Cellulose Acetate Nanofibrous Membranes Research Articles

Harnessing bi-layered supramolecular Janus tissue-adhesive/anti-adhesive fibrous hydrogel for efficient hemostasis, wound healing, and suppressing postoperative tissue adhesion

Inadequate progression of primary (bleeding/infection) and secondary (rebleeding/postoperative tissue adhesion) complications at the wound site pose a substantial burden of morbidity and mortality worldwide. Therefore, developing a multifunctional biomaterial dressing for abrupt tissue adhesion and suppressed postoperative adhesion simultaneously is deemed essential. Herein, we designed a bi-layered Janus fibrous hydrogel (J-FH). The bottom layer comprises zinc-incorporated mesoporous silica nanogranules (ZnMSG) reinforced catechol-modified gelatin methacrylate (GC) hydrogel. GC@ZnMSG supramolecular hydrogel easily adheres to wet wounded tissue and possesses hemostatic, mechanical, and antibacterial properties. On the other hand, the top layer comprises dopamine-modified cellulose acetate nanofibrous membrane (DC) sequentially deposited with polydopamine-conjugated zwitterionic sulfobetaine methacrylate (PDA-SBMA). DC@PDA-SBMA fibrous membrane performs the anti-adhesive function by suppressing fouling and preventing tissue adhesion. The findings of animal experiments show that the bottom layer of the J-FH adheres firmly to the tissue surface, preventing bleeding and supporting tissue closure/regeneration. In contrast, the top layer provides mechanical stability, preventing secondary bleeding and suppressing postoperative tissue adhesion. Overall, J-FH demonstrated excellent biocompatibility, antibacterial properties, superior mechanical strength, asymmetric adhesion, robust hemostasis, and accelerated wound healing. It can replace traditional sutures, non-degradable dressings, and double-sided adhesive scaffolds for hemostasis, external, and internal postoperative wound healing.

Functionalization of cellulose acetate nanofibrous membranes for removal of particulate matters and dyes

Particulates and organic toxins, such as microplastics and dye molecules, are contaminants in industrial wastewater that must be purified due to environmental and sustainability concerns. Carboxylated cellulose acetate (CTA-COOH) nanofibrous membranes were fabricated using electrospinning followed by an innovative one-step surface hydrolysis/oxidation replacing the conventional two-step reactions. This approach offers a new pathway for the modification strategy of cellulose-based membranes. The CTA-COOH membrane was utilized for the removal of particulates and cationic dyes through filtration and adsorption, respectively. The filtration performance of the CTA-COOH nanofibrous membrane was carried out; high separation efficiency and low pressure drop were achieved, in addition to the high filtration selectivity against 0.6-μm and 0.8-μm nanoparticles. A cationic Bismarck Brown Y, was employed to challenge the adsorption capability of the CTA-COOH nanofibrous membrane, where the maximum adsorption capacity of the membrane for BBY was 158.73 mg/g. The self-standing CTA-COOH membrane could be used to conduct adsorption-desorption for 17 cycles with the regeneration rate as high as 97.0 %. The CTA-COOH nanofibrous membrane has excellent mechanical properties and was employed to manufacture a spiral wound adsorption cartridge, which exhibited remarkable separation efficiency in terms of treated water volume, which was 5.96 L, and retention rate, which was 100 %.

Portable smartphone-integrated AuAg nanoclusters electrospun membranes for multivariate fluorescent sensing of Hg2+, Cu2+ and l-histidine in water and food samples

Detection of heavy metals have been pivotal due to their non-biodegradability and food chain accumulation. Herein, a multivariate ratiometric sensor was developed by in situ integrating AuAg nanoclusters (NCs) into electrospun cellulose acetate nanofibrous membranes (AuAg-ENM) for visual detection of Hg2+, Cu2+ and consecutive sensing of l-histidine (His), which was integrated into a smartphone platform for quantitative on-site detection. AuAg-ENM achieved multivariate detection of Hg2+ and Cu2+ by fluorescence quenching, and subsequent selective recovery of the Cu2+-quenched fluorescence by His, which distinguished Hg2+ and Cu2+ and fulfilled determination of His simultaneously. Notably, AuAg-ENM achieved selective monitoring of Hg2+, Cu2+ and His in water, food and serum samples with high accuracy comparable to ICP and HPLC tests. A logic gate circuit was devised to further explain and promote the application of AuAg-ENM detection by smartphone App. This portable AuAg-ENM provides a promising reference for fabricating intelligent visual sensors for multiple detection.

Electrospun Nanofibrous Membranes Accelerate Biofilm Formation and Probiotic Enrichment: Enhanced Tolerances to pH and Antibiotics.

Biofilms are the oldest, most successful, and most widely distributed form of microorganism life on earth, existing even in extreme environments. Presently, probiotics in biofilm phenotype are thought as the most advanced fourth-generation probiotics. However, high-efficiency and large-scale biofilm enrichment in an artificial way is difficult. Here, fibrous membranes as probiotic biofilm-enriching materials are studied. Electrospun cellulose acetate nanofibrous membranes with nano-sized fibers show outstanding superiority over fibrous membranes with micron-sized fibers in Lactobacillus paracasei biofilm enrichment. The special 3D structure of electrospun nanofibrous membranes makes other facilitating biofilm formation factors insignificant. With a suitable scaffold/culture medium ratio, nearly 100% of L. paracasei cells exist as biofilm phenotype on the membrane from the very beginning, not planktonic state. L. paracasei biofilms possess a potential for long-term survival and high tolerances toward strong acidic and alkali conditions and antibiotics. RNA sequencing results explain why L. paracasei biofilms possess high tolerances toward harsh environments as compared to planktonic L. paracasei. Electrospun nanofibrous membranes can serve as powerful biofilm-enriching scaffolds for probiotics and other valuable microbes.

Development of prolonged drug delivery system using electrospun cellulose acetate/polycaprolactone nanofibers: Future subcutaneous implantation

AbstractImplantable drug delivery systems (IDDSs) play a vital role in treating chronic diseases by reducing dosing frequency and enhancing drug efficacy due to targeted delivery. In the present study, an IDDS was developed from electrospun cellulose acetate (CA) and polycaprolactone (PCL) nanofiber membranes. The implant core consists of a drug‐loaded CA nanofiber (CA + Vit.D3) enclosed in a rate limiting of the PCL membrane (CA + Vit.D3/PCL). The CA and PCL nanofibrous membranes were characterized using a scanning electron microscope (SEM), Fourier transform infrared spectroscopy, X‐ray diffraction, and UV–Vis spectroscopy. This research also investigated in‐vitro cytotoxicity and whether the PCL membrane prolonged drug delivery or led to enhanced mechanical properties. A smooth, beadless surface morphology was observed with fiber diameters of 325 ± 101 nm and 333 ± 79 nm for CA and PCL, respectively. In‐vitro drug release and tensile testing showed that surrounding the core's implants with a PCL membrane improved mechanical properties and kinetic drug release. The modulus and tensile strength of CA + Vit.D3/PCL were 161 ± 14 and 13.07 ± 2.5 MPa, respectively—these values were significantly higher than those obtained for CA + Vit.D3 (132 ± 52 MPa and 8.16 ± 2.36 MPa, respectively). The drug release pattern exhibited by CA + Vit.D3 was burst release, which fits the first‐order kinetic model. In contrast, CA + Vit.D3/PCL exhibited slow drug release, which fits the zero‐order kinetic model. In conclusion, based on the outcomes and facility of the technologies outlined in this article, electrospun CA and PCL nanofibers are suitable for developing long‐term IDDSs.

Electrospun Cellulose Acetate Nanofiber Morphology and Property Derived from CaCl2-Formic Acid Solvent System

Background: Electrospun Cellulose Acetate (CA) nanofibrous membrane can be used in many areas such as biomedicine, water treatment. However, due to the strong hydrogen-bond interaction, the rare solvent can dissolve the CA and the resulting CA nanofibrous membranes always show bad morphology and poor performance. Aims: To research the effect of CaCl2-Formic acid (CaCl2-FA) solvent system on the morphology and structure of CA nanofibrous membrane. Methods: CA nanofibrous membrane was fabricated with a two-step dissolution method using the first step of CaCl2-FA solvent system followed by the second step of FA solvent solely. Subsequently, the CA nanofibrous membrane morphology and structure property were systematically investigated. Results and Conclusion: The results show that the CaCl2-FA can dissolve the CA efficiently. Additionally, the regenerated CA nanofibers are well-formed under all the CA concentrations with controlling fiber diameter ranging from 224.9 ± 38.6 nm to 367.8 ± 80.4 nm. The results suggest that this two-step dissolution method can be an effective and alternative approach to dissolve CA and regenerate CA nanofibrous membrane.

A signal-on electrochemical aptasensor based on silanized cellulose nanofibers for rapid point-of-use detection of ochratoxin A.

An innovative ultrasensitive electrochemical aptamer-based sensor was developed for ochratoxin A (OTA) detection in cold brew coffee through revolutionary combination of nanofibers, electrochemicalmethod, and aptamer technologies. The assembly of the aptasensor was based on the activation of silanized cellulose nanofibrous membranes as a supporting matrix for methylene blue (MB) redox probe-labeled aptamer tethering. Cellulose nanofibrous membranes were regenerated by deacetylating electrospun cellulose acetate nanofibrous membranes with deacetylation efficacy of 97%, followed by silanization of the nanofiber surfaces by using (3-aminopropyl)triethoxysilane (APTES). A replacement of conventionally casted membranes by the nanofibrous membranes increased the active surface area on the working electrode of a screen-printed three-electrode sensor by more than two times, consequently enhancing the fabricated aptasensor performance. The developed aptasensor demonstrated high sensitivity and specificity toward OTA in a range 0.002-2ngmL-1, with a detection limit of 0.81pgmL-1. Moreover, the assembled aptamer-based sensor successfully detected OTA in cold brew coffee samples without any pretreatment. The aptasensor exhibited good reusability and stability over longstorage time. Graphical abstract.

Highly Efficient Removal of Methylene Blue Dye from an Aqueous Solution Using Cellulose Acetate Nanofibrous Membranes Modified by Polydopamine.

A new type of deacetylated cellulose acetate (DA)@polydopamine (PDA) composite nanofiber membrane was fabricated by electrospinning and surface modification. The membrane was applied as a highly efficient adsorbent for removing methylene blue (MB) from an aqueous solution. The morphology, surface chemistry, surface wettability, and effects of operating conditions on MB adsorption ability, as well as the equilibrium, kinetics, thermodynamics, and mechanism of adsorption, were systematically studied. The results demonstrated that a uniform PDA coating layer was successfully developed on the surface of DA nanofibers. The adsorption capacity of the DA@PDA nanofiber membrane reached up to 88.2 mg/g at a temperature of 25 °C and a pH of 6.5 after adsorption for 30 h, which is about 8.6 times higher than that of DA nanofibers. The experimental results showed that the adsorption behavior of DA@PDA composite nanofibers followed the Weber’s intraparticle diffusion model, pseudo-second-order model, and Langmuir isothermal model. A thermodynamic analysis indicated that endothermic, spontaneous, and physisorption processes occurred. Based on the experimental results, the adsorption mechanism of DA@PDA composite nanofibers was also demonstrated.

Electronic textiles based on aligned electrospun belt-like cellulose acetate nanofibers and graphene sheets: portable, scalable and eco-friendly strain sensor

Recently, there has been strong interest in flexible and wearable electronics to meet the technological demands of modern society. Environmentally-friendly and scalable electronic textiles is a key area that is still significantly underdeveloped. Here, we describe a novel strain sensor composed of aligned cellulose acetate (CA) nanofibers with belt-like morphology and a reduced graphene oxide (RGO) layer. The unique spatial alignment, microstructure and wettability of CA nanofibrous membranes facilitate their close contact with deposited GO colloids. After a portable and fast hot-press process within 700 s at 150 °C, the GO on CA membrane can be facilely reduced to a conductive RGO layer. Moreover, the connection among contiguous CA nanofibers and the interaction between the GO and CA substrate were both highly enhanced, resulting in superior mechanical strength with Young’s modulus of 1.3 GPa and small sheet resistance lower than 10 kΩ. Therefore, the conductive RGO/CA membrane was successfully utilized as a strain sensor in a broad deformation range and with versatile deformation types. Moreover, the distinctive mechanical strength under different stretch angles endowed the well-aligned RGO/CA film with intriguing sensitivity against stress direction. Such a cost-effective and environmentally-friendly method can be easily extended to the scalable production of graphene-based flexible electronic textiles.

Improved properties and drug delivery behaviors of electrospun cellulose acetate nanofibrous membranes by introducing carboxylated cellulose nanocrystals

Cellulose acetate (CA) composite nanofibrous membranes were electrospun by introducing carboxylated cellulose nanocrystals (CCNCs) as organic nanoreinforcements which were prepared by firstly extracting the cellulose nanocrystals from microcrystal celluloses with hydrochloric acid under hydrothermal condition, and followed by oxidization with ammonium persulfate at different temperatures. The influences of the degree of carboxylation and particle size of the CCNCs on the morphology, chemical structure, thermal stability and mechanical properties of as-prepared CA composite nanofibrous membranes were investigated by scanning electron microscopy, Fourier-transform infrared spectroscopy, wide angle X-ray diffraction analysis, thermogravimetric analysis and mechanical test. Furthermore, contact angle measurement and drug release test were used to evaluate the feasibility of these nanofibrous membranes as a sustained release drug delivery system. It is found that due to the incorporation of the CCNCs, remarkable improvements on the thermal stability and mechanical properties as well as drug delivery behavior of CA nanofibrous membrane could be achieved. Especially for the CCNCs prepared at 75 °C, a long-term sustained drug delivery property with a maximum drug release content of 94% within 420 h could be obtained, benefiting from the strong hydrogen bonding between CCNCs and CA matrix, high chain orientation of CA and microstructure of nanofibrous membranes. Therefore, this kind of totally cellulose-based nanofibrous membranes would possess great potential as promising materials for controlled drug delivery applications.

Fabrication of cellulose acetate/polybenzoxazine cross-linked electrospun nanofibrous membrane for water treatment

Herein, polybenzoxazine based cross-linked cellulose acetate nanofibrous membrane exhibiting enhanced thermal/mechanical properties and improved adsorption efficiency was successfully produced via electrospinning and thermal curing. Initially, suitable solution composition was determined by varying the amount of the benzoxazine (BA-a) resin, cellulose acetate (CA) and citric acid (CTR) to obtain uniform nanofibrous membrane via electrospinning. Subsequently, thermal curing was performed by step-wise at 150, 175, 200 and 225°C to obtain cross-linked composite nanofibrous membranes. SEM images and solubility experiments demonstrated that most favorable result was obtained from the 10% (w/v) CA, 5% (w/v) BA-a and 1% (w/v) CTR composition and cross-linked nanofibrous membrane (CA10/PolyBA-a5/CTR1) was obtained after the thermal curing. Chemical structural changes (ring opening) occurred by thermal curing revealed successful cross-linking of BA-a in the composite nanofibrous membrane. Thermal, mechanical and adsorption performance of pristine CA and CA10/PolyBA-a5/CTR1 nanofibrous membranes were studied. Char yield of the pristine CA nanofibrous membrane has increased notably from 12 to 24.7% for composite CA10/PolyBA-a5/CTR1 membrane. When compared to pristine CA membrane, CA10/PolyBA-a5/CTR1 nanofibrous membrane has shown superior mechanical properties having tensile strength and Young’s modulus of 8.64±0.63MPa and 213.87±30.79MPa, respectively. Finally, adsorption performance of pristine CA and CA10/PolyBA-a5/CTR1 nanofibrous membranes was examined by a model polycyclic aromatic hydrocarbon (PAH) compound (i.e. phenanthrene) in aqueous solution, in which CA10/PolyBA-a5/CTR1 nanofibrous membrane has shown better removal efficiency (98.5%) and adsorption capacity (592μg/g).

Electrospun H4SiW12O40/cellulose acetate composite nanofibrous membrane for photocatalytic degradation of tetracycline and methyl orange with different mechanism

H4SiW12O40 (SiW12)/cellulose acetate (CA) composite nanofibrous membrane was prepared by electrospinning in which CA was employed as the support of SiW12. Characterization with Fourier transformation infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) indicated that SiW12 has been successfully loaded into the CA membrane and its Keggin structure remained intact. The as-prepared composite membrane exhibited enhanced photocatalytic activity in the decomposition of tetracycline (TC) and methyl orange (MO) compared with pure SiW12 under ultraviolet irradiation. The optimal mass ratio of SiW12 to CA was 1:4, and the corresponding degradation efficiency for TC and MO was 63.8% and 94.6%, respectively. It is noteworthy that the degradation rate of MO increased more evidently than that of TC under the same conditions, which may be attributed to the different role that CA nanofibrous membrane played in the TC and MO photodegradation process. Besides providing more contact area between SiW12 and the pollutant in TC photodegradation, CA membrane played an additional role that donated electron to SiW12 in the MO degradation process, leading to a different photocatalytic mechanism with greatly enhanced degradation rate. Moreover, the composite membrane presented an excellent reusability, which was mainly ascribed to the water-insolubility of CA and the hydrogen bonds between CA and SiW12. This work will be useful for the design of biopolymer-based membrane photocatalysts applied to antibiotics and dyes wastewater treatment.

Cellulose acetate electrospun nanofibrous membrane: fabrication, characterization, drug loading and antibacterial properties

Cellulose-based materials are one of the most commonly used materials for biomedical applications, which normally applied as carriers for pharmaceuticals and drug-releasing scaffolds. In this study, cellulose acetate (CA) was used to fabricate the nanofibrous membrane using the electrospinning technique. CA solutions at different concentrations were prepared by dissolving the polymer in a mixture of acetic acid/acetone solvents with the ratio of 3 : 1. The field emission scanning electron microscope results showed that electrospinning of 10% (w/v) CA produced nanofibres with many beads. When the CA concentration was increased to 14% (w/v), bead-free nanofibres were produced. The contact angle measurement results confirmed the hydrophilic properties of nanofibres. In order to prevent common bacterial infections, a model drug, Tetracycline ⋅ HCL was incorporated into the CA nanofibres. The drug-loaded CA nanofibres showed antibacterial activity against Gram-positive and Gram-negative bacteria. CA nanofibres had high water uptake properties. The CA nanofibrous membrane was non-toxic to human skin fibroblast cells. Thus the CA nanofibres with 14% (w/v) concentration exerted suitable properties for wound healing application.

Electrospinning of silver nanoparticles loaded highly porous cellulose acetate nanofibrous membrane for treatment of dye wastewater

In this paper, silver nanoparticles (NPs) were reduced form silver nitrate. Morphology and distribution of the synthesized silver NPs were characterized. In order to obtain cellulose acetate (CA), nanofibrous membrane with high effective adsorption performance to carry silver NPs for treatment of dye wastewater, different solvent systems were used to fabricate CA nanofibrous membranes with different morphologies and porous structures via electrospinning. Morphologies and structures of the obtained CA nanofibrous membranes were compared by scanning electron microscopy (SEM), which showed that CA nanofibrous membrane obtained from acetone/dichloromethane (1/2, v/v) was with the highly porous structure. SEM, energy-dispersive spectrometry and Fourier transform infrared spectrometry showed that the silver NPs were effectively incorporated in the CA nanofibrous membrane and the addition of silver NPs did not damage the porous structure of the CA nanofibrous membrane. Adsorption of dye solution (rhodamine B aqueous solution) revealed that the highly porous CA nanofibrous membrane exhibited effective adsorption performance and the addition of silver NPs did not affect the adsorption of the dye. Antibacterial property of the CA nanofibrous membrane showed that the silver-loaded highly porous CA nanofibrous membrane had remarkable antibacterial property when compared to the CA nanofibrous membrane without silver NPs. The silver-loaded highly porous CA nanofibrous membrane could be considered as an ideal candidate for treatment of the dye wastewater.

Highly permeable cellulose acetate nanofibrous composite membranes by freeze-extraction

Ultrafiltration is widely used in waste water treatment and has become more crucial with increasing concerns in the living environment. Here we demonstrate a facile method to prepare 10nm-diameter cellulose acetate (CA) nanofiber dispersions from very dilute CA solutions via freeze-extraction, and further fabricate nanofibrous composite membranes for ultrafiltration. The nanofibrous composite membranes are fabricated by directly filtering the dispersions on a CA microfiltration membrane (support), on which an ultrathin free-standing nanofibrous layer is formed. This layer, acting as a separation layer, has a uniform porous structure and ultrahigh porosity of up to 71%. The as-prepared membranes present ultrahigh water permeability and high efficient separation performance for ultrafiltration. The membrane with a 458nm-thick nanofibrous layer has ferritin rejection of 90.7% and water flux of 3540lm−2h−1bar−1 that is almost 10 times greater than that of most commercial membranes. These newly developed CA nanofibrous composite membranes have a great potential application in various separation processes.

An in situ polymerization approach for the synthesis of superhydrophobic and superoleophilic nanofibrous membranes for oil–water separation

Superhydrophobic and superoleophilic nanofibrous membranes exhibiting robust oil-water separation performance were prepared by a facile combination of electrospun cellulose acetate (CA) nanofibers and a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) functional layer that incorporated silica nanoparticles (SiO(2) NPs). By employing the F-PBZ/SiO(2) NPs modification, the pristine hydrophilic CA nanofibrous membranes were endowed with a superhydrophobicity with the water contact angle of 161° and a superoleophilicity with the oil contact angle of 3°. Surface morphological studies have indicated that the wettability of resultant membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. The quantitative hierarchical roughness analysis using the N(2) adsorption method has confirmed the major contribution of SiO(2) NPs on enhancing the porous structure, and a detailed correlation between roughness and solid-liquid interface pinning is proposed. Furthermore, the as-prepared membranes exhibited fast and efficient separation for oil-water mixtures and excellent stability over a wide range of pH conditions, which would make them a good candidate in industrial oil-polluted water treatments and oil spill cleanup, and also provided a new insight into the design and development of functional nanofibrous membranes through F-PBZ modification.

Fungal Growth Inhibition of Regenerated Cellulose Nanofibrous Membranes Containing Quillaja Saponin

Antifungal properties were introduced in nonwoven regenerated cellulose (RC) nanofibrous membrane using Quillaja saponin. To generate cellulose membranes, deacetylation of electrospun cellulose acetate (CA) nanofibrous membranes was performed using 0.05 M NaOH and ethanol for membranes both loaded and unloaded with Quillaja saponin. Chemical and physical properties of nonwoven CA and RC nanofibrous membrane were characterized using scanning electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, differential scanning calorimetry, and tensile properties. Our results showed that saponin doping did not affect the morphology of the resulting fibers and that the membrane structure was maintained during deacetylation. The antifungal properties of saponin-loaded fabric were determined at 0 and 24 h against two household fungi, Penicillium roguefortii and Aspergillus ochraceus, and compared with control samples. Our findings show that after 24 h the saponin-loaded fabrics had spores kill of 80.4% and 53.6% for P. roguefortii and A. ochraceus, respectively. Fabric containing Quillaja saponin has potential for household applications and could be evaluated further for medical applications.

Super-hydrophobic surfaces of layer-by-layer structured film-coated electrospun nanofibrousmembranes

We have recently fabricated super-hydrophobic membrane surfaces based on the inspirationof self-cleaning silver ragwort leaves. This biomimetic super-hydrophobic surface was composedof fluoroalkylsilane (FAS)-modified layer-by-layer (LBL) structured film-coated electrospunnanofibrous membranes. The rough fibre surface caused by the electrostatic LBL coating ofTiO2 nanoparticles and poly(acrylic acid) (PAA) was used to imitate the rough surface ofnanosized grooves along the silver ragwort leaf fibre axis. The results showed that the FASmodification was the key process for increasing the surface hydrophobicity of thefibrous membranes. Additionally, the dependence of the hydrophobicity of themembrane surfaces upon the number of LBL coating bilayers was affected bythe membrane surface roughness. Moreover, x-ray photoelectron spectroscopy(XPS) results further indicated that the surface of LBL film-coated fibresabsorbed more fluoro groups than the fibre surface without the LBL coating. A(TiO2/PAA)10 film-coated cellulose acetate nanofibrous membrane with FASsurface modification showed the highest water contact angle of162° and lowestwater-roll angle of 2°.

Electrospinning of Cellulose Acetate in Solvent Mixture N,N-Dimethylacetamide (DMAc)/Acetone

Electrospinning of cellulose acetate (CA) was studied in relation to factors of solvent composition, size of spinnerete orifice, viscosity, and molecular weight. It was found that cellulose acetate nanofibers were obtained from solvent mixture N,N-dimethylacetamide (DMAc)/acetone with volume ratio of 2:1 and 1:2. Beaded nanofibers were more likely formed from solvent 2:1 DMAc/acetone, whereas bead-free CA nanofibers were produced at lower CA concentration in 1:2 DMAc/acetone. The size of spinnerete orifice showed no significant effect on the mean diameter of CA nanofiber, but small size of spinnerete orifice often resulted in nanofibers with large fiber size distribution. With respect to the effect of molecular weight on electrospinning, nanofibers of CA-398-3 (Mw=3.0×104) had wide size distribution of 90–790 nm with large amounts of big spindle-like beads along fibers. The diameters of nanofibers from CA-398-6 (Mw=3.5×104) were in the range of 90–430 nm with a few conical shape beads on fiber. In the case of CA-398-10 (Mw=4.0×104), its nanofiber diameters increased to 90–550 nm without noticeable bead defects. The water contact angles of nanofibers of CA-398-3, CA-398-6 and CA-398-10 were 81°, 50.5° and 40.4°, respectively, suggesting the orientation of hydrophobic and hydrophilic groups on the very outer fiber surface got changed when CA fiber size is down to nanometer range. The interconnected pore volume of CA nanofibrous membranes is tripled with CA molecular weight increasing from 3.0×104 to 4.0×104.