Research

16 pages, 7028 KiB

Open AccessArticle

Synthesis and Biocompatibility Evaluation of PCL Electrospun Membranes Coated with MTA/HA for Potential Application in Dental Pulp Capping

by Soumya Sheela, Fatma Mousa AlGhalban, Khalil Abdelrazek Khalil, Tahar Laoui and Vellore Kannan Gopinath

Polymers 2022, 14(22), 4862; https://doi.org/10.3390/polym14224862 - 11 Nov 2022

Cited by 4 | Viewed by 1594

Abstract

This study aimed to develop polycaprolactone (PCL) electrospun membranes coated with mineral trioxide aggregate/hydroxyapatite (MTA/HA) as a potential material for dental pulp capping. Initially, the PCL membrane was prepared by an electrospinning process, which was further surface coated with MTA (labeled as PCLMTA) [...] Read more.

This study aimed to develop polycaprolactone (PCL) electrospun membranes coated with mineral trioxide aggregate/hydroxyapatite (MTA/HA) as a potential material for dental pulp capping. Initially, the PCL membrane was prepared by an electrospinning process, which was further surface coated with MTA (labeled as PCLMTA) and HA (labeled as PCLHA). The physico-chemical characterization of the fabricated membranes was carried out using field emission scanning electron microscopy (FE-SEM)/Energy dispersive X-ray (EDX), X-ray diffraction (XRD), Raman spectroscopy, and contact angle analysis. The biocompatibility of the human dental pulp stem cells (hDPSCs) on the fabricated membranes was checked by XTT assay, and the hDPSCs adhesion and spreading were assessed by FE-SEM and confocal microscopy. The wound healing ability of hDPSCs in response to different electrospun membrane extracts was examined by scratch assay. The surface morphology analysis of the membranes by FE-SEM demonstrated a uniform nanofibrous texture with an average fiber diameter of 594 ± 124 nm for PCL, 517 ± 159 nm for PCLHA, and 490 ± 162 nm for PCLMTA. The elemental analysis of the PCLHA membrane indicated the presence of calcium and phosphorous elements related to HA, whereas the PCLMTA membrane showed the presence of calcium and silicate, related to MTA. The presence of MTA and HA in the PCL membranes was also confirmed by Raman spectroscopy. The water contact analysis demonstrated the hydrophobic nature of the membranes. The results indicated that PCL, PCLHA, and PCLMTA membranes were biocompatible, while PCLMTA exhibited better cell adhesion, spreading, and migration. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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16 pages, 4584 KiB

Open AccessArticle

Production of rGO-Based Electrospinning Nanocomposites Incorporated in Recycled PET as an Alternative Dry Electrode

by Michelle Chizzolini Barbosa, Claudia do Amaral Razzino, Thiago Domingues Stocco, Moisés das Virgens Santana, Anupama Ghosh, Luiz Fernando Pereira, Carlos Julio Tierra-Criollo and Anderson Oliveira Lobo

Polymers 2022, 14(20), 4288; https://doi.org/10.3390/polym14204288 - 12 Oct 2022

Cited by 2 | Viewed by 1420

Abstract

In this work, Coca-Cola^® bottles were reused as a PET polymer (rPET) source to produce electrospun polymeric nanofibers. The nanofibers were electrospun from polymer solutions with different concentrations of reduced graphene oxide (rGO) incorporated for applications in somatosensory electrical stimulation. The rPET/rGO [...] Read more.

In this work, Coca-Cola^® bottles were reused as a PET polymer (rPET) source to produce electrospun polymeric nanofibers. The nanofibers were electrospun from polymer solutions with different concentrations of reduced graphene oxide (rGO) incorporated for applications in somatosensory electrical stimulation. The rPET/rGO nanofiber mats were characterized by SEM, TEM, Raman, DSC, TGA, and DMA and the results showed that the incorporation of rGO in electrospun rPET fibers produced rPET/rGO composites. The rPET/rGO composites were then evaluated for possible application as dry electrodes. Moreover, with a preliminary test of numerous volunteers, the rPET/rGO dry electrode showed promising results. The rPET/rGO electrodes showed good performance and applicability to make dry electrodes, and these have applications as dry or wearable electrodes to produce electrochemical sensors. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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25 pages, 10888 KiB

Open AccessArticle

Fabrication of Gelatin Nanofibers by Electrospinning—Mixture of Gelatin and Polyvinyl Alcohol

by Hsiu Yu Chi, Nai Yun Chang, Chuan Li, Vincent Chan, Jang Hsin Hsieh, Ya-Hui Tsai and Tingchao Lin

Polymers 2022, 14(13), 2610; https://doi.org/10.3390/polym14132610 - 27 Jun 2022

Cited by 15 | Viewed by 3507

Abstract

Gelatin, one of the most abundant, naturally derived biomacromolecules from collagen, is widely applicable in food additives, cosmetic ingredients, drug formulation, and wound dressing based on their non-toxicity and biodegradability. In parallel, polyvinyl alcohol (PVA), a synthetic polymer, has been commonly applied as [...] Read more.

Gelatin, one of the most abundant, naturally derived biomacromolecules from collagen, is widely applicable in food additives, cosmetic ingredients, drug formulation, and wound dressing based on their non-toxicity and biodegradability. In parallel, polyvinyl alcohol (PVA), a synthetic polymer, has been commonly applied as a thickening agent for coating processes in aqueous systems and a major component in healthcare products for cartilage replacements, eye lubrication, and contact lenses. In this study, a new type of mixed hydrogel nanofiber was fabricated from gelatin and polyvinyl alcohol by electrospinning under a feasible range of polymer compositions. To determine the optimal composition of gelatin and polyvinyl alcohol in nanofiber fabrication, several key physicochemical properties of mixed polymer solutions such as viscosity, surface tension, pH, and electrical conductance were thoroughly characterized by a viscometer, surface tensiometer, water analyzer, and carbon electron probe. Moreover, the molecular structures of polymeric chains within mixed hydrogel nanofibers were investigated with Fourier-transform infrared spectroscopy. The morphologies and surface elemental compositions of the mixed hydrogel nanofibers were examined by the scanning electron microscope and energy-dispersive X-ray spectroscopy, respectively. The measurement of water contact angles was performed for measuring the hydrophilicity of nanofiber surfaces. Most importantly, the potential cytotoxicity of the electrospun nanofibers was evaluated by the in vitro culture of 3T3 fibroblasts. Through our extensive study, it was found that a PVA-rich solution (a volumetric ratio of gelatin/polyvinyl alcohol <1) would be superior for the efficient production of mixed hydrogel nanofibers by electrospinning techniques. This result is due to the appropriate balance between the higher viscosity (~420–~4300 10⁻² poise) and slightly lower surface tension (~35.12–~32.68 mN/m²) of the mixed polymer solution. The regression on the viscosity data also found a good fit by the Lederer–Rougier’s model for a binary mixture. For the hydrophilicity of nanofibers, the numerical analysis estimates that the value of interfacial energy for the water contact on nanofibers is around ~−0.028 to ~−0.059 J/m². Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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18 pages, 7810 KiB

Open AccessArticle

Carbon Nanofiber Double Active Layer and Co-Incorporation as New Anode Modification Strategies for Power-Enhanced Microbial Fuel Cells

by Nasser A. M. Barakat, Mohamed Taha Amen, Rasha H. Ali, Mamdouh M. Nassar, Olfat A. Fadali, Marwa A. Ali and Hak Yong Kim

Polymers 2022, 14(8), 1542; https://doi.org/10.3390/polym14081542 - 11 Apr 2022

Cited by 8 | Viewed by 1763

Abstract

Co-doped carbon nanofiber mats can be prepared by the addition of cobalt acetate to the polyacrylonitrile/DMF electrospun solution. Wastewater obtained from food industries was utilized as the anolyte as well as microorganisms as the source in single-chamber batch mode microbial fuel cells. The [...] Read more.

Co-doped carbon nanofiber mats can be prepared by the addition of cobalt acetate to the polyacrylonitrile/DMF electrospun solution. Wastewater obtained from food industries was utilized as the anolyte as well as microorganisms as the source in single-chamber batch mode microbial fuel cells. The results indicated that the single Co-free carbon nanofiber mat was not a good anode in the used microbial fuel cells. However, the generated power can be distinctly enhanced by using double active layers of pristine carbon nanofiber mats or a single layer Co-doped carbon nanofiber mat as anodes. Typically, after 24 h batching time, the estimated generated power densities were 10, 92, and 121 mW/m² for single, double active layers, and Co-doped carbon nanofiber anodes, respectively. For comparison, the performance of the cell was investigated using carbon cloth and carbon paper as anodes, the observed power densities were smaller than the introduced modified anodes at 58 and 62 mW/m², respectively. Moreover, the COD removal and Columbic efficiency were calculated for the proposed anodes as well as the used commercial ones. The results further confirm the priority of using double active layer or metal-doped carbon nanofiber anodes over the commercial ones. Numerically, the calculated COD removals were 29.16 and 38.95% for carbon paper and carbon cloth while 40.53 and 45.79% COD removals were obtained with double active layer and Co-doped carbon nanofiber anodes, respectively. With a similar trend, the calculated Columbic efficiencies were 26, 42, 52, and 71% for the same sequence. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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15 pages, 31495 KiB

Open AccessArticle

Methylene Blue Dye as Photosensitizer for Scavenger-Less Water Photo Splitting: New Insight in Green Hydrogen Technology

by Nasser A. M. Barakat, Gehan M. K. Tolba and Khalil Abdelrazek Khalil

Polymers 2022, 14(3), 523; https://doi.org/10.3390/polym14030523 - 27 Jan 2022

Cited by 16 | Viewed by 2674

Abstract

In this study, hydrogen generation was performed by utilizing methylene blue dye as visible-light photosensitizer while the used catalyst is working as a transfer bridge for the electrons to H⁺/H₂ reaction. Silica NPs-incorporated TiO₂ nanofibers, which have a more [...] Read more.

In this study, hydrogen generation was performed by utilizing methylene blue dye as visible-light photosensitizer while the used catalyst is working as a transfer bridge for the electrons to H⁺/H₂ reaction. Silica NPs-incorporated TiO₂ nanofibers, which have a more significant band gap and longer electrons lifetime compared to pristine TiO₂, were used as a catalyst. The nanofibers were prepared by electrospinning of amorphous SiO₂ NPs/titanium isopropoxide/poly (vinyl acetate)/N, N-dimethylformamide colloid. Physicochemical characterizations confirmed the preparation of well morphology SiO₂–TiO₂ nanofibers with a bandgap energy of 3.265 eV. Under visible light radiation, hydrogen and oxygen were obtained in good stoichiometric rates (9.5 and 4.7 mL/min/gcat, respectively) without any considerable change in the dye concentration, which proves the successful exploitation of the dye as a photosensitizer. Under UV irradiation, SiO₂ NPs incorporation distinctly enhanced the dye photodegradation, as around 91 and 94% removal efficiency were obtained from TiO₂ nanofibers containing 4 and 6 wt% of the used dopant, respectively, within 60 min. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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19 pages, 11138 KiB

Open AccessArticle

Pyrrole Plasma Polymer-Coated Electrospun Scaffolds for Neural Tissue Engineering

by Diana María Osorio-Londoño, José Rafael Godínez-Fernández, Ma. Cristina Acosta-García, Juan Morales-Corona, Roberto Olayo-González and Axayácatl Morales-Guadarrama

Polymers 2021, 13(22), 3876; https://doi.org/10.3390/polym13223876 - 10 Nov 2021

Cited by 7 | Viewed by 1933

Abstract

Promising strategies for neural tissue engineering are based on the use of three-dimensional substrates for cell anchorage and tissue development. In this work, fibrillar scaffolds composed of electrospun randomly- and aligned-oriented fibers coated with plasma synthesized pyrrole polymer, doped and undoped with iodine, [...] Read more.

Promising strategies for neural tissue engineering are based on the use of three-dimensional substrates for cell anchorage and tissue development. In this work, fibrillar scaffolds composed of electrospun randomly- and aligned-oriented fibers coated with plasma synthesized pyrrole polymer, doped and undoped with iodine, were fabricated and characterized. Infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction analysis revealed the functional groups and molecular integration of each scaffold, as well as the effect of plasma polymer synthesis on crystallinity. Scanning microscopy imaging demonstrated the porous fibrillar micrometric structure of the scaffolds, which afforded adhesion, infiltration, and survival for the neural cells. Orientation analysis of electron microscope images confirmed the elongation of neurite-like cell structures elicited by undoped plasma pyrrole polymer-coated aligned scaffolds, without any biochemical stimuli. The MTT colorimetric assay validated the biocompatibility of the fabricated composite materials, and further evidenced plasma pyrrole polymer-coated aligned scaffolds as permissive substrates for the support of neural cells. These results suggest plasma synthesized pyrrole polymer-coated aligned scaffolds are promising materials for tissue engineering applications. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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15 pages, 4002 KiB

Open AccessArticle

Investigation on the Preparation of Rice Straw-Derived Cellulose Acetate and Its Spinnability for Electrospinning

by Juntao Yan, Jinhong Liu, Ya Sun, Guangsen Song, Deng Ding, Guozhi Fan, Bo Chai, Chunlei Wang and Linbing Sun

Polymers 2021, 13(20), 3463; https://doi.org/10.3390/polym13203463 - 09 Oct 2021

Cited by 8 | Viewed by 3603

Abstract

Rice straw-derived cellulose (RSC) with purity of 92 wt.% was successfully extracted from rice straw by a novel and facile strategy, which integrated the C₂H₅OH/H₂O autocatalytic process, dilute alkali treatment and H₂O₂ bleaching process. [...] Read more.

Rice straw-derived cellulose (RSC) with purity of 92 wt.% was successfully extracted from rice straw by a novel and facile strategy, which integrated the C₂H₅OH/H₂O autocatalytic process, dilute alkali treatment and H₂O₂ bleaching process. Influencing factors of the cellulose extraction were systematically examined, such as ethanol concentration, alkali concentration, H₂O₂ bleaching process and so on; the optimal extraction conditions of cellulose was determined. A series of rice straw-derived cellulose acetate (RSCA) with different degree of substitution (DS) were prepared by the acetylation reaction; the effects of Ac₂O/cellulose ratio, reaction temperature and reaction time on the acetylation reaction were investigated. Results of FTIR and XRD analysis demonstrated that highly purified RSC and RSCA were prepared comparing with the commercial cellulose and cellulose acetate. Solubility analysis of RSCA with different DS indicated as-prepared RSCA with DS of 2.82 possessed the best solubleness, which was suitable for electrospinning. Moreover, the flexible RSCA fibrous membrane was easily fabricated by a facile electrospinning method. Our proposed method provided a strategy for realizing the high-value utilization of waste rice straw resource, as prepared RSC and RSCA can be used as chemical raw material, and electrospun RSCA fibrous membrane has various applications in medical materials, food packaging, water purification and so on. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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11 pages, 2925 KiB

Open AccessArticle

An Electrospun Porous CuBi₂O₄ Nanofiber Photocathode for Efficient Solar Water Splitting

by Xiuhua Yuan, Yeling Liu, Hui Yuan, Bingxin Liu, Tianyu Guo, Huawei Zhou and Xia Li

Polymers 2021, 13(19), 3341; https://doi.org/10.3390/polym13193341 - 29 Sep 2021

Cited by 2 | Viewed by 2231

Abstract

While the CuBi₂O₄-based photocathode has emerged as an ideal candidate for photoelectrochemical water splitting, it is still far from its theoretical values due to poor charge carrier transport, poor electron–hole separation, and instability caused by self-photoelectric-corrosion with electrolytes. Establishing [...] Read more.

While the CuBi₂O₄-based photocathode has emerged as an ideal candidate for photoelectrochemical water splitting, it is still far from its theoretical values due to poor charge carrier transport, poor electron–hole separation, and instability caused by self-photoelectric-corrosion with electrolytes. Establishing synthesis methods to produce a CuBi₂O₄ photocathode with sufficient cocatalyst sites would be highly beneficial for water splitting. Here, the platinum-enriched porous CuBi₂O₄ nanofiber (CuBi₂O₄/Pt) with uniform coverage and high surface area was prepared as a photocathode through an electrospinning and electrodeposition process for water splitting. The prepared photocathode material was composed of a CuBi₂O₄ nanofiber array, which has a freestanding porous structure, and the Pt nanoparticle is firmly embedded on the rough surface. The highly porous nanofiber structures allow the cocatalyst (Pt) better alignment on the surface of CuBi₂O₄, which can effectively suppress the electron–hole recombination at the electrolyte interface. The as-fabricated CuBi₂O₄ nanofiber has a tetragonal crystal structure, and its band gap was determined to be 1.8 eV. The self-supporting porous structure and electrocatalytic activity of Pt can effectively promote the separation of electron–hole pairs, thus obtaining high photocurrent density (0.21 mA/cm² at 0.6 V vs. RHE) and incident photon-to-current conversion efficiency (IPCE, 4% at 380 nm). This work shows a new view for integrating an amount of Pt nanoparticles with CuBi₂O₄ nanofibers and demonstrates the synergistic effect of cocatalysts for future solar water splitting. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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14 pages, 12576 KiB

Open AccessArticle

Fabrication and Photocatalytic Properties of Electrospun Fe-Doped TiO₂ Nanofibers Using Polyvinyl Pyrrolidone Precursors

by Kyeong-Han Na, Bo-Sung Kim, Han-Sol Yoon, Tae-Hyeob Song, Sung-Wook Kim, Churl-Hee Cho and Won-Youl Choi

Polymers 2021, 13(16), 2634; https://doi.org/10.3390/polym13162634 - 07 Aug 2021

Cited by 10 | Viewed by 2486

Abstract

For the removal of pollutants, a modified TiO₂ photocatalyst is attracting attention. Fe-doped TiO₂ nanofibers were prepared through a combination of electrospinning and calcination. Morphological characterization of the sample was conducted using field-emission scanning electron and transmission electron microscopy. The crystal [...] Read more.

For the removal of pollutants, a modified TiO₂ photocatalyst is attracting attention. Fe-doped TiO₂ nanofibers were prepared through a combination of electrospinning and calcination. Morphological characterization of the sample was conducted using field-emission scanning electron and transmission electron microscopy. The crystal structure of each sample was analyzed using high-resolution transmission electron microscopy, selected area electron diffraction, and Fast Fourier Transform imaging. The average diameter of the Fe-doped TiO₂ nanofibers was measured to be 161.5 nm and that of the pure TiO₂ nanofibers was 181.5 nm. The crystal phase when heat treated at 350 °C was anatase for TiO₂ nanofibers and rutile for Fe-doped TiO₂ nanofibers. The crystal phase of the TiO₂ matrix was easily transitioned to rutile by Fe-doping. The photocatalytic performance of each sample was compared via the photodegradation of methylene blue and acid orange 7 under ultraviolet and visible light irradiation. In the Fe-doped TiO₂ nanofibers, photodegradation rates of 38.3% and 27.9% were measured under UV irradiation and visible light, respectively. Although other catalysts were not activated, the photodegradation rate in the Fe-doped TiO₂ nanofibers was 9.6% using acid orange 7 and visible light. For improved photocatalytic activity, it is necessary to study the concentration control of the Fe dopant. Full article

(This article belongs to the Special Issue Advanced Electrospinning Technology)

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