Assembly of kafirin/carboxymethyl chitosan nanoparticles to enhance the cellular uptake of curcumin

Progress in Colloid Delivery Systems for Protection and Delivery of Phenolic Bioactive Compounds: Two Study Cases-Hydroxytyrosol and Curcumin

Insufficient intake of beneficial food components into the human body is a major issue for many people. Among the strategies proposed to overcome this complication, colloid systems have been proven to offer successful solutions in many cases. The scientific community agrees that the production of colloid delivery systems is a good way to adequately protect and deliver nutritional components. In this review, we present the recent advances on bioactive phenolic compounds delivery mediated by colloid systems. As we are aware that this field is constantly evolving, we have focused our attention on the progress made in recent years in this specific field. To achieve this goal, structural and dynamic aspects of different colloid delivery systems, and the various interactions with two bioactive constituents, are presented and discussed. The choice of the appropriate delivery system for a given molecule depends on whether the drug is incorporated in an aqueous or hydrophobic environment. With this in mind, the aim of this evaluation was focused on two case studies, one representative of hydrophobic phenolic compounds and the other of hydrophilic ones. In particular, hydroxytyrosol was selected as a bioactive phenol with a hydrophilic character, while curcumin was selected as typical representative hydrophobic molecules.

Enhanced Stability and Oral Bioavailability of Cannabidiol in Zein and Whey Protein Composite Nanoparticles by a Modified Anti-Solvent Approach

Wide applications of cannabidiol (CBD) in the food and pharmaceutical industries are limited due to its low bioavailability, sensitivity to environmental pressures and low water solubility. Zein nanoparticles were stabilized by whey protein (WP) for the delivery of cannabidiol (CBD) using a modified anti-solvent approach. Particle size, surface charge, encapsulation efficiency, and re-dispersibility of nanoparticles were influenced by the zein to WP ratio. Under optimized conditions at 1:4, zein–WP nanoparticles were fabricated with CBD (200 μg/mL) and further characterized. WP absorbed on zein surface via hydrogen bond, hydrophobic forces, and electrostatic attraction. The zein–WP nanoparticles showed excellent storage stability (4 °C, dark) and effectively protected CBD degradation against heat and UV light. In vivo pharmacokinetic study demonstrated that CBD in zein–WP nanoparticles displayed 2-times and 1.75-fold enhancement in maximum concentration (C max) and the area under curve (AUC) as compared to free-form CBD. The data indicated the feasibility of developing zein–WP based nanoparticles for the encapsulation, protection, and delivery of CBD.

Curcumin, a potent therapeutic nutraceutical and its enhanced delivery and bioaccessibility by pickering emulsions

Curcumin is a biomolecule with functional moieties, which contribute to its anti-inflammatory, anticancer, and antioxidant properties. It has shown several therapeutic effects on treating inflammatory and neurodegenerative diseases and contributes to the reduction of oxidative stress and damage to body tissues. However, its low solubility and fast metabolism limit its absorption in the gastrointestinal (GI) tract and lead to its low bioavailability. Preparation of Pickering emulsions stabilized with mineral or biopolymer-based nanoparticles can be an effective strategy for enhancing the stability of curcumin against degradation, increasing its bioaccessibility in the GI tract, and achieving its controlled release at various locations based on changes in environmental conditions. Various nanoparticles prepared from minerals, proteins, and polysaccharides show potential for stabilizing the curcumin-loaded emulsions, and their wettability can be altered through complexation and formation of hybrid nanoparticles. Stabilization of Pickering emulsions with polysaccharide-based nanoparticles and their complexes can enhance the stability of the curcumin against degradation. Moreover, various protein-based nanoparticles and their conjugated forms with other proteins or polysaccharides can enable the preparation of high internal phase Pickering emulsions (HIPEs) with concomitant higher loading and bioaccessibility of the curcumin molecule. In light of the several therapeutic properties of curcumin, this review article aims to highlight recent studies and the strategies used for the preparation of curcumin Pickering emulsions stabilized by various nanoparticles for enhancing its bioaccessibility during metabolism. These may be useful in pharmaceutical and food industries for drug development and delivery and fortification of food products with this nutraceutical component.

A self-assembled amphiphilic polysaccharide-based co-delivery system for egg white derived peptides and curcumin with oral bioavailability enhancement

Egg white derived peptides (EWDP) and curcumin are well known for diverse biological activities, but the combinational usage of the two natural nutraceuticals is extremely limited by their low oral bioavailability and distinctly different polarities. Therefore, this study aimed to exploit a facile self-assembled amphiphilic system for oral co-delivery of hydrophilic egg white derived peptides (EWDP) and hydrophobic curcumin. The hydrophobic curcumin was first loaded into the hydrophobic cavity of β-cyclodextrin (β-CD) as a core. Then, the hydrophilic EWDP was absorbed into the region between the core and the N-[(2-hydroxy-3-trimethyl ammonium) propyl] chitosan (HTCC) shell to form the amphiphilic nanoparticles (NPs) via layer-by-layer self-assembly. The resulting NPs showed ideal oral applicability with excellent colloidal properties and encapsulation capacity for EWDP and curcumin at pH 2.0-7.0. X-ray Photoelectron Spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H NMR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results indicated that hydrogen bonding and hydrophobic interaction were the main driving force for the formation of amphiphilic NPs. Upon combination with HTCC, EWDP (both shell material and core nutraceuticals) could facilitate curcumin loading into the deeper β-CD cavity site with admirable solubility improvement. Moreover, EWDP and curcumin after co-delivery exhibited superior bioavailability (especially for bioactivity and cellular absorption) than the simple mixture and conventional curcumin inclusion complex. Overall, these findings are enlightening for the rational peptide based oral co-delivery system formulations for a broader range of hydrophilic and hydrophobic nutraceuticals (initially synergistic or not) in the food and related health-promoting fields.

Fabrication and characterization of oil-in-water pickering emulsions stabilized by ZEIN-HTCC nanoparticles as a composite layer

In this work, the ZEIN-HTCC nanoparticles formed by zein and N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC) were used as stabilizers to prepare oil-in-water (O/W) Pickering emulsions. The preparation conditions including shearing time, volume fraction of corn oil, mass ratio of ZEIN:HTCC and total concentration of ZEIN-HTCC of emulsions were optimized by measuring the droplet size, zeta potential, PDI and surface tension of emulsions. The ZEIN-HTCC emulsions are stable at the pH range of 4-9 and in the low salt ion concentrations up to 0.2 mol L^-1, and can keep stable up to 21 d during low temperature storage. Fourier transform infrared spectroscopy (FTIR), the confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM) were used to analyze the interaction between emulsion components, revealing that zein and HTCC form a composite layer by flocculation to adsorb on the surface of oil droplets, thus preventing emulsion droplets from aggregation. This novel, long-term stable, surfactant-free, and edible zein-based Pickering emulsion could be used as potential carriers for lipophilic nutrients delivery.

Phospholipid/zein hybrid nanoparticles as promising carriers for the protection and delivery of all-trans retinoic acid

A totally biodegradable mixed system made up of phospholipids and zein was developed in order to effectively improve the photostability of all-trans retinoic acid (ATRA) preserving its pharmacological properties. Photon correlation spectroscopy showed that the formulation obtained using phospholipon 85G and zein at a ratio of 7:3 w/w was characterized by an average diameter of less than 200 nm, a narrow size distribution and a significant time- and temperature-dependent stability. The use of specific cryoprotectants such as mannose and glucose favoured the long-term storage of the nanocarriers after the freeze-drying procedure. The nanoparticles increased the stability of the ATRA against photochemical degradation with respect to the free drug and its antitumor effect was preserved as a consequence of the cell uptake of the colloidal systems. The results demonstrate the potential of the proposed hybrid nanosystems to provide a high level of stabilization for sensitive and labile antitumor compounds.

Foxtail millet prolamin as an effective encapsulant deliver curcumin by fabricating caseinate stabilized composite nanoparticles

The development of food proteins as effective delivery systems is of great significance for the encapsulation of active compounds. Foxtail millet prolamin (FP) has a high level of hydrophobic amino acids and proline, meets the basic characteristics of delivery system, and was described here for the first time as an effective delivery system for the encapsulation of curcumin. The interaction between FP and curcumin was confirmed by fluorescence spectroscopy, showing the joint driving of hydrophobic forces and hydrogen bonds. Curcumin-loaded caseinate-stabilized FP nanodispersions were prepared by anti-solvent/evaporation method. The mean particle size was about 220-235 nm, sharing features of a spherical shape, uniform particle size, and smooth surfaces. High level of curcumin was encapsulated in the FP-based nanoparticles, exhibiting high particle yield (>88.4%) and encouraging encapsulation efficiency (>71.3%). X-ray diffraction and Fourier transform infrared spectroscopy demonstrated that the encapsulated curcumin was amorphous state and interacted with proteins via non-covalent bonds. The nano-sized particles can effectively prevent the degradation of curcumin during heat treatment, and significantly enhance the antioxidant and anti-tumor properties. This study provides a new encapsulant for effective protection and targeted delivery of hydrophobic active biomolecules.

Nanotechnological Manipulation of Nutraceuticals and Phytochemicals for Healthy Purposes: Established Advantages vs. Still Undefined Risks

Numerous foods, plants, and their bioactive constituents (BACs), named nutraceuticals and phytochemicals by experts, have shown many beneficial effects including antifungal, antiviral, anti-inflammatory, antibacterial, antiulcer, anti-cholesterol, hypoglycemic, immunomodulatory, and antioxidant activities. Producers, consumers, and the market of food- and plant-related compounds are increasingly attracted by health-promoting foods and plants, thus requiring a wider and more fruitful exploitation of the healthy properties of their BACs. The demand for new BACs and for the development of novel functional foods and BACs-based food additives is pressing from various sectors. Unfortunately, low stability, poor water solubility, opsonization, and fast metabolism in vivo hinder the effective exploitation of the potential of BACs. To overcome these issues, researchers have engineered nanomaterials, obtaining food-grade delivery systems, and edible food- and plant-related nanoparticles (NPs) acting as color, flavor, and preservative additives and natural therapeutics. Here, we have reviewed the nanotechnological transformations of several BACs implemented to increase their bioavailability, to mask any unpleasant taste and flavors, to be included as active ingredients in food or food packaging, to improve food appearance, quality, and resistance to deterioration due to storage. The pending issue regarding the possible toxic effect of NPs, whose knowledge is still limited, has also been discussed.

Photo-enhanced antibacterial activity of polydopamine-curcumin nanocomposites with excellent photodynamic and photothermal abilities

Background and objective Photodynamic therapy (PDT) and photothermal therapy (PTT) have gradually become options for select anti-tumor and antibacterial treatment . The combination of PDT and PTT show great research value, which may greatly improve the curative effect. The aim of the present study was to prepare a compound system of polydopamine and curcumin (PDA-Cur nanocomposites) with excellent antibacterial effect towards Gram-positive and Gram-negative bacteria. Methods Dopamine hydrochloride was oxidized and self polymerized in alkaline condition to form PDA-Cur nanocomposites. The structure and morphology of PDA-Cur were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), laser scattering microscopy (LSM), ultraviolet spectrophotometer (UV-vis), infrared spectroscopy (IR) and fluorescence emission spectrometer. Using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), 1,3-diphenylbenzofuran (DPBF) and 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) were used to detect the production of reactive oxygen species (ROS). The thermal stability of PDA-Cur nanocomposites was investigated by temperature rising test. The antibacterial effect of PDA-Cur was determined by plate counting technique using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as models. In addition, the stability and antibacterial mechanism of PDA-Cur were investigated. Finally, the biocompatibility was evaluated by cytotoxicity and hemolysis tests. Results The compound system of polydopamine and curcumin was successfully prepared, which showed improved stability compared with Cur. The consumption of DPBF by the singlet oxygen produced by PDA-Cur was as high as 80%. In the heating test, the highest temperature increased to 59 °C, which contributed to the photodynamic and photothermal inactivation of bacteria. PDA-Cur nanocomposites showed good antibacterial activity against S. aureus and E. coli. Under 405 nm light, the bactericidal rate of PDA-Cur against S. aureus can reach 100% at a low concentration of 10^-4 nM, and that against E. coli was 100% at 1 nM. Under 405 + 808 nm light, the bactericidal rate of PDA-Cur against E. coli enhanced to 100% at 0.1 nM. In addition, PDA-Cur had low cytotoxicity and negligible hemolytic activity, showing good biocompatibility. Conclusion PDA-Cur nanocomposites had good photodynamic effect, photo thermal conversion ability and biocompatibility. Compared with free Cur, the antibacterial activity of PDA-Cur was significantly improved, and the antibacterial effect with combined light was stronger than that of free Cur. Therefore, the construction of PDA-Cur nanocomposites have confirmed that the combination of PDT and PTT can greatly improve the antibacterial effect and reach bactericidal effect at low concentration, which provides a strategy for the design of next generation antimicrobial agents.

Fabrication and characterization of zein-tea polyphenols-pectin ternary complex nanoparticles as an effective hyperoside delivery system: Formation mechanism, physicochemical stability, and in vitro release property

Hyperoside (HYP) has various potential benefits, however, its low water-solubility and poor bioavailability have restricted its application. Here, HYP-loaded zein-tea polyphenols (TP)-pectin ternary complex nanoparticles (Z/TP/P-HYP) were prepared by the antisolvent precipitation method for HYP delivery. The formed Z/TP/P-HYP are negatively charged spherical particles with a size of 246 nm, and have the highest HYP encapsulation efficiency (94.2%) at TP was 0.25 mg/mL. Fourier transform infrared spectroscopy revealed that hydrogen bonding, electrostatic interactions, and hydrophobic effects were major interactions to Z/TP/P-HYP formation. Differential scanning calorimetry confirmed that encapsulated HYP was in an amorphous state. Freeze-dried Z/TP/P-HYP displayed good water-redispersibility and high particle yield (95.2%). Z/TP/P-HYP exhibited improved pH (2.0-8.0) and ionic (0-500 mM) stability. Furthermore, Z/TP/P-HYP demonstrated stronger antioxidant properties than free HYP and provided HYP sustained release under simulated gastrointestinal conditions. Therefore, Z/TP/P-HYP have great potential as an effective HYP delivery system for applications in foods.

Development of polyoxyethylene (2) oleyl ether-gliadin nanoparticles: Characterization and in vitro cytotoxicity

Natural polymers have been widely investigated as materials for the delivery of active compounds as a consequence of their biocompatibility, low-cost and the opportunity they furnish to obtain micro- and nanostructures. In this investigation, commercial wheat gliadin was used as raw material with the aim of obtaining a vegetal protein-based nanoformulation to be used for various applications. The influence of non-ionic and anionic surfactants on the physico-chemical properties of gliadin nanoparticles was evaluated in order to propose a suitable candidate able to stabilize the colloidal structure. The use of Super Refined polyoxyethylene (2) oleyl ether gave the best results, promoting the formation of spherical-shaped nanosystems with a narrow size distribution. The oleyl ether-based emulsifier prevented the destabilization of the colloidal systems when pH- and temperature-dependent stress was applied. A freeze-dried formulation was obtained when mannose was used as a cryoprotectant. Polyoxyethylene (2) oleyl ether-stabilized nanosystems were shown to retain and release both hydrophilic and lipophilic model compounds in a controlled manner. The cytotoxicity of the surfactant-free and polyoxyethylene (2) oleyl ether-stabilized gliadin based nanosystems was assessed on human cells, both normal and tumoural, in order to investigate the concentrations of particles that can be used during in vitro experiments. Polyoxyethylene (2) oleyl ether-stabilized gliadin-based nanosystems are promising carriers for the delivery of several active compounds.

Structural design of zein-cellulose nanocrystals core-shell microparticles for delivery of curcumin

The novel core-shell microparticles were fabricated to deliver curcumin by using hydrophobic zein microparticles as the core and hydrophilic cellulose nanocrystals (CNCs) as the shell. Different concentrations (0.10-1.50%, w/v) of CNCs were utilized to regulate the microstructure, physicochemical stability, and in vitro digestion of the core-shell microparticles. The size of the microparticles ranged from 1017.3 to 3663.7 nm. Electrostatic attraction and hydrophobic interactions were responsible for the assembly of zein-CNCs core-shell microparticles. The microstructure of the microparticles was dependent on the CNCs level. The retention rate of curcumin in the core-shell microparticles was increased by 76.41% after UV radiation. Furthermore, the rise of CNCs level delayed the release of curcumin from the microparticles in gastrointestinal tract and reduced its bioaccessibility. The potential of utilizing hydrophilic nanoparticles was explored to stabilize hydrophobic microparticles through interparticle interactions, which was useful to develop the novel core-shell microparticles for the application in functional foods.

Curcumin-loaded core-shell biopolymer nanoparticles produced by the pH-driven method: Physicochemical and release properties

In this study, core-shell biopolymer nanoparticles were fabricated for the encapsulation and delivery of curcumin using a pH-driven method. The influences of the coating composition on the physicochemical properties and curcumin release characteristics of the core-shell nanoparticles were studied. Fourier transform infrared spectroscopy and X-ray diffraction analyses indicated that curcumin was encapsulated in an amorphous state inside the nanoparticles. Particle size and ζ-potential measurements indicated that the biopolymer nanoparticles were relatively stable under different environmental conditions: long term storage, heating, pH changes and salt. The DPPH radical scavenging activity of the curcumin was increased after encapsulation within the nanoparticles, whereas the gastrointestinal release of curcumin was prolonged. These results were attributed to the ability of alginate and NaCas to form a thick layer around the nanoparticles, which increased the steric and electrostatic repulsion between them, as well as inhibiting the release of curcumin.

Chitosan Nanomedicine in Cancer Therapy: Targeted Delivery and Cellular Uptake

Nanomedicine has gained much attention for the management and treatment of cancers due to the distinctive physicochemical properties of the drug-loaded particles. Chitosan's cationic nature is attractive for the development of such particles for drug delivery, transfection, and controlled release. The particle properties can be improved by modification of the polymer or the particle themselves. The physicochemical properties of chitosan particles are analyzed in 126 recent studies, which allows to highlight their impact on passive and active targeted drug delivery, cellular uptake, and tumor growth inhibition (TGI). From 2012 to 2019, out of 40 in vivo studies, only 4 studies are found reporting a reduction in tumor size by using chitosan particles while all other studies reported tumor growth inhibition relative to controls. A total of 23 studies are analyzed for cellular uptake including 12 studies reporting cellular uptake mechanisms. Understanding and exploiting the processes involved in targeted delivery, endocytosis, and exocytosis by controlling the physicochemical properties of chitosan particles are important for the development of safe and efficient nanomedicine. It is concluded based on the recent literature available on chitosan particles that combination therapies can play a pivotal role in transformation of chitosan nanomedicine from bench to bedside.

Fabrication and characterization of sunflower protein isolate nanoparticles, and their potential for encapsulation and sustainable release of curcumin

In this research, first, the effects of two desolvating agents (ethanol and methanol) at three temperature values (4, 25, and 50 °C) on the fabrication of sunflower protein isolate (SnPI) nanoparticles were studied using a desolvation method. Second, the ability of the nanoparticles to encapsulate curcumin was investigated. Results showed that ethanol led to smaller nanoparticles compared to methanol as the desolvating agent at 4 and 50 °C. However, at 25 °C, ethanol formed the most uniform nanoparticles with the lowest polydispersity index (0.188 ± 0.091) and particle size of 174.64 ± 30.61 nm. The encapsulation efficiency was in the range of 39.1 to 95.4% according to the fabrication condition and curcumin-to-protein mass ratio. A biphasic trend of curcumin release from nanoparticles was observed; in which, over 50% of curcumin was released from the curcumin-loaded nanoparticles in the first 2 h, which is attributed to the burst effect of the protein matrix.

Complexation of β-lactoglobulin with gum arabic: Effect of heat treatment and enhanced encapsulation efficiency

Heat treatment is widely used in food industry. Proteins and polysaccharides as important natural polymers in food, under heat treatment, the interactions between them could mediate the conformation and functional properties of proteins. Thermally induced β-lactoglobulin-gum arabic complexes (β-Lg-GA) were fabricated, and the effect of heat treatment on physicochemical properties of the complexes was systematically investigated. The average particle size of β-Lg-GA complexes decreased with temperature increased, at 85°C, a smaller size of 273 nm was obtained. A saturated adsorption of GA was found when mass ratio of β-Lg/GA was <1:2. At pH = 4.2-7.0, electrostatic attraction between β-Lg and GA was low and a fairly constant turbidity was observed, the formed composite particles had good stability to the pH value. Through UV, fluorescence, and FTIR spectroscopy, it was found that formation of the nanoparticles relied on thermal denaturation and aggregation of protein, the electrostatic, hydrophobic, and hydrogen bonding interactions between β-Lg and GA were also important. Scanning electron microscope further indicated β-Lg and GA had good compatibility, and the complexes had a spherical core-shell structure at molecular level. In addition, these prepared natural nanoparticles by heat treatment show significantly higher encapsulation efficiency for (-)-epigallocatechin-3-gallate (EGCG) than that of unheated, thus could be used as a promising carrier for biologically active substances.

Prolamin-based complexes: Structure design and food-related applications

Prolamins are a group of safe food additives that are biocompatible, biodegradable, and sustainable. Zein, gliadin, kafirin, and hordein are common prolamins that have been extensively studied, particularly as these form colloidal particles because of their amphiphilic properties. Prolamin-based binary/ternary complexes, which have stable physicochemical properties and superior functionality, are formed by combining prolamins with polysaccharides, polyphenols, water-soluble proteins, and surfactants. Although the combination of prolamins with other components has received attention, the relationship between the structural design of prolamin-based complexes and their functionalities remains uncertain. This review discusses the production methods of prolamin-based complexes, the factors influencing their structural characteristics, and their applications in the food industry. Further studies are needed to elucidate the structure-function relationships between prolamins and other biopolymers, as well as the toxicological effects of these complexes in food.

One-step self-assembly of curcumin-loaded zein/sophorolipid nanoparticles: physicochemical stability, redispersibility, solubility and bioaccessibility

Curcumin, a polyphenolic compound isolated from turmeric, exhibits various biological activities. The application of this nutraceutical in foods, however, is limited due to its extreme hydrophobicity, inferior stability, and poor bioaccessibility. The purpose of this paper is to prepare alcohol-free curcumin-loaded zein/sophorolipid nanoparticles (Cur-Z/SNPs) by one-step self-assembly to overcome the abovementioned challenges of curcumin. In detail, Cur-Z/SNPs were formed by mixing curcumin, zein, and sophorolipid under neutral conditions without any organic reagents or high energy equipment. The encapsulation efficiency and loading capacity of Cur-Z/SNPs were 94.08% and 11.50%, respectively. The spherical shape of Cur-Z/SNPs was observed by using a transmission electron microscope. The self-assembly mechanism involved hydrogen bonding, hydrophobic and electrostatic interactions, and the crystalline nature of curcumin changed to amorphous during self-assembly. Cur-Z/SNPs enhanced the zein denaturation resistance. They exhibited complete redispersibility and improved the aqueous solubility by approximately 246 times compared with free curcumin. The fresh Cur-Z/SNPs exhibited physicochemical stability at pH 5.0-8.0, ionic strength within 250 mM, and storage at 25 °C and 4 °C for 30 days. Notably, Cur-Z/SNPs could achieve excellent storage stability at room temperature as compared to those at refrigeration. Furthermore, lyophilization had a positive effect on storage stability, did not change the pH stability, and slightly reduced the ionic strength stability. Besides, Cur-Z/SNPs increased the 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH˙) scavenging capacity compared to free curcumin. The bioaccessibility of curcumin was increased by about 6 times by Cur-Z/SNPs. These findings provided new insight into the application of hydrophobic nutrients in alcohol-free functional foods.

Water-in-Oil Pickering Emulsions Stabilized Solely by Water-Dispersible Phytosterol Particles

Water-in-oil (W/O) Pickering emulsions were successfully synthesized by water-dispersible phytosterol (PS) particles formed through simple antisolvent precipitation. The effects of the organic/aqueous ratio on the particle morphology, crystallinity, and contact angle were investigated. Sheet-like PS particles with reduced crystallinity were further used as W/O Pickering emulsion stabilizers. The properties of the formed W/O emulsions could be transformed by changing the oil type, water-phase fraction, or particle contents. Results showed that emulsions with 80% water fraction could be stabilized by 3% particles in the aqueous phase, where dodecane was used as the oil phase. W/O Pickering emulsions stabilized by PS particles showed temperature responsiveness. When dried, PS particles could be well dispersed either in the water or oil phase to stabilize W/O Pickering emulsions. Therefore, this kind of PS particles could not only enrich the family of food-grade Pickering stabilizers, especially the W/O type, but also provide a smart Pickering stabilizer to fabricate environmental-responsive emulsion products.

pH-shifting encapsulation of curcumin in egg white protein isolate for improved dispersity, antioxidant capacity and thermal stability

Curcumin (Cur) has many functions, such as antioxidant and anti-inflammatory. However, its poor solubility and thermal stability at aqueous solutions limit its application in the food industry. In this study, egg white protein isolate (EPI) was complexed with Cur via a pH-shifting method. The effects of ultimate pH (from 5.0 to 7.0) on the physicochemical properties of the complex were studied. Cur could reach 84.4% encapsulation efficiency at pH 6.0. Meanwhile, the EPI complex could remain stable at pH 7.0 after 30 days and protect Cur from thermal degradation, thereby improving the Cur retention rate with the increasing ultimate pH. Compared with those of EPI and free Cur, the antioxidant capacity of the complex was enhanced effectively. The EPI-Cur complex was certified using UV-vis and fluorescence spectra. The fluorescence results indicated that Cur and EPI are combined through a static quenching and with a strong affinity of 1.8 × 10⁵ M^-1 at pH 6.0. In summary, this work provides a biocompatible and straightforward method for the development of nanoparticles based on egg white protein isolates, which can be used as a promising carrier for insoluble nutritional compounds.

Synthesis, Characterization, and Evaluation of Genistein-Loaded Zein/Carboxymethyl Chitosan Nanoparticles with Improved Water Dispersibility, Enhanced Antioxidant Activity, and Controlled Release Property

Genistein is one of major isoflavones derived from soybean products and it is believed to have beneficial effects on human health. However, its low water-solubility and poor oral bioavailability severely hamper its use as a functional food ingredient or for pharmaceutical industry. In this study, zein and zein/carboxymethyl chitosan (CMCS) nanoparticles were prepared to encapsulate genistein using a combined liquid-liquid phase separation method. The physicochemical properties of fabricated nanoparticles were characterized by dynamic light scattering (DLS), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that genistein encapsulated with zein nanoparticles significantly improved its water dispersibility, antioxidant activity in the aqueous phase, and photostability against UV light. Moreover, genistein encapsulated in zein nanoparticles showed a sustained release property. Furthermore, it was found that encapsulation efficiency of genistein was significantly enhanced after CMCS coating, and this effect was more pronounced after the complex nanoparticles cross-linked with calcium ions when compared with the use of zein as a single encapsulant. In addition, compared to zein nanoparticles without biopolymer coating, CMCS coating significantly enhanced the thermal and storage stability of the formed nanoparticles, and delayed the release of genistein. A schematic diagram of zein and zein/carboxymethyl chitosan (CMCS) nanoparticles formation mechanism for encapsulation of genistein was proposed. According to the results of the current study, it could be concluded that encapsulation of genistein in zein/CMCS nanoparticles is a promising approach to improve its water dispersibility, antioxidant activity, photostability against UV light and provide controlled release for food/pharmaceutical applications.

Modeling the release of food bioactive ingredients from carriers/nanocarriers by the empirical, semiempirical, and mechanistic models

The encapsulation process has been utilized in the field of food technology to enhance the technofunctional properties of food products and the delivery of nutraceutical ingredients via food into the human body. The latter application is very similar to drug delivery systems. The inherent sophisticated nature of release mechanisms requires the utilization of mathematical equations and statistics to predict the release behavior during the time. The science of mathematical modeling of controlled release has gained a tremendous advancement in drug delivery in recent years. Many of these modeling methods could be transferred to food. In order to develop and design enhanced food controlled/targeted bioactive release systems, understanding of the underlying physiological and chemical processes, mechanisms, and principles of release and applying the knowledge gained in the pharmaceutical field to food products is a big challenge. Ideally, by using an appropriate mathematical model, the formulation parameters could be predicted to achieve a specific release behavior. So, designing new products could be optimized. Many papers are dealing with encapsulation approaches and evaluation of the impact of process and the utilized system on release characteristics of encapsulated food bioactives, but still, there is no deep insight into the mathematical release modeling of encapsulated food materials. In this study, information gained from the pharmaceutical field is collected and discussed to investigate the probable application in the food industry.

Formation, structural characterization, stability and in vitro bioaccessibility of 7,8-dihydroxyflavone loaded zein-/sophorolipid composite nanoparticles: effect of sophorolipid under two blending sequences

Anti-solvent co-precipitation (ASCP) is the most commonly used method of fabricating food-grade nanoparticles, while the impact of the blending sequence on the formation of nanoparticles lacks research. In this study, 7,8-dihydroxyflavone (7,8-DHF) loaded zein-/sophorolipid nanoparticles with two blending sequences (DHF-Z-S and DHF-Z/S) were successfully fabricated by the ASCP method and used to improve the storage stability and the in vitro bioaccessibility of 7,8-DHF. The results showed that blending sequences significantly affect the physicochemical properties of nanoparticles. DHF-Z-S nanoparticles had smaller particle size, lower polydispersity index and turbidity, and higher negative charge, entrapment efficiency and loading capacity compared to DHF-Z/S nanoparticles. Transmission electron microscopy and scanning electron microscopy revealed that DHF-Z-S and DHF-Z/S nanoparticles have core-shell spherical shape at the nanoscale and sophorolipid changed the surface morphology of zein nanoparticles. Fourier transform infrared spectroscopy and fluorescence spectrum analysis confirmed the presence of effective hydrogen bonding, electrostatic interactions and hydrophobic effects between 7,8-DHF, zein and sophorolipid and the presence of stronger hydrogen bonding and hydrophobic effects in DHF-Z-S nanoparticles. The encapsulated 7,8-DHF was in an amorphous state rather than a crystalline form as determined by X-ray diffraction analysis. Circular dichroism revealed that 7,8-DHF and sophorolipid were capable of changing the secondary structure of zein remarkably. More importantly, compared to DHF-Z/S nanoparticles, the DHF-Z-S nanoparticles possessed higher storage stability and in vitro bioaccessibility. Collectively, DHF-Z-S nanoparticles developed in this study might be a promising means of encapsulating, protecting and delivering hydrophobic nutraceuticals for applications in functional foods.

Fabrication, structural characterization and functional attributes of polysaccharide-surfactant-protein ternary complexes for delivery of curcumin

In this study, the nanocomplexes as a novel delivery system for curcumin, were successfully fabricated using high methoxyl pectin (HMP), individual surfactants (rhamnolipid (Rha), tea saponin (TS) and ethyl lauroyl arginate hydrochloride (ELA)) and pea protein isolate (PPI). The optimum mass ratio between PPI and curcumin was 40:1. The HMP-Rha-PPI-Cur, HMP-TS-PPI-Cur and HMP-ELA-PPI-Cur complexes which had particle sizes of 453, 422 and 587 nm, exhibited encapsulation efficiencies of curcumin with 93.46, 92.05 and 86.73%, respectively. The analysis of FTIR revealed that HMP-surfactant-PPI-Cur complexes were formed mainly by hydrogen bonding and electrostatic attraction. XRD result showed that curcumin exhibited a non-crystallized state in the ternary complexes. Moreover, the curcumin within the HMP-Rha-PPI ternary complexes showed better stability under UV-light, thermal and simulated gastrointestinal conditions.

Preparation and characterization of zein/carboxymethyl dextrin nanoparticles to encapsulate curcumin: Physicochemical stability, antioxidant activity and controlled release properties

In this work, zein/carboxymethyl dextrin nanoparticles were successfully fabricated at different zein to carboxymethyl dextrin (CMD) mass ratios. Zein/CMD nanoparticles with the negative charge and the smallest size (212 nm) were formed when the mass ratio of zein to CMD was 2:1, exhibiting improved encapsulation efficiency of curcumin (85.5%). Electrostatic interactions, hydrogen bonding and hydrophobic interactions were main driven forces for nanoparticles formulation and curcumin encapsulation. Fourier transform infrared spectroscopy determined curcumin might be partially embedded in CMD during encapsulation. The spherical structures of zein/CMD nanoparticles and curcumin-loaded zein/CMD nanoparticles were observed by transmission electron microscopy. The photothermal stability and antioxidant activity of curcumin were significantly enhanced after be loaded in zein/CMD nanoparticles. Furthermore, encapsulation of curcumin in zein/CMD nanoparticles significantly delayed the release of curcumin in simulated gastrointestinal fluids. These results indicated that zein/CMD nanoparticles could be effective encapsulating materials for bioactive compounds in food industry.

Enhancement of Skin Wound Healing by rhEGF-Loaded Carboxymethyl Chitosan Nanoparticles

The self-assembly of hydrophobically modified polymers has become a research hotspot due to its wide application in the biomedical field. Recombinant human epidermal growth factors (rhEGFs) are molecules that are able to enhance wound healing; however, they have a short half-life and require sustained action to enhance their mitogenic effect on epithelial cells. Here, we proposed a new delivery system to avoid the inhibition of rhEGF by various enzymes, thus improving its bioavailability and sustained release. The amphiphilic polymer was composed of conjugated linoleic acid (CLA) and carboxymethyl chitosan (CMCS), which were further characterized by fourier transformed infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). Then, the self-assembly behavior of CLA-CMCS (CC) polymer in water was observed in which the particle size of CC decreased from 196 to 155 nm with the degree of CLA substitution increasing. The nanoparticles were loaded with rhEGF and the maximum rhEGF loading efficiency (LE) of CC3 nanoparticles was 82.43 ± 3.14%. Furthermore, CC nanoparticles (NPs) exhibited no cytotoxicity for L929 cells, and cell proliferation activity was well preserved after rhEGF loading to CC-NPs and was comparable to that of free rhEGF. Topically applied rhEGF:CC-NPs significantly accelerated the wound-closure rate in full thickness, which was most probably due to its sustained release and enhanced skin permeation. In conclusion, carboxymethyl chitosan-based nanoparticles were constructed and showed good cytocompatibility. Moreover, these findings also demonstrated the therapeutic potential of rhEGF:CC-NPs as a topical wound-healing drug carrier.

Modulation of interfacial phenolic antioxidant distribution in Pickering emulsions via interactions between zein nanoparticles and gallic acid

The impacts of protein nanoparticles on the interfacial distribution of antioxidants and the oxidative stability in Pickering emulsions are attracting increasing research interests. In the present work, the distribution of gallic acid (GA) in zein nanoparticles-stabilized Pickering emulsions (ZPE) was determined by employing a pseudophase kinetic model. The interfacial distribution of GA was found to be favored in ZPEs with higher zein nanoparticle concentration (C_zein). Upon increasing C_zein, the interfacial loading of nanoparticles (Γ) dominated the modulation of %GA_I via hydrogen bonding between zein nanoparticles and GA. The interfacial percentage of GA (%GA_I) increased from 28% to 39% as Γ increased from 0.48 to 1.12 mg/m²_. In the presence of GA, a direct correlation between C_zein or Γ and oxidation stability was recognized, whereas the oxidative stability showed a non-linear dependence on either C_zein or Γ in the absence of GA. By excluding antioxidant effects of zein nanoparticles, we found that the %GA_I, which was regulated by Γ, took the leading role over the physical barrier effect on the oxidative stability of emulsions. The present work extends our current knowledge on how protein based nanoparticles manipulate the interfacial distribution of antioxidant and then affect the oxidative stability of emulsions.

Fabrication of Carboxylmethyl Chitosan Nanocarrier via Self-Assembly for Efficient Delivery of Phenylethyl Resorcinol in B16 Cells

Micro-molecular drugs have special advantages to cope with challenging diseases, however their structure, physical and chemical properties, stability, and pharmacodynamics have more requirements for the way they are delivered into the body. Carrier-based drug delivery systems can circumvent many limited factors of drug delivery and increase their bioavailability. In this context, stable drug nanocarriers of alkaline amino acids (arginine, Arg) modified conjugated linoleic acid-carboxymethyl chitosan (CLA-CMCS) conjugate were developed, which could generate supramolecular micelles to effectively encapsulate the tyrosinase inhibitor phenylethyl resorcinol (PR). The resulting CCA-NPs were spherical nanoparticles with a mean size around 175 nm. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and cellular uptake investigation demonstrated that the CCA-NPs were non-cytotoxic and had excellent cell transport ability. In addition, these CCA-NPs were able to effectively deliver PR and inhibited melanin formation to reduce pigmentation by enhancing cellular uptake. In conclusion, our research indicated that nanocarriers based on self-assembly amphiphilic polymers constituted a promising and effective drug delivery system in hyperpigmentation targeting.

In vitro investigation of hyaluronan-based polymeric micelles for drug delivery into the skin: The internalization pathway

In our previous research, we concluded that polymeric micelles based on hyaluronic acid are able to penetrate into the deeper layers of skin tissue. The aim of this work was to characterize the mechanisms involved in the uptake by skin cells, which is important for understanding the influence of the carrier composition on the drug penetration. To reach this goal, we used micelles encapsulating curcumin made of oleyl-hyaluronan (HAC18:1) and hexyl-hyaluronan (HAC6) covalently linked with fluorescent Nile Blue. This labeling enabled us to track the micelle-forming derivative and also micelle payload into the keratinocytes and fibroblasts by fluorescent microscopy and flow cytometry. The regulation of both the passive and active cellular uptake was used to determine the mechanism of micelle internalization. Furthermore, the changes of membrane fluidity were measured for these derivatives by FRAP. Using these methods we concluded that carriers entered the cells using both active and passive transport. Passive transport was facilitated by the affinity of the carrier to the cell membrane, especially in the case of HAC18:1 carrier, which changed significantly the membrane fluidity. The active transport was dependent on cell type, but mainly driven by the clathrin-mediated endocytosis and macropinocytosis. Surprisingly, the main HA receptor, CD44, was not involved in the uptake. We can conclude that these carrier systems could be used for the local transport of active substances or hydrophobic drugs into the skin cells using the advantage of passive transport of oleyl-HA derivative.

N-Acetyl-l-cysteine/l-Cysteine-Functionalized Chitosan-β-Lactoglobulin Self-Assembly Nanoparticles: A Promising Way for Oral Delivery of Hydrophilic and Hydrophobic Bioactive Compounds

Self-assembled and cross-linked hybrid hydrogels for entrapment and delivery of hydrophilic and hydrophobic bioactive compounds were developed based on N-acetyl-l-cysteine (NAC)- or l-cysteine (CYS)-functionalized chitosan-β-lactoglobulin nanoparticles (NPs). In both the systems, amphiphilic protein β-lactoglobulin (β-lg) was self-assembled by using glutaraldehyde for affinity binding with egg white-derived peptides (EWDP) and curcumin and then coated with NAC- or CYS-functionalized chitosan (CS) by electrostatic interaction. The resulting NPs were characterized in terms of size, polydispersity, and surface charge by dynamic light scattering. Results corroborated pH-sensitive properties of NAC-CS-β-lg NPs and CYS-CS-β-lg NPs with the particle size as small as 118 and 48 nm, respectively. The two kinds of NPs also showed excellent entrapment of EWDP and curcumin with the entrapment efficiency (EE) of EWDP and curcumin ranging from 51 to 89% and 42 to 57% in NAC-CS-β-lg NPs, as well as 50-81% and 41-57% in CYS-CS-β-lg NPs under different pH values. Fourier transform infrared and molecular docking studies provided support for the interaction mechanism of NAC/CYS-CS with β-lg as well as the NPs with EWDP and curcumin. Strikingly, the in vitro release kinetics of EWDP and curcumin exhibited the controlled and sustained release properties up to 58 and 70 h from the NPs, respectively. Note that the permeability of QIGLF (pentapeptide, isolated from EWDP) and curcumin passing through Caco-2 cell monolayers were all improved after the entrapment in the NPs. This work offers promising methods for effective entrapment and oral delivery of both hydrophilic and hydrophobic bioactive compounds.