Micro- and nanoparticles by electrospray: advances and applications in foods

Microneedle arrays coated with Middle East respiratory syndrome coronavirus DNA vaccine via electrospray deposition

Microneedle arrays have been shown to be a minimally invasive method of transdermal drug delivery. However, methods to coat these arrays often require a reservoir of the active ingredient, leading to unused and wasted material. Electrospray deposition is a targeted coating method that offers a competitive alternative for coating microneedles. By architecting the charge landscape of the setup, this technology can achieve coating deposition efficiencies nearing 100%, with little to no material wasted during the coating process. A Middle East respiratory syndrome coronavirus DNA vaccine was used as the model material to assess deposition efficiency as well as the efficacy of fragile biological materials subjected to electrospray deposition. Trehalose and polystyrene-block-polyacrylic acid were used as excipients to encourage coating dispersion. These coatings were inserted into Sprague Dawley rats where the antigen was subsequently detected and located using immunohistochemistry. Both coatings, with and without excipients, showed that protein expression is achieved after the vaccine is subjected to electrospray, however, the presence of excipients qualitatively leads to a more disperse diffusion profile. Further, this work demonstrates the capability of electrospray deposition as a highly efficient method to coat microneedles for transdermal drug delivery.

The novel nano-electrospray delivery of curcumin via ultrasound assisted Balangu (Lallemantia royleana) hydrocolloid-chickpea protein interaction

This research examines the development of complexes between chickpea protein isolate and Balangu seed gum using ultrasound (200 W, 350 W, 500 W, 650 W, and 800 W) to curcumin delivery by electrospray. Higher ultrasound powers (650 W and 800 W) enhanced the formation of complexes, as confirmed by FTIR and XRD. Complexes treated at 650 W demonstrated optimal solution properties for electrospraying, featuring the lowest surface tension of 31.79 mN/m and the highest zeta potential an electrical conductivity of -68.46 mV, and 1896 μS/cm, respectively. The electrospray effectively produced nanoparticles from the 650 W-treated complex solution, achieving a high curcumin encapsulation efficiency (93.67 ± 1.22 %). Loading curcumin into the complex solution altered the nanoparticles' morphology, resulting in more uniform particles. In the small intestine simulation, the hydrolysis of complex particles led to a significant curcumin release of 100 % within 480 min. The best-fitting model for curcumin release from complexes was the Peppas-Sahlin.

Chitosan and Its Nanoparticles: A Multifaceted Approach to Antibacterial Applications

Chitosan, a multifaceted amino polysaccharide biopolymer derived from chitin, has extensive antibacterial efficacy against diverse pathogenic microorganisms, including both Gram-negative and Gram-positive bacteria, in addition to fungi. Over the course of the last several decades, chitosan nanoparticles (NPs), which are polymeric and bio-based, have garnered a great deal of interest as efficient antibacterial agents. This is mostly due to the fact that they are used in a wide variety of applications, including medical treatments, food, chemicals, and agricultural products. Within the context of the antibacterial mechanism of chitosan and chitosan NPs, we present a review that provides an overview of the synthesis methods, including novel procedures, and compiles the applications that have been developed in the field of biomedicine. These applications include wound healing, drug delivery, dental treatment, water purification, agriculture, and food preservation. In addition to this, we focus on the mechanisms of action and the factors that determine the antibacterial activity of chitosan and its derivatives. In conjunction with this line of inquiry, researchers are strongly urged to concentrate their efforts on developing novel and ground-breaking applications of chitosan NPs.

Evaluation of Antioxidant and Antibacterial Activity of Gelatin Nanoparticles with Bitter Orange Peel Extract for Food Applications

Bitter orange is a citrus fruit rich in bioactive compounds, but its waste is currently underutilized. One potential solution is to encapsulate these bioactive compounds. This research aims to synthesize gelatin nanoparticles loaded with an ethanolic extract of bitter orange peel and to evaluate their in vitro antioxidant and antibacterial activities. Coaxial electrospray was used to encapsulate the ethanolic extract of bitter orange with bovine gelatin as wall material, considering a voltage of 15 kV, a wall solution flow rate of 0.1 mL/h, and a core solution flow rate of 0.08 mL/h. Characterization of the nanoparticles was performed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Antioxidant activity was evaluated by the total phenolic content, flavonoids, and antioxidant capacity by the DPPH•, ABTS•+, and FRAP assays. Antibacterial activity was assessed by the well diffusion technique on Mueller-Hinton agar against Listeria monocytogenes and Escherichia coli O157:H7 bacteria. SEM images confirmed that the nanoparticles were spherical in shape, while FT-IR analysis indicated that the incorporation of the extract did not alter the amide bonds of the gelatin protein. The nanoparticles containing the extract exhibited higher antioxidant activity and heightened inhibition against E. coli O157:H7, indicating their potential food applications.

Protective fibrous structures based on cellulose fibers functionalized with metal oxide nanoparticles by electrospinning and electrospray deposition

This work aims to develop a bio-based fibrous material that is able to adsorb and degrade chemical and biological hazardous agents. Thus, cellulosic fabrics (flax) were functionalized with chitosan (CS) and poly(ethylene oxide) (PEO) electrospun nanofibers doped with titanium dioxide (TiO2) and cerium dioxide (CeO2) nanoparticles (NPs). The electrospray deposition of these NPs was also tested. The TiO2 NPs were synthesized using a very straightforward precipitation method. The successful synthesis was confirmed by Scanning Transmission Electron Microscopy (STEM) and Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FTIR). The functionalization of the fabrics with the NPs and the nanofibers doped with NPs was proved by Field Emission Scanning Electron Microscopy (FESEM), ATR-FTIR, and Ground-State Diffuse Reflectance (GSDR). The developed samples presented antibacterial activity against Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 434), reaching values of 99.97 and 100.0 %, respectively. The degradation of methylene blue (MB) and dimethyl methylphosphonate (DMMP) was evaluated. The best samples were able to decompose 97.82 % of DMMP. The wash durability of the nanocoating was also tested. The developed fibrous structures show great potential for personal protection applications.

Oxidative Stability of Fish Oil-Loaded Nanocapsules Produced by Electrospraying Using Kafirin or Zein Proteins as Wall Materials

The encapsulation of fish oil by monoaxial electrospraying using kafirin or zein proteins as hydrophobic wall materials was investigated. Kafirin resulted in spherical fish oil-loaded nanocapsules (>50% of capsules below 1 µm), whereas zein led to fish oil-loaded nanocapsules with non-spherical morphology (>80% of capsules below 1 µm). Both hydrophobic encapsulating materials interacted with fish oil, successfully entrapping the oil within the protein matrix as indicated by Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy results. FTIR also suggested hydrogen bonding between fish oil and the proteins. Trapped radicals in the encapsulation matrix that were detected by electron paramagnetic resonance (EPR), indicated oxidation during electrospraying and storage. Results from isothermal (140 °C) differential scanning calorimetry (DSC) denoted that the encapsulation of fish oil by electrospraying using both kafirin or zein as wall materials protected fish oil from oxidation. In particular, the zein-based nanocapsules were 3.3 times more oxidatively stable than the kafirin-based nanocapsules, which correlates with the higher oil encapsulation efficiency found for zein-based capsules. Thus, this study shows that kafirin might be considered a hydrophobic wall material for the encapsulation of fish oil by electrospraying, although it prevented lipid oxidation to a lower extent when compared to zein.

Alginate-gelatine hydrogel microspheres protect NK cell proliferation and cytotoxicity under hypoxic conditions

AIMS

This study aimed to encapsulate natural killer (NK) cells in a hydrogel to sustain their function within the hypoxic tumour microenvironments.

METHODS

An alginate-gelatine hydrogel was generated via electrospray technology. Hydrogel biocompatibility was assessed through cell counting kit-8 and Live/Dead assays to ascertain cell. Moreover, we analysed lactate dehydrogenase assays to evaluate the cytotoxicity against tumours and utilised RT-qPCR to analyse cytokine gene level.

RESULTS

Alginate and gelatine formed hydrogels with diameters ranging from 489.2 ± 23.0 μm, and the encapsulation efficiency was 34.07 ± 1.76%. Encapsulated NK cells exhibited robust proliferation and tumour-killing capabilities under normoxia and hypoxia. Furthermore, encapsulation provided a protective shield against cell viability under hypoxia. Importantly, tumour-killing cytotoxicity through cytokines upregulation such as granzyme B and interferon-gamma was preserved under hypoxia.

CONCLUSION

The encapsulation of NK cells not only safeguards their viability but also reinforces anticancer capacity, countering the inhibition of activation induced by hypoxia.

Encapsulation of Cadmium-Free InP-based Quantum Dots in Cross-Linked Core-Shell Microparticles via Coaxial Electrospraying

Quantum dots (QDs) are inorganic semiconductor nanocrystals capable of emitting light. The current major challenge lies in the use of heavy metals, which are known to be highly toxic to humans and pose significant environmental risks. Researchers have turned to indium (In) as a promising option for more environmentally benign QDs, specifically indium phosphide (InP). A significant obstacle remains in sustaining the long-term photostability of InP-based QDs when exposed to the environment. To tackle this, electrospraying is used in this work to protect indium phosphide/zinc selenide/zinc sulfide (InP/ZnSe/ZnS) QDs by embedding them within polymer core-shell microparticles of poly[(lauryl methacrylate)-co-(ethylene glycol dimethacrylate)]/poly(methyl methacrylate) (poly(LMA-co-EGDMA)/PMMA). During the flight of droplets, the liquid monomer core of LMA and EGDMA with QDs is encapsulated by the solid shell of PMMA formed due to solvent evaporation, resulting in a liquid-core/solid-shell particle structure. After that, the captured core of monomers is polymerized into a cross-linked polymer with the embedded QDs via a thermal initiation. They demonstrate how a successful core-shell particle formation is achieved to produce structures for initially liquid monomer systems via coaxial electrospraying that are used for cross-linked polymers, which are of major interest for the encapsulation of InP-based QDs for generally improved photostability over pristine QDs.

Current research status and development prospects of embolic microspheres containing biological macromolecules and others

Transcatheter arterial embolization (TACE) has been used in the treatment of malignant tumors, sudden hemorrhage, uterine fibroids, and other diseases, and with advances in imaging techniques and devices, materials science, and drug release technology, more and more embolic agents that are drug-carrying, self-imaging, or have multiple functions are being developed. Microspheres provide safer and more effective therapeutic results as embolic agents, with their unique spherical appearance and good embolic properties. Embolic microspheres are the key to arterial embolization, blocking blood flow and nutrient supply to the tumor target. This review summarizes some of the currently published embolic microspheres, classifies embolic microspheres according to matrix, and summarizes the characteristics of the microsphere materials, the current status of research, directions, and the value of existing and potential applications. It provides a direction to promote the development of embolic microspheres towards multifunctionalization, and provides a reference to promote the research and application of embolic microspheres in the treatment of tumors.

An Emerging Trend in the Synthesis of Iron Titanate Photocatalyst Toward Water Splitting

Hydrogen gas is a prominent focus in pursuing renewable and clean alternative energy sources. The quest for maximizing hydrogen production yield involves the exploration of an ideal photocatalyst and the development of a simple, cost-effective technique for its generation. Iron titanate has garnered attention in this context due to its photocatalytic properties, affordability, and non-toxic nature. Over the years, different synthesis routes, different morphologies, and some modifications of iron titanate have been carried out to improve its photocatalytic performance by enhancing light absorption in the visible region, boosting charge carrier transfer, and decreasing recombination of electrons and holes. The use of iron titanate photocatalyst for hydrogen evolution reaction has seen an upward trend in recent times, and based on available findings, more can be done to improve the performance. This review paper provides a comprehensive overview of the fundamental principles of photocatalysis for hydrogen generation, encompassing the synthesis, morphology, and application of iron titanate-based photocatalysts. The discussion delves into the limitations of current methodologies and present and future perspectives for advancing iron titanate photocatalysts. By addressing these limitations and contemplating future directions, the aim is to enhance the properties of materials fabricated for photocatalytic water splitting.

bFGF-releasing biodegradable nanoparticles for effectively engrafting transplanted hepatocyte sheet

Hepatic tissue engineering has been applied for the treatment of intractable liver diseases, and hepatocyte sheets are promising for this purpose. However, hepatocyte sheets have poor survival after transplantation because of their high metabolic activity. In this study, we aimed to develop basic fibroblast growth factor (bFGF)-releasing nanoparticles to prolong the survival of hepatocyte sheets after transplantation. The nanoparticles were prepared by electrospraying a bFGF-dispersed poly(D,l-lactide-co-glycolide) emulsion. bFGF-loaded PLGA nanoparticles can be developed by optimizing the applied electrospray voltage and the oil:water ratio of the emulsion. The prepared nanoparticles exhibited prompt release at the initial duration and continuous gradual release at the subsequent duration. Hepatocyte sheet engraftment was evaluated by transplanting hepatocyte sheets containing the prepared nanoparticles into rats. The hepatocyte sheets with the prepared nanoparticles exhibited longer survival than those without the bFGF nanoparticles or solution owing to the local and continuous release of bFGF from the nanoparticles and the subsequent enhanced angiogenesis at the transplantation site. These results indicated that the prepared bFGF-releasing nanoparticles can enhance the efficiency of hepatocyte sheet transplantation. The developed bFGF-releasing nanoparticles would be useful for the transplantation of cellular tissue with post-transplantation survival challenges.

Experimental Investigation of Electrospraying Properties Based on Ring Electrode Modification

Electrospraying uses a high-voltage potential difference to create fine droplets. This study conducts a comparative analysis of the spray pattern and droplet properties using ring electrode parameters. The spray pattern and droplet characteristics are analyzed based on the experimental parameters of the ring electrode. The results show that the cone-jet mode forms quickly for the ring electrode. In addition, as the ring diameter decreases, the ring voltage increases and an increase in the distance between the ring and the nozzle in the bottom direction decreases the Sauter mean diameter and its standard deviation. The optimal conditions for the formation of fine and uniform droplets include a ring diameter of 15 mm, a ring voltage of 7 kV, and a nozzle-to-ring distance of (+) 20 mm.

Hydrogel Microparticles for Bone Regeneration

Hydrogel microparticles (HMPs) stand out as promising entities in the realm of bone tissue regeneration, primarily due to their versatile capabilities in delivering cells and bioactive molecules/drugs. Their significance is underscored by distinct attributes such as injectability, biodegradability, high porosity, and mechanical tunability. These characteristics play a pivotal role in fostering vasculature formation, facilitating mineral deposition, and contributing to the overall regeneration of bone tissue. Fabricated through diverse techniques (batch emulsion, microfluidics, lithography, and electrohydrodynamic spraying), HMPs exhibit multifunctionality, serving as vehicles for drug and cell delivery, providing structural scaffolding, and functioning as bioinks for advanced 3D-printing applications. Distinguishing themselves from other scaffolds like bulk hydrogels, cryogels, foams, meshes, and fibers, HMPs provide a higher surface-area-to-volume ratio, promoting improved interactions with the surrounding tissues and facilitating the efficient delivery of cells and bioactive molecules. Notably, their minimally invasive injectability and modular properties, offering various designs and configurations, contribute to their attractiveness for biomedical applications. This comprehensive review aims to delve into the progressive advancements in HMPs, specifically for bone regeneration. The exploration encompasses synthesis and functionalization techniques, providing an understanding of their diverse applications, as documented in the existing literature. The overarching goal is to shed light on the advantages and potential of HMPs within the field of engineering bone tissue.

Electrospinning Microencapsulation of Lactobacillus fermentum K73 Using Gelatin as the Main Component of a Food-Grade Matrix

This work aimed to establish the conditions that improve the viability of Lactobacillus fermentum K73 during and after the electrospinning process. A mixture of experimental designs were performed to select the formulation (gelatin and bacterial culture) that improves the probiotic viability after blending and under simulated gastrointestinal conditions. A Box-Behnken design was performed to improve the encapsulation yield and survival during the electrospinning process. For the Box-Behnken design, the factors were soy lecithin and bacteria culture concentration at the blend and collector distance for electrospinning. It was hypothesized that soy lecithin improved the electrospinnability, acting as a surfactant in the mixture and allowing lower voltage to be used during the process. The selected volume ratio of the gelatin (25%)/bacterial culture mixture was 0.66/0.34. The physicochemical parameters of the selected blend were in the recommended range for electrospinning. The conditions that improved the encapsulation yield and survival during electrospinning were 200 g/L of bacterial culture, 2.5% (w/v) soy lecithin, and 7 cm collector distance. The experimental encapsulation yield and survival was 80.7%, with an experimental error of 7.2%. SEM micrographs showed the formation of fibers with gelatin/bacterial culture beads. Encapsulation improved the viability of the probiotic under simulated gastrointestinal conditions compared to free cells.

AIEgen orthopalladated hybrid polymers for efficient inactivation of the total coliforms in urban wastewater

Monitorable AIE polymers with a bioactive pattern are employed in advanced biomedical applications such as functional coatings, theranostic probes, and implants. After the global COVID-19 pandemic, interest in developing surfaces with superior antimicrobial, antiproliferative, and antiviral activities dramatically increased. Many formulations for biocide surfaces are based on hybrid organic/inorganic materials. Palladium (II) complexes display relevant activity against common bacteria, even higher when compared to their uncoordinated ligands. This article reports the design and synthesis of two series of orthopalladated polymers obtained by grafting a cyclopalladated fragment on two different O, N chelating Schiff base polymers. Different grafting percentages were examined and compared for each organic polymer. The fluorescence emission in the solid state was explored on organic matrixes and grafted polymers. DFT analysis provided a rationale for the role of the coordination core. The antibacterial response of the two series of hybrid polymers was tested against the total coliform group of untreated urban wastewater, revealing excellent inactivation ability.

Application of Physical-Chemical Approaches for Encapsulation of Active Substances in Pharmaceutical and Food Industries

BACKGROUND

Encapsulation is a valuable method used to protect active substances and enhance their physico-chemical properties. It can also be used as protection from unpleasant scents and flavors or adverse environmental conditions.

METHODS

In this comprehensive review, we highlight the methods commonly utilized in the food and pharmaceutical industries, along with recent applications of these methods.

RESULTS

Through an analysis of numerous articles published in the last decade, we summarize the key methods and physico-chemical properties that are frequently considered with encapsulation techniques.

CONCLUSION

Encapsulation has demonstrated effectiveness and versatility in multiple industries, such as food, nutraceutical, and pharmaceuticals. Moreover, the selection of appropriate encapsulation methods is critical for the effective encapsulation of specific active compounds. Therefore, constant efforts are being made to develop novel encapsulation methods and coating materials for better encapsulation efficiency and to improve properties for specific use.

Current Trends in Gelatin-Based Drug Delivery Systems

Gelatin is a highly versatile natural polymer, which is widely used in healthcare-related sectors due to its advantageous properties, such as biocompatibility, biodegradability, low-cost, and the availability of exposed chemical groups. In the biomedical field, gelatin is used also as a biomaterial for the development of drug delivery systems (DDSs) due to its applicability to several synthesis techniques. In this review, after a brief overview of its chemical and physical properties, the focus is placed on the commonly used techniques for the development of gelatin-based micro- or nano-sized DDSs. We highlight the potential of gelatin as a carrier of many types of bioactive compounds and its ability to tune and control select drugs' release kinetics. The desolvation, nanoprecipitation, coacervation, emulsion, electrospray, and spray drying techniques are described from a methodological and mechanistic point of view, with a careful analysis of the effects of the main variable parameters on the DDSs' properties. Lastly, the outcomes of preclinical and clinical studies involving gelatin-based DDSs are thoroughly discussed.

Micro-/bio-/nano-/syn-encapsulations and co-treatments of bioactive microbial feed supplementation in augmenting finfish health and aquaculture nutrition: a review

Finfish and fish products are globally the most acknowledged health-promoting foods. The rising incidence of pathogenic and disease outbreaks have had a sizeable impact on aquaculture. Microbial supplementation of food in the form of probiotics, prebiotics, and their controlled release combinations (=co-encapsulations) as 'synbiotics' is noted for its significant biotherapeutic and health benefits. Supplementation of probiotic microbial feed additives in the fish diet claims to improve fish health by modulation of resident intestinal microbiota and by introducing healthy microbiota procured from an exogenous source, capable of combating pathogens, improving nutrient uptake, assimilation, growth as well as survival. Prebiotics are selectively digestible substrates beneficially used by host gut microbes to enhance probiotic effects. Formulating a fish diet with augmented probiotics and prebiotic microbial bio-supplements can ensure a sustainable alternative for establishing fish health in a naturally susceptible aquaculture scenario. Micro-encapsulation, co-encapsulation, and nano-encapsulation are novel strategies of biotechnical interventions in functional feeds for finfish. These aim to improve probiotic persistence, survivability, and efficacy in commercial formulations during probiotic transit through the host-gut environment. This review discusses the importance of co-treatment and encapsulation strategies for improving probiotic and prebiotic potential in aquafeed formulations, reliably improving finfish health and nutritional returns from aquaculture, and, consequently, for consumers.

Improving mass transfer rates in microbial cell immobilization system for environmental applications: Synergistic interaction of cells on crude oil biodegradation

Among the various techniques used to clean up polluted environments, bioremediation is the most cost-effective and eco-friendly option. The diversity of microbial communities in a consortium can significantly affect the biodegradability of hazardous organic pollutants, particularly for in situ bioremediation processes. This is largely attributed to interactions between members of a consortium. In this study, the effect of internal diffusion limitations in substrate model biodegradation was firstly examined by immobilized bacterial cells at different particle sizes produced by the electrospray technique. According to the obtained results, for particles with large size, the effectiveness factors (η) were about 0.58-0.67, and the resistance to diffusive on the biodegradation rate was significant, while with decreasing the particle size, η increases and approaches about 1. After selection of suitable bead size, heavy crude oil biodegradation was investigated using a consortium consisting of three oil-degrading bacterial strains at different treatment systems. The removal rate in the suspended co-culture system stands at minimum value of 38% with all three strains which is an indicator of negative interactions among consortium members. Independent immobilization of microorganisms minimizes the competition and antagonistic interactions between strains and leads to more crude oil removal, so that, the biodegradation rate reached 60%.

Valorisation of Micro/Nanoencapsulated Bioactive Compounds from Plant Sources for Food Applications Towards Sustainability

The micro- and nanoencapsulation of bioactive compounds has resulted in a large improvement in the food, nutraceutical, pharmaceutical, and agriculture industries. These technologies serve, on one side, to protect, among others, vitamins, minerals, essential fatty acids, polyphenols, flavours, antimicrobials, colorants, and antioxidants, and, on the other hand, to control the release and assure the delivery of the bioactive compounds, targeting them to specific cells, tissues, or organs in the human body by improving their absorption/penetration through the gastrointestinal tract. The food industry has been applying nanotechnology in several ways to improve food texture, flavour, taste, nutrient bioavailability, and shelf life using nanostructures. The use of micro- and nanocapsules in food is an actual trend used mainly in the cereal, bakery, dairy, and beverage industries, as well as packaging and coating. The elaboration of bio capsules with high-value compounds from agro-industrial by-products is sustainable for the natural ecosystem and economically interesting from a circular economy perspective. This critical review presents the principal methodologies for performing micro- and nanoencapsulation, classifies them (top-down and/or bottom-up), and discusses the differences and advantages among them; the principal types of encapsulation systems; the natural plant sources, including agro-industrial by-products, of bioactive compounds with interest for the food industry to be encapsulated; the bioavailability of encapsulates; and the main techniques used to analyse micro- and nanocapsules. Research work on the use of encapsulated bioactive compounds, such as lycopene, hydroxytyrosol, and resveratrol, from agro-industrial by-products must be further reinforced, and it plays an important role, as it presents a high potential for the use of their antioxidant and/or antimicrobial activities in food applications and, therefore, in the food industry. The incorporation of these bioactive compounds in food is a challenge and must be evaluated, not only for their nutritional aspect, but also for the chemical safety of the ingredients. The potential use of these products is an available economical alternative towards a circular economy and, as a consequence, sustainability.

Controlling morphology in electrosprayed methylcellulose nanowires via nanoparticle addition: coarse-grained modeling and experiments

Electrospray deposition (ESD) has shown great promise for manufacturing micro- and nanostructured coatings at scale on versatile substrates with complex geometries. ESD exhibits a broad spectrum of morphologies depending upon the properties of spray fluids. Among them are nanowire forests or foams obtained via the in-air gelation of electrospray droplets formed from methylcellulose (MC) solutions. In this study, we explored MC ESD loaded with nanoparticles of various shapes and uncovered the effects of particle fillers on morphology evolution using coarse-grained simulations and physical experiments. Utilizing electrostatic dissipative particle dynamics, we modeled the electrohydrodynamic deformation of particle-laden MC droplets undergoing in-flight evaporation. The simulations quantitatively predict the suppression of droplet deformation as the size or concentration of spherical nanoparticles increases. While small particles can be readily encapsulated into the nanowire body, large particles can arrest nanowire formation. The model was extended to nanoparticles with complex topologies, showing MC nanowires emerging from particle edges and vertices due to curvature-enhanced electric stress. In all cases, strong agreements were found between simulation and experimental results. These results demonstrate the efficacy of the coarse-grained model in predicting the morphology evolution of electrosprayed droplets and lay the groundwork for employing MC nanowires for developing nanostructured composites.

Superhydrophobic and highly moisture-resistant PVA@EC composite membrane for air purification

Electrospun fiber membranes have great potential in the field of air filtration because of their high porosity and small pore size. Conventional air filtration membranes are hydrophilic, leading to weak moisture-barrier properties, which hinders their application in high-humidity environments. In this study, eugenol was added to polyvinyl alcohol and ethyl cellulose (EC) for electrospinning and electrospraying, respectively, of superhydrophobic bilayer composite fiber membranes to efficiently filter particulate matter (PM) in air. Owing to its surface microstructure, electrosprayed EC increased the water contact angle of the PVA membrane from 142.8 to 151.1°. More importantly, the composite air-filter membrane showed a low filtration pressure drop (168.1 Pa) and exhibited high filtration efficiencies of 99.74 and 99.77% for PM1.0 and PM2.5, respectively, and their respective quality factors were 0.0351 and 0.0358 Pa-1. At the same time, the filtration performance of the air filtration membrane remained above 99% at high air humidity. This work reports composite membranes that can effectively capture PM of various sizes and thus may provide a reference for the manufacturing of green air filters for high-humidity environments.

Osmotic Pressure as Driving Force for Reducing the Size of Nanoparticles in Emulsions

We describe here a method to decrease particle size of nanoparticles synthesized by miniemulsion polymerization. Small nanoparticles or nanocapsules were obtained by generating an osmotic pressure to induce the diffusion of monomer molecules from the dispersed phase of a miniemulsion before polymerization to an upper oil layer. The size reduction is dependent on the difference in concentration of monomer in the dispersed phase and in the upper oil layer and on the solubility of the monomer in water. By labeling the emulsion droplets with a copolymer of stearyl methacrylate and a polymerizable dye, we demonstrated that the migration of the monomer to the upper hexadecane layer relied on molecular diffusion rather than diffusion of monomer droplets to the oil layer. Moreover, surface tension measurements confirmed that the emulsions were still in the miniemulsion regime and not in the microemulsion regime. The particle size can be tuned by controlling the duration during which the miniemulsion stayed in contact with the hexadecane layer, the interfacial area between the miniemulsion and the hexadecane layer and by the concentration of surfactant. Our method was applied to reduce the size of polystyrene and poly(methyl methacrylate) nanoparticles, nanocapsules of a copolymer of styrene and methyl methacrylic acid, and silica nanocapsules. This work demonstrated that a successful reduction of nanoparticle size in the miniemulsion process can be achieved without using excess amounts of surfactant. The method relies on building osmotic pressure in oil droplets dispersed in water which acts as semipermeable membrane.

Electrospraying of Bio-Based Chitosan Microcapsules Using Novel Mixed Cross-Linker: Experimental and Response Surface Methodology Optimization

Chitosan microcapsules draw attention due to their biodegradability, biocompatibility, antibacterial behavior, low cost, easy processing, and the capability to be used for different applications. This study utilized the electrospraying technique for the chitosan microcapsules formulation. As a novel cross-linking agent, a mixture of oxalic acid and sodium phosphate dibasic was utilized as a collecting solution for the first time in the electrospraying of chitosan microcapsules. Scanning Electron Microscopy (SEM) was utilized to optimize the spherical morphology and size of the experimentally obtained microcapsules. The different parameters, including chitosan concentration, applied voltage, flow rate, and tip-to-collector (TTC) distance, affecting the microcapsules' size, sphericity, yield, and combined effects were optimized using Surface Responses Methodology (RSM). The Analysis of Variance (ANOVA) was utilized to obtain the impact of each parameter on the process responses. Accordingly, the results illustrated the significant impact of the voltage parameter, with the highest F-values and least p-values, on the capsule size, sphericity, and yield. The predicted optimum conditions were determined as 5 wt% chitosan concentration, 7 mL/h flow rate, 22 kV, and 8 cm TTC distance. The predicted responses at the optimized conditions are 389 µm, 0.72, and 80.6% for the capsule size, sphericity, and yield, respectively. While the validation of the model prediction was conducted experimentally, the obtained results were 369.2 ± 23.5 µm, 0.75 ± 0.04, and 87.3 ± 11.4%, respectively. The optimization process was successfully examined for the chitosan microcapsules manufacturing.

Microgels based on 0D-3D carbon materials: Synthetic techniques, properties, applications, and challenges

Microgels are three-dimensional (3D) colloidal hydrogel particles with outstanding features such as biocompatibility, good mechanical properties, tunable sizes from submicrometer to tens of nanometers, and large surface areas. Because of these unique qualities, microgels have been widely used in various applications. Carbon-based materials (CMs) with various dimensions (0-3D) have recently been investigated as promising candidates for the design and fabrication of microgels because of their large surface area, excellent conductivity, unique chemical stability, and low cost. Here, we provide a critical review of the specific characteristics of CMs that are being incorporated into microgels, as well as the state-of-the art applications of CM-microgels in pollutant adsorption and photodegradation, H₂ evoluation, CO₂ capture, soil conditioners, water retention, drug delivery, cell encapsulation, and tissue engineering. Advanced preparation techniques for CM-microgel systems are also summarized and discussed. Finally, challenges related to the low colloidal stability of CM-microgels and development strategies are examined. This review shows that CM-microgels have the potential to be widely used in various practical applications.

Peroxide mediated oxygen delivery in cancer therapy

Hypoxia is a serious obstacle in cancer treatment. The aberrant vascular network as well as the abnormal extracellular matrix arrangement results in formation of a hypoxic regions in tumors which show high resistance to the curing. Hypoxia makes the cancer treatment challengeable via two mechanisms; first and foremost, hypoxia changes the cell metabolism and leads the cells towards an aggressive and metastatic phenotype and second, hypoxia decreases the efficiency of the various cancer treatment modalities. Most of the cancer treatment methods including chemotherapy, radiotherapy, photodynamic therapy, sonodynamic therapy and immunotherapy are negatively affected by the oxygen deprivation. Therefore, the regional oxygenation is requisite to alleviate the negative impacts of the hypoxia on tumor cells and tumor therapy modalities. A great deal of effort has been put forth to resolve the problem of hypoxia in tumors. Peroxides have gained tremendous attention as oxygen generating components in cancer therapy. The concurrent loading of the peroxides and cancer treatment components into a single delivery system can bring about a multipurpose delivery system and substantially encourage the success of the cancer amelioration. In this review, we have tried to after the description of a relation between hypoxia and cancer treatment modalities, discuss the role of peroxides in tumor hyperoxygenation and cancer therapy success. Thereafter, we have summarized a number of vehicles for the delivery of the peroxide alone or in combination with other therapeutic components for cancer treatment.

Preparation of Solid Lipid Nanoparticle-Ferrous Sulfate by Double Emulsion Method Based on Fat Rich in Monolaurin and Stearic Acid

Ferrous sulfate is one type of iron that is commonly used in iron supplementation and fortification in food products, but it has low stability and an unfavorable flavor, causing its use to be limited. Encapsulation in a solid lipid nanoparticle (SLN) system is one technology that offers stable active compound protection and a good delivery system; however, a solid lipid matrix should be selected which has good health effects, such as glycerol monolaurate or monolaurin. The purpose of this study was to obtain SLN-ferrous sulfate based on stearic acid and fat rich in monolaurin. SLN-Ferrous sulfate was synthesized at various concentrations of monolaurin-rich fat (20%; 30%; 40% w/w lipid) and various concentrations of ferrous sulfate (5%; 10%; 15% w/w lipid). The results showed that the use of monolaurin-rich fat 40% w/w lipid and 15% w/w ferrous sulfate produced the best characteristics with high entrapment efficiency and loading capacity of 0.06%. The Z-average value of SLN was 292.4 nm with a polydispersity index (PI) of 1.03. SLN-ferrous sulfate showed a spherical morphology, where the Fe trapped in the SLN was evenly dispersed in the lipid matrix to form a nanosphere system. Preparation of SLN-ferrous sulfate by double emulsion method based on stearic acid and fat rich in monolaurin effectively encapsulated ferrous sulfate with high entrapment efficiency and good physicochemical properties.

Recent Trends in the Preparation of Nano-Starch Particles

Starch is affected by several limitations, e.g., retro-gradation, high viscosity even at low concentrations, handling issues, poor freeze-thaw stability, low process tolerance, and gel opacity. In this context, physical, chemical, and enzymatic methods have been investigated for addressing such limitations or adding new attributes. Thus, the creation of biomaterial-based nanoparticles has sparked curiosity. Because of that, single nucleotide polymorphisms are gaining a lot of interest in food packaging technology. This is due to their ability to increase the mechanical and water vapor resistance of the matrix, as well as hide its re-crystallization during storage in high-humidity atmospheres and enhance the mechanical properties of films when binding in paper machines and paper coating. In medicine, single nucleotide polymorphisms (SNPs) are suitable as carriers in the field of drug delivery for immobilized bioactive or therapeutic agents, as well as wastewater treatments as an alternative to expensive activated carbons. Starch nanoparticle preparations can be performed by hydrolysis via acid hydrolysis of the amorphous part of a starch molecule, the use of enzymes such as pullulanase or isoamylase, or a combination of two regeneration and mechanical treatments with the employment of extrusion, irradiation, ultrasound, or precipitation. The possibility of obtaining cheap and easy-to-use methods for starch and starch derivative nanoparticles is of fundamental importance. Nano-precipitation and ultra-sonication are rather simple and reliable methods for nanoparticle production. The process involves the addition of a diluted starch solution into a non-solvent, and ultra-sonication aims to reduce the size by breaking the covalent bonds in polymeric material due to intense shear forces or mechanical effects associated with the collapsing of micro-bubbles by sound waves. The current study focuses on starch nanoparticle manufacturing, characterization, and emerging applications.

Electrospun alginate mats embedding silver nanoparticles with bioactive properties

Polysaccharide-based composites embedding silver nanoparticles (AgNPs) represent a promising alternative to common antimicrobial materials because of the effective, broad-spectrum biocidal properties of AgNPs combined with the biocompatibility and environmental safety of the naturally occurring polymeric component. In this work, AgNPs stabilized with alginate chains (Alg@AgNPs) were successfully synthesized in situ within the polysaccharide solution through a wet chemical approach carried out at different concentrations of the silver salt precursor. Once obtained, the aqueous suspensions were electrospun to prepare non-woven membranes, showing a homogeneous nanostructured texture (with fiber diameter between 100 and 150 nm), which was found to be influenced by the size (between 20 and 35 nm) of the embedded metal nanoparticles. The biocidal potential of the nanocomposite mats was preliminarily tested against Gram-negative E. coli. The results showed that the antimicrobial response of the investigated samples occurred within a day of incubation and can be observed for AgNPs content in the polysaccharide fibers far below the nanomolar regime.

Fabrication of protein nanomaterials as delivery systems

Bioactive compounds in foods, nutraceuticals and pharmaceutical have been gaining interest due to health benefits, which can help to reduce the risk of certain chronic diseases. Recently, nanoencapsulation have attract attention because it is an efficient and promising approach for protection of bioactive compounds, and delivery them to the target physiological sites for controlled release and improvement absorption. Food proteins are promising materials to be fabricated into a variety of nanostructured delivery systems because of their high nutritional value, good functional properties, and health-benefiting effects. Various techniques and approaches are utilized to prepare nanostructured food protein. This chapter introduces the major techniques for the fabrication of nanoparticles and nanoemulsions from food proteins. The basic principles, advantages, and limitations of the techniques are discussed. The encapsulation and release of bioactive compounds in different nanostructured food proteins are illustrated in specific case studies. Due to the fast growing interest of bioactive encapsulation in various sectors, this chapter is of importance for guiding the development of nanostructured food protein loaded with bioactive ingredients for food, nutraceutical and pharmaceutical applications.

Impact of Deacetylation Degree on Properties of Chitosan for Formation of Electrosprayed Nanoparticles

Biopolymer of natural origin as chitosan has been studied and applied widely in practice. In the pharmaceutical field, especially, chitosan nanoparticles have been researched for a variety of drug delivery systems. There are many factors influencing the success of the chitosan nanoparticle delivery system. Therein, the specific parameters to the physicochemical nature of chitosan greatly determine the efficiency of its drugs carrier. The degree of deacetylation (DD) of chitosan is one of those parameters. In this study, the influence of DD on chitosan properties was clarified to facilitate the preparation of nanoparticles by the electrospraying method. DD can affect the solubility, crystallinity, and surface tension of chitosan, but it cannot strongly impact the viscosity of chitosan solution as much as the molecular weight (Mv). From these results, M3 chitosan, owning a high DD of 86.70%, and crystalline index of 44%, was dissolved in acetic acid for the collection of electrosprayed nanoparticles. The M3 solution having low viscosity of under 50 mm2/s displayed the easy adjustment of the stable Taylor-cone droplet at the nozzle tip. Particularly, the M3 chitosan solution with a concentration of 1.5 wt.% in acetic acid of 90 wt.% concentration operated at the working condition of 12 kV voltage, a distance between the two electrodes of 10 cm created spherical particles with an average diameter of 338 nm, narrow size distribution. These chitosan nanoparticles can obtain the initial requirement for application as injectable drugs carrier.

Multifunctional hydrogels based on oxidized pectin and gelatin for wound healing improvement

Gelatin (G) cross-linked with oxidized pectin (OP) was studied as a potential scaffold material for tissue engineering. The effect of oxidation on the chemical properties of pectin was investigated by determining the carbonyl and carboxyl amounts. The OP treatment led to a significant decrease of all values (Mn, Mw, [η] and Rh) determined by size exclusion chromatography (SEC) coupled on line with multiangle light scattering and viscometer detectors. Cross-linking parameters were elucidated by FTIR and TNBS assay. In general, the degree of crosslinking increased with the oxidation of pectin. It was found that the presence of the crosslinking agents caused a reduction in swelling and in the gelatin release which was determined by the BCA kit assay. From the hemolysis test, the membrane of red blood cells was not disrupted by the contact of films and the rate of release of hemoglobin was lower than 5%. The coagulation properties were evaluated by the dynamic blood clotting test. The G/OP hydrogels manifested a good activity of wound healing in the albino rats' model. Moreover, the films did not produce any unwilling symptoms. So, it was concluded that studied films have the potentiality to be used as wound healing biomaterials.

Bifidobacterium Treated by Electrostatic Spray Drying Relieved Constipation by Changing the Relative Abundance of Bacteria Associated With Gastrointestinal Regulatory Peptides

In this study, three different microencapsulation methods were used to embed Bifidobacterium to explore the alleviating effects of embedding methods on constipated mice. By measuring the defecation-related parameters, it was found that the Bifidobacteria treated by electrostatic spray drying had the best ability to relieved constipation. Furthermore, by detecting constipation-related gastrointestinal regulatory peptides, inflammatory factors, intestinal microbiota, and SCFAs, it was discovered that Bifidobacteria treated by electrostatic spray drying changed the composition of intestinal microbiota, especially the relative abundance of bacteria that were positively correlated with AQP3, but negatively correlated with ET-1 and SS, then increased the level of AQP3 in the intestine, and finally relieved constipation by increasing the fecal water content and small intestinal propulsion rate. In conclusion, the electrostatic spray drying method was superior to the other two methods in maintaining the activity of Bifidobacteria and relieved constipation by changing the relative abundance of bacteria that were correlated with gastrointestinal regulatory peptides and increasing the content of fecal water and small intestinal propulsion rate.

Application of Pickering emulsions in probiotic encapsulation- A review

Probiotics are live microorganisms that confer health benefits to host organisms when consumed in adequate amounts and are often incorporated into foods for human consumption. However, this has negative implications on their viability as large numbers of these beneficial bacteria are deactivated when subjected to harsh conditions during processing, storage, and passage through the gastrointestinal tract. To address these issues, numerous studies on encapsulation techniques to protect probiotics have been conducted. This review focuses on emulsion technology for probiotic encapsulation, with a special focus on Pickering emulsions. Pickering emulsions are stabilized by solid particles, which adsorb strongly onto the liquid-liquid interfaces to prevent aggregation. Pickering emulsions have demonstrated enhanced stability, high encapsulation efficiency, and cost-effectiveness compared to other encapsulation techniques. Additionally, Pickering emulsions are regarded as safe and biocompatible and utilize natural materials, such as cellulose and chitosan derived from plants, shellfish, and fungi, which may also be viewed as more acceptable in food systems than common synthetic and natural molecular surfactants. This article reviews the current status of Pickering emulsion use for probiotic delivery and explores the potential of this technique for application in other fields, such as livestock farming, pet food, and aquaculture.

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Probiotics play an important role in maintaining the health of humans and animals.

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Encapsulation improves probiotic viability in harsh environments.

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Probiotics can be encapsulated by many techniques such as emulsification.

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Pickering emulsions use particles instead of molecules to stabilize emulsions.

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Natural particles are more acceptable to some consumers than synthetic emulsifiers.

Triggered and controlled release of active gaseous/volatile compounds for active packaging applications of agri-food products: A review

Gaseous and volatile active compounds are versatile to enhance safety and preserve quality of agri-food products during storage and distribution. However, the use of these compounds is limited by their high vapor pressure and/or chemical instability, especially in active packaging (AP) applications. Various approaches for stabilizing and controlling the release of active gaseous/volatile compounds have been developed, including encapsulation (e.g., into supramolecular matrices, polymer-based films, electrospun nonwovens) and triggered release systems involving precursor technology, thereby allowing their safe and effective use in AP applications. In this review, encapsulation technologies of gases (e.g., CO₂ , ClO₂ , SO₂ , ethylene, 1-methylcyclopropene) and volatiles (e.g., ethanol, ethyl formate, essential oils and their constituents) into different solid matrices, polymeric films, and electrospun nonwovens are reviewed, especially with regard to encapsulation mechanisms and controlled release properties. Recent developments on utilizing precursor compounds of bioactive gases/volatiles to enhance their storage stability and better control their release profiles are discussed. The potential applications of these controlled release systems in AP of agri-food products are presented as well.

Electrosprayed Nanoparticles as Drug Delivery systems for Biomedical Applications

BACKGROUND

Nanotechnology is a tool being used intensely in the area of drug delivery systems in the biomedical field. Electrospraying is one of the nanotechnological methods, which is growing due to its importance in the development of nanoparticles comprising bioactive compounds. It is helpful in improving the efficacy, reducing side effects of active drug elements, and is useful in targeted drug delivery. When compared to other conventional methods like nanoprecipitation, emulsion diffusion, and double emulsification, electrospraying offers better advantages to produce micro/nanoparticles due to its simplicity, cost-effectiveness, and single-step process.

OBJECTIVE

The aim of this paper is to highlight the use of electrosprayed nanoparticles for biomedical applications.

METHODS

We conducted a literature review on the usage of natural and synthetic materials to produce nanoparticles, which can be used as a drug delivery system for medical purposes.

RESULTS

We summarized a possible key role of electrosprayed nanoparticles in different therapeutic applications (tissue regeneration, cancer).

CONCLUSION

The modest literature production denotes that further investigation is needed to assess and validate the promising role of drug-loaded nanoparticles through the electrospraying process as noninvasive materials in the biomedical field.

Electrosprayed Chitosan-Copper Complex Microspheres with Uniform Size

Chitosan-based nano- and microspheres have shown great potential in a broad range of applications, including drug delivery, bone tissue engineering, wastewater treatments, etc. The preparation of uniformly sized spheres with controlled morphology and microstructure is still a challenge. This work investigates the influence of cupric ions (Cu²⁺) on the size, shape, morphology and stability of electrosprayed chitosan–copper (CHT–Cu²⁺) complex microspheres, using chitosans with different degrees of deacetylation. The dynamic viscosity of CHT–Cu²⁺ solutions was measured by Höppler viscometer, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used for the identification of dried microspheres. The size, shape and morphology of microspheres were analyzed by light microscope and scanning electron microscopy (SEM), while stability of dried microspheres was evaluated in different buffer solutions. The volume ratio of wet and dry microspheres was assessed based on the estimated diameter of microspheres. The higher concentration of Cu²⁺ ions resulted in a decrease in viscosity of CHT–Cu²⁺ solutions and volume ratio of prepared microspheres. Changes in the intensities and wave numbers of absorption bands of amino and hydroxyl groups, amide I and amide II suggested that the nitrogen and oxygen atoms in chitosan are coordinating the cupric ions. Micrographs obtained by light microscope and SEM showed that all prepared samples are spherical. The increase of cupric ions concentration changed the topography of microspheres and decreased their size. These results indicated the successful electrospraying of CHT–Cu²⁺ microspheres with uniform size and good stability in aqueous medium.