Cellulose Nanofibrous Mats Research Articles

Digital ink‐jet printing of regenerated cellulose nanofibrous mats with reactive inks

AbstractThe versatility of nanofibres enables them to be used for various technological applications such as filtration, biomedicine and healthcare, composites, protective and functional textiles. Recently, in addition to the functional properties of electrospun nanofibrous mats, their aesthetic properties have been explored. Herein, attempts have been made to develop digital ink‐jet printing of regenerated cellulose nanofibrous mats with reactive inks. First, a cellulose acetate polymer was created to fabricate electrospun cellulose acetate nanofibrous mats, which were then converted into regenerated cellulose nanofibrous mats through deacetylation. Next, the cellulose nanofibrous mats were treated with an alkaline solution then coloured with four (cyan, magenta, yellow and black) commercially available reactive inks by a digital ink‐jet printing method using a piezoelectric digital ink‐jet printer. Various parameters were investigated, including the optimal concentration of the pretreatment agents, fixation temperature and time, colour yield and the absorbency of the electrospun nanofibrous mats. The digital ink‐jet printed cellulose nanofibrous mats exhibited excellent colour yield and colour fastness properties. Morphological analysis through scanning electron microscopy and chemical analysis through Fourier Transform–infrared were also carried out.

In vitro biocompatibility, antibacterial activity, and release behavior of halloysite nanotubes loaded with diclofenac sodium salt incorporated in electrospun soy protein isolate/hydroxyethyl cellulose nanofibers

• SPI/HEC nanofibers loaded with DS and HNT were fabricated using PVA as carrier. • FTIR and XRD confirmed inclusion of DS and HNT in nanofibers. • Drug loading do not adversely affect the biocompatibility of composite mats. • HNT inclusion resulted in a sustained drug release over 14 days. Wound healing is a complicated process with overlapping stages, and a suitable supporting environment is required to accelerate the healing process. The fabrication of wound dressings with antibiotic, antibacterial, and sustained drug release properties is necessary in wound care. Herein, we report the fabrication of soy protein isolate/hydroxyethyl cellulose (HEC) nanofibrous mats loaded with diclofenac sodium (DS) and halloysite nanotubes (HNTs) for sustained delivery and antibacterial applications. The morphology of the nanofibers was uniform and smooth, with an average diameter of ∼450 nm after cross-linking. Fourier transform infrared spectroscopy and X-ray diffraction analysis confirmed the inclusion of DS and HNT in the nanofibers. The inclusion of HNTs improved the surface wettability properties of the composite nanofibers. Loading DS into the HNTs resulted in the sustained release of DS over 14 days. In vitro biocompatibility analysis showed that loading DS into the composite nanofibers had no adverse effects on their biocompatibility, which was confirmed by the non-cytotoxic nature of the composite nanofibers in lactate dehydrogenase and WST-1 assays. The drug-loaded nanofibers were effective against Escherichia coli and Bacillus subtilis . These fabricated nanofibrous mats with sustained antibacterial efficacy and biocompatibility have great potential for applications in wound care.

Citric acid-incorporated cellulose nanofibrous mats as food materials-based biosorbent for removal of hexavalent chromium from aqueous solutions

Nanoscale biomass materials derived from food materials (e.g., polysaccharide, protein, organic acid) have shown great promises with regard to the removal of heavy metal in wastewater treatment. Herein, we have developed the functionalized cellulose nanofibrous mats as an environment-friendly biosorbent via electrospinning of cellulose acetate solution, followed by deacetylation and citric acid modification. The morphology, chemical, and structural characterizations of the cellulose nanofibrous mats were examined by SEM, FTIR, XRD, DSC, and TGA to follow each stage of the preparation process of them. The effect of the incorporation of citric acid in the cellulose molecule on the adsorption performance of the naofibrous mats was then studied by batch adsorption experiments. Consequently, citric acid-modified cellulose nanofibrous mats with reasonably high absorption selectivity for Cr(VI) can be readily prepared. Results from this study may provide a promising food materials-based biosorbent that can be used as an emerging material in wastewater treatment application.

Chitosan/tannic acid bilayers layer-by-layer deposited cellulose nanofibrous mats for antibacterial application

The research and development of environmentally friendly and nontoxic biomass products has become an important topic of worldwide concern. In this study, natural materials were used for producing a kind of antibacterial mats. Cellulose acetate (CA) mats prepared by electrospinning technology were converted to cellulose mats via alkali hydrolysis. Chitosan (CS) and tannic acid (TA) were used to fabricate the composite mats by using layer-by-layer (LBL) self-assembly technology. The cellulose mats exhibited good fibrous structure, three-dimensional network and small average fiber diameter ranging from 300 to 400 nm. Besides, the results of mechanical properties testing and water contact angle measurements of these LBL-structured mats demonstrated that the LBL technology was able to improve their surface characteristics, hydrophilicity and mechanical properties. The analysis of antibacterial activity of the mats revealed over 86% antibacterial activity against Escherichia coli and up to 99% antibacterial activity against Staphylococcus aureus. Hence, the LBL-structured cellulose mats have excellent antibacterial activity and mechanical properties. Therefore, these nano-cellulose mats can be expected to have considerable development prospects for food packaging or wound dressing.

Egg source natural proteins LBL modified cellulose nanofibrous mats and their cellular compatibility

Natural-based nanocomposites are competitive and promising materials for biomedical applications due to their biocompatibility. Herein, a novel natural-based composite was fabricated by alternately depositing lysozyme (LY) and albumin egg (AE) on electrospun cellulose nanofibrous mats via layer-by-layer self-assembly (LBL) technology. To indicate the successful deposition process and investigate the variations of the mats during LBL process, the surface morphology, physical property, chemical composition, wetting behavior and thermal stability were systematically studied. The results showed that the surface morphology and composition of the mats were significantly influenced by LBL process, which further resulted in the variation of wetting behavior. Besides, the mechanical properties were enhanced after LBL modification. In addition, the LBL structured nanofibrous mats exhibited antibacterial activity and excellent biocompatibility with L929 fibroblasts. In brief, LY and AE coated LBL structured cellulose nanofibrous mats, especially the 15 bilayers coated mats, have considerably potential applications in the biomedical field.

Quick water‐responsive shape memory hybrids with cellulose nanofibers

ABSTRACTA type of quick water‐responsive shape memory hybrids is fabricated by introducing cellulose nanofibrous mats as the filler in a polymeric matrix. Cellulose nanofibrous mats are obtained through hydrolyzing electrospun cellulose acetate (CA) nanofibers, then casted in thermoplastic polyurethane (TPU) solution to form the hybrids. The quick shape memory behavior of the formed hybrids is demonstrated using dynamic mechanical analysis (DMA) and stress–strain cyclic test. According to a predetermined protocol, the hybrids present desirable shape fixation and recovery, and the elastic modulus (E′) is shown to be responsive promptly and reversibly against drying and wetting cycle. Shape memory mechanism of the hybrids involves the reversible and competitive hydrogen bonds within cellulose before and after water immersion as well as the entropy elasticity of the TPU matrix. This study can pave a way to design novel smart materials by facile methods through incorporating natural nanomaterials as water sensitive fillers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 767–775

Layer-by-layer immobilization of quaternized carboxymethyl chitosan/organic rectorite and alginate onto nanofibrous mats and their antibacterial application.

Quaternized carboxymethyl chitosan (QCM-chitosan) and organic rectorite (OREC) immobilized nanofibrous mats are fabricated via layer-by-layer (LBL) technique in a self-assembly manner. The negatively charged cellulose nanofibrous mats hydrolyzed from electrospun cellulose acetate (CEL) mats are alternately modified with the positively charged QCM-chitosan and OREC intercalated composites and the negatively charged sodium alginate (ALG) via LBL technique. The morphology and antibacterial activity of the resultant mats are studied by changing the number of deposition bilayers, the compositions of dipping solutions and outermost layer. X-ray photoelectron spectroscopy results imply that QCM-chitosan and OREC are coated on cellulose mats. Besides, wide angle X-ray diffraction and small angle X-ray diffraction are applied to investigate the crystalline of the composite mats and the interlayer distance of OREC, respectively. The antibacterial activity of the mats increases with the incorporation of OREC into LBL films.

Pectin/lysozyme bilayers layer-by-layer deposited cellulose nanofibrous mats for antibacterial application.

Positively charged lysozyme (LZ) and negatively charged pectin, were alternately deposited on the surface of the cellulose nanofibrous mats by layer-by-layer (LBL) self-assembly technique. Scanning electron microscopy images showed that the nanofibers were orderly and compactly arrayed after LBL. Besides, as the number of LZ/pectin bilayers increased, the average diameter of nanofibers increased. LZ has assembled on the cellulose mats successfully, which was confirmed by X-ray photoelectron spectroscopy analysis. Thermal gravimetric analysis results showed that the thermal properties of LZ/pectin films coated mats was better than that of the unmodified cellulose mats. Importantly, the results of the bacterial inhibition test for LBL structured mats and cellulose mats indicated that the nanofibrous mats coated by 10.5 LZ/pectin bilayers (with LZ on the outmost layer) possessed the strongest inhibitory effect against both Escherichia coli and Staphylococcus aureus.

Layer-by-layer immobilized catalase on electrospun nanofibrous mats protects against oxidative stress induced by hydrogen peroxide.

Catalase, a kind of redox enzyme and generally recognized as an efficient agent for protecting cells against hydrogen peroxide (H2O2)-induced cytotoxicity. The immobilization of catalase was accomplished by depositing the positively charged chitosan and the negatively charged catalase on electrospun cellulose nanofibrous mats through electrospining and layer-by-layer (LBL) techniques. The morphology obtained from Field emission scanning electron microscopy (FE-SEM) indicated that more orderly arranged three-dimension (3D) structure and roughness formed with increasing the number of coating bilayers. Besides, the enzyme-immobilized nanofibrous mats were found with high enzyme loading and activity, moreover, X-ray photoelectron spectroscopy (XPS) results further demonstrated the successful immobilization of chitosan and catalase on cellulose nanofibers support. Furthermore, we evaluated the cytotoxicity induced by hydrogen peroxide in the Human umbilical vascular endothelial cells with or without pretreatment of nanofibrous mats by MTT assay, LDH activity and Flow cytometric evaluation, and confirmed the pronounced hydrogen peroxide-induced toxicity, but pretreatment of immobilized catalase reduced the cytotoxicity and protected cells against hydrogen peroxide-induced cytotoxic effects which were further demonstrated by scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM) images. The data pointed toward a role of catalase-immobilized nanofibrous mats in protecting cells against hydrogen peroxide-induced cellular damage and their potential application in biomedical field.

Nanofibrous Mats Layer-by-Layer Assembled by HTCC/Layered Silicate Composites withIn Vitro Antitumor Activity Against SMMC-7721 Cells

Organic rectorite (OREC) was used to prepare the intercalated nanocomposites with N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC), and then the immobilization of the positively charged HTCC-OREC nanocomposites and the negatively charged sodium alginate (ALG) on cellulose nanofibrous mats was performed through layer-by-layer (LBL) technique. Fiber diameter distribution results from Field Emission Scanning Electron Microscopy (FE-SEM) images showed that the average fiber diameter of (HTCC-OREC/ALG)(n) films coating obviously increased from 433 to 608 nm. Moreover, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results further confirmed the interaction between HTCC and OREC and their successful immobilization on cellulose template. MTT assay indicated that the prepared nanofibrous mats exhibited strong inhibitory activity against human hepatocellular carcinoma cells (SMMC-7721) but a little cytotoxic effect on human Chang liver (CCL-13) cells. Furthermore, the experimental results from FE-SEM and Inverted Fluorescence Microscope of SMMC-7721 cells cultured on LBL structured nanofibrous mats demonstrated the significant antitumor activity of prepared samples. The developed approach to immobilize nanocomposites onto polymer nanofibers with controllable thickness may also be utilized to tumor therapy.

Aligned electrospun cellulose fibers reinforced epoxy resin composite films with high visible light transmittance

Uniaxially oriented cellulose nanofibers were fabricated by electrospinning on a rotating cylinder collector. The fiber angular standard deviation (a parameter of fiber orientation) of the mats was varied from 65.6 to 26.2o by adjusting the rotational speed of the collector. Optically transparent epoxy resin composite films reinforced with the electrospun cellulose nanofibrous mats were then prepared by the solution impregnation method. The fiber content in the composite films was in the range of 5–30 wt%. Scanning electron microscopy studies showed that epoxy resin infiltrated and completely filled the pores in the mats. Indistinct epoxy/fiber interfaces, epoxy beads adhering on the fiber surfaces, and torn fiber remnants were found on the fractured composite film surfaces, indicating that the epoxy resin and cellulose fibers formed good interfacial adherence through hydrogen-bonding interaction. In the visible light range, the light transmittance was 88–92% for composite films with fiber loadings of 16–32 wt%. Compared to the composite films reinforced with 20 wt% randomly oriented fibers, the mechanical strength and Young’s modulus of the composite films reinforced with same amount of aligned fibers increased by 71 and 61%, respectively. Dynamical mechanical analysis showed that the storage moduli of the composite films were greatly reinforced in the temperature above the glass transition temperature of the epoxy resin matrix.

Effects of fiber surface chemistry and size on the structure and properties of poly(vinyl alcohol) composite films reinforced with electrospun fibers

Electrospun cellulose nanofibrous mats (CNM) and cellulose acetate nanofibrous mats (CANM) reinforced poly(vinyl alcohol) (PVA) composites films were fabricated through solution impregnation method. The effect of fiber size and surface structure on the fiber/PVA interfacial adhesion, and consequently on the macroscopic properties such as optical, tensile, and dynamical mechanical properties of composite films were studied. The fractured surface morphology was examined by scanning electron microscopy. It showed that interfacial debonding happened to CANM/PVA composites, whereas good interfacial adhesion was formed for CNM/PVA composites. The visible light transmittance and the mechanical properties of PVA composite films were evaluated. CNM/PVA showed higher optical transparency than CANM/PVA composite films. Additionally, the light transmittance of CNM/PVA was insensitive to temperature. Dynamical mechanical analysis demonstrated that the storage moduli of electrospun fiber/PVA composite films were obviously improved in the glass–rubber transition and rubbery zone, but more significantly in the melting zone.

Enhanced bacterial inhibition activity of layer-by-layer structured polysaccharide film-coated cellulose nanofibrous mats via addition of layered silicate

Organic rectorite (OREC) was used to prepare the intercalated composites with chitosan (CS). The negatively charged cellulose nanofibers hydrolyzed from electrospun cellulose acetate fibrous mats were modified with multilayers of the positively charged CS-OREC intercalated composite and the negatively charged sodium alginate (ALG) via layer-by-layer (LBL) technique. The morphology and antibacterial activity of the resultant samples were studied by regulating the number of deposition bilayers, the compositions of dipping solutions and outermost layer of films. Field emission scanning electron microscopy images indicated that the thickness of CS-OREC/ALG bilayer formed on fibers was estimated from 12 to 26 nm. Additionally, the energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy results indicated that CS and OREC were successfully deposited on cellulose fibers. The bacterial inhibition experiments demonstrated that LBL films modified fibrous cellulose mats with the addition of OREC can increase the degree of inhibition on Escherichia coli.

Layer-by-layer structured polysaccharides film-coated cellulose nanofibrous mats for cell culture

For the first time, a novel fibrous polysaccharide scaffold for cell culture was fabricated by the combination of electrospinning and electrostatic layer-by-layer (LBL) self-assembly technique. Oppositely charged chitosan (CS) and alginate (ALG) in aqueous media were alternatively deposited onto the negatively charged cellulose nanofibrous mats which hydrolyzed from electrospun cellulose acetate mats. The morphology and biocompatibility of the resultant scaffolds were investigated by regulating the pH of dipping solutions, the number of deposition bilayers, and the composition of outermost layer. Field emission scanning electron microscopy images indicated that the scaffolds possessed the fibrous structure and the thickness of CS/ALG bilayer formed on fibers was estimated in the range of 8–15 nm. The X-ray photoelectron spectroscopy results verified the existence of nitrogen element of CS on the surface of LBL films. The cell culture experiments demonstrated that the scaffolds have good biocompatibility for Beas-2B human bronchial epithelial cells in vitro.

Electrospun cellulose nanofiber reinforced soybean protein isolate composite film

AbstractThis article presents the fabrication of cellulose nanofibrous mats (CNM) reinforced soybean protein isolate (SPI) composite with high visible light transmittance. The CNM was composed of cellulose nanofibers generated from electrospinning technique. The microstructure of the fractured surface of composite films was characterized by scanning electron microscopy (SEM). The light transmittance, mechanical properties, and swelling ratio of CNM/SPI composite were investigated in terms of CNM content in the composite. Because of the ultrafine diameter and superhigh length‐to‐diameter ratio of nanofibers, large amount of cellulose nanofibers fibers distribute in the SPI matrix to form an interpenetrating network (IPN) like composite material. It was found that strong interfacial interactions occurred at the cellulose nanofiber/SPI interfaces. The incorporation of 20 wt % cellulose nanofibers in the SPI matrix resulted in great improvement of mechanical strength and Young's modulus by respectively 13 and 6 times more than neat SPI film. More interestingly, this composite was translucent with light transmittance of over 75% at 700 nm. Furthermore, the swelling ratio of this IPN‐like CNM/SPI composite decreased from 106 to 22% as CNM content increased from 0 to 20 wt %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008