Reinforced ZnONPs/ rosemary essential oil-incorporated zein electrospun nanofibers by κ-carrageenan

An overview of fucoidan electrospun nanofibers: Fabrication, modification, characterizations and applications

Nanofibers provide tunable attributes which make them promising for various applications. The electrospinning technique provides nanofibers with a large surface area and eases functionalization for various food and pharmaceutical applications. Numerous biopolymers have been employed to produce nanofibers due to their biocompatibility, biodegradability, and absorbability. Among different biopolymers, algal polysaccharides have gained much attention. Fucoidan is a sulfated polysaccharide isolated from brown macroalgae with a broad range of biological properties; therefore, it is highly investigated as a functional and therapeutic agent in foods and pharmaceuticals. Thus, different chemical modifications, such as depolymerization, oversulfation, phosphorylation, amination, acetylation, and benzoylation, or conjugation and functionalization with other polymers, have been used to make them desirable for target applications. The present study comprehensively reviews the electrospinning technique, applications, and crosslinking methods, then highlights the fucoidan attributes, fabrication of fucoidan-based electrospun nanofibers, their properties and functionality for food and biomedical applications.

Poly(lactide)-Based Materials Modified with Biomolecules: A Review

Poly(lactic acid) (PLA) is characterized by unique features, e.g., it is environmentally friendly, biocompatible, has good thermomechanical properties, and is readily available and biodegradable. Due to the increasing pollution of the environment, PLA is a promising alternative that can potentially replace petroleum-derived polymers. Different biodegradable polymers have numerous biomedical applications and are used as packaging materials. Because the pure form of PLA is delicate, brittle, and is characterized by a slow degradation rate and a low thermal resistance and crystallization rate, these disadvantages limit the range of applications of this polymer. However, the properties of PLA can be improved by chemical or physical modification, e.g., with biomolecules. The subject of this review is the modification of PLA properties with three classes of biomolecules: polysaccharides, proteins, and nucleic acids. A quite extensive description of the most promising strategies leading to improvement of the bioactivity of PLA, through modification with these biomolecules, is presented in this review. Thus, this article deals mainly with a presentation of the major developments and research results concerning PLA-based materials modified with different biomolecules (described in the world literature during the last decades), with a focus on such methods as blending, copolymerization, or composites fabrication. The biomedical and unique biological applications of PLA-based materials, especially modified with polysaccharides and proteins, are reviewed, taking into account the growing interest and great practical potential of these new biodegradable biomaterials.

Preparation and Characterization of Zein-Metformin/Gelatin Nanofibers by Coaxial Electrospinning

Metformin is a drug commonly used for the treatment of type 2 diabetes. However, it has been associated with damaging side effects when used over a long period of time. A potential solution to this problem is the implementation of a prolonged-release system for metformin, which would enhance the efficiency of the doses administered to patients. To achieve this, it is necessary to use materials compatible with humans. Electrospinning is an efficient technique that can be employed for this purpose, utilizing solvents that are safe for human use. Therefore, the objective of this study was to prepare and characterize a system for the prolonged release of metformin from zein and gelatin through coaxial electrospinning as well as to investigate its in vitro release. Metformin-loaded zein/gelatin coaxial nanofibers were prepared using the coaxial electrospinning technique and then characterized by morphological, structural, and thermal analysis. Morphologically, metformin-loaded zein/gelatin coaxial nanofibers were obtained with an average diameter of 322.6 ± 44.5 nm and a smooth surface. Fourier transform infrared spectroscopy (FTIR) analysis showed band shifts at a higher wavenumber due to drug-protein interactions by hydrogen bonding between N-H and C=O groups. Thermal gravimetric analysis (TGA) results suggested a possible interaction between materials due to an increase in the degradation temperatures of zein and gelatin when metformin was included. The transition of the crystallinity of metformin to the amorphous form was also confirmed by differential scanning calorimetry (DSC). Coaxial nanofibers exhibited an encapsulation efficiency of 66% and a profile release that showed an initial release of metformin (40%) in the first hour, followed by a gradual release until it reached equilibrium at 60 h and a cumulative release of 97% of metformin. It was concluded that using the coaxial electrospinning technique, it is possible to obtain nanofibers from polymeric solutions of zein and gelatin to encapsulate metformin, with a potential application as a prolonged-release system.

Development and characterization of active packaging system based on zein nanofibers mat incorporated with geraniol-loaded nanoliposomes

In recent years, development of biopolymeric nanofibers as an active biodegradable packaging system has attracted specific attention. The objective of this research was to develop zein-based electrospun nanofibers (NFs) incorporated with geraniol-loaded nanoliposomes (G-loaded NLPs). Geraniol was encapsulated into NLPs with an efficiency of 79.23%. The particle size and zeta potential of G-loaded NLPs were 121.50 nm and -38.30 mV, respectively. The successful loading of geraniol in the NLPs was approved by Fourier transform infrared (FT-IR) spectroscopy. The liposomal vesicles showed spherical shapes. G-loaded NLPs were added in the zein-based electrospun NFs at three different concentrations (0.25, 0.5, and 1%w/v). All NFs samples exhibited fibrillar structure. The increase of NLPs concentration enhanced the thermal stability of the NFs. However, the crystalline structure of zein NFs did not change by the addition of G-loaded NLPs. The highest surface hydrophobicity was related to the NFs containing 1% G-loaded NLPs. The mechanical parameters of NFs depend on the concentration of NLPs. The NFs incorporated with G-loaded NLPs showed inhibition activity against four foodborne pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium) with an inhibition zone of 4.5-22 mm. Moreover, the α-diphenyl-β-picrylhydrazyl (DPPH) scavenging activity of NFs samples was located at the range of 20%-48%. These findings represent the Efficiency of the G-loaded NLPs for use as bioactive compound in the zein-based NFs as an active packaging material.

Development and characterization of semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2/ZnO nanoparticles

Food packaging based on natural polymers from polysaccharides and proteins can be an alternative to replace conventional plastics. In the present study, semi-refined iota carrageenan (SRIC) and fish gelatin (FG) were used as polymer matrix film with different concentration ratios (0.5:1.5 %, 1.0:1.0 % and 1.5:0.5 % w/w) and SiO2-ZnO nanoparticles were incorporated as fillers with the same concentration in all formulas (0.5:1.5 % w/w carrageenan-fish gelatin). This study aimed to develop films for food packaging applications with desirable physical, mechanical, optical, chemical, and microbiological properties. The results showed that incorporating SiO2-ZnO nanoparticles significantly (p < 0.05) improved the films' elongation at break, UV-screening properties, and antimicrobial activity. Also, the films' thickness, degradability, and transparency significantly (p < 0.05) increased with the higher concentration of fish gelatin addition in the SRIC matrix polymer. The best formula was obtained on the SRIC-FG film at the ratio of 1.5:0.5 % w/w, which performed excellent antimicrobial activity. Thus, semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2-ZnO nanoparticles can be potentially developed as eco-friendly and intelligent food packaging materials to resolve traditional plastic-related issues and prevent food waste.

Antimicrobial activity of geranium (Pelargonium graveolens) essential oil and its encapsulation in carioca bean starch ultrafine fibers by electrospinning

Geranium (Pelargonium graveolens) is known for being an aromatic plant rich in bioactive compounds with antibacterial properties. In this study, geranium essential oil (GEO) was extracted and encapsulated in ultrafine bean starch fibers produced by electrospinning as an antibacterial agent. GEO revealed a composition rich in volatile compounds, including citronellol, cis-geraniol, β-linalool, citronellyl formate, and linalool formate. In its free form, GEO exhibited high antibacterial activity against pathogenic bacteria strains (L. monocytogenes, S. aureus, and E. coli). The bean starch fibers, produced with and without the addition of GEO, were uniform and continuous, with an average diameter ranging from 249 to 373 nm. Confocal analysis indicated a uniform distribution of GEO in the fibers, with a loading capacity of 54.0 %, 42.9 %, and 36.5 % for 20 %, 30 %, and 40 % GEO concentrations, respectively. Remarkably, fibers containing 40 % GEO showed a significant reduction in tested bacteria (L. monocytogenes, S. aureus, and E. coli), suggesting promising applications in preventing losses and extending the shelf life of food through active packaging.

Multilayer PVA/gelatin nanofibrous scaffolds incorporated with Tanacetum polycephalum essential oil and amoxicillin for skin tissue engineering application

Wound infection is still an important challenge in healing of different types of skin injuries. This highlights the need for new and improved antibacterial agents with novel and different mechanisms of action. In this study, by electrospinning process Tanacetum polycephalum essential oil (EO), as a natural antibacterial and anti-inflammatory agent, along with Amoxicillin (AMX) as an antibiotic are incorporated into PVA/gelatin-based nanofiber mats individually and in combination to fabricate a novel wound dressing. Briefly, we fabricated PVA/gelatin loaded by Amoxicillin as first layer for direct contact with wound surface to protects the wound from exogenous bacteria, and then built a PVA/gelatin/Tanacetum polycephalum essential oil layer on the first layer to help cleanses the wound from infection and accelerates wound closure. Finally, PVA/gelatin layer as third layer fabricated on middle layer to guarantee desirable mechanical properties. For each layer, the electrospinning parameters were adjusted to form bead-free fibers. The morphology of fabricated nanofiber scaffolds was characterized by Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM). Microscopic images demonstrated the smooth bead-free microstructures fabrication of every layer of nanofiber with a uniform fiber size of 126.888 to 136.833 nm. While, EO and AMX increased the diameter of nanofibers but there was no change in physical structure of nanofiber. The water contact angle test demonstrated hydrophilicity of nanofibers with 47.35°. Although EO and AMX had little effect on reducing hydrophilicity but nanofibers with contact angle between 51.4° until 65.4° are still hydrophilic. Multilayer nanofibers loaded by EO and AMX killed 99.99 % of both gram-negative and gram-positive bacteria in comparison with control and PVA/gelatin nanofiber. Also, in addition to confirming the non-toxicity of nanofibers, MTT results also showed the acceleration of cell proliferation. In vivo wound evaluation in mouse models showed that designed nanofibrous scaffolds could be an appropriate option for wound treatment due to their positive effect on angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound closure.

Revolution of nanotechnology in food packaging: Harnessing electrospun zein nanofibers for improved preservation - A review

Zein, a protein-based biopolymer derived from corn, has garnered attention as a promising and eco-friendly choice for packaging food due to its favorable physical attributes. The introduction of electrospinning technology has significantly advanced the production of zein-based nanomaterials. This cutting-edge technique enables the creation of nanofibers with customizable structures, offering high surface area and adjustable mechanical and thermal attributes. Moreover, the electrospinning process allows for integrating various additives, such as antioxidants, antimicrobial agents, and flavoring compounds, into the zein nanofibers, enhancing their functionalities for food preservation. In this comprehensive review, the various electrospinning techniques employed for crafting zein-based nanofibers, and we delve into their enhanced properties. Furthermore, the review illuminates the potential applications of zein nanofibers in active and intelligent packaging materials by incorporating diverse constituents. Altogether, this review highlights the considerable prospects of zein-based nanocomposites in the realm of food packaging, offering sustainable and innovative solutions for food industry.

Electrospun plant protein-based nanofibers in food packaging

Electrospinning is a relatively simple technology capable to produce nano- and micron-scale fibers with different properties depending on the electrospinning conditions. This review critically investigates the fabrication of electrospun plant protein nanofibers (EPPNFs) that can be used in food and food packaging applications. Recent progress in the development and optimization of electrospinning techniques for production of EPPNFs is discussed. Finally, current challenges to the implementation of EPPNFs in food and food packaging applications are highlighted, including potential safety and scalability issues. The production of plant protein nanofibers and microfibers is likely to increase in the future as many industries wish to replace synthetic materials with more sustainable, renewable, and environmentally friendly biopolymers. It is therefore likely that EPPNFs will find increasing applications in various fields including active food packaging and drug delivery.

Cytotoxicity studies and antibacterial modification of poly(ethylene 2,5-furandicarboxylate) nonwoven

Novel poly(ethylene 2,5-furandicarboxylate) PEF nonwovens were produced by solution electrospinning and further modification. To improve the wettability of the hydrophobic nonwovens with water, they were treated with sodium hydroxide. Cytotoxicity tests carried out with human keratinocytes confirmed that the nonwovens did not have a toxic effect on healthy cells. The hydrophilicity of the sodium hydroxide treated nonwoven favored the adherence of the cells and their growth. In turn, the two-step modification of the nonwovens by reactions with (3-mercaptopropyl)methyldimethoxysilane and silver nitrate permitted to deposit silver particles on the fiber surfaces. The bacteria growth inhibition zones around the tested specimens were observed evidencing their antibacterial activity against Escherichia coli and Staphylococcus aureus.

The effect of κ-carrageenan and ursolic acid on the physicochemical properties of the electrospun nanofibrous mat for biomedical application

Wound dressing materials such as nanofiber (NF) mats have gained a lot of attention in recent years owing to their wonderful effect on accelerating the healing process and protection of wounds. In this regard, three different types of NF mats were fabricated using pure polyvinylpyrrolidone (PVP), PVP/κ-carrageenan (KG), and ursolic acid (UA) in the optimal PVP/KG ratio by electrospinning method to apply them as wound dressings. The morphology, chemical structure, degradation, porosity, mechanical properties and antioxidant activity of the produced NFs were investigated. Moreover, cell studies (e.g., cell proliferation, adhesion, and migration) and their antibacterial properties were evaluated. Adding KG and UA reduced the mean diameter size of the PVP-based NFs to ∼98 nm in the optimal sample, with defect-free morphology. The PVP/KG/UA 0.25 % exhibited the highest porosity, hydrophilicity, and degradation rate and a wound closure rate of 60 %, 2.5 times higher than that of the control group. Furthermore, this sample's proliferation and antibacterial ability were significantly higher than the other groups. These findings confirmed that the produced UA-loaded NFs have excellent properties as wound dressing.

Evaluation of therapeutic effects of nanofibrous mat containing mycophenolate mofetil on oral lichen planus: In vitro and clinical trial study

Objectives

Recently, topical drug delivery system has gained increasing interest in the treatment of oral lesions. Lichen planus is a chronic inflammatory disease affecting mucous membranes and skin. The current study aimed to fabricate a drug delivery system containing mycophenolate mofetil for the treatment of oral lichen planus lesions.

Methods

Firstly, a nanofibrous mat containing mycophenolate mofetil, zinc oxide nanoparticles, and aloe vera was designed and fabricated. The antimicrobial, cytocompatibility, anti-inflammatory, and antioxidative characteristics of fabricated scaffolds were evaluated. Then, this nanofibrous mat was applied to 12 patients suffering from bilateral erythematous/erosive Oral Lichen planus (OLP) lesions for 2 weeks. The treatment outcomes, including oral symptoms and lesion size, were compared with the routine topical treatment of these lesions; Triamcinolone ointment.

Results

The characterization of nanofibrous mat approved the successful fabrication of scaffolds. The fabricated nanofibers showed notable antimicrobial activity. The amounts of TNF 𝛼, IL6, and reactive oxygen species (ROS) of stimulated human gingival fibroblasts were decreased after exposure to NFs/Myco/Alv/ZnO scaffolds. The clinical trial results demonstrated the same therapeutic effects compared to the commercial ointment, while the symptoms of patients were significantly improved in the mats group.Significance. Considering the successful results of this study, the application of nanofibrous mat can be a promising product for improving treatment outcomes of OLP.

Label-free electrochemical immunosensor for detection of insulin-like growth factor-1 (IGF-1) using a specific monoclonal receptor on electrospun Zein-based nanofibers/rGO-modified electrode

A novel electrochemical immunosensor was developed for ultrasensitive determination of the hormone insulin-like growth factor 1 (IGF-1) based on immobilization of a specific monoclonal antibody on the electrospun nanofibers of Polyacrylonitrile (PAN)/Zein-reduced graphene oxide (rGO) nanoparticle. The nanofibers deposited on glassy carbon electrode (GCE) showed good electrochemical behaviors with synergistic effects between PAN, Zein, and rGO. PAN/Zein nanofibers were used due to flexibility, high porosity, good mechanical strength, high specific surface area, and flexible structures, while rGO nanoparticles were used to improve the detection sensitivity and anti-IGF-1 immobilizing. Different characterization techniques were applied consisting of FE-SEM, FT-IR, and EDS for the investigation of morphological features and nanofiber size. The redox reactions of [Fe(CN)6]4-/3- on the modified electrode surface were probed for studying the immobilization and determination processes, using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Under optimal conditions, LOD (limit of detection) and LOQ (limit of quantification) were obtained as 55.72 fg/mL and 185.73 fg/mL respectively, and sensitivity was acquired 136.29 μA/cm2.dec. Moreover, a wide linear range was obtained ranging from 1 pg/mL to 10 ng/mL for IGF-1. Furthermore, the proposed method was applied for the analysis of IGF-1 in several human plasma samples with acceptable results, and it also exhibited high selectivity, stability, and reproducibility.

Polysaccharide-based antibacterial coating technologies

To tackle antimicrobial resistance, a global threat identified by the United Nations, is a common cause of healthcare-associated infections (HAI) and is responsible for significant costs on healthcare systems, a substantial amount of research has been devoted to developing polysaccharide-based strategies that prevent bacterial attachment and biofilm formation on surfaces. Polysaccharides are essential building blocks for life and an abundant renewable resource that have attracted much attention due to their intrinsic remarkable biological potential antibacterial activities. If converted into efficient antibacterial coatings that could be applied to a broad range of surfaces and applications, polysaccharide-based coatings could have a significant potential global impact. However, the ultimate success of polysaccharide-based antibacterial materials will be determined by their potential for use in manufacturing processes that are scalable, versatile, and affordable. Therefore, in this review we focus on recent advances in polysaccharide-based antibacterial coatings from the perspective of fabrication methods. We first provide an overview of strategies for designing polysaccharide-based antimicrobial formulations and methods to assess the antibacterial properties of coatings. Recent advances on manufacturing polysaccharide-based coatings using some of the most common polysaccharides and fabrication methods are then detailed, followed by a critical comparative overview of associated challenges and opportunities for future developments. STATEMENT OF SIGNIFICANCE: Our review presents a timely perspective by being the first review in the field to focus on advances on polysaccharide-based antibacterial coatings from the perspective of fabrication methods along with an overview of strategies for designing polysaccharide-based antimicrobial formulations, methods to assess the antibacterial properties of coatings as well as a critical comparative overview of associated challenges and opportunities for future developments. Meanwhile this work is specifically targeted at an audience focused on featuring critical information and guidelines for developing polysaccharide-based coatings. Including such a complementary work in the journal could lead to further developments on polysaccharide antibacterial applications.

Essential oil encapsulation by electrospinning and electrospraying using food proteins: A review

Proteins are excellent polymeric materials for encapsulating essential oils (EOs) by electrospinning and electrospraying to protect these compounds and form nanomaterials with active properties. Proteins can encapsulate bioactive molecules by several mechanisms, including surface activity, absorption and stabilization mechanisms, amphiphilic nature, film-forming capacity, foaming, emulsification, and gelation, due to interactions among their functional groups. However, proteins have some limitations in encapsulating EOs by the electrohydrodynamic process. Their properties can be improved by using auxiliary polymers, increasing their charges by adding ionic salts or polyelectrolytes, denaturing their structure by heat, and exposure to specific pH conditions and ionic strength. This review addresses the main proteins used in electrospinning/electrospraying techniques, production methods, their interactions with EOs, bioactive properties, and applications in food matrices. Multivariate analysis associated with bibliometrics of metadata extracted from studies in Web of Science using the keywords electrospinning and essential oil (EO) were used as the search strategy.

A propitious role of marine sourced polysaccharides: Drug delivery and biomedical applications

Numerous compounds, with extensive applications in biomedical and biotechnological fields, are present in the oceans, which serve as a prime renewable source of natural substances, further promoting the development of novel medical systems and devices. Polysaccharides are present in the marine ecosystem in abundance, promoting minimal extraction costs, in addition to their solubility in extraction media, and an aqueous solvent, along with their interactions with biological compounds. Certain algae-derived polysaccharides include fucoidan, alginate, and carrageenan, while animal-derived polysaccharides comprise hyaluronan, chitosan and many others. Furthermore, these compounds can be modified to facilitate their processing into multiple shapes and sizes, as well as exhibit response dependence to external conditions like temperature and pH. All these properties have promoted the use of these biomaterials as raw materials for the development of drug delivery carrier systems (hydrogels, particles, capsules). The present review enlightens marine polysaccharides providing its sources, structures, biological properties, and its biomedical applications. In addition to this, their role as nanomaterials is also portrayed by the authors, along with the methods employed to develop them and associated biological and physicochemical properties designed to develop suitable drug delivery systems.

Encapsulation of Rosemary Extracts using High Voltage Electrical Discharge in Calcium Alginate/Zein/Hydroxypropyl Methylcellulose Microparticles

The increased demand for functional food with added health benefits is directing industrial procedures toward more sustainable production of naturally added bioactive compounds. The objective of this research was to investigate the potential of bioactive compounds from rosemary extract obtained using high-voltage electrical discharge as a green extraction method, for microencapsulation as a protective method for future application in functional food. Four types of microparticles were made via the ionic gelation method using alginate (Alg), zein (Z), and hydroxypropyl methylcellulose (HPMC) biopolymers and were analyzed considering the physicochemical properties. The diameter of dry microparticles ranged from 651.29 to 1087.37 μm. The shape and morphology analysis of microparticles showed that the obtained microparticles were quite spherical with a granular surface. The high encapsulation efficiency was obtained with a loading capacity of polyphenols up to 11.31 ± 1.47 mg GAE/g (Alg/Z microparticles). The microencapsulation method showed protective effects for rosemary polyphenols against pH changes during digestion. Specifically, the addition of both zein and HPMC to calcium-alginate resulted in microparticles with a prolonged release for better availability of polyphenols in the intestine. This research background indicates that the release of rosemary extract is highly dependent on the initial biopolymer composition with high potential for further functional food applications.

PDGF and VEGF-releasing bi-layer wound dressing made of sodium tripolyphosphate crosslinked gelatin-sponge layer and a carrageenan nanofiber layer

The use of dressings is one of the most common methods for wound treatment. Since most single-layer dressings cannot mimic the hierarchical structure of the skin well, multi-layer dressings have been considered. In this study, a bilayer dressing was fabricated using a gelatin sponge layer cross-linked with sodium tripolyphosphate (Gel-STPP) and a layer of carrageenan nanofibers containing platelet-rich fibrin (Carr-PRF). Chemical interactions between the two layers were characterized by FTIR, and the microstructure was visualized by SEM. It was found that the presence of Carr-PRF nanofiber layer increased tensile strength by 12.96 % (from 0.216 ± 0.015 to 0.268 ± 0.036 MPa) and elastic modulus by 56.70 % (from 0.388 ± 0.072 to 0.608 ± 0.029 MPa) compared to Gel-STPP sponge. Gel-STPP/Carr-PRF wound dressing had a 45.76 ± 4.18 % degradability after 7 days of immersion in phosphate buffered saline (PBS). PRF-containing bilayer wound dressing was able to sustainably release growth factors over 7 days. The Carr-PRF nanofiber layer coated on Gel-STPP sponge was an ideal environment for adhesion and proliferation of L929 cells. Gel-STPP/Carr-PRF bilayer dressing outperformed the other tested samples in terms of angiogenic potential. Average wound closure was 94.21 ± 2.06 % in Gel-STPP/Carr-PRF dressing treated rats after 14 days, and based on the histopathological and immunohistochemical examinations, the Gel-STPP/Carr-PRF dressing group augmented full-thickness wound healing, keratin layer and skin appendages formation after 14 days.

Recent Developments and Formulations for Hydrophobic Modification of Carrageenan Bionanocomposites

Versatility of the anionic algal polysaccharide carrageenan has long been discussed and explored, especially for their affinity towards water molecules. While this feature is advantageous in certain applications such as water remediation, wound healing, etc., the usefulness of this biopolymer is extremely limited when it comes to applications such as food packaging. Scientists around the globe are carrying out research works on venturing diverse methods to integrate a hydrophobic nature into these polysaccharides without compromising their other functionalities. Considering these foregoing studies, this review was designed to have an in-depth understanding of diverse methods and techniques adopted for tuning the hydrophobic nature of carrageenan-based bionanocomposites, both via surface alterations or by changes made to their chemical structure and attached functional groups. This review article mainly focused on how the hydrophobicity of carrageenan bionanocomposites varied as a function of the type and refinement of carrageenan, and with the incorporation of additives including plasticisers, nanofillers, bioactive agents, etc. Incorporation of nanofillers such as polysaccharide-based nanoparticles, nanoclays, bioceramic and mineral based nanoparticles, carbon dots and nanotubes, metal oxide nanoparticles, etc., along with their synergistic effects in hybrid bionanocomposites are also dealt with in this comprehensive review article.

Investigating functional properties of halloysite nanotubes and propolis used in reinforced composite film based on soy protein/basil seed gum for food packaging application

This study aimed to investigate the effect of halloysite nanotubes (HNTs) on the physicochemical characteristics of the soy protein isolated/basil seed gum (SPI/BSG) film activated with propolis (PP). The obtained results of scanning electron microscope (SEM), thermal gravimetric analysis (TGA), and tensile investigations illustrated that the addition of HNTs as nanofiller led to positive changes in the morphology, thermal stability, and mechanical characteristics of SPI/BSG films. The barrier properties of films considerably decreased with incorporation of HNTs. Furthermore, the encapsulation of PP as bioactive agent into the produced films significantly increased (P < 0.05) the antioxidant potential of the samples in DPPH radical-scavenging activity assays. The antibacterial effects of film also significantly increased (P < 0.05) after the encapsulation of PP. In conclusion, the produced films illustrated acceptable efficiency for usage in food packaging system.

Obtaining poly (lactic acid) nanofibers encapsulated with peppermint essential oil as potential packaging via solution-blow-spinning

The development of active packaging based on biodegradable material and incorporating active compounds, such as essential oil, is a new technique to ensure food safety without harming the environment. In this study, nanofiber mats of poly (lactic acid)/ polyethylene glycol (PLA/PEG) blend incorporated with peppermint essential oil (PO) at different ratios (5-20 % v/w) were produced by solution-blow-spinning (SBS) for potential packaging application. Electron microscopy showed a cylindrical and interlaced morphology for PLA/PEG/PO and a significant increase in the diameter (139-192 nm) of the nanofibers by increasing PO content. All nanofibers showed high thermal stability (278-345 °C) suitable for use in the food industry. Nuclear magnetic resonance (¹³C NMR) spectrum confirmed PO in the nanofibers after SBS. ATR-FTIR spectral analysis supported the chemical composition of the nanofiber mats. PO addition led to obtaining hydrophobic nanofibers, enhancing the contact angle to 122° and decreasing water vapor permeability (60 % reduction compared to the PLA/PEG (3.0 g.mm.kPa^-1.h^-1.m^-2). Although the PLA/PEG/20%PO nanofibers did not show halo formation in 24 h, they effectively extended the strawberries' shelf-life at 25 °C, evidencing PO release over time. It also reduced weight loss (2.5 % and 0.3 % weight loss after 5 days for PLA/PEG and PLA/PEG/20%PO, respectively) and increased firmness (8-12 N) for strawberries packed with the nanofiber mats. It is suggested that PLA/PEG films incorporating PO may be used as an active, environmentally friendly packaging material.

Reflections on food security and smart packaging

Estimating the number of COVID-19 cases in 2020 exacerbated the food contamination and food supply issues. These problems make consumers more concerned about food and the need to access accurate information on food quality. One of the main methods for preserving the quality of food commodities for export, storage, and finished products is food packaging itself. In the food industry, food packaging has a significant role in the food supply which acts as a barrier against unwanted substances and preserves the quality of the food. Meanwhile, packaging waste can also harm the environment; namely, it can become waste in waterways or become garbage that accumulates because it is nonrenewable and nonbiodegradable. The problem of contaminated food caused by product packaging is also severe. Therefore, to overcome these challenges of safety, environmental impact, and sustainability, the role of food packaging becomes very important and urgent. In this review, the authors will discuss in more detail about new technologies applied in the food industry related to packaging issues to advance the utilization of Smart Packaging and Active Packaging.

Polyurethane and cellulose acetate micro-nanofibers containing rosemary essential oil, and decorated with silver nanoparticles for wound healing application

In this study, polyurethane (PU) and cellulose acetate (CA) electrospun fibers encapsulating rosemary essential oil (REO) and adsorbed silver (Ag) nanoparticles (NPs) were fabricated. The biologically inspired materials were analyzed for physicochemical characteristics using scanning electron microscopy, X-ray diffractometer, Fourier transform infrared, thermal gravimetric analysis, X-ray photoelectron spectroscopy, water contact angle, and water uptake studies. Results confirmed the presence of CA and Ag NPs on the PU micro-nanofibers increased the hydrophilicity from 107.1 ± 0.36^o to 26.35 ± 1.06^o. The water absorption potential increased from 0.07 ± 0.04 for pristine PU fibers to 12.43 ± 0.49 % for fibers with 7 wt% of CA, REO, and Ag NPs. The diffractometer confirmed the 2θ of 38.01°, 44.13^o, and 64.33^o, corresponding to the diffraction planes of Ag on the fibers. The X-ray photoelectron spectroscopy confirmed microfibers interfacial chemical interaction and surface changes due to CA, REO, and Ag presence. The inhibition tests on Staphylococcus aureus and Escherichia coli indicated that composites are antibacterial in activity. Moreover, synergistic interactions of REO and Ag NPs resulted in superior antibacterial activity. The cell viability and attachment assay showed improved hydrophilicity of the fibers, which resulted in better attachment of cells to the micro-nanofibers, similar to the natural extracellular matrix in the human body.

Recent advances in electrospun protein fibers/nanofibers for the food and biomedical applications

Electrospinning (ES) is one of the most investigated processes for the convenient, adaptive, and scalable manufacturing of nano/micro/macro-fibers. With this technique, virgin and composite fibers may be made in different designs using a wide range of polymers (both natural and synthetic). Electrospun protein fibers (EPF) shave desirable capabilities such as biocompatibility, low toxicity, degradability, and solvolysis. However, issues with the proteins' processibility have limited their widespread utilization. This paper gives an overview of the features of protein-based biomaterials, which are already being employed and has the potential to be exploited for ES. State-of-the-art examples showcasing the usefulness of EPFs in the food and biomedical industries, including tissue engineering, wound dressings, and drug delivery, provided in the applications. The EPFs' future perspective and the challenge they pose are presented at the end. It is believed that protein and biopolymeric nanofibers will soon be manufactured on an industrial scale owing to the limitations of employing synthetic materials, as well as enormous potential of nanofibers in other fields, such as active food packaging, regenerative medicine, drug delivery, cosmetic, and filtration.

Characterization of electrospun nanofibers and solvent-casted films based on Centaurea arvensis anthocyanin-loaded PVA/κ-carrageenan and comparing their performance as colorimetric pH indicator

In this research, PVA/Ҡ-carrageenan-based colorimetric indicators incorporated with Centaurea arvensis anthocyanin (CAE) were fabricated by two electrospinning and solvent casting methods and their performance as pH indicators were assessed. Chemical immobilization of CAE on PVA and PVA/Ҡ-carrageenan matrixes was approved by FT-IR analysis. According to SEM images, Ҡ-carrageenanaddition improved the homogeneity of films and decreased the diameter of nanofibers. The crystalline structure and thermal properties of polymeric matrixes were affected by anthocyanin incorporation. CAE had an adverse effect on mechanical properties of films and nanofibers. The preparation method and type of solid matrix affected the responsiveness and the tonality of responded color. Electrospun nanofibers showed high responsiveness (10 s) than colorimetric films (15-40 min) to pH changes. The indicators displayed color variations from heather violet to green over the 2-12 pH range. The designed indicators have potential to be applied as visual pH label in food intelligent packaging.

Recent advances in carrageenan-based films for food packaging applications

In order to solve the increasingly serious environmental problems caused by plastic-based packaging, carrageenan-based films are drawing much attentions in food packaging applications, due to low cost, biodegradability, compatibility, and film-forming property. The purpose of this article is to present a comprehensive review of recent developments in carrageenan-based films, including fabrication strategies, physical and chemical properties and novel food packaging applications. Carrageenan can be extracted from red algae mainly by hydrolysis, ultrasonic-assisted and microwave-assisted extraction, and the combination of multiple extraction methods will be future trends in carrageenan extraction methods. Carrageenan can form homogeneous film-forming solutions and fabricate films mainly by direct coating, solvent casting and electrospinning, and mechanism of film formation was discussed in detail. Due to the inherent limitations of the pure carrageenan film, physical and chemical properties of carrageenan films were enhanced by incorporation with other compounds. Therefore, carrageenan-based films can be widely used for extending the shelf life of food and monitoring the food freshness by inhibiting microbial growth, reducing moisture loss and the respiration, etc. This article will provide useful guidelines for further research on carrageenan-based films.

Preparation of green film with improved physicochemical properties and enhanced antimicrobial activity using ingredients from cassava peel, bamboo leaf and rosemary leaf

Persistent petroleum based plastic polymers are posing a threat to the environment and human health. Hence, preparation of eco-friendly packaging materials from natural sources is innovative idea to replace persistent plastic films. However, biodegradable films from biomass absorb water that can promote bacterial growth and affect lifetime of film as well as the packed products. In this work, new biodegradable film with improved antimicrobial activity, physicochemical property and less water absorbing and holding property is prepared from modified blend of cassava peel starch (CPS), silica nanoparticle (SNP), glycerol plus rosemary essential oil (REO). The mixture (blend) of CPS, SNPs and glycerol in measured amount of distilled water was treated with acetic anhydride to reduce hydrophilic nature of the blend before adding REO. The content of SNPs in the biofilm was optimized by varying the concentration of SNPs (0.2–0.8%; w/w) keeping other factors constant. Based on the characterization results, the physicochemical property of the biofilms was dependent on the content of SNPs and the best result (film) has been found with 0.6% SNPs which was considered as optimum amount for further experiments. The film prepared from modified blend with 0.6% SNP had shown low water absorption, low water vapor transition rate, improved thermal stability, and less biodegradability. Based on the image from profilometer, the modified blend had shown better homogeneity with REO than unmodified blend and the film with REO had shown better antimicrobial activity as compared to the film without REO (control). The antimicrobial activity of the film with REO was also compared with reference (gentamicin) and its activity was comparable and promising. In general, the prepared film had shown improved physicochemical properties and enhanced antimicrobial activity.

Genipin-Crosslinked Gelatin/Chitosan-Based Functional Films Incorporated with Rosemary Essential Oil and Quercetin

Functional food packaging films were prepared using a binary mixture of chitosan and gelatin through crosslinking with genipin and hybridization with rosemary essential oil and quercetin. The mixture of chitosan and gelatin produced the compatible film, and the added fillers also showed good compatibility. The physical properties of the chitosan/gelatin film were not greatly affected by crosslinking with genipin, and the functionality of the composite film was increased by the addition of rosemary essential oil and quercetin. The bioactive additives did not significantly affect the hydrophobicity and water vapor barrier properties of the chitosan/gelatin film but significantly changed the color, while the mechanical and thermal properties were slightly affected. The addition of these functional fillers significantly improved the UV protection, antioxidant, and antibacterial properties of the chitosan/gelatin film. Therefore, the novel chitosan/gelatin film with genipin crosslinking and the integration of rosemary essential oil and quercetin is considered to have high potential for applications in active food packaging.

Environmentally friendly fabrication of electrospun nanofibers made of polycaprolactone, chitosan and κ-carrageenan (PCL/CS/κ-C)

Electrospun fibers based on biodegradable polyanionic or polycationic biopolymers are highly beneficial for biomedical applications. In this work, electrospun nanofibers made from poly(epsilon caprolactone) (PCL), chitosan (CS) and κ-carrageenan (κ-C) were successfully fabricated using several mixtures of benign solvents containing formic acid (FA) and acetic acid (AA). The addition of κ-carrageenan improved the preparation procedure for the production of PCL/CS fibers by electrospinning. Moreover, a polymer mixture was selected to be stored at -20 °C for one month with the purpose to study the properties of the resulting fiber mat. The results indicated that fiber characteristics were not seriously compromised compared to the ones of those fabricated with the original solution, which represents an important reduction in produced waste. Thus, the interactions that occur between positively and negatively charged hydrophilic polysaccharides might induce higher stability to the linear aliphatic polyester in the polymer mixture. All fiber mats were morphologically, physico-chemically and mechanically characterized, showing average fiber diameters in the nano scale. A direct cell viability assay using ST-2 cells demonstrated cell proliferation after 7 days of incubation for all prepared fiber mats, confirming their suitability as potential candidates for bone tissue engineering and wound healing applications.

Investigation of Mechanical, Chemical, and Antibacterial Properties of Electrospun Cellulose-Based Scaffolds Containing Orange Essential Oil and Silver Nanoparticles

This study demonstrated a controllable release properties and synergistic antibacterial actions between orange essential oil (OEO) and silver nanoparticles (AgNPs) incorporated onto cellulose (CL) nanofibers. The preparation of AgNPs attached on CL nanofibers was conducted through multiple processes including the deacetylation process to transform cellulose acetate (CA) nanofibers to CL nanofibers, the in situ synthesis of AgNPs, and the coating of as-prepared silver composite CL nanofibers using OEO solutions with two different concentrations. The success of immobilization of AgNPs onto the surface of CL nanofibers and the incorporation of OEO into the polymer matrix was confirmed by SEM-EDS, TEM, XRD, and FT-IR characterizations. The tensile strength, elongation at break, and Young’s modulus of the nanofibers after each step of treatment were recorded and compared to pristine CA nanofibers. The high antibacterial activities of AgNPs and OEO were assessed against Gram-positive B. subtilis and Gram-negative E. coli microorganisms. The combined effects of two antimicrobials, AgNPs and OEO, were distinctively recognized against E. coli.

Electrospun ethyl cellulose/poly caprolactone/gelatin nanofibers: The investigation of mechanical, antioxidant, and antifungal properties for food packaging

The purpose of the present research was to fabricate ethylcellulose (ECL)/polycaprolactone (PCL)/gelatin (GEL) electrospun nanofibers containing Zataria multiflora essential oil (ZEO) and zinc oxide nanoparticle (ZnO) to provide an appropriate substrate for food packaging. The ECL/PCL/GEL was incorporated with ZEO and ZnO at the concentrations of 10, 20, 30 and 50 wt% and 3 wt%, respectively. The results of ECL/PCL/GEL/ZEO/ZnO nanofiber exhibited uniform morphology with a mean diameter ranging from 361.85 ± 18.7 to 467.33 ± 14.50 nm and enhanced thermal stability. The ECL/PCL/GEL/ZEO/ZnO nanofiber had the highest mechanical parameters, such as young's modulus (437.49 ± 18), tensile strength (7.88 ± 0.7), and elongation at break (5.02 ± 0.6) and water contact angle (61.13 ± 0.5), compared with the other nanofibers. The cell viability during 48 and 72 h was obtained to be about more than 80% for all the nanofibers. Additionally, the ECL/PCL/GEL incorporated with 50% ZEO and 3% ZnO displayed the highest antioxidant activity (34.61 ± 1.98%) and antifungal properties against Penicillium notatum and Aspergillus niger. In general, the ECL/PCL/GEL with the weight ratio of 20:70:10 nanofiber incorporated with 30% ZEO and 3% ZnO was obtained to have appropriate mechanical, antioxidant, and antimicrobial properties and thermal stability.

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.