Cellulose Acetate Nanofiber Mats Research Articles

Visible‐Light‐Active Electrospun Membranes Based on Cobalt‐Doped ZnO Nanohybrids: Applications for Food Packaging

AbstractA cellulose acetate electrospun membrane based on Cobalt doped ZnO (Co‐ZnO) was developed. The synthesis of pure zinc oxide nanoparticles (NPs) and cobalt‐zinc oxide nanorods with varying cobalt‐to‐zinc atomic ratios of 5 %, 10 %, 15 %, and 20 % was carried out, using the co‐precipitation method. The successful incorporation of cobalt into ZnO was confirmed by using the techniques of Powder X‐ray Diffraction (PXRD), X‐ray Photoelectron Spectroscopy (XPS), and Energy Dispersive X‐ray Spectroscopy (EDX). Scanning Electron Microscopy (SEM) studies denoted the change in shape from spherical to rod‐shaped upon doping Co. A red shift was observed in band gap energies from 3.26‐3.01 eV upon increasing the Co concentration. The photocatalytic activity was evaluated, using methylene blue under sunlight and a 50 W LED lamp. The most effective photocatalyst observed in this study was a composition consisting of 15 % Co‐ZnO. When exposed to sunshine, this photocatalyst demonstrated a degradation rate of 40 % over a one‐hour period. Similarly, when subjected to a lamp, the degradation rate was found to be 24 % over the same duration. A nanofiber membrane was produced by incorporating Co‐ZnO at a concentration of 15 % (w/w) into the cellulose acetate (CA) polymer matrix by the electrospinning technique. The created CA nanofiber mat with Co‐ZnO was employed to extend the shelf life of strawberries up to 18 days along with the reduced pH increase and lower reduction of weight, firmness, and titratable acidity.

Preparation and Characterization of NPK Nutrient Loaded Electrospun Cellulose Acetate Nanofiber Mat to be used as a Slow-release Fertilizer


 
 
 A major unsolved issue with chemical fertilizers is the low nutrient use efficiency. It has been reported that an excessive amount of up to 70% of the nitrogen applied to plants with traditional fertilizers is lost to the surrounding. Hence, the drastic pollution effects of chemical fertilizer usage. Slow-release fertilizers aim to reduce such losses via slow and sustained release of nutrients to the plant. In this study, we report the successful fabrication and characterization of a novel and biodegradable cellulose acetate (CA) electrospun nanofiber (NF) mat loaded with nitrogen, phosphorus and potassium plant nutrients of urea, hydroxyapatite nanoparticles (HANPs) and MOP respectively to be used as a slow-release fertilizer (SRF). It was envisaged that the unique properties of the electrospun NFs could overcome the shortcomings of traditional slow-release fertilizers (SRFs). The fabrication of the NFs was done with 8.5% w/v CA polymer dissolved in a 6 mL solvent system of acetone to dimethylformamide in a 2:1 volume ratio along with the addition of the aforementioned nutrients at 10% of the polymer weight. Electrospinning parameters were set after parameter optimization. The high-voltage supply was set at 16 kV, the spinneret to collector distance was 13cm and the flow rate was 1.5 ml/h. The solutions were electrospun only when the relative humidity was approximately between 65 to 70%. The HANPs incorporated were synthesized by the wet chemical precipitation method. The successful synthesis of the HANPs was confirmed via Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) analysis. The successful loading of the nutrients onto the electrospun NF mat was evident from FTIR, Raman and EDX analysis. Furthermore, the scanning electron microscopy images of the nutrient loaded NFs depicted a reduced average diameter with respect to those of the neat NF mat. The total nitrogen percentage of the nutrient loaded NF mat was determined to be 2.60% from Kjeldahl analysis. The initial nutrient release studies in water depicted a biphasic release model for orthophosphate and potassium nutrients while only a burst release profile was observed for nitrogen. It can be concluded that the electrospun NF mats display a potential application with regards to SRFs. However, several modifications to the NF mat fabrication such as the usage of coaxial electrospinning will have to be made in order to better optimize the nutrient loading and enhance its slow-release properties.
 Keywords: Electrospinning, Nanofiber mat, Slow-release, Hydroxyapatite nanoparticles
 
 

Preparation and Characterization of a Plant-Nutrient-Loaded Cellulose Acetate Nanofiber Mat as a Potential Slow-Release Fertilizer

Preparation and Characterization of a Plant-Nutrient-Loaded Cellulose Acetate Nanofiber Mat as a Potential Slow-Release Fertilizer

Nanoremediation of toxic dyes using a bacterial consortium immobilized on cellulose acetate nanofiber mats

AbstractStenotrophomonas maltophilia and Ochrobactrum sp. demonstrated the highest rates of dye bioremediation. The trials were performed at pH 8, which resulted in the highest bioremediation rate of 64.6% in media containing 21.2 mg L−1 dye. As the dye concentration increased, the pollutant removal decreased, with the maximum bioremoval rate of 70.3%. The removal capacity was increased with an increase in biomass concentration; the highest yield of 91.3% was obtained in media containing 14.2 mg L−1 dye and 12% (v/v) biomass. In nanoremediation studies, the bacterial consortium was immobilized on cellulose acetate nanofiber mats (CA‐NFM). Scanning electron microscopic micrographs showed that bead‐free nanofiber mats were effective in immobilizing bacterial cells. Moreover, nanofiber structures were capable of supporting exopolysaccharides formation, as confirmed by Fourier transform ınfrared spectroscopy. The bacterial consortium immobilized on CA‐NFM showed a maximum bioremoval rate of 56.5%. Reusability tests demonstrated that the consortium immobilized CA‐NFM could be used at least five times. Furthermore, after leaving the mat for 1 month at 4°C, it was still usable, and the removal efficiency was found to be 45.4%. Based on our findings, bacteria immobilized on CA‐NFM have the potential to be used as highly effective and versatile nanobiotechnological biological sorbents in the treatment of wastewater containing dyes.Highlights Stenotrophomonas maltophilia and Ochrobactrum sp. were used as a bacterial consortium. Bacterial consortium immobilized on cellulose acetate nanofiber mats (CA‐NFM) was tested. EPS production by the consortium was confirmed by Fourier transform ınfrared spectroscopy analysis. CA‐NFM could be used at least five times.

Chlorhexidine-Containing Electrospun Polymeric Nanofibers for Dental Applications: An In Vitro Study.

Chlorhexidine is the most commonly used anti-infective drug in dentistry. To treat infected void areas, a drug-loaded material that swells to fill the void and releases the drug slowly is needed. This study investigated the encapsulation and release of chlorhexidine from cellulose acetate nanofibers for use as an antibacterial treatment for dental bacterial infections by oral bacteria Streptococcus mutans and Enterococcus faecalis. This study used a commercial electrospinning machine to finely control the manufacture of thin, flexible, chlorhexidine-loaded cellulose acetate nanofiber mats with very-small-diameter fibers (measured using SEM). Water absorption was measured gravimetrically, drug release was analyzed by absorbance at 254 nm, and antibiotic effects were measured by halo analysis in agar. Slow electrospinning at lower voltage (14 kV), short target distance (14 cm), slow traverse and rotation, and syringe injection speeds with controlled humidity and temperature allowed for the manufacture of strong, thin films with evenly cross-meshed, uniform low-diameter nanofibers (640 nm) that were flexible and absorbed over 600% in water. Chlorhexidine was encapsulated efficiently and released in a controlled manner. All formulations killed both bacteria and may be used to fill infected voids by swelling for intimate contact with surfaces and hold the drug in the swollen matrix for effective bacterial killing in dental settings.

Revisiting the Pharmacological Potential of 3‐Hydroxyflavone Derivatives (3HF) in Transdermal Drug Delivery by Electrospun Cellulose Acetate Nanofiber

AbstractThe unexplored anti‐inflammatory and wound‐scratching assay of 3‐hydroxy‐2‐(2,5‐dimethoxyphenyl)‐4H‐chromen‐4‐one [3HF(B)] was reported for the first time with the subsequent transdermal drug delivery en route electrospun cellulose acetate nanofiber mat. The higher anti‐inflammatory activity of 3HF(B) was revealed by in vitro protein denaturation assay in comparison to Ibuprofen. The wound scratching assay on NIH3T3 cells disclosed the rapid wound healing potential of 3HF(B) in 18 h. The fabricated cellulose acetate nanofiber‘s drug encapsulation efficiency was 82.0±1.0 % whereas drug release ability was 91.29±0.3 % at pH 7.4. The initial rapid release of 37.82±1.3 % of the drug was found to be beneficial for quick recovery from the critical phase of symptoms. These results suggest that the cellulose acetate/3HF(B) composite nanofiber's suitability to be employed as a patch in the transdermal drug delivery system with synergetic anti‐inflammatory activity.

A PTHrP-2 loaded adhesive cellulose acetate nanofiber mat as wound dressing accelerates wound healing

Although various dressings currently used have the effect of promoting wound healing, they still cannot meet the requirements of clinically efficient treatment. Recently, parathyroid hormone (PTH) and its pathway have been shown as the new target for wound repair. However, using PTH in clinical wound treatment can be a question. This study is to develop a novel PTHrP-2 loaded cellulose acetate nanofiber mat (CAP) via electrospinning to benefit wound repair. By observing the effects of prepared CAP on cell proliferation, migration, tube formation, and wound healing in the rat models, we have evaluated the safety and effectiveness of CAP. With the extract of CAP, the viability of human umbilical vein endothelial cells and fibroblasts was enhanced. It also could significantly increase the movement rate of human umbilical vein endothelial cells and promote tube formation. The wound closure speed of CAP treatment was significantly faster than the cellulose acetate group. In conclusion, CAP has a promoting effect in angiogenesis, collagen formation and re-epithelialization, thereby it can accelerate wound healing. CAP is a promising translational nanocomposite material, which might be transferred into a new type of wound dressing.

High pressure laminates reinforced with electrospun cellulose acetate nanofibers

In the work, the non-woven cellulose acetate (CA) nanofiber mats were prepared via electrospinning, and CA nanofiber were incorporated into the core layer of the high-pressure laminates (HPLs). When the concentration of CA was 16 wt%, SEM images demonstrated that the morphology of the CA nanofiber mat was the best, with an average diameter of 654±246 nm. When CA nanofiber mats were incorporated into the core layer of HPLs, the mechanical properties of the resulted HPLs composites were significantly improved. Specifically, the tensile strength and elongation at break of the nanofiber mats reinforced HPLs composites increased remarkably to 40.8 ±1.1 MPa and 27.9 ± 0.9 %, respectively, which were nearly 6 times and 4.4 times higher than those of the pure HPLs. Furthermore, the incorporation of the CA nanofiber mats also significantly improved the flame retardancy of the HPLs, which was revealed from the thermogravimetric analysis (TGA) results.

Bioactive Sambong oil-loaded electrospun cellulose acetate nanofibers: Preparation, characterization, and in-vitro biocompatibility

Blumea balsamifera oil loaded cellulose acetate nanofiber mats were prepared by electrospinning. The inclusion of blumea oil increased the nanofiber diameter. FTIR spectra confirm the addition of blumea oil in the nanofiber mats. The XRD pattern suggests that the inclusion of blumea oil has caused a misalignment in the polymer chains of the cellulose acetate. Thus, a decrease in the tensile strength was observed for the blumea oil loaded nanofibers. The increase in fiber diameter causes a reduction in the porosity of the nanofiber mats. The blumea oil loaded nanofiber mats showed antibacterial efficacy against Escherichia coli and Staphylococcus aureus. The blumea oil showed antioxidant abilities against the DPPH solution. MVTR of the neat and blumea oil loaded nanofiber mats was in the range of 2450–1750 g/m2/day, which is adequate for the transport of air and moisture from the wound surface. Blumea oil loaded mats showed good cell viability ~92% for NIH 3T3 cells in more extended periods of incubation. A biphasic release profile was obtained, and the release followed the first-order kinetics depending upon the highest value of the coefficient of correlation R 2 (88.6%).

Potential of electrospun cellulose acetate nanofiber mat integrated with silver nanoparticles from Azadirachta indica as antimicrobial agent

The present study aimed to assess the anti-microbial and anti-biofilm properties of an electrospun cellulose acetate nanofiber mat integrated with green synthesized silver nanoparticles (CA-g-AgNP nanomat). Electrospun CA and CA-g-AgNP nanomat were fabricated and the characterization was performed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy, and contact angle measurement. Counting of colony-forming units (CFU) and disk diffusion assay were performed to investigate the antimicrobial activity of the CA-g-AgNP nanomat. The anti-biofilm properties of the CA-g-AgNP nanomat were also assessed. Results showed much higher efficacy of the CA-g-AgNP nanomat against gram-positive Staphylococcus aureus, with enhanced internalization of the NPs. The biocompatibility of the CA-g-AgNP nanomat was monitored with MH-S cell lines, macrophage cell lines of Mus musculus. The biofilm formation was significantly inhibited and was found to be reduced by 50% in the presence of the CA-g-AgNP nanomat. Concomitantly, the application of the CA-g-AgNP nanomat resulted in a substantial reduction in CFU/mL. The CA-g-AgNP nanomat, with excellent activity towards biofilms, holds much promise for application in healthcare and the design of antimicrobial nanomat and wound dressing materials.

Manuka honey incorporated cellulose acetate nanofibrous mats: Fabrication and in vitro evaluation as a potential wound dressing

Wound dressings are the primary barrier between the wound surface and the outer environment. Here we report the fabrication of cellulose acetate (CA)–Manuka honey (MH) composite nanofibrous mats as a biocompatible and antimicrobial wound dressing. CA mats with different quantities of MH were developed by electrospinning. The ATR-FTIR spectra confirm the inclusion of MH in the composite CA-MH nanofibrous mats. The fibers were continuous and bead-free with acceptable mechanical properties. The fiber diameter increased with an increase in MH content. Inclusion of MH in the electrospun composite CA-MH nanofibrous mats shows high efficacy to prevent bacterial growth on the wound surface.The MH loaded CA nanofiber mats showed good antioxidant abilities, while the ability to free radicalize the DPPH was dependent upon the factors of MH content in the fiber and the time of immersion in the DPPH solution. Besides, the nanofibrous mat's high porosity (85–90%) and WVTR values of 2600 to 1950 g/m2/day, suitable for wound breathability and the mats show high cytocompatibility to NIH 3T3 cell line in in vitro testing, proving to be effective for promoting wound healing.

Frequency analysis of hexagonal microbeam with 2D nanofiber mat

Flexibility of graphene (Gr) is partially credited to its two-dimensional (2D) molecular structure which resembles like interconnected unit of hexagonal carbon atoms ring. Therefore, to increase the flexibility of micromechanical beams, we analyze the influence of hexagonal shape of microcantilever beam without and with hexagonal hole of varying side length. To carry out the analysis, we first fabricate the hexagonal structure and perform measurement using laser vibrometer. Based on the measurement, we found that the presence of hexagonal holes make the beam flexible by two order of magnitude more than that of a conventional beam without holes. However, we found that the frequency of microcantilever beam with hexagonal shape decreases with increase in hole size. To undo the effect of hexagonal holes on microbeam frequency, we cover the microbeam with an electrospun cellulose acetate nanofiber mat (CAF). Based on the measurements, we found that the frequency can be increased more than that of a solid rectangular microbeam. Finally, we propose a finite element based methodology to model microbeam and nanofiber mat to compute their frequencies. Thus, based on the understanding developed in this work, this hierarchical structure of microcantilever beam with electrosun nanofibers can be used as a best candidate for utilizing it for the development of flexible sensors based on MEMS devices.

Fast and non-destructive determination of active pharmaceutical ingredient concentration in an electrospun nanofiber patch using infrared spectroscopy

Infrared (IR) spectroscopy has been successfully utilized to non-destructively determine the concentration of α–arbutin (ABT) loaded on cellulose acetate (CA) electrospun-nanofiber patches. Initially, the homogeneity of the ABT distribution over the CA nanofiber mat, which would directly influence the sample representation of the acquired transmission IR spectra, was evaluated. IR microscopic mapping performed on the 3.0 wt% ABT sample covering an area of 800 × 800 μm2 revealed that ABT concentrations were moderately homogeneous (relative standard deviation: 3.3%). Another issue to consider for accurate analysis is the potential thickness variation from sample to sample, which makes the ABT peak intensity considerably less concentration-representative. The absolute amount of loaded ABT varies depending on the thickness of the nanofibers, thereby causing the intensity of the ABT peak to fluctuate. To resolve this problem, a method involving the peak area ratio between the ABT and CA band was used. When the IR sampling area was 800 × 800 μm2, the correlation between the ABT concentration (1.5–4.8 wt%) and the peak area ratio was linear, but the accuracy was not sufficient. Increasing the sampling area to 4 × 4 mm2 yielded better accuracy with a standard error of prediction (SEP) of 0.10 wt%. The acquisition of more concentration-representative sample spectra with wide area coverage was attributed to accurate concentration determination. In addition, the potential of utilizing near-infrared (NIR) and Raman spectroscopy for the same analysis was evaluated and discussed.

Facile fabrication of a "Catch and Release" cellulose acetate nanofiber interface: a platform for reversible glycoprotein capture and bacterial attachment.

Surfaces engineered to selectively capture and release target biomolecules and cells "on demand" are of considerable interest in a variety of biomedical applications, such as diagnostics and detection. In this work, a strategy is proposed to achieve "catch and release" using boronic acid ligand-functionalized electrospun cellulose acetate (CA) nanofiber mats. To achieve this goal, a simple method based on the one-step visible light-induced grafting copolymerization of 3-(acrylamido)phenylboronic acid (BA) and acrylamide (AM) is established. The copolymer poly(AM-co-BA)-grafted CA nanofiber mats (CA-g-P(AM-co-BA)) showed high capacity for the binding of glycoproteins such as horseradish peroxidase (HRP) and ovalbumin (OVA) under alkaline (pH 9.0) and physiological conditions (pH 7.4). Moreover, the bound glycoproteins can be released from the CA-g-P(AM-co-BA) mats by simple exposure to an acetic acid-sodium acetate (HAc-NaAc) buffer solution (pH 4.0). In addition, this system can be applied to directly extract glycoproteins from egg white samples. Likewise, the CA-g-P(AM-co-BA) mats acted as favorable substrates for Gram-negative E. coli bacterial attachment. The release of the attached bacteria is triggered by competitive sugar binding involving the addition of glucose. It can be envisioned that such boronic acid ligand-functionalized CA nanofiber mats that can "catch and release" biomolecules and bacterial cells hold considerable promise for diverse applications.

Br-PADAP embedded in cellulose acetate electrospun nanofibers: Colorimetric sensor strips for visual uranyl recognition

In this work, a new visual colorimetric strip based on cellulose acetate nanofiber mats modified by 2-(5-Bromo-2-pyridylazo)-5-(diethylamino) phenol was successfully prepared via electrospinning technology. The prepared colorimetric strip showed high sensitivity towards UO22+ with the yellow-to-purple color change signal. Upon the optimal conditions of solution pH at 6.0 and response time for 80min, the detection limit for UO22+ can reach 50 ppb. Moreover, the strip also exhibited excellent anti-interference ability in the presence of other metal ions. In order to achieve the quantitative detection for UO22+, a color-differentiation map was established, which was prepared from converted H values. Finally, the strip was also used to detect UO22+ in the seawater and showed high sensitivity.

Effect of solvent treatment on morphology, crystallinity and tensile properties of cellulose acetate nanofiber mats

Aligned nanofiber mats were prepared from cellulose acetate using an electrospinning technique. The nanofiber mats were then immersed in an ethanol/acetone mixture. The solvent treatment led to denser, more compact fibrous structure and slight decrease in fiber alignment. It increased fiber diameter and polymer crystallinity within fibers. These effects resulted in increase in the tensile strength of fibrous mats. Solvent treatment may offer a simple, efficient approach to improve the mechanical strength of nanofibrous mats.

Cellulose acetate nanofiber mat with honeycomb-like surface structure

Developing nanofiber mats with unique three-dimensional morphology (3D) are of great interest to biomedical engineers working on nanotechnology. Herein, we report cellulose acetate nanofiber mat with honeycomb-like surface structure for the very first time. Cellulose acetate nanofiber mats (CANFs) were prepared via a simple electrospinning technique. A new and straightforward oil spray method was developed to create the honeycomb like structure on the nanofiber mats. The patterned structure of the prepared nanofiber mat (hs-CANFs) was investigated. The diameter of the honeycombs created on the nanofiber mat ranged from 150µm to 450µm. XRD data revealed the amorphous nature of the prepared CANFs and hs-CANFs. The structure of the nanofiber mat was also studied by FT-IR analysis.

Decoration of phthalocyanine on multiwalled carbon nanotubes/cellulose nanofibers nanocomposite for decoloration of dye wastewater

Abstract We describe the incorporation of multiwalled carbon nanotubes (MWNT) into cellulose nanofibers for the subsequent functionalization of cobalt tetraaminophthalocyanine (CoPc) catalyst. MWNT doped cellulose acetate nanofiber mats (MWNT/CA-NM) was prepared by electrospinning MWNT-cellulose acetate mixed solution. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) confirmed the morphologies of nanofibers and the aligned distribution of MWNT along the nanofiber axis. Both the thermal stability and the mechanical properties of nanofibers were significantly improved with increased MWNT concentration. CoPc was covalently immobilized onto the surface of nanofibers after MWNT/CA-NM was hydrolyzed with KOH, oxidized with NaIO 4 , and spacer-arm attached with tetraethylenepentamine (TEPA), using glutaraldehyde as a coupling agent. The resulting cellulose nanofiber-based functional nanomaterial, MWNT doped, CoPc functionalized cellulose nanofiber mats (MWNT/CoPc-spacer-NM), can efficiently decolorize reactive dye wastewater, and the introduction of MWNT obviously improved the catalytic efficiency of CoPc. Ultraviolet–visible light spectroscopy (UV) and fluorescence spectroscopy (FL) experiments identified the communication between the CoPc and the MWNT, which might be responsible for the improvement of catalytic activity.

Synthesis and characterization of novel drug delivery system based on cellulose acetate electrospun nanofiber mats

Cellulose acetate nanofiber mats containing tetracycline hydrochloride were prepared by electrospinning. Incorporation of tetracycline hydrochloride (20 wt% based on the weight of cellulose acetate) in the cellulose acetate solution (17% wt/vol in 2:1 vol/vol ethanol-dimethyl sulfoxide) did not affect the morphology of the obtained fibers, as tetracycline hydrochloride-loaded cellulose acetate fibers were smooth. The average diameters of these fibers ranged between 50 and 90 nm. Determination of the release characteristics of tetracycline hydrochloride from the cellulose acetate nanofiber mats was carried out by total immersion in phosphate buffer solution, that is, in the total immersion method, the maximum amounts of the tetracycline hydrochloride released from the cellulose acetate nanofiber into the medium were 10 and 25% µg/100 ml. Antibacterial activity of prepared tetracycline hydrochloride-loaded as-spun cellulose acetate fiber mate was achieved using Escherichia coli and Staphylococcus aureus as a representative each of Gram-negative and Gram-positive bacteria, respectively. Antibacterial activity of tetracycline hydrochloride-loaded as-spun cellulose acetate fiber mat showed effectiveness with 77–88% bacteria reduction after 10 min–1 h for Escherichia coli and approximately 83–85% reduction after 10 min–1 h for Staphylococcus aureus.

Preparation and Properties of Electrospun Cellulose Acetate Nanofiber Mats

Four kinds of solutions were prepared by dissolving cellulose acetate in dichloromethane, formic acid, acetic acid and trifluoroacetic acid respectively, and then were electrospun into fibers. The solutions were characterized for their viscosity and conductivity using rotary viscosimeter and conductivity meter, respectively. The morphology and performance of the electrospun CA fibers were investigated by scanning electron microscopy (SEM), digital microscope and X-ray diffraction (XRD). Results showed that the important factors determining the electro-spinnability of the CA solutions were boiling point, viscosity and conductivity of the resulting solutions. 8% CA spinning solution with trifluoroacetic acid as solvent had good spinnability, and the average diameter reached 236nm; the obtained fibers were mainly amorphous, but characterized for good mechanical properties.