Encapsulation of Bioactive Compound in Electrospun Fibers and Its Potential Application

Encapsulation of rosemary essential oil in zein by electrospinning technique

In this study, rosemary essential oil was encapsulated in zein-electrospun fibers at different concentrations of loading (0%, 2.5%, 5%, and 10% v/v). The chemical composition of rosemary essential oil was determined by GC-MS. The resultant zein-electrospun fibers were characterized by SEM, AFM, XRD, DSC, FTIR, and NMR. After being loaded with the essential oil, the fibers were evaluated for antimicrobial properties by the disc diffusion method against S. aureus (ATCC 1112) and E. coli (ATCC 1330). The release test was studied at pH values of 3 and 7.2 in phosphate buffer for 180 min. The GC-MS indicated that α-pinene occurred as a major compound in rosemary essential oil. Diameters of the zein-electrospun fibers increased in response to higher concentrations of rosemary essential oil. The AFM assay attributed a tubular morphology to the fibers. The physical status of rosemary essential oil in zein-electrospun fibers was determined by X-ray diffraction (XRD). DSC thermograms and FTIR spectra confirmed the existence of the rosemary essential oil in zein-electrospun fibers. FTIR spectra also indicated that adding rosemary essential oil to the fibers affected the secondary structure of zein protein. The NMR study showed that the electrospinning process did not change the secondary structure of zein. Disc diffusion indicated that zein-electrospun mats generated inhibition zones against S. aureus and E. coli. The release test revealed that pH values significantly affect the release of rosemary essential oil from fibers. The results demonstrated how loading zein-electrospun fibers with rosemary essential oil can benefit food packaging. PRACTICAL APPLICATION: In this study, electrospun fibers were produced from food-grade biopolymer to encapsulate rosemary essential oil. This product can be produced at industrial scale as an active food packaging/coating, controlled release, and delivery of the rosemary essential oil to food products and gastrointestinal. Also, it can be considered as a functional food to increase health.

Polysaccharide-Based Materials Created by Physical Processes: From Preparation to Biomedical Applications

Polysaccharide-based materials created by physical processes have received considerable attention for biomedical applications. These structures are often made by associating charged polyelectrolytes in aqueous solutions, avoiding toxic chemistries (crosslinking agents). We review the principal polysaccharides (glycosaminoglycans, marine polysaccharides, and derivatives) containing ionizable groups in their structures and cellulose (neutral polysaccharide). Physical materials with high stability in aqueous media can be developed depending on the selected strategy. We review strategies, including coacervation, ionotropic gelation, electrospinning, layer-by-layer coating, gelation of polymer blends, solvent evaporation, and freezing-thawing methods, that create polysaccharide-based assemblies via in situ (one-step) methods for biomedical applications. We focus on materials used for growth factor (GFs) delivery, scaffolds, antimicrobial coatings, and wound dressings.

Electrospun Nanofibrous Scaffolds: Review of Current Progress in the Properties and Manufacturing Process, and Possible Applications for COVID-19

Over the last twenty years, researchers have focused on the potential applications of electrospinning, especially its scalability and versatility. Specifically, electrospun nanofiber scaffolds are considered an emergent technology and a promising approach that can be applied to biosensing, drug delivery, soft and hard tissue repair and regeneration, and wound healing. Several parameters control the functional scaffolds, such as fiber geometrical characteristics and alignment, architecture, etc. As it is based on nanotechnology, the concept of this approach has shown a strong evolution in terms of the forms of the materials used (aerogels, microspheres, etc.), the incorporated microorganisms used to treat diseases (cells, proteins, nuclei acids, etc.), and the manufacturing process in relation to the control of adhesion, proliferation, and differentiation of the mimetic nanofibers. However, several difficulties are still considered as huge challenges for scientists to overcome in relation to scaffolds design and properties (hydrophilicity, biodegradability, and biocompatibility) but also in relation to transferring biological nanofibers products into practical industrial use by way of a highly efficient bio-solution. In this article, the authors review current progress in the materials and processes used by the electrospinning technique to develop novel fibrous scaffolds with suitable design and that more closely mimic structure. A specific interest will be given to the use of this approach as an emergent technology for the treatment of bacteria and viruses such as COVID-19.

Bioactive Zinc(II) complex incorporated PCL/gelatin electrospun nanofiber enhanced bone tissue regeneration

Bone tissue regeneration is augmented by biocompatible nanofiber scaffolds, that supports reliable and enhanced bone formation. Zinc is an essential mineral that is vital for routine skeletal growth and it emerges to be able to improve bone regeneration. Phytochemicals, particularly flavonoids have achieved prominent interest for their therapeutic ability, they have demonstrated promising effects on bone by encouraging osteoblastogenesis, which finally leads to bone formation. In this study, we have synthesized bioactive zinc(II) quercetin complex material and used for nanofibers scaffold fabrication to enhance bone tissue regeneration property. Two derivatives of zinc(II) quercetin complexes [(Zn(quercetin) (H₂O)₂) (Zn+Q), and Zn(quercetin)(phenanthroline) (Zn+Q(PHt)) have been synthesized and characterized using UV-Visible spectrophotometer and Fourier Transform-IR spectroscopy. The UV-Visible absorption and IR spectra prove the B-ring chelation of the flavonoid quercetin to zinc(II) rather C-ring chelation. The potential ability of the above synthesized metal complexes on osteogenesis and angiogenesis have been studied. Besides the bioactivity of the metal complexes, the control quercetin has also been examined. The chick embryo chorioallantoic membrane (CAM) assay demonstrated that the angiogenic parameters were increased by the (Zn+Q(PHt)) complex. Amongst, (Zn+Q(PHt)) complex showed significant activity and thereby this complex has been further examined for the bone tissue activity by incorporating the complex into a nanofiber through electrospinning method. At the molecular level, Runx2, mRNA and protein, ALP and type 1 collagen mRNAs, and osteoblast-specific microRNA, pre-mir-15b were examined using real time RT-PCR and Western blot assay. Histology studies showed that the (PCL/gelatin/Zn+Q(PHt)) was biocompatibility in-ovo. Overall, the present study showed that quercetin-zinc complex (Zn+Q(PHt)) incorporated into PCL/gelatin nanofiber can act as a pharmacological agent for treating bone associated defects and promote bone regeneration.

Electrospun fibers based on botanical, seaweed, microbial, and animal sourced biomacromolecules and their multidimensional applications

This review summarizes and broadly classifies all of the major sustainable natural carbohydrate bio-macromolecular manifestations in nature - from botanical (cellulose, starch, and pectin), seaweed (alginate, carrageenan, and agar), microbial (bacterial cellulose, dextran, and pullulan), and animal (hyaluronan, heparin, chitin, and chitosan) sources - that have been contrived into electrospun fibers. Furthermore, a relative study of these biomaterials for the fabrication of nanofibers by electrospinning and their characteristics viz. solution behavior, blending nature, as well as rheological and fiber attributes are discussed. The potential multidimensional applications of nanofibers (filtration, antimicrobial, biosensor, gas sensor, energy storage, catalytic, and tissue engineering) originating from these polysaccharides and their major impacts on the properties, functionalities, and uses of these electrospun fibers are compared and critically examined.

Encapsulation of Flavours and Fragrances into Polymeric Capsules and Cyclodextrins Inclusion Complexes: An Update

Flavours and fragrances are volatile compounds of large interest for different applications. Due to their high tendency of evaporation and, in most cases, poor chemical stability, these compounds need to be encapsulated for handling and industrial processing. Encapsulation, indeed, resulted in being effective at overcoming the main concerns related to volatile compound manipulation, and several industrial products contain flavours and fragrances in an encapsulated form for the final usage of customers. Although several organic or inorganic materials have been investigated for the production of coated micro- or nanosystems intended for the encapsulation of fragrances and flavours, polymeric coating, leading to the formation of micro- or nanocapsules with a core-shell architecture, as well as a molecular inclusion complexation with cyclodextrins, are still the most used. The present review aims to summarise the recent literature about the encapsulation of fragrances and flavours into polymeric micro- or nanocapsules or inclusion complexes with cyclodextrins, with a focus on methods for micro/nanoencapsulation and applications in the different technological fields, including the textile, cosmetic, food and paper industries.

Novel Electrospun Pullulan Fibers Incorporating Hydroxypropyl-β-Cyclodextrin: Morphology and Relation with Rheological Properties

Fibers produced by electrospinning from biocompatible, biodegradable and naturally occurring polymers have potential advantages in drug delivery and biomedical applications because of their unique functionalities. Here, electrospun submicron fibers were produced from mixtures containing an exopolysaccharide (pullulan) and a small molecule with hosting abilities, hydroxypropyl-β-cyclodextrin (HP-β-CD), thus serving as multi-functional blend. The procedure used water as sole solvent and excluded synthetic polymers. Rheological characterization was performed to evaluate the impact of HP-β-CD on pullulan entanglement concentration (CE); the relationship with electrospinnability and fiber morphology was investigated. Neat pullulan solutions required three times CE (~20% w/v pullulan) for effective electrospinning and formation of bead-free nanofibers. HP-β-CD (30% w/v) facilitated electrospinning, leading to the production of continuous, beadless fibers (average diameters: 853-1019 nm) at lower polymer concentrations than those required in neat pullulan systems, without significantly shifting the polymer CE. Rheological, Differential Scanning Calorimetry (DSC) and Dynamic Light Scattering (DLS) measurements suggested that electrospinnability improvement was due to HP-β-CD assisting in pullulan entanglement, probably acting as a crosslinker. Yet, the type of association was not clearly identified. This study shows that blending pullulan with HP-β-CD offers a platform to exploit the inherent properties and advantages of both components in encapsulation applications.

Encapsulation of β-Glucosidase within PVA Fibers by CCD-RSM-Guided Coelectrospinning: A Novel Approach for Specific Mogroside Sweetener Production

Siamenoside I is a rare mogroside in Siraitia grosvenorii Swingle and has become one of the target ingredients in natural sweetener production. However, the complex structure of siamenoside I has hindered its production in various ways. Here, a yeast cell that produces a specific β-glucosidase for siamenoside I conversion from mogroside V was constructed, and the enzymes were coelectrospun with poly(vinyl alcohol) followed by phenylboronic acid cross-linking to provide potential usage in the batch production process of Siamenoside I. A central composite design (CCD)-response surface methodology (RSM) was used to find the optimum coelectrospinning parameters. The pH stability and sodium dodecyl sulfate tolerance increased for the entrapped enzymes, and positive correlations between the fiber diameter and enzymatic activity were confirmed. The batch process showed an average siamenoside I production rate of 118 ± 0.08 mg L^-1 h^-1 per gram of fiber. This is the first research article showing specific siamenoside I production on enzyme-loaded electrospun fibers.

An Overview of Biopolymeric Electrospun Nanofibers Based on Polysaccharides for Wound Healing Management

Currently, despite the thoroughgoing scientific research carried out in the area of wound healing management, the treatment of skin injuries, regardless of etiology remains a big provocation for health care professionals. An optimal wound dressing should be nontoxic, non-adherent, non-allergenic, should also maintain a humid medium at the wound interfacing, and be easily removed without trauma. For the development of functional and bioactive dressings, they must meet different conditions such as: The ability to remove excess exudates, to allow gaseous interchange, to behave as a barrier to microbes and to external physical or chemical aggressions, and at the same time to have the capacity of promoting the process of healing by stimulating other intricate processes such as differentiation, cell adhesion, and proliferation. Over the past several years, various types of wound dressings including hydrogels, hydrocolloids, films, foams, sponges, and micro/nanofibers have been formulated, and among them, the electrospun nanofibrous mats received an increased interest from researchers due to the numerous advantages and their intrinsic properties. The drug-embedded nanofibers are the potential candidates for wound dressing application by virtue of: Superior surface area-to volume ratio, enormous porosity (can allow oxy-permeability) or reticular nano-porosity (can inhibit the microorganisms'adhesion), structural similitude to the skin extracellular matrix, and progressive electrospinning methodology, which promotes a prolonged drug release. The reason that we chose to review the formulation of electrospun nanofibers based on polysaccharides as dressings useful in wound healing was based on the ever-growing research in this field, research that highlighted many advantages of the nanofibrillary network, but also a marked versatility in terms of numerous active substances that can be incorporated for rapid and infection-free tissue regeneration. In this review, we have extensively discussed the recent advancements performed on electrospun nanofibers (eNFs) formulation methodology as wound dressings, and we focused as well on the entrapment of different active biomolecules that have been incorporated on polysaccharides-based nanofibers, highlighting those bioagents capable of improving the healing process. In addition, in vivo tests performed to support their increased efficacy were also listed, and the advantages of the polysaccharide nanofiber-based wound dressings compared to the traditional ones were emphasized.

Responsive Nanofibers with Embedded Hierarchical Lipid Self-Assemblies

We introduce the design and study of a hybrid electrospun membrane with a dedicated nanoscale structural hierarchy for controlled functions in the biomedical domain. The hybrid system comprises submicrometer-sized internally self-assembled lipid nanoparticles (ISAsomes or mesosomes) embedded into the electrospun membrane with a nanofibrous polymer network. The internal structure of ISAsomes, studied by small-angle X-ray scattering (SAXS) and electron microscopy, demonstrated a spontaneous response to variations in the environmental conditions as they undergo a bicontinuous inverse cubic phase (cubosomes) in solution to a crystalline lamellar phase in the polymer membrane; nevertheless, this phase reorganization is reversible. As revealed by in situ SAXS measurements, if the membrane was put in contact with aqueous media, the cubic phase reappeared and submicrometer-sized cubosomes were released upon dissolution of the nanofibers. Furthermore, the hybrid membranes exhibited a specific anisotropic feature and morphological response under an external strain. While nanofibers were aligned under external strain in the microscale, the semicrystalline domains from the polymer phase were positioned perpendicular to the lamellae of the lipid phase in the nanoscale. The fabricated membranes and their spontaneous responses offer new strategies for the development of structure-controlled functions in electrospun nanofibers for biomedical applications, such as drug delivery or controlled interactions with biointerfaces.

Encapsulation of broccoli extract by electrospraying: Influence of in vitro simulated digestion on phenolic and glucosinolate contents, and on antioxidant and antihyperglycemic activities

Compounds present in broccoli are vulnerable to the digestive process, and encapsulation becomes an alternative for their preservation. The encapsulation of broccoli extract, by electrospraying, was performed with the purpose of evaluating the effect of in vitro simulated digestion on individual compounds and antioxidant and antihyperglycemic potentials. Each digestion fraction was evaluated by chromatography, as well as for antioxidant activity and antihyperglycemic potential. The encapsulated extract showed high encapsulation efficiency and spherical morphology. Losses in the levels of phenolic compounds and glucosinolates were found in both extracts, considering the fractions submitted to digestion. The digestion promoted an increase in the inhibition of hydroxyl, nitric oxide and α-amylase, as well as a decrease in the inhibition of α-glucosidase in both extracts, when compared to undigested fractions. Thus, the digestion affects the compounds content in both encapsulated and unencapsulated extracts. However, they still promote the control of oxidative processes and hyperglycemia.

Electrospun nanofibers: A nanotechnological approach for drug delivery and dissolution optimization in poorly water-soluble drugs

Electrospinning is a novel and sophisticated technique for the production of nanofibers with high surface area, extreme porous structure, small pore size, and surface morphologies that make them suitable for biomedical and bioengineering applications, which can provide solutions to current drug delivery issues of poorly water-soluble drugs. Electrospun nanofibers can be obtained through different methods asides from the conventional one, such as coaxial, multi-jet, side by side, emulsion, and melt electrospinning. In general, the application of an electric potential to a polymer solution causes a charged liquid jet that moves downfield to an oppositely charged collector, where the nanofibers are deposited. Plenty of polymers that differ in their origin, degradation character and water affinity are used during the process. Physicochemical properties of the drug, polymer(s), and solvent systems need to be addressed to guarantee successful manufacturing. Therefore, this review summarizes the recent progress in electrospun nanofibers for their use as a nanotechnological tool for dissolution optimization and drug delivery systems for poorly water-soluble drugs.

Characterization and Release Behavior of a Thiosemicarbazone from Electrospun Polyvinyl Alcohol Core-Shell Nanofibers

Mats of polyvinyl alcohol (PVA) core-shell nanofibers were produced using coaxial electrospinning in the presence of a thiosemicarbazone (TSC) N4-(S)-1-phenylethyl)-2-(pyridin-2-yl-ethylidene)hydrazine-1-carbothioamide (HapyTSCmB). Monolithic fibers with 0% or 5% TSC and core-shell fibers with 10% TSC in the spinning solution were studied to compare stability and release rates. SEM showed the formation of uniform, bead-free, cylindrical, and smooth fibers. NMR spectroscopy and thermal analysis (TG/DTA) gave proof for the chemical integrity of the TSC in the fiber mats after the electrospinning process. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy showed no TSC on the surface of the PVA/TSC-PVA fibers confirming the core-shell character. The TSC release profiles of the fibers as studied using UV-vis absorption spectroscopy showed a slower release from the PVA/TSC-PVA core-shell structure compared with the monolithic PVA/TSC fibers as well as lower cumulative release percentage (17%). Out of several release models, the Korsmeyer-Peppas model gave the best fit to the experimental data. The main release phase can be described with a Fick-type diffusion mechanism. Antibacterial properties were tested against the Gram-positive Staphylococcus aureus bacterium and gave a minimal inhibitory concentration of 12.5 μg/mL. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT)-based cytotoxicity experiments showed that the cell viability of fibroblast at different contents of TSC was slightly decreased from 1.5% up to 3.5% when compared to control cells.

Rapid-Release Griffithsin Fibers for Dual Prevention of HSV-2 and HIV-1 Infections

The biologic griffithsin (GRFT) has recently emerged as a candidate to safely prevent sexually transmitted infections (STIs), including human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus 2 (HSV-2). However, to date, there are few delivery platforms that are available to effectively deliver biologics to the female reproductive tract (FRT). The goal of this work was to evaluate rapid-release polyethylene oxide (PEO), polyvinyl alcohol (PVA), and polyvinylpyrrolidone (PVP) fibers that incorporate GRFT in in vitro (HIV-1 and HSV-2) and in vivo (HSV-2) infection models. GRFT loading was determined via enzyme-linked immunosorbent assay (ELISA), and the bioactivity of GRFT fibers was assessed using in vitro HIV-1 pseudovirus and HSV-2 plaque assays. Afterwards, the efficacy of GRFT fibers was assessed in a murine model of lethal HSV-2 infection. Finally, murine reproductive tracts and vaginal lavage samples were evaluated for histology and cytokine expression, 24 and 72 h after fiber administration, to determine safety. All rapid-release formulations achieved high levels of GRFT incorporation and were completely efficacious against in vitro HIV-1 and HSV-2 infections. Importantly, all rapid-release GRFT fibers provided potent protection in a murine model of HSV-2 infection. Moreover, histology and cytokine levels, evaluated from collected murine reproductive tissues and vaginal lavage samples treated with blank fibers, showed no increased cytokine production or histological aberrations, demonstrating the preliminary safety of rapid-release GRFT fibers in vaginal tissue.

Encapsulation Systems for Antimicrobial Food Packaging Components: An Update

Antimicrobially active packaging has emerged as an effective technology to reduce microbial growth in food products increasing both their shelf-life and microbial safety for the consumer while maintaining their quality and sensorial properties. In the last years, a great effort has been made to develop more efficient, long-lasting and eco-friendly antimicrobial materials by improving the performance of the incorporated antimicrobial substances. With this purpose, more effective antimicrobial compounds of natural origin such as bacteriocins, bacteriophages and essential oils have been preferred over synthetic ones and new encapsulation strategies such as emulsions, core-shell nanofibres, cyclodextrins and liposomes among others, have been applied in order to protect these antimicrobials from degradation or volatilization while trying to enable a more controlled release and sustained antimicrobial action. On that account, this article provides an overview of the types of antimicrobials agents used and the most recent trends on the strategies used to encapsulate the antimicrobial agents for their stable inclusion in the packaging materials. Moreover, a thorough discussion regarding the benefits of each encapsulation technology as well as their application in food products is presented.

Fabrication and characterization of a novel polysaccharide based composite nanofiber films with tunable physical properties

In this study, the pullulan/ethyl cellulose composite nanofiber films with tunable physical properties were fabricated by blend electrospinning process. The solution properties of polysaccharide polymers were investigated and related with the morphology of the nanofiber films, and the results showed that the addition of ethyl cellulose caused decreasing viscosity and conductivity of solutions, which gave rise to the smaller fiber diameter. The Fourier transform infrared spectroscopy indicated that pullulan and ethyl cellulose chains interacted with each other through hydrogen bonding. X-ray diffraction analysis showed that electrospinning process retarded the crystallization of polysaccharide molecules. Thermal analysis showed that the composite nanofiber films possessed higher melting temperature and degradation temperature than the pure pullulan nanofiber film. Water contact angle and water stability test proved that the composite nanofiber films possessed tunable surface wettability (94.6°-120.1°) and improved water stability. The mechanical test showed that the composite nanofiber films had enhanced mechanical strength.

Electrospun Polymer Nanofiber from Moringa Oleifera Kernel Oil with Coaxial Electrospinning Method

Background:

Moringa oleifera kernel oil consist of monounsaturated fatty acid with high percentage of oleic acid. The oil consist of phytochemicals, bioactive compounds and nutrients that have several application in health industries. However, the oil degrades on exposure to light, heat and oxygen overtime. In addition, rancidity cause the oil quality to defect and reduce the shelf-life. Therefore, microencapsulation techniques are uniquely applied to oil to preserve their native quality and prolong their shelf life.

Objective:

This study examines different polymer concentrations and injection flowrates of zein nanofiber from Moringa oleifera kernel oil using coaxial electrospinning method.

Methods:

A 40% w/v zein polymer was the optimal loading concentration and 0.7 mL/hour of zein polymer with 0.1 mL/hour of Moringa oleifera kernel oil was the optimal injection flowrates for electrospun nanofiber. Analysis of the Moringa oleifera kernel oil and polymer sample micromorphology, were investigated with Field Emission Scanning Electron Microscopy (FESEM) and transmission electron microscopy (TEM).

Result:

result shows uniformly layered nanofiber. The nanofiber has no beads formation and the fiber strands are continuous with no entanglement. The polymer encapsulated the oil efficiently. Furthermore, thermal analysis through Differential Scanning Calorimetry (DSC) showed consistency in the nanofiber thermal behavior. Thermogravimetric (TGA) analysis revealed the weight loss and thermal dissociation of the polymer structure. The electrospun nanofiber average diameter was 450 ± 24 nm and exhibited hydrophobicity.

Conclusion:

The co-axial electrospine technique was effective in fabricating electrospune nanofibers.

The miscibility and spatial distribution of the components in electrospun polymer–protein mats

Biodegradable blended electrospun mats are promising for biomedical applications such as wound dressing, tissue engineering, and drug delivery. Electrospun mats based on polyesters can be modified by the addition of other polymers or proteins to accelerate the degradation, improve mechanical properties or biocompatibility. However, relatively little is known about the distribution of the components throughout the blended mats. In the present work, we prepared polylactide (PLA), bovine serum albumin (BSA), and the blended PLA–BSA electrospun mats. We demonstrated that PLA and BSA are miscible in a common solvent HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) at concentrations below 3%, but become immiscible as concentration increases. We used three methods (fluorescence microscopy, EDX, and Raman microspectroscopy) to validate that PLA and BSA can be blended in a single electrospun fiber despite the phase separation in the blend. The homogeneity of the blend influences on the homogeneity of the distribution of PLA and BSA components throughout the electrospun mat, as measured by Raman microspectroscopy. When the blended electrospun mats were incubated in water, they demonstrated the prolonged release of BSA. The presented results show a step-by-step approach for manufacturing blended electrospun mats made of immiscible components, which involves the analysis of component miscibility, the mat morphology, and composition. This approach can be used for the rational design of multicomponent electrospun mats.

Polylactide and bovine serum albumin can be combined in a single electrospun fiber, despite the phase separation.

Design of polymer-free Vitamin-A acetate/cyclodextrin nanofibrous webs: antioxidant and fast-dissolving properties

Polymer-free inclusion complex nanofibers of Vitamin-A acetate/cyclodextrin were prepared having fast-dissolving and enhanced antioxidant properties for the purpose of new-generation food/dietary supplement systems.

Encapsulation and Stabilization of α-Lipoic Acid in Cyclodextrin Inclusion Complex Electrospun Nanofibers: Antioxidant and Fast-Dissolving α-Lipoic Acid/Cyclodextrin Nanofibrous Webs

In this study, electrospinning of nanofibers from alpha-lipoic acid/cyclodextrin inclusion complex systems was successfully performed without having any polymeric matrix. Alpha-lipoic acid (α-LA) is a natural antioxidant compound which is widely used as a food supplement. However, it has limited water solubility and poor thermal and oxidative stability. Nevertheless, it is possible to enhance its water solubility and thermal stability by inclusion complexation with cyclodextrins. Here, hydroxypropyl-beta-cyclodextrin (HP-β-CyD) and hydroxypropyl-gamma-cyclodextrin (HP-γ-CyD) were chosen as host molecules for forming inclusion complexation with α-LA. Accordingly, α-LA was inclusion complexed with HP-β-CyD and HP-γ-CyD by using very high concentrated aqueous solutions of CyD (200%, w/v) having 1/1 and 2/1 molar ratio of α-LA/CyD. Except α-LA/HP-β-CyD (1/1) solution, other α-LA/CyD solutions were turbid indicating the presence of some noncomplexed α-LA whereas α-LA/HP-β-CyD (1/1) solution was very homogeneous signifying that α-LA was fully complexed with HP-β-CyD. Even so, electrospinning was performed for all of the α-LA/HP-β-CyD (1/1 and 2/1) and α-LA/HP-γ-CyD (1/1 and 2/1) aqueous solutions, and defect-free bead-less and uniform nanofibers were successfully obtained for all of the α-LA/CyD solutions. However, the electrospinning process for α-LA/CyD (1/1) systems was much more efficient than the α-LA/CyD (2/1) systems, and we were able to produce self-standing and flexible nanofibrous webs from α-LA/CyD (1/1) systems. α-LA was efficiently preserved during the electrospinning process of α-LA/CyD (1/1) systems and the resulting electrospun α-LA/HP-β-CyD and α-LA/HP-γ-CyD nanofibers were produced with the molar ratios of ∼1/1 and ∼0.85/1 (α-LA/CyD), respectively. The better encapsulation efficiency of α-LA in α-LA/HP-β-CyD nanofibers was due to higher solubility increase and higher binding strength between α-LA and HP-β-CyD as revealed by the phase solubility test. α-LA was in the amorphous state in α-LA/CyD nanofibers and both α-LA/HP-β-CyD and α-LA/HP-γ-CyD nanofibers were dissolved very quickly in water and also when they wetted with artificial saliva. Additionally, the antioxidant activity of pure α-LA and α-LA/CyD nanofibers was comparatively evaluated using ABTS radical cation assay. α-LA/CyD nanofibers have shown significantly higher antioxidant performance compared to pure α-LA owing to improved water solubility by CyD inclusion complexation. The thermal stability enhancement of α-LA in α-LA/CyD nanofibers was achieved compared to pure α-LA under heat treatment (100 °C for 24 h). These promising results support that antioxidant α-LA/CyD nanofibers may have potential applications as orally fast-dissolving food supplements.

Biohybrid Electrospun Membrane for the Filtration of Ketoprofen Drug from Water

A current challenge in materials science and biotechnology is to express a specific and controlled functionality on the large interfacial area of a nanostructured material to create smart biohybrid systems for targeted applications. Here, we report on a biohybrid system featuring poly(vinyl alcohol) as the supporting synthetic polymer and bovine serum albumin as the biofunctional element. The optimal processing conditions to produce these self-standing composite membranes are determined, and the composition and distribution of the bioactive agent within the polymeric matrices are analyzed. A post-processing cross-linking using glutaraldehyde enables this functional membrane to be used as a chemical filter in aqueous environments. By demonstrating that our mats can remove large amounts of ketoprofen from water, we show that the combination of a BSA-induced biofunctionality with a nanostructured fibrous material allows for the development of an efficient biohybrid filtering device for the large and widely used family of nonsteroidal anti-inflammatory drugs (NSAIDs). The crystal structure of the complex between BSA and ketoprofen is determined for the first time and confirms the interaction between the two species.

Citronella oil-loaded electrospun micro/nanofibrous matrices as sustained repellency systems for the Asian tiger mosquito Aedes albopictus

BACKGROUND

Mosquitoes are hematophagous insects of major public health concern, serving as vectors of many diseases. Available products for personal protection against mosquitoes lack adequate efficacy and in most cases need to be reapplied or replaced frequently. In recent years, the encapsulation of the active repellents in various matrices has arisen as an alternative method for the development of new-generation repellent systems. The aim of the present study was to explore the potential of functional micro/nanofibrous matrices as systems for the sustained release of the highly volatile insect-repellent citronella oil.

RESULTS

Micro/nanofibrous single- and triple-layer systems incorporating citronella oil as the active agent were developed via the electrospinning technique using the low-cost, non-toxic, biodegradable polymers cellulose acetate and polyvinylpyrrolidone. All the micro/nanofiber systems produced exhibited prolonged release of citronella oil and a high repellent activity in laboratory bioassays against the mosquito Aedes albopictus for at least 4 weeks.

CONCLUSION

Considering the high volatility of the embedded repellent, the present study demonstrates the strong potential of the micro/nanofibrous matrices to act as carriers of highly volatile repellents for an effective and sustained protection from mosquitoes. © 2019 Society of Chemical Industry.

Fast dissolving oral films for drug delivery prepared from chitosan/pullulan electrospinning nanofibers

In this study, Chitosan/pullulan composite nanofiber fast dissolving oral films (FDOFs) were prepared via electrospinning technology. The ratio of chitosan/pullulan (C/P) had an influence on solution property and nanofiber morphology, with the increase of chitosan, viscosity and conductivity of solutions increased, the morphology obtained by scanning electron microscopy indicated that the diameter of nanofibers decreased initially then increased. The Fourier transform infrared spectra indicated hydrogen bond interactions between chitosan and pullulan molecules. X-ray diffraction analysis proved that electrospinning process decreased the crystallinity of materials. Thermal analysis showed that melting point, degradation temperature and glass transition temperature increased with the addition of chitosan content in the FDOF. Water solubility test proved that the FDOF can dissolve in water completely within 60 s. Finally, in order to prove its practicability in future, a model drug of aspirin was encapsulated in the FDOF successfully.

Carvacrol encapsulated nanocarrier/ nanoemulsion abrogates angiogenesis by downregulating COX-2, VEGF and CD31 in vitro and in vivo in a lung adenocarcinoma model

Nanoemulsion-based synthesis has been introduced to enhance the bioavailability of natural compounds at target sites for their various biomedical applications. In this study, we synthesized carvacrol nanoemulsion (CN) an oil-in-water (O/W) as a nano-emulsion vehicle system by using ultrasonication emulsification for anti-angiogenesis therapy formulated by combining MCT, lecithin, and polysorbate 80 at the O/W interface called carvacrol encapsulated nanoemulsion (CEN). The diameter of CEN determined by TEM analysis was 105.32 nm. The hydrodynamic droplet size was 101.0 nm with a -39.38-mV zeta potential. The stability of the synthesized CEN was approved till 100 days without any change in diameter size distribution and encapsulation efficiency. We evaluated the role of CEN on angiogenesis in lung adenocarcinoma A549 cells both in vitro and in vivo and observed that it reduced the growth and MMP levels of A549 cells in a dose-dependent manner. Exposure to CEN decreased the activation of MAPK p38 as well as ERK. Moreover, we found that CEN reduced the expression of VEGF and CD31 in A549 cells both in vitro and in vivo. Our in-silico study also indicated the binding of carvacrol to COX-2 and VEGF at the active and allosteric sites of CD31 with low binding energy. Overall, CEN induced anti-angiogenic effects in A549 cells in vitro, in silico, and in vivo, thereby establishing its potential as targeted drug delivery vehicle against angiogenesis.

Significant fat reduction in deep-fried kamaboko by fish protein hydrolysates derived from common carp (Cyprinus carpio)

BACKGROUND

To evaluate their fat reduction effect, common carp fish protein hydrolysates (FPH) were made using four methods: the conventional enzymatic process, a microwave-intensified enzymatic process, the conventional alkaline hydrolysis process, and a microwave-intensified alkaline hydrolysis process.

RESULTS

The efficiency of protein extraction was significantly enhanced by microwave intensification. The oil-holding capacities of FPH produced by these four processes were all lower than that of raw fish protein. The water-holding capacities of FPH produced by these four processes were all higher than that of raw fish protein. The FPH from the four processes and raw fish protein were used in the preparation of deep-fried kamaboko. The fat content of deep-fried kamaboko was drastically reduced from approximately 160 g kg^-1 to about 50 g kg^-1 by replacing 20 g kg^-1 fish mince with FPH, regardless of the process. Texture profile analysis (TPA) of deep-fried kamaboko found no significant difference in hardness and brittleness among all the deep-fried kamaboko samples. The similar interior protein cross-linking micro-structure of all these samples further explained the TPA finding.

CONCLUSION

With the involvement of FPH in the formulation, the fat content of deep-fried kamaboko can be significantly reduced from approximately 160 to 50 g kg^-1 , without a change in its texture. © 2018 Society of Chemical Industry.

A comprehensive perspective of food nanomaterials

Nanotechnology is a rapidly developing toolbox that provides solutions to numerous challenges in the food industry and meet public demands for healthier and safer food products. The diversity of nanostructures and their vast, tunable functionality drives their inclusion in food products and packaging materials to improve their nutritional quality through bioactive fortification and probiotics encapsulation, enhance their safety due to their antimicrobial and sensing capabilities and confer novel sensorial properties. In this food nanotechnology state-of-the-art communication, matrix materials with particular focus on food-grade components, existing and novel production techniques, and current and potential applications in the fields of food quality, safety and preservation, nutrient bioaccessibility and digestibility will be detailed. Additionally, a thorough analysis of potential strategies to assess the safety of these novel nanostructures is presented.

Tree gum-based renewable materials: Sustainable applications in nanotechnology, biomedical and environmental fields

The prospective uses of tree gum polysaccharides and their nanostructures in various aspects of food, water, energy, biotechnology, environment and medicine industries, have garnered a great deal of attention recently. In addition to extensive applications of tree gums in food, there are substantial non-food applications of these commercial gums, which have gained widespread attention due to their availability, structural diversity and remarkable properties as 'green' bio-based renewable materials. Tree gums are obtainable as natural polysaccharides from various tree genera possessing exceptional properties, including their renewable, biocompatible, biodegradable, and non-toxic nature and their ability to undergo easy chemical modifications. This review focuses on non-food applications of several important commercially available gums (arabic, karaya, tragacanth, ghatti and kondagogu) for the greener synthesis and stabilization of metal/metal oxide NPs, production of electrospun fibers, environmental bioremediation, bio-catalysis, biosensors, coordination complexes of metal-hydrogels, and for antimicrobial and biomedical applications. Furthermore, polysaccharides acquired from botanical, seaweed, animal, and microbial origins are briefly compared with the characteristics of tree gum exudates.

Improved Viability and Thermal Stability of the Probiotics Encapsulated in a Novel Electrospun Fiber Mat

For the enhancement of the probiotics' survivability, a nanostructured fiber mat was developed by electrospinning. The probiotic Lactobacillus plantarum was encapsulated in the nanofibers with fructooligosaccharides (FOS) as the cell material. Fluorescence microscope image and scanning electron microscopy (SEM) showed that viable cells were successfully encapsulated in nanofibers (mean diameter = 410 ± 150 nm), and the applied voltage had no significant influence on their viability ( P > 0.05). A significantly improved viability (1.1 log) was achieved by incorporating 2.5% (w/w) of FOS as the electrospinning material ( P < 0.001). Additionally, compared with free cells, the survivability of cells encapsulated in electrospun FOS/PVA/ L. plantarum nanofibers was significantly enhanced under moist heat treatment (60 and 70 °C). This study shows that the obtained nanofiber is a feasible entrapment structure to improve the viability and thermal stability of encapsulated probiotic cells and provides an alternative approach for the development of functional food.

Influence of polymer composition and drug loading procedure on dual drug release from PLGA:PEG electrospun fibers

Poly(lactide-co-glycolide) (PLGA) has been widely investigated for fabricating electrospun fibers due to their biocompatibility, paired with the capacity for encapsulating different drugs. However, such scaffolds shrink and distort upon contact with biological media, which is undesired for local drug application. To address this issue, we fabricated composite fiber scaffolds with the combination of PLGA and poly(ethylene glycol) (PEG). Scaffold shrinkage could successfully be overcome, however, the release kinetics of the encapsulated drug was strongly dependent on the amount of PEG. The addition of 5% PEG resulted in slower drug release due to a significant increase in fiber diameters. In contrast, the drug release rate was accelerated for fibers containing 10% PEG due to the water-soluble nature of the polymer. Furthermore, co-delivery of two different drugs, the small molecule acyclovir and the model protein bovine serum albumin was realized by two different approaches, coaxial electrospinning and immobilization of the drugs on the surface of the fibers, and drug release was found to be strongly dependent on the loading procedure. Based on our findings, key factors for understanding and controlling physicochemical properties of PLGA/PEG composite fibers as well as tuning drug release could be identified, providing an essential basis for rational design of electrospun fiber-based drug carriers.

Nanoscale and Macroscale Scaffolds with Controlled-Release Polymeric Systems for Dental Craniomaxillofacial Tissue Engineering

Tremendous progress in stem cell biology has resulted in a major current focus on effective modalities to promote directed cellular behavior for clinical therapy. The fundamental principles of tissue engineering are aimed at providing soluble and insoluble biological cues to promote these directed biological responses. Better understanding of extracellular matrix functions is ensuring optimal adhesive substrates to promote cell mobility and a suitable physical niche to direct stem cell responses. Further, appreciation of the roles of matrix constituents as morphogen cues, termed matrikines or matricryptins, are also now being directly exploited in biomaterial design. These insoluble topological cues can be presented at both micro- and nanoscales with specific fabrication techniques. Progress in development and molecular biology has described key roles for a range of biological molecules, such as proteins, lipids, and nucleic acids, to serve as morphogens promoting directed behavior in stem cells. Controlled-release systems involving encapsulation of bioactive agents within polymeric carriers are enabling utilization of soluble cues. Using our efforts at dental craniofacial tissue engineering, this narrative review focuses on outlining specific biomaterial fabrication techniques, such as electrospinning, gas foaming, and 3D printing used in combination with polymeric nano- or microspheres. These avenues are providing unprecedented therapeutic opportunities for precision bioengineering for regenerative applications.

Butylated hydroxyanisole encapsulated in gelatin fiber mats: Volatile release kinetics, functional effectiveness and application to strawberry preservation

Butylated hydroxyanisole (BHA) encapsulated in gelatin (GA) (GA-BHA) fiber mats were fabricated via electrospinning technique and applied to strawberry preservation. The volatile release kinetics and functional effectiveness of the mats were investigated. BHA was high efficiently encapsulated in GA fibers and the antioxidant activity of BHA could be well protected. The encapsulation of BHA enhanced the stability of GA and favored structure transition of GA from random coil and β-turns to α-helix and β-sheet. The GA-BHA mats showed good antibacterial activity against Staphylococcus aureus, and the predominant volatile release mechanism of BHA from mats was Fickian diffusion. Furthermore, the mats also showed broad-spectrum antifungal activity against four mould genera (Rhizopus sp., Mucor sp., Aspergillus sp. and Penicillium sp.). The shelf-life of strawberry can be prolonged effectively in the presence of GA-BHA mats during storage. Results suggested that the GA-BHA mats may have a great potential in active food packaging.