Surface Of Cellulose Nanofibers Research Articles

Surface Modification of Cellulose Nanofiber (CNF) from Banana (<i>Musa paradisiaca</i>) Pseudo-Stem with Cetyltrimethylammonium Bromide (CTAB)

Modifying cellulose nanofiber (CNF) is necessary to improve its hydrophobic properties for broader applications. The surface of CNF from the banana pseudo-stem (Musa paradisiaca) was modified using a cationic surfactant, Cetyltrimethylammonium Bromide (CTAB). Principally, CNF surface sulfate ester group counterions are substituted for cetyltrimethylammonium (CTA+), which acts as a bulky, amphiphilic cation. Three steps produce CNF from banana pseudo-stem: delignification, bleaching, and acid hydrolysis. The acid hydrolysis process was optimized by adjusting the concentration of sulfuric acid. A 50% sulfuric acid concentration produced CNF with a size of 118 nm and the highest stability of its zeta potential value of -28.4 mV. The hydrophobicity of CNF increased after CTAB modification, as demonstrated by a change in surface charge from -28.4 mV to +3.63 mV. The modified CNF50-CTAB had a contact angle of 45.5º. In addition, CNF50-CTAB was unstable in water and formed stable colloidal suspensions in chloroform.

The nanocellulose fiber scaffold to construct a hierarchical phenolic coating on cotton fiber surfaces for inactivating pathogens through an enhanced protein adsorption mechanism

Emerging pathogens present a significant societal threat, and biological protection textiles are expected to play a pivotal role in controlling their spread. However, incorporating highly effective pathogen transmission-blocking abilities into textiles while ensuring their large-scale production remains challenging. This work has successfully developed a hierarchically structured coating for cotton fibers, which exhibits enhanced antiviral and antibacterial functionalities compared to existing phenolic coating methods. The multilevel coating consisted of a cellulose nanofibers (CNFs) scaffold on cotton fibers, along with a phenolic layer constructed of 4,4-bis(4-hydroxyphenyl)valeric acid (DPA) on the CNF surfaces. The bioactive textile exhibited remarkable antiviral and antibacterial capabilities with exceptional durability, while demonstrating strong protein affinity for pathogen destruction. Especially, the CNFs with diameters below 10 nm show significant size effect in capturing phi6. This is primarily due to their complementary shape matching the spike proteins, resulting in an increased number of binding sites and improved inactivation effectiveness. Moreover, the modification process was demonstrated to be scalable in a pad-dry-cure line commonly employed by textile finishing factories, and the resultant coating ensured reliable safety for human skin without sacrificing wearing comfort. This approach opens up new possibilities for developing protective textiles that effectively block pathogen transmission.

P(MMA-co-MAA)/cellulose nanofibers composites: Effect of hydrogen bonds on molecular mobility

Cellulose nanofibers (CNFs) nanocomposites were prepared using poly(methylmethacrylate-co-methacrylic acid) (PMMA-co-MAA) to investigate the macromolecular mobility within the composite, with particular focus on the effect of H-bonding. Dynamic mechanical analysis (DMA) and broadband dielectric spectroscopy (BDS) were used to fully characterize the molecular mobility for which the effect of the introduction of H-bond forming moieties and the addition of CNFs (5 and 15 wt%) were assessed. Despite similar Tg values (determined by Differential Scanning Calorimetry), a deeper analysis of the relaxation times associated with the α-relaxation evidenced a significant effect induced by CNFs, which is in fact slowing down the macromolecular relaxation processes. The activation energy of the β-relaxation remained unchanged despite the introduction of MAA units in the main chain and the successive addition of CNFs. However, the latter led to the appearance at low frequencies of a new β’-relaxation correlated with the interactions between the CNF surface -OH groups and the -COOH groups of the matrix. The γ-relaxation showed a 45 % increase in activation energy from PMMA to PMMA-co-MAA + CNF nanocomposites regardless of the CNF content, due to the possibility of CNFs to interact and hinder the motion of the main chain methyl groups in α position.

Cellulose Nanofiber-Based Nanocomposite Films with Efficient Electromagnetic Interference Shielding and Fire-Resistant Performance.

Cellulose nanofiber (CNF) has been widely used as a flexible and lightweight polymer matrix for electromagnetic shielding and thermally conductive composite films because of its excellent mechanical strength, environmental performance, and low cost. However, the lack of flame retardancy seriously hinders its further application. Herein, renewable and biomass-sourced l-arginine (AR) was used to surface-modify ammonium polyphosphate (APP) and an environmentally friendly biobased flame retardant was synthesized by the coordination of zinc sulfate heptahydrate (ZnSO4·7H2O), which was named AAZ. AAZ was deposited on the surface of CNF by electrostatic adsorption and Zn2+ complexation. The biobased compatibilizer Triton X-100 was employed to assist the exfoliation of graphene nanoplatelets (GNPs) and their dispersion in the CNF matrix. Due to the formation of a dense lamellar layer resembling a shell structure, the CNF/GNPs composite films with a tensile strength of 52 MPa were obtained via vacuum-assisted filtration. Because the phosphorus-containing group produces a protective layer of PxOy compound and promotes the formation of a carbon layer by CNF and the combustion releases ammonia gas, the fire-resistant performance of the composite films was greatly improved. Compared with the pure CNF film, the composite film exhibits 33% reduction in PHRR value and 40% reduction in THR. In addition, the CNF/GNPs composite film with 20 wt % GNPs possessed high conductivity (2079.2 S/m) and electromagnetic interference (EMI) shielding effectiveness (37 dB). The ultrathin CNF/GNPs composite films have excellent potential for use as efficient flame retardant and EMI shielding materials.

Developing Bio-Nano Composites Using Cellulose-Nanofiber-Reinforced Epoxy

This study introduces the development of a novel bio-nano composite via the dispersion of cellulose nanofibers (CNF) in epoxy. The surface of cellulose nanofibers was functionalized using a two-step chemical treatment to enhance dispersion. The interfacial characteristics of CNF were improved using alcohol/acetone treatments. The modified CNF (M-CNF) demonstrated enhanced compatibility and improved dispersion in the epoxy matrix as evidenced by scanning electron microscopy. Based on the analysis of X-ray diffraction patterns, M-CNF did not disturb the crystalline phases at the interface. The results of mechanical testing showed that M-CNF worked as a reinforcing agent in the bio-nano composite. The flexural modulus increased from 1.4 to 3.7 GPa when M-CNF was introduced. A similar trend was observed for tensile strength and impact resistance. The optimum performance characteristics were observed at M-CNF of 0.6%. At higher dosages, some agglomeration was observed, which weakened the interfacial properties. This study promotes sustainability and resource conservation while offering CNF as a sustainable reinforcing agent to develop bio-nano composites.

Cellulose Nanofiber Films with Gold Nanoparticles Electrostatically Adsorbed for Facile Surface-Enhanced Raman Scattering Detection.

Cellulose nanofiber (CNF) holds great promise in applications such as surface-enhanced Raman scattering (SERS), catalysis, esthesia, and detection. This study aimed to build novel CNF-based SERS substrates through a facile synthetic method. Citrate-reduced gold nanoparticles (AuNPs) were adsorbed on the cationized CNF surface due to electrostatic interactions, and uniform AuNPs@(2,3-epoxypropyl trimethylammonium chloride)EPTMAC@CNF flexible SERS substrates were prepared by a simple vacuum-assisted filtration method. The probe molecule methylene blue was chosen to assess the performance of the CNF-based SERS substrate with a sensitivity up to 10-9 M, superior signal reproducibility (relative standard deviation (RSD) = 4.67%), and storage stability (more than 30 days). Tensile strength tests indicated that the CNF-based films had good mechanical properties. In addition, CNF-based substrates can easily capture and visually identify microplastics in water. These results demonstrate the potential application of the flexible, self-assembled AuNPs@EPTMAC@CNF flexible SERS substrate for prompt and sensitive detection of trace substances.

Pengembangan Acetylated Cellulose Nanofibers dari Microcrystalline Cellulose: Studi Perubahan Gugus Fungsi dan Indeks Kristalinitas melalui Asetilasi dan Nanofibrilasi

Cellulose nanofiber (CNF) has promising potential as a reinforcement in polymer matrix nanocomposites. CNF is polar or hydrophilic due to having many hydroxyl groups. When CNF particles are combined with a non-polar polymer matrix, the CNF is difficult to distribute evenly and tends to agglomerate due to differences in polarity so that the strengthening effect of CNF is limited. To overcome this problem, it is necessary to chemically modify the CNF surface. Acetylation is one of the most widely used CNF surface modification methods to increase the compatibility between a non-polar polymer matrix and CNF. Through the acetylation process, some of the hydroxyl groups of CNF are replaced with acetyl groups which are hydrophobic. Furthermore, the CNF resulting from the acetylation process is known as acetylated CNF (acetylated cellulose nanofibers or ACNF). The acetylation process is carried out by first mixing microcrystalline cellulose (MCC) particles into 75 mL of acetic anhydride solution. Next, the mixture was stirred using a high-speed blender for 30 minutes for the MCC nanofibrillation process to occur. In this research, the influence of acetylation and nanofibrillation processes on the characteristics of ACNF was studied through studying chemical structure changes using ATR-FTIR and crystallinity index using XRD. The results of the ATR-FTIR analysis show that there are 3 new peaks in the ACNF spectrum, namely at 1720, 1369 and 1203 cm-1, which proves that there is a change in the structure of cellulose after being given acetylation treatment. The results of XRD show that surface treatment of acetylation and nanofibrillation with a high-speed blender increases the ACNF crystallinity index value by 82.53%. Overall, the resulting ACNF has great potential as a reinforcement for polymer matrix nanocomposites.

Rapid arsenate removal using novel adsorbent: Iron–zirconium nanoneedle-modified cellulose nanofibers

Developing an environmentally benign, low-cost, and upgraded adsorbent possesses a great demand for arsenic removal from natural water systems. In this study, cellulose nanofibers (CNF) modified with iron and zirconium oxide nanoneedles (Fe-Zr-NN-CNF) were successfully synthesized for the rapid removal of As(V). Fe-Zr-NNs were homogeneously distributed on the surface of CNF using a simple hydrothermal synthesis route, which helped to overcome the agglomeration and loss of active sites of as-synthesized adsorbents. The vertical arrangement of the nanoneedles makes the active sites easily accessible to As(V), enabling its rapid and efficient removal. The surface morphology of the adsorbent and the successful chemical modification of CNF by impregnating iron and zirconium oxide nanoneedles were confirmed by field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray absorption near-edge structure, and X-ray powder diffraction. In addition, the metal concentration on the CNF surface was optimized by spectroscopic analysis to attain the superior efficiency of the adsorbent. The experimental kinetic data were fitted to a pseudo-second-order kinetic model, which suggested that the As(V) adsorption was chemisorption. The adsorption isotherm data were more closely fitted by the Langmuir model than by the Freundlich model. The maximum As(V) adsorption capacity (213 µmol g−1) was observed at pH 7.0 and at 25 °C. The kinetic study revealed that the As(V) adsorption rate was rapid in the first minute, and reached to equilibrium within 20 min. These results indicate that the adsorbent can efficiently and rapidly remove As(V) from natural water.

Nitrogen and sulfur doped carbon dots coupled cellulose nanofibers: A surface functionalized nanocellulose membranes for air filtration

BackgroundThe current study demonstrates a process to produce a hybrid bio-organic cellulose nanofiber (CNF) membrane with high filtration performance and mechanical strength. This was accomplished by 1) tailoring the functional groups of CNFs, notably using the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical oxidation and 2) coupling them with carbon dots (CDs). MethodsThe surface chemistry of CNF was modified through TEMPO oxidation. Subsequently, a coupling reaction was conducted with CDs synthesized hydrothermally, as well as synthesized N/S-CDs derived from palm bunch. The impact of these modifications on the formation of air filters was investigated. Modification and coupling of surface modified CNF were evaluated by advanced analytical techniques. The toxicity of pristine and N/S-CDs coupled cellulose nanofibers was studied by cytotoxicity assay. Vacuum filtration and sequential compression molding techniques were applied to fabricate CNF filters, and the particle filtration efficiency of different filters was determined. Significant findingsThe coupling of N/S-CDs to CNF significantly enhanced the tensile strength of the membranes. Coupling of N/S-CDs to TEMPOCNF membrane showed the highest tensile strength (9.3 ± 1.9 MPa), while N/S-CDs coupling to CNF membrane exhibited slightly lower tensile strength (9.0 ± 1.3 MPa). The average pore diameter of the filters was slightly reduced after the CNF surface modification, which led to higher differential pressure across the filters. Both the pristine and TEMPO-modified CNF filters displayed high filtration efficiency for 0.3 μm-aerosol particles (∼70–81 %) and 0.1 μm-aerosol model particles (∼50–68 %), which was in a range of bacteria and viruses. This study provided detailed information about the fabrication of modified CNF filters with high air filtration efficiency for micro/nano-sized particles using cost-effective biodegradable raw materials.

Ambient Aqueous Synthesis of Imine-Linked Covalent Organic Frameworks (COFs) and Fabrication of Freestanding Cellulose Nanofiber@COF Nanopapers.

Covalent organic frameworks (COFs) are usually synthesized under solvothermal conditions that require the use of toxic organic solvents, high reaction temperatures, and complicated procedures. Additionally, their insolubility and infusibility present substantial challenges in the processing of COFs. Herein, we report a facile, green approach for the synthesis of imine-linked COFs in an aqueous solution at room temperature. The key behind the synthesis is the regulation of the reaction rate. The preactivation of aldehyde monomers using acetic acid significantly enhances their reactivity in aqueous solutions. Meanwhile, the still somewhat lower imine formation rate and higher imine breaking rates in aqueous solution, in contrast to conventional solvothermal synthesis, allow for the modulation of the reaction equilibrium and the crystallization of the products. As a result, highly crystalline COFs with large surface areas can be formed in relatively high yields in a few minutes. In total, 16 COFs are successfully synthesized from monomers with different molecular sizes, geometries, pendant groups, and core structures, demonstrating the versatility of this approach. Notably, this method works well on the gram scale synthesis of COFs. Furthermore, the aqueous synthesis facilitates the interfacial growth of COF nanolayers on the surface of cellulose nanofibers (CNFs). The resulting CNF@COF hybrid nanofibers can be easily processed into freestanding nanopapers, demonstrating high efficiency in removing trace amounts of antibiotics from wastewater. This study provides a route to the green synthesis and processing of various COFs, paving the way for practical applications in diverse fields.

A novel and ultrasensitive electrochemical immunosensor based on nanocellulose-Ti3C2Tx@ZrO2 nano framework for the detection of ovalbumin

A versatile and highly sensitive sensing platform based on nanocellulose/MXene/ZrO2 nano framework has been developed at the surface of a glassy carbon electrode (GCE) for detecting ovalbumin (Ova). To create this innovative nano framework, dialdehyde groups were introduced onto the surface of cellulose nanofibers (CNFs), which were then decorated with MXene nanosheets and nanostructured zirconia. Nanocellulose/MXene/ZrO2 nano framework was used as electrochemical mediator and immobilization environment that provided the large surface area and 197 % increment in the electrochemical signal which allowed the Ova detection in the femtomolar range. Ovalbumin antibody was immobilized on the surface of dialdehyde cellulose nanofiber through covalent bonding between amino groups of Ova and dialdehyde groups of CNFs. The assembly process of nano framework, anti-Ova, and Ova antigen were characterized using electrochemical approaches (CV and DPV). The fabricated immunosensor is further applied to DPV detection of Ova and it demonstrated a linear response to Ova antigen in the linear range of 0.01–1000 pg/mL. With optimal experimental conditions, the detection limit, quantification limit and sensitivity of Ova were found to be 1.1 fg/mL, 0.01 pg/mL and 0.1497 μA pg/mL cm−2, respectively. The fabricated immunosensor exhibited high selectivity, reproducibility, and interference resistance and achieved excellent recoveries in real food samples spiked with Ova, indicating its potential applicability in food safety monitoring.

A Polyelectrolyte Colloidal Brush Based on Cellulose: Perspectives for Future Applications.

This feature article is devoted to the evaluation of different techniques for producing colloidal polyelectrolyte brushes (CPEBs) based on cellulose nanofibers modified with grafted polyacrylates. The paper also reviews the potential applications of these CPEBs in designing electrode materials and as reinforcing additives. Additionally, we discuss our own perspectives on investigating composites with CPEBs. Herein, polyacrylic acid (PAA) was grafted onto the surface of cellulose nanofibers (CNFs) employing a "grafting from" approach. The effect of the PAA shell on the morphological structure of a composite with polypyrrole (PPy) was investigated. The performance of as-obtained CNF-PAA/PPy as organic electrode material for supercapacitors was examined. Furthermore, this research highlights the ability of CNF-PAA filler to act as an additional crosslinker forming a physical sub-network due to the hydrogen bond interaction inside chemically crosslinked polyacrylamide (PAAm) hydrogels. The enhancement of the mechanical properties of the material with a concomitant decrease in its swelling ratio compared to a pristine PAAm hydrogel was observed. The findings were compared with the recent theoretical foundation pertaining to other similar materials.

Preparation of cellulose nanofiber/Fe3O4/CaCO3 magnetic biocomposite by air capture and its application on purifying lead-contaminated water: Removal, immobilization and separation

Utilizing nature resource is one of the most effective ways to achieve sustainability development. In this work, super low-concentration CO2 in the atmosphere and rich and cheap biomaterial cellulose were used to prepare magnetic bio-composite, cellulose nanofiber/Fe3O4/CaCO3 (CFeCa). By capturing CO2 in air, Ca2+ was transformed into calcite CaCO3, which subsequently coated on cellulose nanofiber (CNF). Fe3O4 with about 50 nm in size were also observed to attach to the CNF. Thus, CNF bridged these two inorganic materials, which together fabricated stable composite with strong mutual coupling. The prepared CFeCa was applied to purify the lead-polluted water as water treatment agent. Its up-taken capacity for Pb2+ reached as high as 1010 mg·g−1. Almost 100% removal efficiency was attained, even treating Pb2+ wastewater in a wide concentration range from 5 to 250 ppm. Meanwhile, CFeCa is stable property during application. After running for 30 cycles, the treated water still met drinkable water standard. More importantly, the recovered lead was also bound on the surface of CNF, which make it easy to be separated from water and avoiding the risk of second pollution. Cheap raw materials and multiple merits of resulted composite offer CFeCa a perspective application as water treatment agent.

Triple physical cross-linking cellulose nanofibers-based poly(ionic liquid) hydrogel as wearable multifunctional sensors

A novel triple physical cross-linking poly(ionic liquid) hydrogel, composed of poly(acrylamide-co-dodecyl methacrylate-co-1-vinyl-3-methyluracil-imidazolium chloride)/cellulose nanofibers-Ca2+ (PADV/CNFs-Ca2+), was synthesized through micellar-copolymerization followed by a solvent-soaked procedure. The synergistic interactions in polymer network (i.e. the hydrophobic association of dodecyl methacrylate moiety in surfactant micelles, the hydrogen bondings between imidazolium monomer segments and other monomer segments in polymers, and the ionic coordination between Ca2+ and -COO− on cellulose nanofibers surface) endowed the hydrogel with excellent mechanical properties, including high strength (754 kPa of tensile strength and 1905 kPa of compressive strength), outstanding stretchability (1963 %), elastic modulus (56.5 kPa) and remarkable mechanical durability (200 cycles with 500 % deformations and 100 cycles at 50 % compression strain). Besides, this hydrogel exhibited other advantages, such as satisfied conductivity (28.7 mS/cm), high strain/pressure/temperature-sensitive behavior, precise and stable signal transmission, varying degrees of antibacterial activity, and biocompatibility. Owing to the exceptional comprehensive performance, the hydrogel was then assembled as a multifunctional sensor to monitor the joint motion, vocal cord vibration, tactile sensation and body temperature with remarkable sensitivity in real time. This work offered a new strategy for the fabrication of durable, biocompatible, antibacterial and conductive materials for wearable multifunctional electronic devices.

Supramolecular systems based on chitosan and chemically functionalized nanocelluloses as protective and reinforcing fillers of paper structure

Supramolecular systems based on chitosan and cellulose nanofibers (CNFs) with a different surface modification (TEMPO-oxidation and carboxymethylation) were investigated and utilized for the functional consolidation of paper. Prior to the paper consolidation, the interactions between chitosan and CNFs dispersed in aqueous solvent were studied. It was detected that the peculiar surface functionalization of nanocellulose is crucial to control the chitosan/CNFs electrostatic attractions and, consequently, the entropic/enthalpic contributions and the stoichiometry of the biopolymer adsorption onto the cellulose nanofibers. Dynamic Light Scattering and rheological experiments revealed that the presence of biopolymeric chains on the CNFs surface favors the entanglement and the aggregation between the nanofibers reinforcing their network. It was observed that chitosan and nanocellulose exhibit synergetic effects on the paper consolidation in terms of reinforcing action, surface hydrophobization and enhancement of the fire-resistance. In conclusion, this paper demonstrates that the electrostatic interactions between chitosan and functionalized nanocellulose drive the formation of hybrid fillers suitable for paper consolidation. Chitosan coated CNFs possess an improved capacity to penetrate the paper structure causing an enhancement of the mechanical resistance and surface hydrophobization. Moreover, chitosan/CNFs create a protective barrier for heat transfer that prevents the paper combustion.

Preparation and environmental analysis of biodegradable polylactic acid and modified cellulose nanofiber composites

Polylactic acid (PLA) and cellulose nanofibers (CNFs) show promise as bio-based alternatives to non-degradable plastics, which pose environmental challenges. Yet, CNFs' hydrophilicity hampers their dispersion in hydrophobic PLA. This study modifies CNF surfaces with diisocyanate compounds to create hydrophobic isocyanate-modified CNFs (mCNFs), enhancing their compatibility with PLA. One isocyanate of the diisocyanate compound is grafted onto the surface of CNF and the isocyanate content varied by adjusting grafting reaction time. PLA-mCNF composites are produced by a twin-screw extruder and show improved mechanical properties and biodegradability compared to pristine PLA and PLA-unmodified CNF composite. The environmental impacts of PLA-mCNF composites are evaluated using a life-cycle assessment method and compared to corn grain-based PLA. The optimized PLA-mCNF composite (6 h of grafting reaction) has lower environmental impacts than corn grain-based PLA, with global warming and fossil resource scarcity of 3.021 kg eq and 0.813 kg oil eq, respectively. This study underscores the feasibility of optimizing PLA composite properties by employing a small proportion of toxic diisocyanate on CNF surfaces. The findings highlight the potential of such modified composites to offer improved sustainability and performance characteristics, contributing to the development of eco-friendly materials.

A facile route for concurrent fabrication and surface selective functionalization of cellulose nanofibers by lactic acid mediated catalysis

Celulose nanofibers are lightweight, recycable, biodegradable, and renewable. Hence, there is a great interest of using them instead of fossil-based components in new materials and biocomposites. In this study, we disclose an environmentally benign (green) one-step reaction approach to fabricate lactic acid ester functionalized cellulose nanofibrils from wood-derived pulp fibers in high yields. This was accomplished by converting wood-derived pulp fibers to nanofibrillated “cellulose lactate” under mild conditions using lactic acid as both the reaction media and catalyst. Thus, in parallel to the cellulose nanofibril production, concurrent lactic acid-catalyzed esterification of lactic acid to the cellulose nanofibers surface occured. The direct lactic acid esterification, which is a surface selective functionalization and reversible (de-attaching the ester groups by cleavage of the ester bonds), of the cellulose nanofibrils was confirmed by low numbers of degree of substitution, and FT-IR analyses. Thus, autocatalytic esterification and cellulose hydrolysis occurred without the need of metal based or a harsh mineral acid catalysts, which has disadvantages such as acid corrosiveness and high recovery cost of acid. Moreover, adding a mineral acid as a co-catalyst significantly decreased the yield of the nanocellulose. The lactic acid media is successfully recycled in multiple reaction cycles producing the corresponding nanocellulose fibers in high yields. The disclosed green cellulose nanofibril production route is industrial relevant and gives direct access to nanocellulose for use in variety of applications such as sustainable filaments, composites, packaging and strengthening of recycled fibers.

Improved anti-biofilm activity and long-lasting effects of novel serratiopeptidase immobilized on cellulose nanofibers.

Today, enzymatic treatment is a progressive field in combating biofilm producing pathogens. In this regard, serratiopeptidase, a medicinally important metalloprotease, has been recently highlighted as an enzyme with proved anti-biofilm activity. In the present study, in order to increase the long-lasting effects of the enzyme, serratiopeptidase and the novel engineered forms with enhanced anti-biofilm activity were immobilized on the surface of cellulose nanofibers (CNFs) as a natural polymer with eminent properties. For this, recombinant serratiopeptidases including the native and previously designed enzymes were produced, purified and conjugated to the CNF by chemical and physical methods. Immobilization was confirmed using different scanning and microscopic methods. The enzyme activity was assessed using casein hydrolysis test. Enzyme release analysis was performed using dialysis tube method. Anti-biofilm activity of free and immobilized enzymes has been examined on Staphylococcus aureus and Pseudomonas aeruginosa strains. Finally, cytotoxicity of enzyme-conjugated CNFs was performed by MTT assay. The casein hydrolysis results confirmed fixation of all recombinant enzymes on CNFs by chemical method; however, inadequate fixation of these enzymes was found using cold atmospheric plasma (CAP). The AFM, FTIR, and SEM analysis confirmed appropriate conjugation of enzymes on the surface of CNFs. Immobilization of enzymes on CNFs improved the anti-biofilm activity of serratiopeptidase enzymes. Interestingly, the novel engineered serratiopeptidase (T344 [8-339ss]) exhibited the highest anti-biofilm activity in both conjugated and non-conjugated forms. In conclusion, incorporation of serratiopeptidases into CNFs improves their anti-biofilm activities without baring any cytotoxicity. KEY POINTS: • Enzymes were successfully immobilized on cellulose nanofibers using chemical method. • Immobilization of enzymes on CNFs improved their anti-biofilm activity. • T344 [8-339ss] exhibited the highest anti-biofilm activity in both conjugated and non-conjugated forms.

Enhanced stability of methylammonium lead bromide perovskite interlaced on cellulose nanofiber

The interest in highly luminescent organic-inorganic hybrid perovskite, methylammonium lead bromide (MLB) nanocrystals (NCs) has grown significantly due to their many applications in optoelectronics. However, the biggest hurdle has been the effective use of the materials in large optoelectronic applications and their poor stability in various environmental conditions. To address the problem of the poor stability of highly luminescent MLB nanostructures, we synthesized MLB NCs on the surface of cellulose nanofibers (CNF) for the first time. The synthesized (MLB@CNF) composite shows green emission peak at 529 nm. The scanning electron microscopy images confirm that perovskite NCs are well attached to the surface of cellulose nanofiber. These composite materials offer improved stability and luminescent features in moist environments for over six months. The developed interfacial interaction strategy will provide a novel approach to obtain durable nanocrystals using cellulose-based materials.

Novel Environmentally Superior Tribomaterial with Superlow Friction: 100% Cellulose Nanofiber Molding

In this paper, we report on a novel, environmentally superior tribomaterial with superlow friction of 100% cellulose nanofiber (CNF) molding. Based on our experimental results, the CNF molding exhibited a superlow friction coefficient of approximately 0.01 under lubrication with a fatty acid: glycerin monooleate (GMO) diluted with poly-alfa-olefine. Attenuated total reflection Fourier-transform infrared spectroscopy and high-resolution frequency-modulation atomic force microscopy analyses demonstrated that superlow friction of the CNF molding was realized by GMO-assisted functionalization of the CNF surface, which effectively promoted the formation of a soft absorption film or soft swollen CNF layer. Our findings indicate that the in-situ functionalization of OH-terminated CNF surfaces during the friction process plays a crucial role in achieving superlow friction.Graphical