and Thermal Decomposition Kinetics of New Nanoenergetic Composite Based on Hydrazine 3-Nitro-1,2,4-triazol-5-one and Nanostructured Cellulose Nitrate.

This research aims to develop new high-energy dense ordinary- and nano-energetic composites based on hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) and nitrated cellulose and nanostructured nitrocellulose (NC and NMCC). The elaborated energetic formulations (HNTO/NC and HNTO/NMCC) were fully characterized in terms of their chemical compatibility, morphology, thermal stability, and energetic performance. The experimental findings implied that the designed HNTO/NC and HNTO/NMCC formulations have good compatibilities with attractive characteristics such as density greater than 1.780 g/cm3 and impact sensitivity around 6 J. Furthermore, theoretical performance calculations (EXPLO5 V6.04) displayed that the optimal composition of the as-prepared energetic composites yielded excellent specific impulses and detonation velocities, which increased from 205.7 s and 7908 m/s for HNTO/NC to 209.6 s and 8064 m/s for HNTO/NMCC. Moreover, deep insight on the multi-step kinetic behaviors of the as-prepared formulations was provided based on the measured DSC data combined with isoconversional kinetic methods. It is revealed that both energetic composites undergo three consecutive exothermic events with satisfactory activation energies in the range of 139–166 kJ/mol for HNTO/NC and 119–134 kJ/mol for HNTO/NMCC. Overall, this research displayed that the new developed nanoenergetic composite based on nitrated cellulose nanostructure could serve as a promising candidate for practical applications in solid rocket propellants and composite explosives.

Property evaluation of bacterial cellulose nanostructures produced from confectionery wastes

Bacterial cellulose (BC) was produced using crude confectionery waste hydrolysates. The highest BC concentration (5.7 g/L) was achieved by Komagataeibacter sucrofermentans cultivated in static cultures at carbon to free amino nitrogen ratio of 24.5 g/g and pH 5. BC was treated with H2SO4, HCl and combined H2SO4-HCl at varying hydrolysis times to produce BC nanostructures (BCNs). FTIR spectra of all BCNs demonstrated typical cellulose vibration bands, while the peaks at 709 cm−1 and 746 cm−1 indicated the presence of Iα and Ιβ allomorphs. Dynamic light scattering analysis showed polydispersity, while lower hydrodynamic radiuses (Rh) of 56 nm and 385 nm were observed in the case of H2SO4-assisted hydrolysis after 48 h. The crystallinity index (CrI) of BC (77.9%) was lower than that of BCNs, which demonstrated CrIs up to 98.1%. The ζ-potential values of BCNs reached up to − 34.3 mV after 48 h hydrolysis using H2SO4. SEM micrographs showed rodlike-shaped nanocrystals with a strong tendency towards aggregation and overlapping. Overall, ex-situ modification of waste derived BC led to effective nanostructures production with distinct properties and potential applications as bio-based packaging reinforcing agent.

A kinetic and isotherm study on removing methylene blue from aqueous solutions by oxidized cellulose nanostructure

A kinetic and isotherm study on removing methylene blue from aqueous solutions by oxidized cellulose nanostructure

A systematic study on the fabrication of transparent nanopaper based on controlled cellulose nanostructure from oil palm empty fruit bunch

A systematic study on the fabrication of transparent nanopaper based on controlled cellulose nanostructure from oil palm empty fruit bunch

Cellulose nanostructures obtained using enzymatic cocktails with different compositions

Cellulose nanostructures obtained from lignocellulosic biomass by the enzymatic route can offer advantages in terms of material properties and processing sustainability. However, most of the enzymatic cocktails commonly used in the saccharification of biomass are designed to promote the complete depolymerization of the cellulose structure into soluble sugars. Here, investigation was made of the way that the action of different commercially available cellulase enzyme cocktails can affect the production of nanocellulose. For this, enzymatic cocktails designed for complete or partial saccharification were compared, using eucalyptus cellulose pulp as a model feedstock. The results showed that all the enzymatic cocktails were effective in the formation of nanocellulose structures, with the complete saccharification enzymes being more efficient in promoting the coproduction of glucose (36.5 g/L, 87% cellulose conversion). The presence of auxiliary enzymes, especially xylanases, acted cooperatively to favor the production of nanostructures with higher crystallinity (up to 79%), higher surface charge (zeta potential up to −30.9 mV), and more uniform dimensions within the size range of cellulose nanocrystals (80 to 350 nm). Interestingly, for the enzymatic cocktails designed for partial saccharification, the xylanase activity was more important than the endoglucanase activity in the production of nanocellulose with improved properties. The findings showed that the composition of the enzymatic cocktails already used for complete biomass saccharification can be suitable for obtaining nanocellulose, together with the release of a glucose stream, in a format compatible with the biorefinery concept.

Beneficiation of cactus fruit waste seeds for the production of cellulose nanostructures: Extraction and properties

Cactus fruit waste seeds (CWS) are a by-product of the cactus fruit processing industry. Until now, CWS are not recoverable in any sector. The valorization of these residues may reduce their volume in the environment and transform them into valuable products. In this work, CWS have been identified for the first time as a sustainable lignocellulosic source. Cellulose microfibers (CMFs) and nanocrystals (CNCs) were successfully produced via alkali and bleaching treatments followed by sulfuric acid hydrolysis. It was found that the extracted CMFs showed an average diameter of 11 μm, crystallinity of 72%, and a yield of 25%. The as-produced CNCs exhibited a needle-like shape with a diameter of 13 ± 3 nm and length of 419 ± 48 nm, giving rise to an aspect ratio of 30.7, with a zeta potential value of – 30 mV and a charge content of sulfate groups of 287.8 mmol·kg−1. Herein, the obtained cellulosic derivatives with excellent properties from this underutilized waste can draw the attention of researchers towards CWS as a new type of biomass with virtually no hemicellulose, which could be of great interest to isolate and study the effects of how lignin interacts with cellulose.

Concentration and carbon chain length effects of cationic surfactant in enzymatic production of cellulose nanostructures

This work evaluated the effect of cationic surfactants [cetyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TDTAB), and dodecyltrimethylammonium bromide (DTAB)], and its concentration (0.03, 0.30, and 3.00 mM) on the production by enzymatic hydrolysis and surface modification of cellulose nanostructures (CNSs), from the one-step method. From FTIR spectra, changes and surfactant peaks and bands for modified CNSs compared to CNS were observed. For XRD results, the crystalline structure was more altered for CTAB and TDTAB, especially for higher concentrations, not changing cellulose’s crystalline structure. The surfactants affected colloidal stability, which CTAB promoted a higher shielding effect than DTAB and TDTAB, reducing the negative charges present in nanocellulose, while high concentrations lead to saturation of colloidal system, creating micelles and causing agglomerates. However, CNS CTAB showed smaller particle sizes for lower concentrations (90–100 nm), lower sugar production (50 µg g−1) for high concentrations, and cellulose nanocrystals obtaining. CNS DTAB and CNS TDTAB did not present statistical differences for particle size. Thermal stability was also affected. CNS DTAB presented the highest Tonset (250–254 °C) compared to CNS TDTAB and CNS CTAB. Thus, these results prove and suggest the possible application of these modified CNSs to develop nanocomposites with excellent dispersion, resulting in promising properties.

Polysaccharide-Based Nanocomposites for Food Packaging Applications.

The article presents a review of the literature on the use of polysaccharide bionanocomposites in the context of their potential use as food packaging materials. Composites of this type consist of at least two phases, of which the outer phase is a polysaccharide, and the inner phase (dispersed phase) is an enhancing agent with a particle size of 1–100 nm in at least one dimension. The literature review was carried out using data from the Web of Science database using VosViewer, free software for scientometric analysis. Source analysis concluded that polysaccharides such as chitosan, cellulose, and starch are widely used in food packaging applications, as are reinforcing agents such as silver nanoparticles and cellulose nanostructures (e.g., cellulose nanocrystals and nanocellulose). The addition of reinforcing agents improves the thermal and mechanical stability of the polysaccharide films and nanocomposites. Here we highlighted the nanocomposites containing silver nanoparticles, which exhibited antimicrobial properties. Finally, it can be concluded that polysaccharide-based nanocomposites have sufficient properties to be tested as food packaging materials in a wide spectrum of applications.