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Owing to significant differences across species in liver functions, in vitro human liver models are used for screening the metabolism and toxicity of compounds, modeling diseases, and cell-based therapies. However, the extracellular matrix (ECM) scaffold used for such models often does not mimic either the complex composition or the nanofibrous topography of native liver ECM. Thus, here novel methods are developed to electrospin decellularized porcine liver ECM (PLECM) and collagen I into nano- and microfibers (≈200-1000 nm) without synthetic polymer blends. Primary human hepatocytes (PHHs) on nanofibers in monoculture or in coculture with nonparenchymal cells (3T3-J2 embryonic fibroblasts or primary human liver endothelial cells) display higher albumin secretion, urea synthesis, and cytochrome-P450 1A2, 2A6, 2C9, and 3A4 enzyme activities than on conventionally adsorbed ECM controls. PHH functions are highest on the collagen/PLECM blended nanofibers (up to 34-fold higher CYP3A4 activity relative to adsorbed ECM) for nearly 7 weeks in the presence of the fibroblasts. In conclusion, it is shown for the first time that ECM composition and topography synergize to enhance and stabilize PHH functions for several weeks in vitro. The nanofiber platform can prove useful for the above applications and to elucidate cell-ECM interactions in the human liver., (© 2023 The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH.)

Electrospinning has emerged as a versatile and accessible technology for fabricating polymer fibers, particularly for biological applications. Natural polymers or biopolymers (including synthetically derivatized natural polymers) represent a promising alternative to synthetic polymers, as materials for electrospinning. Many biopolymers are obtained from abundant renewable sources, are biodegradable, and possess inherent biological functions. This review surveys recent literature reporting new fibers produced from emerging biopolymers, highlighting recent developments in the use of sulfated polymers (including carrageenans and glycosaminoglycans), tannin derivatives (condensed and hydrolyzed tannins, tannic acid), modified collagen, and extracellular matrix extracts. The proposed advantages of these biopolymer-based fibers, focusing on their biomedical applications, are also discussed to highlight the use of new and emerging biopolymers (or new modifications to well-established ones) to enhance or achieve new properties for electrospun fiber materials., (© 2021 Wiley-VCH GmbH.)

Ideal wound dressings should be biocompatible, exhibit high antibacterial activity, and promote blood coagulation. To impart these imperative functions, carboxymethyl-kappa-carrageenan was incorporated into poly(vinyl alcohol) nanofibers (PVA-CMKC). The antibacterial activity of the nanofibers was evaluated. Adsorption of two important blood proteins, fibrinogen and albumin, was also assessed. The adhesion and activation of platelets, and the clotting of whole blood were evaluated to characterize the ability of the nanofibers to promote hemostasis. Adhesion and morphology of both Staphylococcus aureus and Pseudomonas aeruginosa were evaluated using fluorescence microscopy and scanning electron microscopy. CMKC-containing nanofibers demonstrated significant increases in platelet adhesion and activation, percentage of coagulation in whole blood clotting test and fibrinogen adsorption, compared to PVA nanofibers, showing blood coagulation activity. Incorporating CMKC also reduces adhesion and viability of S. aureus and P. aeruginosa bacteria after 24 h of incubation. PVA-CMKC nanofibers show potential application as dressings for wound healing applications., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study presents a new type of biocompatible nanofiber based on poly(vinyl alcohol) (PVA) and carboxymethyl-kappa-carrageenan (CMKC) blends, produced with no generation of hazardous waste. The nanofibers are produced by electrospinning using PVA:CMKC blends with ratios of 1:0, 1:0.25, 1:0.4, 1:0.5, and 1:0.75 (w/w PVA:CMKC) in aqueous solution, followed by thermal crosslinking. The diameter of the fibers is in the nanometer scale and below 300 nm. Fourier transform infrared spectroscopy shows the presence of the carboxyl and sulfate groups in all the fibers with CMKC. The nanofibers from water-soluble polymers are stabilized by thermal crosslinking. The incorporation of CMKC improves cytocompatibility, biodegradability, cell growth, and cell adhesion, compared to PVA nanofibers. Furthermore, the incorporation of CMKC modulates phenotype of human adipose-derived stem cells (ADSCs). PVA/CMKC nanofibers enhance ADSC response to osteogenic differentiation signals and are therefore good candidates for application in tissue engineering to support stem cells., (© 2020 Wiley-VCH GmbH.)

Growth factors are potent signaling proteins for tissue engineering, but they are susceptible to loss of activity when exposed to solvents used for polymer processing. This work explores preservation of fibroblast growth factor-2 (FGF-2) activity in chitosan nanofibers using two-phase electrospinning via a compound coaxial needle and from a water-in-oil emulsion FGF-2 in aqueous poly(vinyl alcohol) is added on either the inside (A/O) or the outside (O/A) of an organic chitosan phase, using the compound needle. FGF-2 is further stabilized by complexation to heparin-based nanoparticles. The emulsion method does not result in detectable incorporation of FGF-2. The A/O fibers incorporate the highest amount of FGF-2. Nanoparticle-stabilized FGF-2 in A/O nanofibers is most active toward bone-marrow stromal cells., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new method is presented for functionalizing electrospun nanofibers with GAGs and growth factors by PEM deposition. Electrospun chitosan nanofibers, spun from trifluoroacetic acid and dichloromethane, were coated with PEMs, using the polysaccharides heparin and N,N,N-trimethyl chitosan. FGF-2 was adsorbed on the PEM-coated nanofibers. Nanofiber neutralization, PEM construction, and FGF-2 adsorption were monitored using FT-IR spectroscopy and X-ray photoelectron spectroscopy. Alcian blue staining was used to confirm the presence of heparin. SEM was used to study nanofiber morphology., (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nanofiber poly(epsilon-caprolactone) (PCL) scaffolds were fabricated by electrospinning, and their ability to enhance the osteoblastic behavior of marrow stromal cells (MSCs) in osteogenic media was investigated. MSCs were isolated from Wistar rats and cultured on nanofiber scaffolds to assess short-term cytocompatibility and long-term phenotypic behavior. Smooth PCL substrates were used as control surfaces. The short-term cytocompatibility results indicated that nanofiber scaffolds supported greater cell adhesion and viability compared with control surfaces. In osteogenic conditions, MSCs cultured on nanofiber scaffolds also displayed increased levels of alkaline phosphatase activity for 3 weeks of culture. Calcium phosphate mineralization was substantially accelerated on nanofiber scaffolds compared to control surfaces as indicated through von Kossa and calcium staining, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Increased levels of intra- and extracellular levels of osteocalcin and osteopontin were observed on nanofiber scaffolds using immunofluorescence techniques after 3 weeks of culture. These results demonstrate the enhanced tissue regeneration property of nanofiber scaffolds, which may be of potential use for engineering osteogenic scaffolds for orthopedic applications., (Copyright 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Human activities are producing increasing amounts of oily water. Therefore, methods for oil/water separation are attracting great attention. Membranes, including nanofibers for oil/water separation based on superwetting surfaces have advantages of low cost, high efficiency, and environmental friendliness. In addition to the common superhydrophobic and superhydrophilic surfaces, other novel superwetting membranes have been developed for oil/water separation. This review introduces and discusses membranes and nanofibers reported in recent years for oil/water separation, with emphasis on coupling the wettability characteristics with the structural features. We mainly discuss five types of membranes with superwetting surfaces. In each category, representative research, manufacturing technology, membrane structure, and applications are discussed in detail. Finally, the challenges and future opportunities for superwetting membranes in the field of oil/water separation are put forward. [ABSTRACT FROM AUTHOR]

A novel anhydrous preparation of silica (SiO2)-encapsulated terbium (Tb3+) complex nanoparticles has been investigated. The SiO2-Tb3+ nanoparticles are incorporated in electrospun polyvinylpyrrolidone hybrid nanofibers. Transmission electron microscopy confirms that Tb3+ complexes are uniformly and stably encapsulated in or carried by nanosilica. The influence of pH on the fluorescence of Tb3+ complexes is discussed. The properties, composition, structure, and luminescence of the resulting SiO2–Tb3+ hybrid nanoparticles are investigated in detail. There is an increase in the fluorescence lifetime of SiO2–Tb3+ nanoparticles and SiO2–Tb3+/polyvinylpyrrolidone (PVP) hybrid nanofibers compared with the pure Tb3+ complexes. Due to the enhanced optical properties, the fluorescent hybrid nanofibers have potential applications as photonic and photoluminescent materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • HFPNM undergoes fluorescence quenching upon contact with Cu2+. • HFPNM is capable of accurately detecting 100–1000 nmol/L of Cu2+. • HFPNM can still be used as a Cu2+ sensor after 5 cycles of use. • HFPNM have the advantages of high detection sensitivity and environmental friendliness for recycling compared to other Cu2+ sensors. Cu2+ contamination in drinking water poses a threat to humans and the environment, and high concentrations of Cu2+ in human blood can induce disease. In recent years, fluorescence sensing of Cu2+ prepared from rare earth elements has been widely used for the accurate detection and quantification of Cu2+. In this paper, we report that europium (Eu), 4,4′,4-trimethyltriphenylamine (TTA), and 1,10-phenanthroline (Phen) undergo a complexation reaction to form the Eu(TTA) 3 Phen complex, which is loaded on SiO 2 nanoparticle to form SiO 2 @Eu3+. We use electrospinning of SiO 2 @Eu3+ and polyacrylonitrile (PAN) co-blended solutions to prepare PAN fluorescent nanofiber membranes (FPNM). FPNM are hydrolyzed hydrolysis to obtain Cu2+ sensors (HFPNM). The super hydrophilic surface of HFPNM undergoes fluorescence quenching upon contact with Cu2+. HFPNM is capable of accurately detecting 100–1000 nmol/L of Cu2+. Moreover, EDTA can be used as a reversible on/off switch for detection, and HFPNM can still be used as a Cu2+ sensor after 5 cycles of use. The HFPNM have the advantages of high detection sensitivity and environmental friendliness for recycling compared to other Cu2+ sensors. Fluorescent nanofibers can be combined with bio-nanotechnology allowing for promising future applications in Cu2+ detection and wearable smart fabrics. [ABSTRACT FROM AUTHOR]

CH/PEO-SiO 2 @Eu3+ fiber is prepared by electrospinning. Due to the fluorescence of Eu3+ complex, the film appears red under the excitation of UV-light. When the Cu2+ solution is dropped to the film, the color of the film will no longer appear red, and the fluorescence of the composite chitosan nanofibers can be quickly and sensitively quenched. [Display omitted] • CH/PEO-SiO 2 @Eu3+ nanofiber is prepared by electrospinning. • Due to the fluorescence of Eu3+ complex, the film appears red under the excitation of UV-light. • The fluorescence of the CH/PEO-SiO 2 @Eu3+ film can be quenched after Cu2+ solution is dropped on it. Trace amounts of heavy metal ions in the human body are essential for maintaining health. However, heavy metal ion excess or deficiency causes toxicity or disease. This study examines the sensitivity of luminescent europium complexes for the detection of Cu2+. Here, Eu3+ is complexed with1,10-phenanthroline (phen) and 4,4′,4-trimethyltriphenylamine (TTA) to form luminescent [Eu3+(TTA) 3 phen] complexes, encapsulated in silica (SiO 2) nanoparticles. The silica nanoparticles are then formed into a composite with a blend of chitosan and polyethylene oxide (PEO), to make electrospun nanofibers. The combination of Eu3+ complexes with SiO 2 nanoparticles doped in chitosan enhances the fluorescence performance. Photophysical measurements show that when the Cu2+ concentration is 100 μmol/L, the fluorescence of the composite chitosan nanofibers can be quickly and sensitively quenched, and that concentrations as low as 10 μmol/L Cu2+ can be detected. Furthermore, the use of chitosan and PEO to prepare the material makes these new fluorescence-based copper sensing materials suitable for Cu2+ detection in biological systems. [ABSTRACT FROM AUTHOR]