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12 pages, 2752 KiB

Open AccessArticle

Production of Nanofibers by Blow Spinning from Polylactide Containing Propolis and Beeswax

by Agata Penconek, Maciej Kilarski, Anna Soczewka, Michał Wojasiński and Arkadiusz Moskal

Fibers 2024, 12(1), 8; https://doi.org/10.3390/fib12010008 - 12 Jan 2024

Viewed by 1306

The growing pollution of the environment with slowly decomposing waste, as well as the increasing drug resistance of pathogens, including the antibiotic resistance of bacteria, has led to a search for new solutions based on biodegradable and natural materials, which are known for [...] Read more.

The growing pollution of the environment with slowly decomposing waste, as well as the increasing drug resistance of pathogens, including the antibiotic resistance of bacteria, has led to a search for new solutions based on biodegradable and natural materials, which are known for their potential bacteriostatic properties. This study aimed to produce nanofibers by blowing from a polylactide (PLA) polymer solution containing natural compounds (e.g., beeswax, propolis). As a result of the conducted research, nanofibers were produced from PLA solutions containing various additives. The fibers’ mean diameter ranges from 0.36 to 2.38 µm, depending on the process parameters. To the authors’ knowledge, fibers were produced for the first time by blow spinning from a polymer solution containing propolis and beeswax. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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13 pages, 3631 KiB

Open AccessArticle

Theoretical and Experimental Investigations of Oxygen Activation Effect of Carbon Nanofibers Interacting with Polypyrrole

by Yibing Xie, Yiting Wang, Lijun Wang and Jiawei Liang

Fibers 2024, 12(1), 4; https://doi.org/10.3390/fib12010004 - 27 Dec 2023

Viewed by 1231

Abstract

Theoretical modeling calculations and experimental measurements were adopted to investigate the oxygen activation effect of carbon nanofibers (CNFs) interacting with polypyrrole (PPY). The CNF undergoes a hydrothermal oxidation process to form epoxy and hydroxyl groups containing carbon nanofibers (CNF-O). The oxygen activation effect [...] Read more.

Theoretical modeling calculations and experimental measurements were adopted to investigate the oxygen activation effect of carbon nanofibers (CNFs) interacting with polypyrrole (PPY). The CNF undergoes a hydrothermal oxidation process to form epoxy and hydroxyl groups containing carbon nanofibers (CNF-O). The oxygen activation effect of CNF on the electronic and electrochemical properties was investigated through the interfacial interaction between CNF-O and PPY. Theoretical modeling calculation discloses that CNF-O/PPY exhibits lower electronic bandgaps (0.64 eV), a higher density of states (10.039 states/eV), and a lower HOMO–LUMO molecular orbital energy gap (0.077 eV) than CNF/PPY (1.56 eV, 7.946 states/eV and 0.112 eV), presenting its superior electronic conductivity and electroactivity. The Mulliken population and charge density difference analysis disclose the stronger interface interaction of CNF-O/PPY caused by epoxy and hydroxyl groups. Cyclic voltammogram measurements reveal that CNF-O/PPY exhibits a higher response current and a higher specific capacitance (221.1–112.2 mF g⁻¹) than CNF/PPY (57.6–24.2 mF g⁻¹) at scan rates of 5–200 mV s⁻¹. Electrochemical impendence spectrum measurements disclose that CNF-O/PPY exhibits a lower charge transfer resistance (0.097 Ω), a lower ohmic resistance (0.336 Ω), a lower Warburg impedance (317 Ω), and a higher double-layer capacitance (0.113 mF) than CNF/PPY (1.419 Ω, 9.668 Ω, 7865 Ω, and 0.015 mF). Both theoretical and experimental investigations prove that CNF-O/PPY presents an intensified intermolecular interaction rather than CNF/PPY. The promotive oxygen activation effect of CNF could contribute to improving the electronic and electrochemical properties of CNF-O/PPY. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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22 pages, 4062 KiB

Open AccessArticle

Conversion of Animal-Derived Protein By-Products into a New Dual-Layer Nanofiber Biomaterial by Electrospinning Process

by Carmen Gaidău, Maria Râpă, Laura Mihaela Stefan, Ecaterina Matei, Andrei Constantin Berbecaru, Cristian Predescu and Liliana Mititelu-Tartau

Fibers 2023, 11(10), 87; https://doi.org/10.3390/fib11100087 - 14 Oct 2023

Cited by 1 | Viewed by 1574

Abstract

The aim of this study was to design a dual-layer wound dressing as a new fibrous biomaterial based on the valorization of animal-derived proteins. The first layer was fabricated by the deposition of poly(ethylene oxide) (PEO) loaded with keratin hydrolysate (KH) via a [...] Read more.

The aim of this study was to design a dual-layer wound dressing as a new fibrous biomaterial based on the valorization of animal-derived proteins. The first layer was fabricated by the deposition of poly(ethylene oxide) (PEO) loaded with keratin hydrolysate (KH) via a mono-electrospinning process onto a poly(lactic acid) (PLA) film, which was used as a support. The second layer consisted of encapsulating a bovine collagen hydrolysate (CH) into poly(vinyl pyrrolidone) (PVP) through a coaxial electrospinning process, which was added onto the previous layer. This assemblage was characterized by electronic microscopy for morphology and the controlled release of KH. In vitro biocompatibility was evaluated on the L929 (NCTC) murine fibroblasts using quantitative MTT assay and qualitative cell morphological examination after Giemsa staining. Additionally, in vivo biocompatibility methods were used to assess the impact of the biomaterial on white Swiss mice, including the evaluation of hematological, biochemical, and immunological profiles, as well as its impact on oxidative stress. The results revealed a nanofibrous structure for each layer, and the assembled product demonstrated antioxidant activity, controlled release of KH, a high degree of in vitro biocompatibility, negligible hematological and biochemical changes, and minimal impact of certain specific oxidative stress parameters compared to the use of patches with textile support. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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16 pages, 2969 KiB

Open AccessFeature PaperArticle

Optimization of Polyvinyl Alcohol-Based Electrospun Fibers with Bioactive or Electroconductive Phases for Tissue-Engineered Scaffolds

by Zeynep Renkler, Iriczalli Cruz Maya and Vincenzo Guarino

Fibers 2023, 11(10), 85; https://doi.org/10.3390/fib11100085 - 12 Oct 2023

Viewed by 1837

Abstract

The accurate mimicking of the fibrillary structure of the extracellular matrix represents one of the critical aspects of tissue engineering, playing a significant role in cell behavior and functions during the regenerative process. This work proposed the design of PVA-based multi-component membranes as [...] Read more.

The accurate mimicking of the fibrillary structure of the extracellular matrix represents one of the critical aspects of tissue engineering, playing a significant role in cell behavior and functions during the regenerative process. This work proposed the design of PVA-based multi-component membranes as a valuable and highly versatile strategy to support in vitro regeneration of different tissues. PVA can be successfully processed through electrospinning processes, allowing for the integration of other organic/inorganic materials suitable to confer additive bio-functional properties to the fibers to improve their biological response. It was demonstrated that adding polyethylene oxide (PEO) improves fiber processability; moreover, SEM analyses confirmed that blending PVA with PEO or gelatin enables the reduction of fiber size from 1.527 ± 0.66 μm to 0.880 ± 0.30 μm and 0.938 ± 0.245 μm, respectively, also minimizing defect formation. Furthermore, in vitro tests confirmed that gelatin integration allows the formation of bioactive nanofibers with improved biological response in terms of L929 adhesion and proliferation. Lastly, the processability of PVA fibers with conductive phases such as polyvinylpyrrolidone (PVP) or poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has also been verified. From this perspective, they could be promisingly used to design electroactive composite fibers able to support the regeneration process of electrically stimulated tissues such as nerves or muscles. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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12 pages, 3588 KiB

Open AccessArticle

Solution Blow Spinning to Prepare Preferred Oriented Poly(ethylene oxide) Submicrometric Fibers

by Javier González-Benito, Miguel A. Lorente, Dania Olmos and Ana Kramar

Fibers 2023, 11(9), 79; https://doi.org/10.3390/fib11090079 - 21 Sep 2023

Cited by 2 | Viewed by 1121

Abstract

In this work, materials with potential biomedical applications constituted by fibrous poly(ethylene oxide), PEO, are prepared by solution blow spinning (SBS). The SBS setup has a cylindrical collector for which the rotational speed and size are varied to study its effect on the [...] Read more.

In this work, materials with potential biomedical applications constituted by fibrous poly(ethylene oxide), PEO, are prepared by solution blow spinning (SBS). The SBS setup has a cylindrical collector for which the rotational speed and size are varied to study its effect on the final morphology of the materials. The morphology is inspected using field emission scanning electron microscopy and studied using image analysis. As a result, many doubts were generated because of the use of different methods of image analysis, therefore a simpler and more conventional method using Image J open-source software was used to ensure the accuracy of the final interpretation. It is shown that fiber size and orientation depend on the linear speed associated with the surface of the collector more than on its rotational speed; therefore, it can be said that the morphology of materials prepared by SBS will depend on the size, shape, and rotational speed of the collector. When the linear speed of the cylindrical collector increases, fibers get thinner, less entangled, and more oriented. It is clear, therefore, that the linear speed of material collection by solution blow spinning is a very important parameter of processing to control the final morphology of materials manufactured by that method. Since morphology can affect the final properties of the materials the simple variation of the linear speed might have important implications on their final performance for different biomedical applications. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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12 pages, 5696 KiB

Open AccessArticle

Highly Efficient CeO₂–CuCrO₂ Composite Nanofibers Used for Electrochemical Detection of Dopamine in Biomedical Applications

by Heng-Jyun Lei, Homg-Ming Su, Dhanapal Vasu, Yu-Feng You, Te-Wei Chiu and Naratip Vittayakorn

Fibers 2023, 11(8), 66; https://doi.org/10.3390/fib11080066 - 25 Jul 2023

Viewed by 1291

Abstract

Dopamine (DA) plays a crucial role in the functioning of the human central nervous system, participating in both physiological and psychological processes. It is an important research topic in biomedical science. However, we need to constantly monitor the concentration of dopamine in the [...] Read more.

Dopamine (DA) plays a crucial role in the functioning of the human central nervous system, participating in both physiological and psychological processes. It is an important research topic in biomedical science. However, we need to constantly monitor the concentration of dopamine in the body, and the sensors required for this usually require good sensitivity in order to achieve fast and accurate measurements. In this research project, a CeO₂ and CuCrO₂ composite nanofiber was prepared for the electrochemical detection of dopamine. Coaxial electrospinning techniques were used to prepare CeO₂–CuCrO₂ composite nanofibers. The characterization techniques of X-ray diffractometer (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) were used to analyze the composite’s crystal structure, vibrational bonds, and elemental composition, while SEM and TEM were used to analyze the composite’s surface structure, morphology, and microstructure. The prepared nanofiber outer layer was found to have an average thickness of 70.96 nm, average fiber diameter of 192.49 nm, and an average grain size of about ~12.5 nm. The BET analysis was applied to obtain the specific surface area (25.03 m²/gm). The proposed nanofiber-decorated disposable screen-printed carbon electrode acted as a better electrochemical sensor for the detection of dopamine. Moreover, the electrocatalyst had a better limit of detection, 36 nM with a linear range of 10 to 100 μM, and its sensitivity was 6.731 μA μM⁻¹ cm⁻². In addition, the proposed electrocatalyst was successfully applied to real-time potential applications, namely, to the analysis of human urine samples in order to obtain better recovery results. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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Review

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25 pages, 2412 KiB

Open AccessReview

Overcoming Challenges and Limitations Regarding the Atomic Force Microscopy Imaging and Mechanical Characterization of Nanofibers

by Stylianos Vasileios Kontomaris, Andreas Stylianou, Georgios Chliveros and Anna Malamou

Fibers 2023, 11(10), 83; https://doi.org/10.3390/fib11100083 - 09 Oct 2023

Cited by 1 | Viewed by 1818

Abstract

Atomic force microscopy (AFM) is a powerful tool that enables imaging and nanomechanical properties characterization of biological materials. Nanofibers are the structural units of many biological systems and their role in the development of advanced biomaterials is crucial. AFM methods have proven to [...] Read more.

Atomic force microscopy (AFM) is a powerful tool that enables imaging and nanomechanical properties characterization of biological materials. Nanofibers are the structural units of many biological systems and their role in the development of advanced biomaterials is crucial. AFM methods have proven to be effective towards the characterization of fibers with respect to biological and bioengineering applications at the nanoscale. However, both the topographical and mechanical properties’ nanocharacterizations of single fibers using AFM are challenging procedures. In particular, regarding imaging procedures, significant artifacts may arise from tip convolution effects. The geometrical characteristics of the AFM tip and the nanofibers, and the fact that they have similar magnitudes, may lead to significant errors regarding the topographical imaging. In addition, the determination of the mechanical properties of nanofibers is also challenging due to their small dimensions and heterogeneity (i.e., the elastic half-space assumption is not valid in most cases). This review elucidates the origins of errors in characterizing individual nanofibers, while also providing strategies to address limitations in experimental procedures and data processing. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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40 pages, 4925 KiB

Open AccessFeature PaperReview

Mechanical Properties and Morphological Alterations in Fiber-Based Scaffolds Affecting Tissue Engineering Outcomes

by James Dolgin, Samerender Nagam Hanumantharao, Stephen Farias, Carl G. Simon, Jr. and Smitha Rao

Fibers 2023, 11(5), 39; https://doi.org/10.3390/fib11050039 - 29 Apr 2023

Cited by 8 | Viewed by 2646

Abstract

Electrospinning is a versatile tool used to produce highly customizable nonwoven nanofiber mats of various fiber diameters, pore sizes, and alignment. It is possible to create electrospun mats from synthetic polymers, biobased polymers, and combinations thereof. The post-processing of the end products can [...] Read more.

Electrospinning is a versatile tool used to produce highly customizable nonwoven nanofiber mats of various fiber diameters, pore sizes, and alignment. It is possible to create electrospun mats from synthetic polymers, biobased polymers, and combinations thereof. The post-processing of the end products can occur in many ways, such as cross-linking, enzyme linking, and thermal curing, to achieve enhanced chemical and physical properties. Such multi-factor tunability is very promising in applications such as tissue engineering, 3D organs/organoids, and cell differentiation. While the established methods involve the use of soluble small molecules, growth factors, stereolithography, and micro-patterning, electrospinning involves an inexpensive, labor un-intensive, and highly scalable approach to using environmental cues, to promote and guide cell proliferation, migration, and differentiation. By influencing cell morphology, mechanosensing, and intracellular communication, nanofibers can affect the fate of cells in a multitude of ways. Ultimately, nanofibers may have the potential to precisely form whole organs for tissue engineering, regenerative medicine, and cellular agriculture, as well as to create in vitro microenvironments. In this review, the focus will be on the mechanical and physical characteristics such as porosity, fiber diameter, crystallinity, mechanical strength, alignment, and topography of the nanofiber scaffolds, and the impact on cell proliferation, migration, and differentiation. Full article

(This article belongs to the Special Issue Nanofibers: Biomedical Applications)

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