Electrospun Cellulose Acetate Nanofibers Research Articles

Electrochemical Hg2+ sensor based on electrospun cellulose acetate nanofibers doped with Ag nanoparticles

Mercury (Hg) sensors are critical for environmental monitoring, industrial processes, and public health. They are designed to measure the presence and concentration of mercury ions (Hg2+) in various matrices, including air, water, soil, and biological samples. Mercury in the environment raises concerns due to its toxicity and potential for bioaccumulation. Therefore, this work aims to develop an improved, eco-friendly mercury sensor to address the evolving need for monitoring and control of mercury. The electrochemical sensor for reported here is based on the ability of silver (Ag) to catalyze the reduction of the mercury species Hg2+ to elemental mercury (Hg0), forming an Ag/Hg amalgam. To optimize this sensor, the concentration of silver nanoparticles (AgNPs) on modified nanofibers is determined using differential pulse voltammetry (DPV). Morphological studies and chemical characterization reveal a fiber thickness ranging from 250 to 450 nm and characteristic functional groups, respectively. The sensoŕs analytical performance for detecting Hg2+ concentrations is evaluated through cyclic voltammetry (CV) and DPV in 0.1 M potassium chloride as a supporting electrolyte. The sensor’s detection limit (LOD) for Hg2+ was 0.43 μg/L, with a sensitivity of 0.33 mA/μg/L. In conclusion, the electrochemical sensor exhibits sensitivity and selectivity for Hg2+ detection in the presence of other interfering metal ions, along with eco-friendly and cost-effective features, making it a reliable and practical tool for detecting Hg2+ concentration in water samples.

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
 
 

A disposable paper-based electrochemical biosensor decorated by electrospun cellulose acetate nanofibers for highly sensitive bio-detection.

Paper-based electrochemical sensors have the characteristics of flexibility, biocompatibility, environmental protection, low cost, wide availability, and hydropathy, which make them very suitable for the development and application of biological detection. This work proposes electrospun cellulose acetate nanofiber (CA NF)-decorated paper-based screen-printed (PBSP) electrode electrochemical sensors. The CA NFs were directly collected on the PBSP electrode through an electrospinning technique at an optimized voltage of 16 kV for 10 min. The sensor was functionalized with different bio-sensitive materials for detecting different targets, and its sensing capability was evaluated by CV, DPV, and chronoamperometry methods. The test results demonstrated that the CA NFs enhanced the detection sensitivity of the PBSP electrode, and the sensor showed good stability, repeatability, and specificity (p < 0.01, N = 3). The electrochemical sensing of the CA NF-decorated PBSP electrode exhibited a short detection duration of ∼5-7 min and detection ranges of 1 nmol mL-1-100 μmol mL-1, 100 fg mL-1-10 μg mL-1, and 1.5 × 102-106 CFU mL-1 and limits of detection of 0.71 nmol mL-1, 89.1 fg mL-1, and 30 CFU mL-1 for glucose, Ag85B protein, and E. coli O157:H7, respectively. These CA NF-decorated PBSP sensors can be used as a general electrochemical tool to detect, for example, organic substances, proteins, and bacteria, which are expected to achieve point-of-care testing of pathogenic microorganisms and have wide application prospects in biomedicine, clinical diagnosis, environmental monitoring, and food safety.

Investigation of Electrospun Polyacrylonitrile and Cellulose Acetate Smart Nanofibers Doped with Expanded Graphite for the Structure and Photothermal Effect

In this study, photothermal effect by doping expanded graphite (EG) to smart nanofibers produced by electrospinning method was investigated. Fourier transform infrared (FT-IR) spectroscopy was exploited for chemical characterization. Thermal analysis experiments were carried out by heating and cooling curves. Surface morphology of the produced materials was investigated through scanning electron microscope (SEM). Contact angle was determined through contact angle measurement device. The appearance of the peak of the characteristic cyano group in the structure of Polyacrylonitrile (PAN) at 2237.02 cm-1 in the nanofibers having different percentages synthesized with EG and PAN was accepted as the evidence of PAN nanofibers formation. The temperature platforms in the heating/cooling curves exhibited that the temperature of the PAN and cellulose acetate (CA) nanofibers mixed with different EG percentage have higher than pristine nanofibers. The surfaces of the EG@PAN and EG@CA nanofibers were homogeneously distributed fibrous, excessive EG heterogeneously dispersed or electrosprayed in shape. The maximum contacts angles were measured as 67.96° and 52.88° for nanofibers synthesized with EG@CA and EG@PAN, respectively. As the result, the temperature of the nanofibers mixed EG at different percentages increased resulting from having the higher thermal conductivity of EG. Main goal of the study is both investigating photothermal effect in PAN and CA electrospun nanofibers doped with EG of activating heat accumulation property of the produced smart nanofibers for heat energy production from the solar. Thus, it will be possible to develop a new promising method in the production of the smart textile products that have the storage capacity of the solar energy.

Electrospun cellulose nanofibers immobilized with anthocyanin extract for colorimetric determination of bacteria

A novel smart biochromic textile sensor was developed by immobilizing anthocyanin extract into electrospun cellulose acetate nanofibers to detect bacteria for numerous potential uses, such as healthcare monitoring. Red-cabbage was employed to extract anthocyanin, which was then applied to cellulose acetate nanofibers treated with potassium aluminum sulfate as a mordant. Thus, nanoparticles (NPs) of mordant/anthocyanin (65–115 nm) were generated in situ on the surface of cellulose acetate nanofibrous film. The pH of a growing bacterial culture medium is known to change when bacteria multiply. The absorbance spectra revealed a bluish shift from 595 nm (purple) to 448 nm (green) during the growth of Gram-negative bacteria (E. coli) owing to the discharge of total volatile basic amines as secretion metabolites. On the other hand, the absorption spectra of a growing bacterial culture containing Gram-positive bacteria (L. acidophilus) showed a blue shift from 595 nm (purplish) to 478 nm (pink) as a result of releasing lactic acid as a secretion metabolite. Both absorbance spectra and CIE Lab parameters were used to determine the color shifts. Various analytical techniques were utilized to study the morphology of the anthocyanin-encapsulated electrospun cellulose nanofibers. The cytotoxic effects of the colored cellulose acetate nanofibers were tested.

Electrospun Cellulose Acetate Nanofibers Containing Clinacanthus nutans (Phayayo) Crude Extract as Potential Wound Dressings

Extraction of Clinacanthus nutans (Burm.f.) lindau (C. nutans) or Phayayo (PY) leaves was performed by maceration using ethanol as an extractant. The antioxidant activity was evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. The inhibitory concentration at 50% antioxidant activity (IC50) of PY extract was 15.62 mg/mL. The electrospun cellulose acetate (CA) nanofibers containing PY extract at concentrations of 2.5, 5, and 7.5% w/v and silver (Ag) nanoparticles at 0.1% w/v were fabricated. The addition of PY extract and Ag influenced the viscosities of solutions and therefore affected the morphology and fiber diameters. The electrospun CA fiber mat containing 0.1% Ag and 7.5% PY extract was chosen to investigate its potential for use in wound dressing applications. The degrees of weight loss and water swelling of the electrospun CA/PY7.5/Ag fiber mat after immersion in a phosphate buffer solution (pH 7.4) at 37°C were examined in a range of 2-24 h, and found to increase with immersion time. The antioxidant activity of the fiber mat at the same period of immersion time was also studied, which corresponded with the trends of weight loss and water swelling. The antioxidant activity at 24 h of immersion was 68.3±9.2%. The CA/PY7.5/Ag fiber mat had no antibacterial activity against Escherichia coli but slightly inhibited the growth of Staphylococcus aureus. The fiber mat also possesses high hydrophilicity, as examined by the contact angle measurement. These results indicate that the CA/PY7.5/Ag fiber mat is a promising material for use as a topical transdermal patch or wound dressing.

Stretchable polydimethylsiloxane/aligned electrospun cellulose acetate nanofibers composites with high transparency and fracture resistance

AbstractPolydimethylsiloxane (PDMS) is recognized as an excellent stretchable substrate in wearable electronics, due to its desirable properties such as tensile properties, transparency, thermal stability, non‐toxicity, and good biocompatibility. However, its limited fracture toughness and susceptibility to cracking significantly reduce the material's overall durability. In this study, the solution casting method was applied to prepare the nanofibers composites combined stretchable PDMS and aligned electrospun cellulose acetate (CA) to improve its mechanical properties and keep its transparency. The results showed that composites containing 3 wt% loadings of electrospun CA nanofibers exhibited a light transmittance exceeding 85% within the visible light range. Specifically, the PDMS/CA‐400 composites exhibited maximum improvements in comparison to pure PDMS. Notably, the tensile strength increased significantly from 2.1 to 3.0 MPa, while the toughness increased from 0.93 to 2.49 MJ/m3. In addition, the tensile strength of PDMS/CA‐400 composites with pre‐cut cracks increased from 0.2 to 1.4 MPa, and the fracture toughness increased from 14.78 to 174.42 kJ/m3, which were respectively 7 and 12 times compared to pure PDMS. Scanning electron microscope images showed that PDMS formed good interfacial interaction with CA nanofibers. This study introduces a novel method utilizing electrospun nanofibers to create transparent and fracture‐resistant stretchable composites, offering promising enhancements for the durability of wearable electronic devices.Highlights Explore the impact of the speed of receiving rollers on the degree of fiber arrangement. PDMS/CA‐400 composite material shows good light transmittance and high fracture resistance. The tight interface between the fiber and the matrix improves the optical transmission and mechanical properties of the composite materials.

In situ polyaniline polymerization on electrospun cellulose acetate nanofibers derived from recycled waste filter butts of cigarettes for the enhanced removal of methyl orange and rhodamine

In this study, waste cigarette butts (CBs) were processed to produce electrospun cellulose acetate (CA) nanofibrous membranes modified with polyaniline (PANI) via chemical oxidation polymerization. This cost-effective method of preparing CA coated with PANI was initially investigated by comparing CA, CA-PANI, and CA-dPANI (as deprotonated PANI) for the rapid adsorption of cationic and anionic dyes. The results depicted CA-PANI with the highest dye removal capacity. As the optimum material, CA-PANI was applied to remove methyl orange (MO) and rhodamine chloride (RC) dye from an aqueous phase. Essential factors: contact time, solution pH, initial dye concentration, nanofiber dosage, and temperature of solution were evaluated with maximum equilibrium adsorption capacity and removal percentage achieved for MO as 24.87 mg/g and 99 %, for RC as 6.93 mg/g and 55 %, respectively. The adsorptive experimental data for both dyes best fitted the pseudo-second-order kinetic, intraparticle diffusion, and Freundlich models. Moreover, the thermodynamics result indicated the adsorption processes were exothermic and spontaneous in nature. Reusability studies also showed the stable performance of CA-PANI material for up to 7 adsorption-desorption cycles. The high dye removal efficiency suggests that the adsorbent material in the water filtration of azo dyes.

Evaluation of antimicrobial and antioxidant activity of Carum copticum L. essential oil encapsulated in electrospun cellulose acetate nanofibers

ABSTRACT The objective of this research was to nanoencapsulate ajwain (Carum copticum L.) essential oil (EO) in cellulose acetate (CA) using the electrospinning technique and evaluate its antioxidant and antimicrobial activity. The main components of ajwain EO were thymol, p-cymene, and γ- terpinene. A zeta potential of −40.11, −37.85, −35.50, and −31.74 mV was found for nanofibers of pure CA, CA/EO 1%, 2.5%, and 5%, respectively. According to SEM images, CA electrospun nanofiber loaded with different concentrations of ajwain EO had nano-scale size and uniform morphology. The antibacterial activity enhanced with higher concentrations of EO, and it was higher for nanoencapsulated EO at the same concentration. The fibers loaded with EO were effective against the microbial strains according to the following decreasing order: E. coli > S. enteritidis > S. dysenteriae > L. monocytogenes > S. aureus. Results of the antioxidant assays showed that the ABTS and DPPH scavenging capacity and reduction potential of Fe3+ of free and nanoencapsulated EO were as follows: CA/EO 5% = CA/EO 2.5% > EO 5% > CA/EO 1% > EO 2.5% > EO 1%. Antioxidant and antibacterial activities of all EO-loaded CA nanofibers were higher than free EO.

Up-scaling of cellulose acetate electrospun nanofibers with a needleless wire spinneret technique

Up-scaling of cellulose acetate electrospun nanofibers with a needleless wire spinneret technique

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.

Development of cellulose acetate/CuO/AgNP nanofibers based effective antimicrobial wound dressing

The research reports synthesis of the CuO/AgNP composite nanoparticles and their electrospun cellulose acetate (CA) nanofiber for effective and safer antimicrobial wound dressing applications. Synthesis of the composite nanoparticles was confirmed by XRD, TEM and EDS analysis. The SEM confirmed regular morphologies of the composite nanofibers. CA nanofibers with three different concentrations of CuO/AgNPs (3%,6% and 10%) were fabricated. The Kirby-Buyer disk diffusion test and relative cell viability results confirmed sufficiently larger bacteriostatic and bactericidal properties of the nanocomposites. The water absorption/transport, swelling ratio and tensile strength results revealed the nanocomposite’s potential for the application. Our findings suggested the CA/CuO/AgNP as effective antimicrobial wound dressing material.

Fabrication and characterization of electrospun cellulose acetate nanofibers derived from rice husk for potential wound healing application

As one of the world’s most abundant biomass, lignocellulosic materials such as rice husk (RH) has been recognized for its various potential usages. Electrospun nanofibrous mats have been fabricated from various natural and synthetic polymers and offers a wide range of promising criteria suitable for wound dressing applications. Attuned to the environmental concerns in current years have led to finding new resources to replace the synthetic polymers. Natural polymers have grabbed considerable attention due to their desirable properties. Therefore, the application of cellulose-derived materials from agricultural waste becomes crucial as a green alternative to produce electrospun wound dressing with excellent wettability, porosity and tunability to promote wound healing at relatively low costs. Interestingly, a specific study on the utilization of cellulose extracted from RH to produce electrospun nanofibrous mat remains unreported. Therefore, this work aimed to investigate the feasibility of using RH as a source of raw materials to create nanofibrous mats for use as prospective wound dressing materials. As researchers currently focus on environmental sustainability, this study focuses on the physicochemical study of the RH derived nanofibers as a biocompatibility drug carrier that are derived from biomass waste. In this paper, cellulose extracted from RH was converted into its derivate, cellulose acetate and electrospun. The nanofibers were then characterized by scanning electron microscope, attenuated total reflectance- fourier transform spectroscopy, water contact angle to evaluate the main properties, and compatibility of the electrospun nano-fibrous mat for wound dressing applications.

Green Electrospinning of Biodegradable Cellulose Acetate Nanofibrous Membranes with Tunable Porosity

The electrospinning of polymer nanofibers has received significant attention owing to their high surface-area-to-volume ratio, high porosity, adjustable pore size and texture, and highly interconnected porous structure. In particular, the electrospinning of biodegradable cellulose acetate (CA) nanofibers has sparked interest in diverse applications, including drug delivery systems, scaffolding for tissue engineering, air filtration, and affinity membrane systems. However, the electrospinning process has been mostly performed using toxic and hazardous solvents and additives. We developed electrospun CA nanofibers using a green solvent system comprising dimethyl carbonate and cyclopentanone. The use of green additives, namely, tetrabutylammonium bromide salts and sophorolipid-based biosurfactants, obtained from honey yeast, substantially improved the spinnability of the CA solution. Moreover, the nanofiber diameter and porous texture were tunable by adjusting the solvent ratio. Pore generation was induced using volatile dimethyl carbonate, which quickly evaporated from the fiber jet. Molecular dynamics simulations demonstrated that the electrospinning process can be divided into three stages. The addition of the biosurfactant facilitated the evaporation process and improved the uniformity of the nanofibers. Furthermore, the nanofibers can be degraded using esterase and cellulase enzymes. To summarize, the electrospinning of ultrafine CA porous nanofibers with tunable morphology was achieved using green solvents and additives.

Fabrication and Characterization of Ibuprofen and Ceftriaxone loaded Electrospun Cellulose Acetate Nanofiber Layers as a Model of Targeted Drug Delivery System

This study aims to study the process of fabricating and characterization nanofibers based on cellulose acetate polymer filled with ceftriaxone and ibuprofen using the electrospinning method as a model for a targeted drug delivery system. Cellulose acetate has been successfully fabricated into nanofibers using the electrospinning method and filled with ceftriaxone and ibuprofen. The resulting nanofibers have an average diameter in the range of 412.5 – 558.5 nm under the conditions of the electrospinning process, namely 22 kV voltage, 15 cm distance, and flow rate. 0.005 mL/min using acetone/DMAc (2:1). Based on the data generated from the FTIR test, homogeneity, and drug release test, it is known that the resulting nanofibers, namely cellulose acetate, cellulose acetate-ceftriaxone, and cellulose acetate-ibuprofen, have good morphological characteristics, homogeneity, and release rate so that they have the potential to be used as a targeted drug delivery system

Designing a colorimetric nanosensor based on dithizone and cholesteric liquid crystals loaded in electrospun cellulose acetate nanofibers: Monitoring the quality of pistachio as a case study

AbstractWe describe colorimetric electrospun nanosensors designed to work at temperatures of 35–36°C. The mode of operations is based on a combination of the ability of dithizone to exhibit appropriate color and cholesteric liquid crystals presenting a wide range of melting points at various mixing ratios. To this end, different levels of dithizone (IUPAC name 1‐anilino‐3‐phenyliminothiourea), different ratios of cholesteric liquid crystals to cellulose acetate and cholesteryl oleyl carbonate to cholesteryl nanoate were defined as independent variables and the total color difference was considered as the response in the response surface methodology approach. The results showed that the range of color palette changes of the designed samples was diverse and could be applied to different products. As a case study, the applicability of the sensor was evaluated on the 4‐month shelf life of pistachio nuts at 35°C whilst the spoilage criteria were reconciled with the color changes in the designed sensor.

Photoluminescence sensing of Pb2+ using cellulose acetate nanofiber decorated with Au nanoparticles

Lead (II) is the second most hazardous heavy metal to the environment and humanity, due to its accumulation in the food chain and remaining as a persistent toxin in the environment. Thus, the design and fabrication of effective sensing materials and devices for the speedy detection of lead is a great challenge. Herein, we introduce gold nanoparticles deposited on the surface of electrospun cellulose acetate nanofiber Au@CANFs as photoluminescence sensor for detecting trace amount of lead metal ions based on a photoluminescence quenching approach. Despite that the concentration of cellulose acetate used for fabrication of nanofiber is lower than that previously reported, we observed nanofiber with small diameter and uniform shape. The scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis of the as-prepared sensor reveal the formation of nanofiber structure with diameter 90–200 nm and Au NPs are distributed on the surface of nanofiber with size 15–50 nm. The surface structure and chemical compositions of Au@CANFs were performed by Fourier transform infrared (FTIR) and XPS techniques. The UV-Vis spectra, clearly demonstrating that the sensor displayed localized surface plasmon resonance (LSPR) of Au nanoparticles. Both photoluminescence spectroscopy and Inverted Fluorescence microscopy image demonstrating that the CANFs and Au@CANFs display green emission. Under optimum conditions, the Au@CANFs PL sensor showed high sensitivity for detection of Pb2+ ion within a working range of 0 μg/L to 6 μg/L, R2 = 0.992 and a limit of detection of 0.16 ppb. Based on the obtained results, we anticipate that this PL sensor can be easily extended to tune the sensing performance of different heavy metals.

PH-sensitive self-assembled nanofibers based on electrostatic interaction and Schiff base bonding for controlled release of curcumin

In this study, chitosan-dialdehyde-β-cyclodextrin-curcumin (CS-DCD-CUR) and alginate dialdehyde (ADA) were alternately deposited on the surface of electrospun cellulose acetate (CA) nanofibers driven by Schiff base bonding and electrostatic attraction. With the increasing number of bilayers, the self-assembled nanofibers showed an increased average fiber diameter from 441 to 576 nm and had relatively rough surfaces. The improved thermal stability and tensile strength of self-assembled nanofibers were attributed to the interactions between CS-DCD-CUR and ADA. The self-assembled nanofibers exhibited pH-sensitive release characteristics under acidic conditions due to the weakening of the electrostatic interaction and the hydrolysis of Schiff-base. Moreover, the self-assembled nanofibers could be used for sustained and controlled release of the curcumin within 620 min and maintained the antioxidant activities. The highest radical scavenging activities against ABTS and DPPH radicals of the nanofibers were 24.75% and 83.56%, respectively. These results suggested that the layer-by-layer self-assembled nanofibers provided a pH-responsive sustained delivery system for bioactive substances with potential applications in functional foods. • Electrostaic attraction and Schiff base bonding were employed to drive the self-assembly of the nanofibers. • The self-assembled nanofibers had improved thermal stability and mechanical properties. • The self-assembled nanofibers exhibited a controllable pH-sensitive release manner of curcumin.

Chitosan/silk fibroin biomimic scaffolds reinforced by cellulose acetate nanofibers for smooth muscle tissue engineering

Reconstruction of multilayered and functional smooth muscle tissues remains a challenge nowadays. Cryogels possess great advantages in three-dimensional tissue regeneration owing to the interconnected macroporous structure, but their applications have been hindered because of limited mechanical properties. Inspired by the natural extracellular matrix, cellulose acetate electrospun nanofibers (NFs) were incorporated to chitosan/silk fibroin (CS/SF) cryogel scaffolds to address this problem in this work. Compared with pure CS/SF scaffolds, CS/SF/NFs composite scaffolds showed roughened surface and enlarged pore size (216.2 ± 65.3 μm vs. 263.1 ± 75.7 μm) allowing for cell adhesion and proliferation. Incorporation of nanofibers upgraded the mechanical properties of scaffolds with a six-fold increase in compressive modulus. The proliferation and infiltration of smooth muscle cells (SMCs) were remarkably improved with the existence of nanofibers. Besides, SMCs cultured on CS/SF/NFs scaffolds displayed higher expression of contraction-related genes, verifying their potential for smooth muscle tissue engineering.

Moist-electric generators based on electrospun cellulose acetate nanofiber membranes with tree-like structure

Moist-induced electricity generators (MEGs) that harvest electric energy from moisture in the atmosphere show great potential in portable and wearable electronics. Structural properties of active materials are essential for improving the output performance of MEGs. Herein, we developed a novel tree-like structure cellulose acetate (CA) nanofiber membrane by one-step electrospinning of CA solutions added organic branched salt to construct a low-cost, efficient, and wearable MEG. Thanks to the synergistic effects of improved hydrophilicity, increased specific surface area as well as reduced pore size, a single MEG from the optimal CA membrane could generate an output voltage of about 700 mV with a maximum output power density of up to 2.45 μW cm−2. Interestingly, this MEG can drive electronic calculators by connecting in series and can be used to monitor human respiration due to its high sensitivity to moisture. Such strategy of enhancing the output performance of MEGs based on structural design provides new insights for the development of portable electronic devices.