Preparation of PCL/lecithin/bacteriocin CAMT6 antimicrobial and antioxidant nanofiber films using emulsion electrospinning: Characteristics and application in chilled salmon preservation

Multi-functional packaging materials are an important development for food preservation. Emulsion electrospinning is a novel and simple method that can be used to prepare multi-functional packaging materials, which can effectively protect the loaded active substances during the preparation process. In this study, PCL/lecithin/bacteriocin CAMT6 nanofiber films with antimicrobial and antioxidant activity were prepared by emulsion electrostatic spinning. The morphology and homogeneity of the prepared nanofibrous membranes could be improved by optimising the formulation of the emulsion for electrospinning. Analytical testing of the prepared nanofiber films revealed that the nanofibers had a core-shell structure, with bacteriocin CAMT6 effectively encapsulated in the core layer and the PCL and phospholipids homogeneously mixed to form the shell layer. Additionally, the nanofiber films had acceptable tensile properties and water absorption capacity. In chilled salmon meat, the nanofiber film effectively inhibited the growth of bacteria, slowed the oxidation of oil and slowed water loss, which was a good protective effect. This study provides a reference for the encapsulation application of food-active packaging materials and bacteriocins.

Emulsion electrospinning of zein nanofibers with carotenoid microemulsion: Optimization, characterization and fortification

In this study, carotenoid microemulsion was encapsulated in zein nanofibers via emulsion electrospinning. Optimization study was applied to determine optimum parameters by response surface methodology. The voltage, flow rate and distance as optimum conditions were determined as 23 kV, 1.7 mL/h and 12.75 cm, respectively. Lycopene, β-carotene, encapsulation efficiency, encapsulation yield and zeta potential of zein nanofibers in optimum conditions were estimated as 4.054 mg/kg, 0.649 mg/kg, 77.78%, 41.76% and -29.73 mV, respectively. The addition of microemulsion affected nanofibers diameter and morphologies. Diffusion coefficient of zein nanofibers decreased with addition of microemulsion under optimum conditions. The electrospinning improved thermal stability of microemulsion. The carotenoid microemulsion could be entrapped into the zein fibers according to ATR-FTIR spectrum. Model foods were fortificated with zein nanofibers. The addition of nanofibers changed color of the foods during the storage. Carotenoid compounds were more stable in nanofibers followed by olive oil, milk and water.

Psoralea corylifolia formula extract-loaded silk fibroin/polycaprolactone fibrous membrane for the treatment of colorectal cancer

Intestinal obstructions caused by intestinal tumors pose life-threatening risks to patients. Adjuvant treatment using intestinal stents carrying drug loaded membranes has the advantages of timely relief of intestinal obstruction, as well as effective inhibition of tumor progression. The present work is to develop an intestinal stent loaded with a combination of traditional Chinese medicines capable of good biocompatibility, degradability, sustained drug release and anti-tumor properties. The drug combination extract was obtained from Psoralea corylifolia formula (PCF) and then was loaded into silk fibroin (SF)/polycaprolactone (PCL) fibrous membranes using emulsion electrospinning technology. Results showed that the membrane prepared by emulsion electrospinning technology has apparent core-shell structure, and the mechanical property and hydrophilicity of the membrane are gradually improved with the addition of PCF. Drug sustained release results demonstrated that there were no bursting phenomena, and showed a gradual sustained release up to 400 h. The antitumor efficacy was assessed in vitro using a human colorectal cancer cell line HCT-116 and an epithelial cell line NCM-460. Results showed that this drug-loaded membrane sustained antitumor cell growth performance, indicating its great potential for clinical treatment for intestinal cancer in the near future.

Stable encapsulation of camellia oil in core-shell zein nanofibers fabricated by emulsion electrospinning

This study aimed to develop core-shell nanofibers by emulsion electrospinning using zein-stabilized emulsions to encapsulate camellia oil effectively. The increasing oil volume fraction (φ from 10% to 60%) increased the apparent viscosity and average droplet size of emulsions, resulting in the average diameter of electrospun fibers increasing from 124.5 nm to 286.2 nm. The oil droplets as the core were randomly distributed in fibers in the form of beads, and the core-shell structure of fibers was observed in TEM images. FTIR indicated that hydrogen bond interactions occurred between zein and camellia oil molecules. The increasing oil volume fraction enhanced the thermal stability, hydrophobicity, and water stability of electrospun nanofiber films. The core-shell nanofibers with 10%, 20%, 40%, and 60% camellia oil showed encapsulation efficiency of 78.53%, 80.25%, 84.52%, and 84.39%, respectively, and had good storage stability. These findings contribute to developing zein-based core-shell electrospun fibers to encapsulate bioactive substances.

Encapsulation of lycopene into electrospun nanofibers from whey protein isolate-Tricholoma lobayense polysaccharide complex stabilized emulsions: Structural characterization, storage stability, in vitro release, and cellular evaluation

In this study, lycopene-loaded nanofibers were successfully fabricated by electrospinning of oil-in-water (O/W) emulsions stabilized by whey protein isolate-polysaccharide TLH-3 (WPI-TLH-3) complexes. The lycopene encapsulated in the emulsion-based nanofibers exhibited enhanced photostability and thermostability, and achieved improved targeted small intestine-specific release. The release of lycopene from the nanofibers followed Fickian diffusion mechanism in simulated gastric fluid (SGF) and first-order model in simulated intestinal fluid (SIF) with the enhanced release rates. The bioaccessibility and cellular uptake efficiency of lycopene in micelles by Caco-2 cells after in vitro digestion were significantly improved. The intestinal membrane permeability and transmembrane transport efficiency of lycopene in micelles across Caco-2 cells monolayer were greatly elevated, thus promoting the effective absorption and intracellular antioxidant activity of lycopene. This work opens a potential approach for electrospinning of emulsions stabilized by protein-polysaccharide complexes as a novel delivery system for liposoluble nutrients with enhanced bioavailability in functional food industries.

Fabrication of alkali lignin-based emulsion electrospun nanofibers for the nanoencapsulation of beta-carotene and the enhanced antioxidant property

For the greater utilization of β-carotene in antioxidant material, β-carotene-loaded emulsion stabilized by alkali lignin (AL) was successfully electrospinning with poly (vinyl alcohol) (PVA) (PVA/AL/β-carotene nanofiber). Transmission electron microscopy demonstrated the core-shell structure of nanofiber with the average diameter being 356.31 nm, and 85.7 % of β-carotene was effectively encapsulated into the core section. Fourier transform infrared spectra and differential scanning calorimetry revealed the good compatibility and decreased crystallinity of β-carotene, favoring its stability and solubility, respectively. As expected, the PVA/AL/β-carotene nanofiber exhibited higher antioxidant activity than free β-carotene due to the protection of AL matrix and the special structure of nanofiber, as the DPPH free radical scavenging rate being 90.7 % at 7th day. The sustained release behavior of β-carotene and AL from fiber followed Fickian diffusion model, contributing to the greater protection for fish oil than that of emulsion. Thus, this study provides an approach to develop hydrophobic compounds-loaded emulsion electrospun antioxidant material with controlled release property and enhanced activity.

Protein-loaded emulsion electrospun fibers optimized for bioactivity retention and pH-controlled release for peroral delivery of biologic therapeutics

Biologics are the most rapidly growing class of therapeutics, but commonly suffer from low stability. Peroral administration of these therapeutics is an attractive delivery route; however, this route introduces unique physiological challenges that increase the susceptibility of proteins to lose function. Formulation of proteins into biomaterials, such as electrospun fibers, is one strategy to overcome these barriers, but such platforms need to be optimized to ensure protein stability and maintenance of bioactivity during the formulation process. This work develops an emulsion electrospinning method to load proteins into Eudragit® L100 fibers for peroral delivery. Horseradish peroxidase and alkaline phosphatase are encapsulated with high efficiency into fibers and released with pH-specificity. Recovery of protein bioactivity is enhanced through reduction of the emulsion aqueous phase and the inclusion of a hydrophilic polymer excipient. Finally, we show that formulation of proteins in lyophilized electrospun fibers extends the therapeutic shelf life compared to aqueous storage. Thus, this platform shows promise as a novel dosage form for the peroral delivery of biotherapeutics.

Novel poly(ε-caprolactone)/gelatin wound dressings prepared by emulsion electrospinning with controlled release capacity of Ketoprofen anti-inflammatory drug

In the present study, a single and binary Ketoprofen-loaded mats of ultrathin fibers were developed by electrospinning and their physical properties and drug release capacity was analyzed. The single mat was prepared by solution electrospinning of poly(ε-caprolactone) (PCL) with Ketoprofen at a weight ratio of 5wt%. This Ketoprofen-containing PCL solution was also used as the oil phase in a 7:3 (wt/wt) emulsion with gelatin dissolved in acidified water. The resultant stable oil-in-water (O/W) emulsion of PCL-in-gelatin, also containing Ketoprofen at 5wt%, was electrospun to produce the binary mat. Cross-linking process was performed by means of glutaraldehyde vapor on the electrospun binary mat to prevent dissolution of the hydrophilic gelatin phase. The performed characterization indicated that Ketoprofen was successfully embedded in the single and binary electrospun mats, i.e. PCL and PCL/gelatin, and both mats showed high hydrophobicity but poor thermal resistance. In vitro release studies interestingly revealed that, in comparison to the single PCL electrospun mat, the binary PCL/gelatin mat significantly hindered Ketoprofen burst release and exhibited a sustained release capacity of the drug for up to 4days. In addition, the electrospun Ketoprofen-loaded mats showed enhanced attachment and proliferation of L929 mouse fibroblast cells, presenting the binary mat the highest cell growth yield due to its improved porosity. The here-developed electrospun materials clearly show a great deal of potential as novel wound dressings with an outstanding controlled capacity to release drugs.

Nanofibrous scaffold from electrospinning biodegradable waterborne polyurethane/poly(vinyl alcohol) for tissue engineering application

A series of nanofibrous scaffolds, free of organic solvents, are prepared by electrospinning biodegradable waterborne polyurethane (BWPU) emulsion blending with aqueous poly(vinyl alcohol)(PVA). Tuning the proration of BWPU to PVA, various nanofibers with diameter from 370 to 964 nm are obtained. Strong intermolecular interaction existing between them benefits to the electrospun of BWPU emulsion, which is demonstrated by dynamic thermomechanical analysis and Fourier transform infrared spectroscopy. The nontoxic nanofibrous scaffolds with porous structure, which is similar to the natural extracellular matrix, favor to the attachment and proliferation of the L929 fibroblasts. Thus, the scaffolds are promising to be used as biomaterials for many natural tissues repair.

Evaluation of emulsion electrospun polycaprolactone/hyaluronan/epidermal growth factor nanofibrous scaffolds for wound healing

Wound healing scaffolds provide cells with structural integrity and can also deliver biological agents to establish a skin tissue-specific microenvironment to regulate cell functions and to accelerate the healing process. In this study, we fabricated biodegradable nanofibrous scaffolds with an emulsion electrospinning technique. The scaffolds were composed of polycaprolactone, hyaluronan and encapsulating epidermal growth factor. The morphology and core-sheath structure of the nanofibers were characterized by scanning electron microscopy and transmission electron microscopy. The scaffolds were also characterized for chemical composition and hydrophilicity with a Fourier-transform infrared analysis, energy dispersive spectroscopy and the water contact angle. An in vitro model protein bovine serum albumin and epidermal growth factor release study was conducted to evaluate the sustained release potential of the core-sheath structured nanofibers with and without the hyaluronan component. Additionally, an in vitro cultivation of human skin keratinocytes (HaCaT) and fibroblasts on polycaprolactone/hyaluronan and polycaprolactone/hyaluronan-epidermal growth factor scaffolds showed a significant synergistic effect of hyaluronan and epidermal growth factor on cell proliferation and infiltration. Furthermore, there was an up-regulation of the wound-healing-related genes collagen I, collagen III and TGF-β in polycaprolactone/hyaluronan/epidermal growth factor scaffolds compared with control groups. In the full-thickness wound model, the enhanced regeneration of fully functional skin was facilitated by epidermal regeneration in the polycaprolactone/hyaluronan/epidermal growth factor treatment group. Our findings suggest that bioactivity and hemostasis of the hyaluronan-based nanofibrous scaffolds have the capability to encapsulate and control the release of growth factors that can serve as skin tissue engineering scaffolds for wound healing.