Fabrication of zein nanofibrous scaffold containing Scrophularia striata extract for biomedical application

Skin wounds have the potential to rapidly become infected, with bacteria having the ability to quickly penetrate to the skin's deeper layers. Then they enter the lymph nodes and spread throughout the body; therefore, all wounds should be cleaned and have a permanent cover. Modern wound dressings with effective antibacterial and therapeutic properties are required to create a sterile environment for the acceleration of healing. The aim of this work was to prepare zein electrospun nanofibers containing Scrophularia striata extract for wound healing promotion. Electrospun nanofibers made of zein, a natural polymer, have attracted a lot of attention due to their biocompatibility and biodegradability. The prepared nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive X‑ray analysis (EDX), water contact angle test, and Fourier transform infrared spectroscopy (FT-IR). The parameters affected by the electrospinning process were investigated and optimized. The results revealed that the zein nanofibers (25% w/v, zein) containing Scrophularia striata extract (6.7% w/v) had a smooth and bead-free morphology with improved surface hydrophilicity. The measurement of water contact angle confirmed that nanofibers containing extract showed higher wettability (64.9°) compared to fibers without extract (119.8), so the proposed mat adequately moisturizes the wound environment. The antimicrobial studies show that Scrophularia striata extract incorporated nanofibers has the ability to inhibit the growth of both gram-negative and gram-positive bacteria. The biophenols release profile indicated that nanofibrous mat can release more effective substances to promote wound healing. The biocompatibility and biodegradability of nanofibrous scaffold containing Scrophularia striata extract tested in in vivo and in vitro conditions show a significantly higher survival rate of fibroblast cells. In addition, macroscopic and histological observations confirmed that the implanted nanofibers containing the extract did not exhibit any signs of inflammation or redness after a month when inserted beneath the skin of mice surrounded by vessels containing epidermis.

Valorization of Agricultural By-Products (Fragaria vesca) through the Production of Value-Added Micro/Nanostructures Using Electrohydrodynamic Techniques

An innovative approach for the production of bio-micro/nanostructures with high-value compounds from agricultural by-products was studied. This research aimed to valorize bioactive compounds existing in the by-products of the plants of Fragaria vesca (wild strawberry). The particle characteristics, morphology, size, release properties, and antioxidant activity of micro/nanostructures containing the extract of by-products of the plants of Fragaria vesca or quercetin (one of the main polyphenols in the plant) were analyzed. The electrohydrodynamic (EHD) technique was utilized for encapsulation. The results showed that the morphology and size of the structures were influenced by the concentration of zein, with 10% w/v zein concentration leading to irregular and non-uniform nanostructures, while 20% w/v zein concentration resulted in a mixture of microparticles and thin fibers with an irregular surface. The type and concentration of the core material did not significantly affect the morphology of the micro/nanostructures. In vitro release studies demonstrated the controlled release of the core materials from the zein micro/nanostructures. The release profiles were analyzed using the Korsmeyer-Peppas and Weibull models, which provided insights into the release mechanisms and kinetics. The most relevant release mechanism is associated with "Fickian Diffusion". The antioxidant activity of the structures was evaluated using an ABTS radical-scavenging assay, indicating their potential as antioxidants. In conclusion, the EHD technique enabled the successful encapsulation of Fragaria vesca by-product extract and quercetin with zein, resulting in micro/nanostructures with different morphologies.

Functional Polymeric Membranes with Antioxidant Properties for the Colorimetric Detection of Amines

Herein, the ability of highly porous colorimetric indicators to sense volatile and biogenic amine vapors in real time is presented. Curcumin-loaded polycaprolactone porous fiber mats are exposed to various concentrations of off-flavor compounds such as the volatile amine trimethylamine, and the biogenic amines cadaverine, putrescine, spermidine, and histamine, in order to investigate their colorimetric response. CIELAB color space analysis demonstrates that the porous fiber mats can detect the amine vapors, showing a distinct color change in the presence of down to 2.1 ppm of trimethylamine and ca. 11.0 ppm of biogenic amines, surpassing the limit of visual perception in just a few seconds. Moreover, the color changes are reversible either spontaneously, in the case of the volatile amines, or in an assisted way, through interactions with an acidic environment, in the case of the biogenic amines, enabling the use of the same indicator several times. Finally, yet importantly, the strong antioxidant activity of the curcumin-loaded fibers is successfully demonstrated through DPPH● and ABTS● radical scavenging assays. Through such a detailed study, we prove that the developed porous mats can be successfully established as a reusable smart system in applications where the rapid detection of alkaline vapors and/or the antioxidant activity are essential, such as food packaging, biomedicine, and environmental protection.

Electrospinning of Microstructures Incorporated with Vitamin B9 for Food Application: Characteristics and Bioactivities

The food industry has been expanding, and new vectors to entrap vitamins have been constantly investigated, aiming at versatile systems with good physico-chemical characteristics, low-cost production, high stability and the efficient release of active ingredients. The vitamin B9 (folic acid or folate) is essential for the healthy functioning of a variety of physiological processes in humans and is beneficial in preventing a range of disorders. In this study, two approaches were developed to encapsulate vitamin B9. Zein and the combination of modified starch with two plasticizers were the selected encapsulating agents to produce microstructures via the electrospinning technique. The objective was to improve the stability and the B9 antioxidant capacity in the final formulations. The work strategy was to avoid limitations such as low bioavailability, stability and thermosensitivity. The microstructures were fabricated and the morphology and shape were assessed by scanning electron microscopy. The B9 release profiles of modified starch and zein microstructures were analyzed in simulated gastric fluid at 37 °C, and in deionized water and ethanol at room temperature. The B9 encapsulation efficiency and the stability of the systems were also studied. The ABTS assay was assessed and the antioxidant activity of the produced microstructures was evaluated. The physico-chemical characterization of loaded B9 in the microstructures was achieved. High encapsulation efficiency values were achieved for the 1% B9 loaded in 12% w/w modified starch film; 5% B9 vitamin encapsulated by the 15% w/w modified starch with 4% w/w tween 80; and 4% w/w glycerol film with heterogeneous microstructures, 5% w/w zein compact film and 10% w/w zein film. In conclusion, the combinations of 7 wt.% of modified starch with 4 wt.% tween 80 and 4 wt.% glycerol; 15 wt.% of modified starch with 4 wt.% tween 80 and 4 wt.% glycerol; and 12 wt.% modified starch and 5 wt.% zein can be used as delivery structures in order to enhance the vitamin B9 antioxidant activity in the food and nutraceutical fields.

Optimization of Nanofiber Wearable Heart Rate Sensor Module for Human Motion Detection

In order to further improve the detection performance of the wearable heart rate sensor for human physiological and biochemical signals and body kinematics performance, the wearable heart rate sensor module was optimized by using nanofibers. Nanoparticle-doped graphene films were prepared by adding nanoparticles to a graphene oxide solution. The prepared film was placed in toluene, and the nanoparticles were removed to complete the preparation of a graphene film with a porous microstructure. The graphene film and the conductive film together formed a wearable heart rate sensor module. The strain response test of the porous graphene film wearable heart rate sensor module verifies the validity of the research in this paper. The resistance change of the wearable heart rate sensor module based on the PGF-2 film is 8 to 16 times higher than that of the RGO film, and the sensitivity is better, proving that the sensor module designed by this method shows significant application potential in human motion detection.

Nanoencapsulation of casein-derived peptides within electrospun nanofibres

BACKGROUND

Bioactive peptides derived from milk proteins are recognized as functional foods, but their consumption is limited by undesirable or bitter flavour, poor stability, and low bioavailability. Electrospinning is a versatile process for encapsulation of various bioactive compounds in the form of nanosized fibres, which can circumvent these disadvantages. This study was aimed at the preparation of casein-derived peptides-loaded nanofibres through electrospinning and characterizing them for fortification of milk.

RESULTS

Pullulan at 100, 120, and 140 g kg^-1 concentrations was used for electrospinning of peptides. Scanning electron and atomic force micrographs revealed the formation of clean bead-free peptides-loaded pullulan nanofibres at 120 and 140 g kg^-1 concentrations with mean diameter of 60.45-133.05 nm and encapsulation efficiency of 72.95-86.04%. Fourier transform infrared spectra and X-ray diffractograms revealed the absence of interactions between the functional groups of pullulan and peptides during electrospinning. The zeta potential of the peptides-loaded nanofibres ranged from -15.6 to -24.6 mV, and the hydrodynamic diameter varied from 118.7 to 256.2 nm. The peptides from electrospun nanofibres showed sustained release to the extent of 75.3% after 8 h in gastrointestinal pH conditions. The release kinetics of peptides from nanofibres was best fitted to a Peppas-Sahlin model (R²  = 0.987), and through diffusion and erosion mechanisms. The antioxidant activity of pure peptides and those from nanofibres was comparable. The physico-chemical qualities of milk fortified with encapsulated peptides did not show noticeable difference either.

CONCLUSIONS

From the morphological, ultrastructural, particle size, encapsulation efficiency, release kinetics, and antioxidant activity data, it was inferred that electrospinning could be an effective technique for nanoencapsulation of casein-derived bioactive peptides. These peptides-loaded nanofibres could be used for fortification of milk and milk products. © 2021 Society of Chemical Industry.

Nanofiber Systems as Herbal Bioactive Compounds Carriers: Current Applications in Healthcare

Nanofibers have emerged as a potential novel platform due to their physicochemical properties for healthcare applications. Nanofibers’ advantages rely on their high specific surface-area-to-volume and highly porous mesh. Their peculiar assembly allows cell accommodation, nutrient infiltration, gas exchange, waste excretion, high drug release rate, and stable structure. This review provided comprehensive information on the design and development of natural-based polymer nanofibers with the incorporation of herbal medicines for the treatment of common diseases and their in vivo studies. Natural and synthetic polymers have been widely used for the fabrication of nanofibers capable of mimicking extracellular matrix structure. Among them, natural polymers are preferred because of their biocompatibility, biodegradability, and similarity with extracellular matrix proteins. Herbal bioactive compounds from natural extracts have raised special interest due to their prominent beneficial properties in healthcare. Nanofiber properties allow these systems to serve as bioactive compound carriers to generate functional matrices with antimicrobial, anti-inflammatory, antioxidant, antiseptic, anti-viral, and other properties which have been studied in vitro and in vivo, mostly to prove their wound healing capacity and anti-inflammation properties.

Electrospun Polyvinyl Alcohol Loaded with Phytotherapeutic Agents for Wound Healing Applications

In this paper, hydroalcoholic solutions of Thymus vulgaris, Salvia officinalis folium, and Hyperici herba were used in combination with poly (vinyl alcohol) with the aim of developing novel poly (vinyl alcohol)-based nanofiber mats loaded with phytotherapeutic agents via the electrospinning technique. The chemical structure and morphology of the polymeric nanofibers were investigated using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The addition of Thymus vulgaris, Salvia officinalis folium, and Hyperici herba extracts to the pure polyvinyl alcohol fibers led to changes in the morphology of the fibers and a reduction in the fibers’ diameter, from 0.1798 µm in the case of pure polyvinyl alcohol to 0.1672, 0.1425, and 0.1369 µm in the case of polyvinyl alcohol loaded with Thymus vulgaris, Salvia officinalis folium, and Hyperici herba, respectively. The adapted Folin–Ciocalteu (FC) method, which was used to determine the total phenolic contents, revealed that the samples of PVA–Hyperici herba and PVA–Thymus vulgaris had the highest phenol contents, at 13.25 μgGAE/mL and 12.66 μgGAE/mL, respectively. Dynamic water vapor measurements were used in order to investigate the moisture sorption and desorption behavior of the developed electrospun materials. The antimicrobial behavior of these products was also evaluated. Disk diffusion assay studies with Escherichia coli, Staphylococcus aureus, and Methicillin-resistant Staphylococcus aureus were conducted on the developed nanofibers in order to quantify their phytotherapeutic potential.

Encapsulation of Natural Bioactive Compounds by Electrospinning-Applications in Food Storage and Safety

Packaging is used to protect foods from environmental influences and microbial contamination to maintain the quality and safety of commercial food products, to avoid their spoilage and to extend their shelf life. In this respect, bioactive packaging is developing to additionally provides antibacterial and antioxidant activity with the same goals i.e., extending the shelf life while ensuring safety of the food products. New solutions are designed using natural antimicrobial and antioxidant agents such as essential oils, some polysaccharides, natural inorganic nanoparticles (nanoclays, oxides, metals as silver) incorporated/encapsulated into appropriate carriers in order to be used in food packaging. Electrospinning/electrospraying are receiving attention as encapsulation methods due to their cost-effectiveness, versatility and scalability. The electrospun nanofibers and electro-sprayed nanoparticles can preserve the functionality and protect the encapsulated bioactive compounds (BC). In this review are summarized recent results regarding applications of nanostructured suitable materials containing essential oils for food safety.

Incorporation of grape seed extract towards wound care product development

Naturally derived ingredients are becoming more prevalent in therapeutic drug formulations due to consumers' concerns about chemical side effects. In the context of wound care, despite the impressive progress in therapeutic product development, drugs dispensed to treat impaired healing challenged by biofilms; excessive inflammation and oxidation are not yet really effective. Thus, the hunts for improved drug formulations preferably using natural ingredients that are cost-effective in accelerating the wound-healing process are of constant demand. The grape seed extract is extensively studied and is reported to be rich in phenolic compounds, unsaturated fatty acids and vitamins which exhibit numerous therapeutic benefits owing to their anti-inflammatory, anti-microbial, and anti-oxidative properties that support its potential use in the development of wound-healing products. We conducted a literature study using Scopus, PubMed, and Google Scholar including the keywords "grape seed extract" and "wound healing". We also scanned all the references cited by the retrieved articles. Accordingly, this review is aimed to (i) explore the various phytochemical constituents found in grape seed extracts along with their mechanism of action that instigate wound healing, (ii) to highlight the latest pre-clinical and clinical assessments of grape seed extract in wound models, and (iii) to encourage innovation scientists in the field to address current limitations and to effectively develop grape seed extract-based wound care product formulations for commercialization.

Antidiabetic potential evaluation of aqueous extract of waste Syzygium cumini seed kernel's by in vitro α-amylase and α-glucosidase inhibition

Syzygium cumini, owing to higher bioactive constituents, its parts principally kernels are used for the antidiabetic purpose since the olden days. The current manuscript illustrated batch extraction of phenolic compounds from S. cumini using a stirred extractor. The yields 0.61 mg/g, 35.9 mg/g, 79.89 mg GAE/g, and 7.29 mg CE/g of catechin, gallic acid, TPC and TFC, respectively, were obtained in 105 min. at 1:20 SCKP to water, 50 ± 2 °C temperature, 4 pH, at 250 rpm and 106 µm particle size of SCKP. In vitro evaluation of the antioxidant and antidiabetic potential of the obtained aqueous extract was carried out by DPPH, α-amylase, and α-glucosidase inhibitory assays. The IC₅₀ values of SCKP aqueous extract obtained were 12.97, 9.03, and 7.13 µg/mL for DPPH scavenging, inhibition of α-amylase, and α-glucosidase, respectively. The cost required to extract 1 kg of catechin, gallic acid, TPC, and TFC was Rs 6691.6, 113.7, 51.1, and 559.93/-, respectively. Stirred batch extraction technique manifests traditional but simple, ecofriendly, and efficient compared to other traditional techniques. The output of this research bestows support to utilize the SCKP stirred batch extract as a promising source of antioxidant and antidiabetic compounds in ayurvedic formulations.

Encapsulation of Bioactive Compounds from Aloe Vera Agrowastes in Electrospun Poly (Ethylene Oxide) Nanofibers

Aloe Vera is an ancient medicinal plant especially known for its beneficial properties for human health, due to its bioactive compounds. In this study, nanofibers with antioxidant activity were successfully obtained by electrospinning technique with the addition of a natural Aloe Vera skin extract (AVE) (at 0, 5, 10 and 20 wt% loadings) in poly(ethylene oxide) (PEO) solutions. The successful incorporation of AVE into PEO was evidenced by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging (ABTS) and ferric reducing power (FRAP) assays. The incorporation of AVE introduced some changes in the PEO/AVE nanofibers morphology showing bimodal diameter distributions for AVE contents in the range 10-20 wt%. Some decrease in thermal stability with AVE addition, in terms of decomposition onset temperature, was also observed and it was more evident at high loading AVE contents (10 and 20 wt%). High encapsulation efficiencies of 92%, 76% and 105% according to DPPH, FRAP and ABTS assays, respectively, were obtained at 5 wt% AVE content, retaining AVE its antioxidant capacity in the PEO/AVE electrospun nanofibers. The results suggested that the obtained nanofibers could be promising materials for their application in active food packaging to decrease oxidation of packaged food during storage.