5-Amino-8-hydroxyquinoline-containing Electrospun Materials Based on Poly(vinyl alcohol) and Carboxymethyl Cellulose and Their Cu2+ and Fe3+ Complexes with Diverse Biological Properties: Antibacterial, Antifungal and Anticancer

Novel fibrous materials with diverse biological properties containing a model drug of the 8-hydroxyquinoline group-5-amino-8-hydroxyquinoline (5A8Q)-were fabricated using a one-pot method by electrospinning poly(vinyl alcohol) (PVA)/carboxymethyl cellulose (CMC)/5A8Q solutions. Experiments were performed to prepare Cu²⁺ (Fe³⁺) complexes of the crosslinked PVA/CMC/5A8Q materials. The formation of complexes was proven by using scanning electron microscopy (SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The release of 5A8Q and 5A8Q.Cu²⁺ (Fe³⁺) was studied and their in vitro release profiles were mostly impacted by the hydrophilic/hydrophobic properties of the materials. The performed microbiological assays revealed that fibrous materials containing 5A8Q and their complexes exhibited good antibacterial and antifungal efficacy. Their activity was stronger against bacteria S. aureus than against bacteria E. coli and fungi C. albicans. Cell viability tests using MTT showed that the presence of 5A8Q and its complexes in the fibrous materials resulted in a significant decrease in the HeLa and MCF-7 cancer cell viability for the various times of cell incubation. Moreover, the observed cytotoxicity of the mats against cancer cells was greater than that against non-cancer HaCaT keratinocytes. All these properties make the novel materials potential candidates for the design of wound healing materials and as drug delivery systems for local therapy of cervical and breast cancer.

Electrospun Fibers of Biocompatible and Biodegradable Polyesters, Poly(Ethylene Oxide) and Beeswax with Anti-Bacterial and Anti-Fungal Activities

Fibrous materials composed of core-sheath fibers from poly(ethylene oxide) (PEO), beeswax (BW) and 5-nitro-8-hydroxyquinoline (NQ) were prepared via the self-organization of PEO and BW during the single-spinneret electrospinning of a homogeneous blend solution of the partners. Additionally, the application of the same approach enabled the preparation of fibrous materials composed of core-double sheath fibers from PEO, poly(L-lactide) (PLA) and NQ or 5-chloro-7-iodo-8-hydroxyquinoline (CQ), as well as from PEO, poly(ε-caprolactone) (PCL) and NQ. The consecutive selective extraction of BW and of the polyester with hexane and tetrahydrofuran, respectively, evidenced that core-double sheath fibers from PEO/polyester/BW/drug consisted of a PEO core, a polyester inner sheath and a BW outer sheath. In order to evaluate the possibility of the application of fibrous materials from PEO/BW/NQ, PEO/PLA/BW/NQ, PEO/PCL/BW/NQ and PEO/PLA/BW/CQ for plant protection, microbiological studies were performed using both phytopathogenic microorganisms (Pseudomonas corrugata, Fusarium graminearum and Fusarium avenaceum) and beneficial microorganisms (Pseudomonas chlororaphis, Bacillus amyloliquefaciens and Trichoderma asperellum). It was found that the fibrous materials had anti-bacterial and anti-fungal activity against both phytopathogenic and beneficial microorganisms. This is the first report on the activity of fibrous materials loaded with 8-hydroxyquinoline derivatives not only against phytopathogenic but also against beneficial microorganisms that are of importance in agriculture.

Innovative Fibrous Materials Loaded with 5-Nitro-8-hydroxyquinoline via Electrospinning/Electrospraying Demonstrate Antioxidant, Antimicrobial and Anticancer Activities

A new type of fibrous mat based on a cellulose derivative-cellulose acetate (CA) or CA and water-soluble polymers (polyvinylpyrrolidone, PVP or poly(vinyl alcohol), PVA)-loaded with the model drug 5-nitro-8-hydroxyquinoline (5N) was fabricated via electrospinning or electrospinning in conjunction with electrospraying. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), water contact angle measurements and ultraviolet-visible spectroscopy (UV-Vis) were used for the complex characterization of the obtained novel material. The decoration of CA fibers with a water-soluble polymer containing the drug resulted in the facilitation of wetting and fast drug release. The 5N-containing fibrous material showed antioxidant activity. Moreover, the proposed materials' antibacterial and antifungal properties were tested against S. aureus, E. coli, P. aeruginosa and C. albicans. Well-distinguished, sterile zones with diameters above 3.5 cm were observed around all 5N-containing mats. The mats' cytotoxicity toward HeLa carcinoma cells and normal mouse BALB/c 3T3 fibroblasts was assessed. The 5N-in-CA, PVP,5N-on-(5N-in-CA) and PVA,5N-on-(5N-in-CA) fibrous mats possessed anticancer efficacies and much lower levels of toxicity against normal cells. Therefore, the as-created novel electrospun materials, which are based on polymers loaded with the drug 5N via electrospinning/electrospraying, can potentially be applied for topical wound healing and for local cancer therapy.

Physico-Chemical, Mechanical, and Biological Properties of Polylactide/Portulaca oleracea Extract Electrospun Fibers

Electrospinning was used to create fibrous polylactide (PLA) materials loaded with Portulaca oleracea (P. oleracea) plant extract obtained by supercritical carbon dioxide. Morphological, physico-chemical, mechanical, and biological characteristics of the fibers were studied. According to the SEM results, the diameters of smooth and defect-free fibers fabricated by a one-pot electrospinning method were at micron scale. All the obtained materials possess good mechanical properties. Additionally, it was found that the composite fibers exhibited considerable antioxidant activity. The antimicrobial activity of the fibrous materials against Gram-positive and Gram-negative bacteria was determined as well. In vitro studies showed that the electrospun biomaterials had no cytotoxic effects and that the combination of PLA and the P. oleracea extract in the fiber structure promoted cell survival and proliferation of normal mouse fibroblasts. The obtained results reveal that microfibrous mats containing the polyester-PLA and the plant extract-P. oleracea can be suitable for applications in wound healing.

Eco-Friendly Hybrid PLLA/Chitosan/Trichoderma asperellum Nanomaterials as Biocontrol Dressings against Esca Disease in Grapevines

Fungi constitute the largest number of plant pathogens and are responsible for a range of serious plant diseases. Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum) are the main fungal pathogens causing esca disease in grapevines. On the other hand, there are beneficial microorganisms such as Trichoderma spp., which are able to control the growth of many phytopathogens. In the present study, innovative, eco-friendly hybrid nanomaterials were created by electrospinning PLLA, followed by the formation of a film of chitosan/Trichoderma asperellum (T. asperellum) spores on the fibers. The polymer carrier used in this study plays an active role in ensuring the viability of the biological agent during storage and, when placed in contact with moisture, ensures the agent’s normal development. Oligochitosan, as well as low molecular weight and high molecular weight chitosan, were used. The effects of chitosan molecular weight on the dynamic viscosity of chitosan solutions, film formation, mechanical properties, spore incorporation and growth were studied. The morphology of the prepared nanomaterials, and the presence of a film based on the formation of chitosan/T. asperellum spores on the PLLA fibers, were examined using scanning electron microscopy (SEM). The surface chemical compositions of the fibrous materials were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the obtained materials were also tested. The microbiological screening that was performed revealed that the eco-friendly hybrid nanomaterials incorporated with the beneficial microorganism, T. asperellum, to hamper the growth of the pathogenic P. chlamydospora and P. aleophilum fungi. The suppression rate depended on the viscosity of the chitosan solution used for the film formation. The use of oligochitosan resulted in the most effective infection of the material with T. asperellum spores. The environmentally friendly hybrid nanomaterials obtained in this study—in which the bioagent was embedded—are promising bioactive dressings for protecting grapevines against esca disease.

Core-sheath-like Poly(ethylene oxide)/Beeswax Composite Fibers Prepared by Single-spinneret Electrospinning. Antibacterial, Antifungal and Antitumor activities

Composite fibrous materials are prepared from poly(ethylene oxide) (PEO) and beeswax (BW) by single-spinneret electrospinning using chloroform as a common solvent. The obtained fibers have core-sheath-like structure, as evidenced by the water contact angle values and corroborated by the results on the elemental composition of the fibers surface determined by X-ray photoelectron spectroscopy (XPS) and by analyses with scanning electron microscopy (SEM) of fibers before and after selective extraction of PEO or of BW. Furthermore, the core-sheath-like structure is proven by transmission electron microcopy (TEM). This is attributed to self-assembly of BW molecules on the surface of the formed fibers driven by the incompatibility between PEO and BW. 5-Nitro-8-hydroxyquinoline (NQ) is embedded as a model drug with antibacterial, antifungal, and anticancer properties in the PEO/BW fibrous materials. XPS analyses reveal that NQ is present on the surface of the PEO/BW/NQ materials. Using a purposely designed cell for fixation of the fibrous materials the NQ release in phosphate buffer solution with рН 7.4 is followed. The new PEO/BW/NQ fibrous materials exhibit antibacterial activity against S. aureus and E. coli, antifungal effect against C. albicans, and selective anticancer activity against HeLa (human cervical adenocarcinoma cells) and SH-4 (human melanoma cells) cell lines. This article is protected by copyright. All rights reserved.

Electrospun 5-Chloro-7-iodo-8-hydroxyquinoline (Clioquinol)-Containing Poly(3-hydroxybutyrate)/Polyvinylpyrrolidone Antifungal Materials Prospective as Active Dressings against Esca

Esca is a grapevine disease known for centuries which pertains to the group of so-called vine trunk diseases. Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum) are the two main fungal pathogens associated with esca. Novel fibrous materials with antifungal properties based on poly(3-hydroxybutyrate) (PHB), polyvinylpyrrolidone (PVP) and 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol, CQ) were developed. One-pot electrospinning (“in” strategy) or electrospinning in conjunction with electrospraying (“on” strategy) were applied to obtain the materials. The materials’ morphology and their surface chemical composition were examined using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). CQ incorporated in the bulk of the fibers or in PVP particles deposited on the fibers was in the amorphous phase, which was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD). The in vitro release of CQ depended on the composition of the electrospun materials and on their design. The performed microbiological screening revealed that, unlike the non-loaded mats, the fibrous mats loaded with CQ were effective in inhibiting the growth of the pathogenic P. chlamydospora and P. aleophilum fungi. Therefore, the created materials are promising as active dressings for grapevine protection against esca.

Electrospun Poly(methyl methacrylate)/TiO2 Composites for Photocatalytic Water Treatment

Electrospinning was successfully used for the one-step fabrication of poly(methyl methacrylate) (PMMA) fibers loaded with an inorganic photocatalyst—titanium oxide (TiO₂). By tuning the PMMA/TiO₂ ratio and the electrospinning conditions (applied voltage, needle tip-to-collector distance, and flow rates), PMMA/TiO₂ composites with selected organic/inorganic ratios, tailored designs, and targeted properties were obtained. The morphology of the electrospun composites was affected by the amount of TiO₂ incorporated into the PMMA fibers. In addition, the inorganic photocatalyst had an impact on the wettability, thermal stability, and optical properties of the electrospun composites. In particular, the surface wettability of the composites was strongly influenced by UV light irradiation and from hydrophobic became superhydrophilic. Moreover, PMMA/TiO₂ composites had enhanced tensile strength in comparison with those of bare PMMA mats. The electrospun PMMA/TiO₂ composites showed excellent photocatalytic efficiency against the model organic pollutant—methylene blue—which is very promising for the future development of membranes that are highly efficacious for photocatalytic water treatment.

Electrospun Polymer-Fungicide Nanocomposites for Grapevine Protection

Nowadays, diseases in plants are a worldwide problem. Fungi represent the largest number of plant pathogens and are responsible for a range of serious plant diseases. Esca is a grapevine disease caused mainly by fungal pathogens Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum). The currently proposed methods to fight esca are not curative. In this study, polymer composites based on biodegradable polymer containing chemical fungicides with antifungal activity were successfully prepared by electrospinning. The obtained materials were hydrophobic with good mechanical properties. In vitro studies demonstrated that the fungicide release was higher from PLLA/K5N8Q fibrous mats (ca. 72% for 50 h) compared to the released drug amount from PLLA/5-Cl8Q materials (ca. 52% for 50 h), which is due to the better water-solubility of the salt. The antifungal activity of the fibrous materials against P. chlamydospora and P. aleophilum was studied as well. The incorporation of the fungicide in the biodegradable fibers resulted in the inhibition of fungal growth. The obtained materials are perspective candidates for the protection of vines from the penetration and growth of fungal pathogens.

8-Hydroxyquinoline-5-Sulfonic Acid-Containing Poly(Vinyl Alcohol)/Chitosan Electrospun Materials and Their Cu2+ and Fe3+ Complexes: Preparation, Antibacterial, Antifungal and Antitumor Activities

Novel poly(vinyl alcohol) (PVA)/chitosan (Ch)-based fibrous materials containing an ionizable model drug, 8-hydroxyquinoline-5-sulfonic acid (SQ), were successfully fabricated by electrospinning. Complexes between the components of the crosslinked PVA/Ch/SQ mats and Cu2+ and Fe3+ ions were formed. The coordination of these ions in the mats was examined by electron paramagnetic resonance spectroscopy (EPR). The microbiological screening against S. aureus and C. albicans revealed that both the incorporation of SQ in the mats and the complexation with Cu2+ and Fe3+ imparted to these materials antibacterial and antifungal activities. Moreover, the SQ-containing mats and their complexes displayed good cytotoxicity against human cervical HeLa tumor cells. The most prominent was the cytotoxicity of the Cu2+ complex of the mats. The combined antibacterial, antifungal and in vitro antitumor activities render these novel materials promising candidates for wound dressing applications and for application in the local treatment of cervical tumors.

Electrospun Eco-Friendly Materials Based on Poly(3-hydroxybutyrate) (PHB) and TiO2 with Antifungal Activity Prospective for Esca Treatment

Esca is a type of grapevine trunk disease that severely affects vine yield and longevity. Phaeomoniella chlamydospora (P. chlamydospora) is one of the main fungi associated with esca. The aim of the present study was to obtain eco-friendly materials with potential antifungal activity against P. chlamydospora based on biodegradable and biocompatible poly(3-hydroxybutyrate) (PHB), nanosized TiO₂-anatase (nanoTiO₂), and chitosan oligomers (COS) by conjunction of electrospinning and electrospraying. One-pot electrospinning of a suspension of nanosized TiO₂ nanoparticles in PHB solution resulted in materials in which TiO₂ was incorporated within the fibers (design type “in”). Simultaneous electrospinning of PHB solution and electrospraying of the dispersion of nanosized TiO₂ in COS solution enabled the preparation of materials consisting of PHB fibers on which TiO₂ was deposited on the fibers’ surface (design type “on”). Several methods including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), thermogravimetric analyses (TGA) and water contact angle were utilized to characterize the obtained materials. The incorporation of nanoTiO₂ in the PHB fibers, as well as nanoTiO₂ deposition onto the surface of the PHB fibers resulted in increased roughness and hydrophobicity of the obtained composite fibrous materials. Moreover, TiO₂-on-PHB fibrous material exhibited complete inhibition of fungal growth of P. chlamydospora. Therefore, the obtained eco-friendly fibrous materials based on PHB and nanoTiO₂ are promising candidates for protection against esca in agriculture.

Electrospun materials from polylactide and Schiff base derivative of Jeffamine ED® and 8-hydroxyquinoline-2-carboxaldehyde and its complex with Cu2+: Preparation, antioxidant and antitumor activities

Novel fibrous materials from polylactide (PLA) and Schiff base from Jeffamine ED® and 8-hydroxyquinoline-2-carboxaldehyde (Jeff-8Q) or its complex with Cu²⁺ (Jeff-8Q.Cu²⁺) were successfully prepared by using one-pot electrospinning or electrospinning combined with dip-coating. These approaches enabled the fabrication of materials of diverse design: non-woven textile in which Jeff-8Q or Jeff-8Q.Cu²⁺ was predominantly in the fibers' bulk (type "in") or was deposited as a thin film on the surface of the fibers (type "on"). The morphology of the mats and chemical composition of their surface were analyzed by means of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The coordination of Cu²⁺ ions in Jeff-8Q.Cu²⁺/inPLA and Jeff-8Q.Cu²⁺/onPLA mats was examined by electron paramagnetic resonance (EPR) spectroscopy. It was found that the in vitro release of Jeff-8Q (Jeff-8Q.Cu²⁺) from the type "on" mats was more rapid than that of the type "in" mats. Enhancement of the antioxidant activity of the Jeff-8Q.Cu²⁺-containing fibrous mats as compared to mats containing Jeff-8Q was observed. In contrast to the neat PLA mat, the Jeff-8Q- and Jeff-8Q.Cu²⁺-containing mats (both type "in" and "on") displayed high in vitro antitumor activity against human cervical HeLa cells. The obtained materials are promising for use in local tumor treatment.

Nanoparticles based on complex of berberine chloride and polymethacrylic or polyacrylic acid with antioxidant and in vitro antitumor activities

Berberine chloride (Brb) is a natural isoquinoline quaternary alkaloid that displayed a set of beneficial biological properties such as antioxidant, antimicrobial, antitumor, anti-inflammatory, and antiviral. Brb is poorly soluble in water and body fluids and its intestinal absorption is very low, which predetermine its low bioavailability. Polymeric nanoparticles seem to be a good platform to overcome these drawbacks. In this study, for the first time, stable aqueous dispersions of nanoparticles (NPs) based on complexes of Brb and poly(methacrylic acid) (PMA) or poly(acrylic acid) (PAA), were successfully prepared by mixing their dilute aqueous solutions as evidenced by the performed dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses. It was found that the mean diameter and zeta potential of NPs depended on the Brb molar fraction. In the case of Brb/PMA and Brb/PAA NPs the encapsulation efficiency was observed to approach a maximum value of 58.9 ± 0.5% and of 78.4 ± 0.9%, respectively, at values of Brb molar fraction at which maximum amount of complexes was obtained. The performed differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses revealed that Brb incorporated in the NPs was in the amorphous state. The Brb release profile was pH-dependent. The Brb-containing NPs displayed good antioxidant capacity close to that of free Brb. In vitro cell viability studies demonstrated that the Brb/PMA (PAA) NPs exerted a higher cytotoxicity against HeLa tumor cell than non-tumor BALB/c 3T3 mouse fibroblast cells. Thus, the obtained NPs are promising candidates in the drug delivery systems in the treatment of cervical tumors.

Modulating the Mechanical Properties of Electrospun PHB/PCL Materials by Using Different Types of Collectors and Heat Sealing

Two-component fibrous materials based on poly(3-hydroxybutyrate) (PHB, T_m = 160 °C) and poly(ε-caprolactone) (PCL, T_m = 60 °C) were successfully fabricated by dual-jet electrospinning of their separate spinning solutions. The desired alignment of the fibers that compose PHB/PCL mats was achieved by using three types of rotating collectors-drum (smooth), blade and grid. Additional fiber alignment in the direction of collector rotation was achieved by rotating at 2200 rpm. Moreover, the selected concentration of PCL spinning solution resulted in fibers with spindle-like defects along their length. Thus, "segment" sealing of the PHB (high-melting) fibers by the molten PCL (low-melting) fibers/defects sites was achieved after heating the PHB/PCL mats above the melting temperature (T_m) of PCL. The surface morphology, thermal behavior and mechanical properties of the PHB/PCL mats before and after thermal treatment were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and mechanical tests. The results indicated that regardless of the cutting direction of the specimens (0° or 90°), thermal treated PHB/PCL mats reveal enhanced mechanical properties. Therefore, this work provides an easily feasible route for the fabrication of electrospun PHB/PCL mats with tunable mechanical properties and improved performance.

Antioxidant and Antitumor Activities of Novel Quercetin-Loaded Electrospun Cellulose Acetate/Polyethylene Glycol Fibrous Materials

The aim of present study was to obtain novel fibrous materials based on cellulose derivative and polyethylene glycol loaded with natural biologically active compound quercetin by electrospinning. Several methods including scanning electron microscopy (SEM), IR spectroscopy, X-ray diffraction analysis (XRD), water contact angle measurements, differential scanning calorimetry (DSC), and UV-VIS spectroscopy were utilized to characterize the obtained materials. The incorporation of polyethylene glycol in the fibrous material resulted in increased hydrophilicity and burst release of quercetin from the fibers. Quercetin-containing fibrous mats exhibited high antioxidant activity as estimated by DPPH free radical scavenging method. In vitro tests with HeLa tumor cells and SH-4 melanoma skin cells were performed in order to determine the cytotoxicity of the novel materials. It was found that the fibrous CA/PEG/QUE materials exhibited high cytotoxic effect against both cell lines. Therefore, the novel polymeric materials containing quercetin are promising candidates for biomedical and pharmaceutical applications.

Curcumin-PVP Loaded Electrospun Membranes with Conferred Antibacterial and Antitumoral Activities

Electrospun membranes containing curcumin were prepared from poly(L-co-D,L-lactic) acid and polyvinylpyrrolidone. The effect of curcumin concentration on the solution viscosity and the morphology of fiber was studied. Curcumin solubility in aqueous solutions was enhanced by the formation of curcumin/polyvinylpyrrolidone water-soluble complex. Curcumin physico-chemical and therapeutic properties within the membranes were preserved upon UV-Vis light irradiation, as a part of the membranes sterilization. The biomaterials showed antibacterial activity against pathogenic microorganisms such as Staphylococcus aureus and Candida albicans. In-vitro experiments against HeLa and Graffi tumor cells and white blood cells (peritoneal macrophages and spleen lymphocytes) revealed potential biomedical application of the membranes.

Electrospun 5-chloro-8-hydroxyquinoline-Loaded Cellulose Acetate/Polyethylene Glycol Antifungal Membranes Against Esca

Esca is one of the earliest described diseases in grapevines and causes trunk damage and the sudden wilting of the entire plant; it is caused mainly by the species Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum). In practice, there are no known curative approaches for fighting esca directly, which is a huge problem for preserving vineyards. Micro- and nanofibrous membranes from cellulose acetate (CA) and cellulose acetate/polyethylene glycol (CA/PEG) containing 5-chloro-8-hydroxyquinolinol (5-Cl8Q) were successfully prepared by electrospinning. The surface morphologies and optical and mechanical properties of the membranes were characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), water contact angle measurements and mechanical tests. It was found that the bioactive compound release was facilitated by PEG. The antifungal activities of the obtained materials against P. chlamydospora and P. aleophilum were studied. We have demonstrated that 5-Cl8Q is an efficient and sustainable antifungal agent against P. chlamydospora and P. aleophilum. Moreover, for the first time, the present study reveals the possibility of using electrospun polymer membranes containing 5-Cl8Q which impede the penetration and growth of P. chlamydospora and P. aleophilum. Thus, the obtained fibrous materials can be suitable candidates for plant protection against diverse fungi.

Antibacterial and antioxidant electrospun materials from poly(3-hydroxybutyrate) and polyvinylpyrrolidone containing caffeic acid phenethyl ester - "in" and "on" strategies for enhanced solubility

Caffeic acid phenethyl ester (CAPE) possesses a set of valuable biological properties: antioxidant, antibacterial, antitumor, anti-inflammatory, antiviral, etc. However, CAPE is poorly soluble in aqueous environment which is limiting its possible therapeutic applications. In the present study novel fibrous materials enhancing CAPE solubility and accelerating CAPE release were developed. The materials were prepared from poly(3-hydroxybutyrate) (PHB) by electrospinning and by electrospinning combined with dip-coating. The effects of the composition - without/with addition of polyvinylpyrrolidone (PVP) and of the design of fiber (CAPE in the bulk of the fiber or incorporated in the PVP coating) on some of the properties of these materials were studied. X-ray diffraction and differential scanning calorimetry analyses revealed that CAPE was in the amorphous state in CAPE-loaded fibers and in the PVP coating. The new CAPE-containing materials exhibited good antioxidant activity. The microbiological screening demonstrated that incorporation of CAPE in the fibers or in the coating induced complete killing of Gram-positive S. aureus and led to inhibition of the growth of Gram-negative E. coli by the fibrous materials. Moreover, pathogenic S. aureus did not adhere onto CAPE-containing fibrous mats. Therefore, the obtained materials are promising candidates for use as wound dressing materials.

Еlectrospun сellulose acetate membranes decorated with curcumin-PVP particles: preparation, antibacterial and antitumor activities

Curcumin (Curc) exhibits anti-inflammatory, antibacterial and antitumor activity. However, its clinical application is limited by its poor bioavailability related to its extremely low water solubility. Novel materials allowing enhanced release of Curc in aqueous medium were obtained. The new materials consisted of electrospun fibers from cellulose acetate (CA) (mean fiber diameter ca. 780 nm ± 110 nm) with electrosprayed Curc/polyvinylpyrrolidone (Curc/PVP) particles. Scanning electron microscopy (SEM) showed that separated and evenly distributed particles of Curc/PVP were deposited on the surface of the mats and on the inner layers of the mat. X-ray diffraction studies showed that Curc was in amorphous state. In vitro studies demonstrated that Curc release was facilitated from Curc/PVP-on-CA mats (ca. 78% for 24 h) compared with the materials in which Curc was incorporated in CA fibers (17% for 24 h). Moreover, the curcumin-containing materials exhibited antibacterial activity against Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli). Curc/PVP-on-CA fibrous mats exhibited high in vitro cytotoxicity towards HeLa tumor cells. Therefore, the obtained materials are promising for antibacterial wound dressing applications as well as for application in local treatment of cervical tumors.

Hydrolysis of Chitosan, Chitosan-Polyoxyethylene and Chitosan-Poly(2-acryloylamido-2-methylpropanesulfonic acid) by a Crude Enzyme Complex from Trichoderma viride

The degradation of chitosan using a crude enzyme complex from the soil fungus Trichoderma viride was examined in terms of temperature, pH, enzyme activity and the presence of a polymer partner. It was found that chitosan hydrolysis is not suppressed by combining it with polyoxyethylene or poly(2-acryloylamido-2-methylpropanesulfonic acid). The results on Trichoderma viride immobilized on beads imply that chitosan, as well as its polymer complexes are appropriate carriers for development of ecologically safe phytosanitary preparations.

Preparation, Characterization, and Biological Activity of Amides and Esters from 8-Hydroxyquinoline-2-Carboxylic Acid and Jeffamines ED® Or Poly(Ethylene Glycol)S

New macromolecular chelators were synthesized under mild conditions by reaction of 8-hydroxyquinoline-2-carboxylic acid (8Q2COOH) with polyethers having amino end-groups (Jeffamines ED®) or poly(ethylene glycol)s in the presence of dicyclohexylcarbodiimide and dimethylamino-pyridine. The prepared amides (8Q2CONH-POE) and esters (8Q2COO-POE) were characterized by SEC, DSC, IR, 1H and 13C NMR spectroscopy, and MALDI-TOF mass spectrometry. It was found that the polyethers had 8-hydroxy-2-quinolinyl end groups and formed complexes with Fe3+ ions. The obtained complexes were studied with IR spectroscopy and DSC. The plant tests showed that the Fe3+ complex of 8Q2CONH-POE2000 had high efficacy in the remedy of iron-deficient maize plants under hydroponic conditions.

Polyethers with 8-Hydroxy-54-Quinolinyl Chelating End-Groups: Effect on Iron Nutrition of Plants and Antibacterial/Antimycotic Effects

The effect of Fe3+ chelates of polyethers having terminal 8-quinolinol (8Q) residues linked to the polymer chain at different ring positions on the remedy of iron-deficient maize plants was studied. It was found that Fe3+ chelates of polymers with 8Q groups attached at the 5-position (HOQ-P-QOH) were the most effective. Decreasing the temperature and photosynthetic photon flux density caused a four-fold retardation in the remedy of iron-deficient plants. The results are explained in terms of the stability of the Fe3+ complexes. The microbiological tests showed that the polyethers were active against Gram-positive and Gram-negative bacteria. HOQ-P-QOH also exhibited antimycotic activity.

Hydrolysis and Antibacterial Activity of Polymers Containing 8-Quinolinyl Acrylate

The hydrolytic release of 5-chloro-8-hydroxyquinoline (HQ) from 5-chloro-8-quinolinylacrylate (AQ) containing polymers was studied under physiological under conditions (pH 7.2 and 37°C) as well as in acidic and alkaline medium. The hydrolysis rate was influenced by autocatalytic process with participation by quinolinyl groups as well as by neighboring groups. For copolymers of AQ and acrylamide (AM), the release rate increased with increasing pH, temperature, and the content of hydrophilic monomer. Copolymers of AQ and N-vinylpyrrolidone (VP) exhibit a lower rate of HQ release because of steric hindrance of the hydrolysis site and the influence of the alternating VP-AQ sequences which contribute to the enhanced hydrophobicity of the copolymer. The antimicrobial activity of the copolymers was found to be related to their hydrolysis behavior. The attachment of a biologically active agent to a macromolecular carrier can prolong its effect.

Chitosan/Polyoxyethylene Diacid Films for Drug Release

A new method for the dissolution of chitosan in an aqueous medium using polyoxyethylene diacid was developed. Films cast from these solutions were found to swell reversibly. The effect of polyether content and pH on the swelling behavior of the films was studied. Monolayer type devices for drug release applications were prepared using 8-hydroxy-7-iodoquinoline-5-sulfonic acid as a model drug.

Gel Beads Composed of Chitosan and Polyacids and Their Blood Compatibility

Chitosan gel beads were prepared as a model for new chitosan materials and their blood compatibility was evaluated in vitroin human pool plasma and in human whole blood. The one-stage method for the preparation of monolithic beads consisted of performing a template polymerization of 2-acryloylamido-2-methylpropanesulfonic acid (AMPS) or copolymerization of AMPS and acrylic acid. Monolithic beads of semi-interpenetrating networks chitosan/copolymer were prepared in the presence of a cross-linking agent. The equilibrium degree of swelling of the beads was dependent on the composition. Reservoir-type beads consisting of a chitosan core and a coating of polyelectrolyte complex with anticoagulant activity and chitosan were also prepared. The reservoir-type beads and the monolithic beads showed improved compatibility with blood in comparison with the uncoated chitosan beads.

Perspectives On: Criteria for Complex Evaluation of the Morphology and Alignment of Electrospun Polymer Nanofibers

Electrospinning is a promising method for producing polymer materials composed of micro- and nanosized fibers. This method allows the preparation of random and aligned fibers of different morphologies, such as cylindrical or ribbon-shapes, defect-free or with defects, and with or without pores or porous. The increasing number of studies on electrospinning requires a set of criteria for more complex evaluation of the fiber morphology and the topology of these polymer materials to be established. The main characteristics necessary for a complex evaluation of the morphology of electrospun micro- and nanofibers have been systematized in this paper. Examples of characterization of the morphology and of the alignment of various micro- and nanofibers are given.

Preparation of Polyelectrolyte-Containing Nanofibers by Electrospinning in the Presence of a Non-Ionogenic Water-Soluble Polymer

The first successful preparation of nanofibers of a polyampholyte (N-carboxyethylchitosan) by electrospinning was achieved by adding a non-ionogenic water-soluble polymer to the spinning solution. Using this approach, other polyelectrolytes, poly(2-acryloylamido-2-methylpropanesulphonic acid) (PAMPS), and copolymers of 2-acryloylamido-2-methylpropane-sulphonic acid (AMPS) and acrylic acid [P(AMPS- co-AA)] were also electrospun into nanofibers. The non-ionogenic water-soluble polymers were polyacrylamide (PAAm) and poly(vinyl alcohol) (PVA). The average diameters of the electrospun nanofibers were in the range 50-260nm. The average diameter of the nanofibers significantly decreased with increasing polyelectrolyte content. The electrospun nanofibers were crosslinked by heat treatment at 100, 120 or 150°C for the N-carboxyethylchitosan/PAAm pair and at 90°C in the case of P(AMPS- co-AA)/PVA. The presence of an ionizable low-molecular-weight compound (7-iodo-8-hydroxyquinoline-5-sulphonic acid, SQ) led to a more than two-fold decrease in the diameter of the nanofibers and to the appearance of defects. The SQ-containing nanofibers showed antimicrobial activity against pathogenic microorganisms.

Partition of Poly(Oxyethylene)s with 5-Chloro-8-Quinolinoxyl End-Groups between 1-Octanol and Water

Apparent partition coefficients for a series of poly(oxyethylene)s with 5-chloro-8-quinolinoxyl end-groups and different polyether chain lengths; POE*400, POE*1000, POE*1000 and POE*3000 (the subscripts show the molecular weight of the polyether chain) were determined for the system 1-octanol/water at different pHs at 37°. The partition coefficient was found to decrease with increasing polyether chain length. The substituent constants were calculated and the effect of the substituents on the partition behavior of the compounds was estimated. The antibacterial effect of POE* on gram-positive and gram-negative bacteria was found to be lower than that of CHQ. The activity of POE* slightly increased in the presence of Fe3+ ions.

pH-Sensitive Hydrogels Composed of Chitosan and Polyacrylamide: Enzymatic Degradation

The enzymatic degradation of three types of pH-sensitive hydrogels, composed of the natural polyaminosaccharide chitosan and polyacrylamide, was studied. The weight of the films that were made with net-PAAm- i-chitosan, net-chitosan- i-PAAm and net-chitosan- net-PAAm decreased in the presence of the Trichoderma viride enzyme complex ; thus, the chitosan in the composite retained its degradability after crosslinking. The rate of enzymatic degradation depended on the structure of the network, on the amount of crosslinking agents, on the pH of the medium and on the temperature. Crosslinked chitosan alone degraded slower than net-chitosan- i-PAAm; this was attributed to the facilitated penetration of enzyme by the water-soluble PAAm in the semi-IPNs. T. viride embedded in chitosan/PAAm films or beads developed and reproduced normally. However, T. viride embedded in net-chitosani-PAAm developed considerably slower, and development was not detected in the case of net-PAAm- i-chitosan. All of the networks proved to be appropriate carriers of Bacillus subtilis.

Preparation of PLLA/PEG Nanofibers by Electrospinning and Potential Applications

Poly(L-lactide) (PLLA)/polyethylene glycol (PEG) mixed solutions were successfully electrospun into micro-or nanofibrous polymer mats. The fiber diameter was in the range 100nm-6μm. The effect of the concentration of the spinning solutions and the ratio of PLLA/PEG on the fiber diameter and morphology was investigated. The hydrophilicity was tuned by varying the PLLA/PEG ratio. The tissue compatibility of the electrospun nanofibrous scaffolds was screened using two different cell models of human dermal fibroblasts and the osteoblast-like cell line MG-63. Both types of cells attached uniformly and approximately equally to all PLLA/PEG nanofibers. In long-term cultures osteoblast-like cells tend to spatially organize in tissue-like structure, particularly within the scaffold with the highest PEG content (PLLA/PEG at weight ratio 70/30). These results indicate that PLLA mixed with hydrophilic PEG produces a promising new biocompatible material for engineering scaffolds.

Preparation and Properties of Modified Chitosan Films for Drug Release

A novel method of preparing modified chitosan films was developed. Bi- and tri-component chitosan films were prepared by blending chitosan with high molecular weight polyoxyethylene. The films were loaded with 8-hydroxy-7-iodoquinoline-5-sulfonic acid which was chosen as a model drug. The properties of the films were studied with respect to crystallinity, thermal stability and swelling degree. These properties were shown to depend on the ratio of polyoxyethylene/chitosan. The drug release profile from the films was measured in a buffer at pH 6.8 and 37°C. The antimycotic effect of the films against Candida albicans was determined.

Curcumin-loaded poly(l-lactide-co-D,l-lactide) electrospun fibers: Preparation and antioxidant, anticoagulant, and antibacterial properties

Fibrous materials of poly(l-lactide- co-d,l-lactide), poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol), and curcumin were prepared by electrospinning. The incorporation of poly(ethylene glycol) in the fibers caused a decrease in the mean fiber diameters down to 700 nm and in the water contact angle value, the latter being equal to 0 at poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol) 60/40 weight ratio. The water contact angle values of poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials considerably exceeded those of films of the same composition (approximately 120° as compared to approximately 95°, for electrospun mats and solution-cast films, respectively). Curcumin affected the thermal stability of the fibrous materials and the crystallinity degree of the polymers. The mechanical properties of the electrospun materials also depended on the composition of the polymer matrix and the amount of curcumin therein. In the curcumin-containing fibers, curcumin was found in the amorphous state, while higher antioxidant activity was exhibited by poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol)/curcumin fibrous materials. In vitro determination of the activated partial thromboplastin time and prothrombin time showed that poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials displayed anticoagulant activity. Antibacterial effect toward Staphylococcus aureus was manifested by the curcumin-containing mats.

From design of bio-based biocomposite electrospun scaffolds to osteogenic differentiation of human mesenchymal stromal cells

Electrospinning coupled with electrospraying provides a straightforward and robust route toward promising electrospun biocomposite scaffolds for bone tissue engineering. In this comparative investigation, four types of poly(3-hydroxybutyrate) (PHB)-based nanofibrous scaffolds were produced by electrospinning a PHB solution, a PHB/gelatin (GEL) mixture or a PHB/GEL/nHAs (hydroxyapatite nanoparticles) mixed solution, and by electrospinning a PHB/GEL solution and electrospraying a nHA dispersion simultaneously. SEM and TEM analyses demonstrated that the electrospun nHA-blended framework contained a majority of nHAs trapped within the constitutive fibers, whereas the electrospinning-electrospraying combination afforded fibers with a rough surface largely covered by the bioceramic. Structural and morphological characterizations were completed by FTIR, mercury intrusion porosimetry, and contact angle measurements. Furthermore, an in vitro investigation of human mesenchymal stromal cell (hMSC) adhesion and proliferation properties showed a faster cell development on gelatin-containing scaffolds. More interestingly, a long-term investigation of hMSC osteoblastic differentiation over 21 days indicate that hMSCs seeded onto the nHA-sprayed scaffold developed a significantly higher level of alkaline phosphatase activity, as well as a higher matrix biomineralization rate through the staining of the generated calcium deposits: the fiber surface deposition of nHAs by electrospraying enabled their direct exposure to hMSCs for an efficient transmission of the bioceramic osteoinductive and osteoconductive properties, producing a suitable biocomposite scaffold for bone tissue regeneration.