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Wide-bandgap (WBG) perovskite has demonstrated great potential in perovskite-based tandem solar cells. The power conversion efficiency (PCE) of such devices has surpassed 34%, signifying a new era for renewable energy development. However, the ion migration reduces the stability and hinders the commercialization, which is yet to be resolved despite many attempts. A big step forward has now been achieved by the simulation method. The detailed thermodynamics and kinetics of the migration process have been revealed for the first time. The stability has been enhanced by more than 100% via the heterojunction layer on top of the WBG perovskite film, which provided extra bonding for kinetic protection. Hopefully, these discoveries will open a new gate for WBG perovskite research and accelerate the application of perovskite-based tandem solar cells. [ABSTRACT FROM AUTHOR]

The boiling stirred tank reactor (BSTR) is widely used in the chemical industry, while the relevant basic data of hydrodynamics and suspension characteristics for reactor design are quite limited. In this work, the hydrodynamics and suspension characteristics in a BSTR with helical coils (BSTR@HC) were studied using three types of impellers. Particle image velocimetry and visualization experiments reveal different flow fields and nucleation processes of three impellers. Suspension experiments show that superficial vapor velocity, solid loading, and particle size play an important role for just-suspension impeller speed N jsv and power consumption P jsv , while cloud height is mainly determined by superficial vapor velocity. Among the three impellers, radial impeller shows the best suspension performance in BSTR@HC. Correlations of N jsv and P jsv were developed with relative mean deviations of 2.7% and 4.6%, respectively. Furthermore, a model for the estimation of energy efficiency was developed by evaluate specific power consumption ε jsv. [Display omitted] • Hydrodynamics and suspension in a boiling stirred tank reactor were investigated. • Cavitation nucleation process was observed by a high-speed camera. • Radial impellers such as FBT are more energy efficient for just-suspension. • Mathematical correlations for N jsv and P jsv were established and verified. • A model for estimate the energy efficiency was developed by evaluating ε jsv. [ABSTRACT FROM AUTHOR]

The carriers for hydrophobic bioactives have been extensively studied, while those for hydrophilic bioactives are still challenging. The partition of bioactives in the particles depends greatly on their solubility, interaction with carrier materials, as well as structure of carriers. In this study, chitosan-coated hollow zein particles using calcium phosphate as a sacrificing template (CS-HZ) were fabricated to co-encapsulate folic acid (FA) and caffeic acid (CA). Partition, photostability, and antioxidant capacity of bioactive compounds were also studied. The size, polydispersity index and ζ-potential of optimized CS-HZ were 176.3 nm, 0.14 and +39.3 mV, respectively, indicating their small and uniform dimension with excellent colloidal stability. FA interacted with chitosan to form complexes and then coated on the zein particles where CA was encapsulated. After co-encapsulation in CS-HZ, the photostability of both FA and CA was improved in comparison with encapsulation of single compound, with 85% of FA remaining after 240 min of UVA irradiation, and 90% of CA remaining after 80 min. Antioxidant activity of CA decreased upon encapsulation, but significantly increased after irradiation. Findings in this study shed some light on the design of carriers for co-delivery of hydrophilic compounds in acidic condition. [Display omitted] • Chitosan-coated hollow zein particles (CS-HZ) were templated by calcium phosphate. • Folic acid (FA) complexed to chitosan and then coated on the zein particles. • Caffeic acid (CA) was encapsulated in the hollow core of CS-HZ. • Co-encapsulation of FA and CA in particles improved their photostability. • Encapsulation partially masked the antioxidant activity of CA. [ABSTRACT FROM AUTHOR]

In this study, an innovative oral delivery system, solid lipid-polymer hybrid nanoparticles (SLPN), was prepared from all-natural biomaterials without use of synthetic surfactants, toxic chemicals, or organic solvents. SLPN were comprised of three components, solid lipid nanoparticles (SLN) as the inner core, bovine serum albumin (BSA)-dextran (BD) conjugate obtained through Maillard reaction as natural emulsifier anchored on the surface of SLN, and pectin as the secondary polymeric coating. Six types of solid lipids, including two glycerides and four saturated fatty acids, were comprehensively tested for their applicability to prepare SLN core and their compatibility with polymeric shells to form SLPN. SLPN prepared with glycerides exhibited superior colloidal properties, including smaller particle size, narrower size distribution, and better stability under simulated gastrointestinal fluids, compared to those prepared with fatty acids. Hydrophobic interactions were the driving force to form SLPN with BD conjugate, while pectin coating afforded greater surface hydrophilicity responsible for exceptional colloidal stability under gastrointestinal conditions. SLPN demonstrated high encapsulation efficiency and controlled release of curcumin, with glycerides as lipid core being more desirable than those prepared with fatty acids. Fluorescence microscope images revealed that encapsulation in SLPN significantly facilitated cellular uptake of curcumin by Caco-2 cells without any cytotoxicity. Collectively, this study provides a promising strategy to develop safe and effective oral delivery platform for lipophilic bioactives, which may open new avenues in functional foods. [ABSTRACT FROM AUTHOR]

Encapsulation of lipophilic bioactives into solid lipid nanoparticles (SLNs) has been a promising approach to incorporate them into functional foods with attempt to improve bioavailability. Nevertheless, how these bioactives should be loaded into the lipid core have never been systematically studied before. Thus, in the present study, biopolymer-emulsified SLNs were prepared using a recently developed synthetic surfactant-free technique, and four different loading methods were tested for their efficacy to encapsulate curcumin into SLNs. Sodium caseinate (NaCas) and pectin were used as natural emulsifier and stabilizer, respectively, to prepare food-grade SLNs using stearic acid. Four loading methods varied in the use of organic solvent, and the order of critical steps including addition of curcumin and solid lipids, deprotonation of NaCas at pH 12, as well as pectin adsorption at pH 4. The resulting four types of curcumin-loaded SLNs were subject to comprehensive characterization, such as measurement of particle size, polydispersibility, zeta potential, stability test in simulated gastrointestinal (GI) fluids, antioxidant activities of encapsulated curcumin, as well as morphological observation under transmission electron microscopy. Nano spray drying technology was then exploited to obtain ultrafine powders from colloidal SLNs and their redispersibility in water was also evaluated. Our results suggested that solubilization of curcumin in deprotonated NaCas was a better approach than using organic solvent which resulted in large and aggregated SLNs. Furthermore, mixing curcumin with deprotonated NaCas and then adding melted lipid and pectin at pH 12 before emulsification were the two critical steps in fabricating uniform and small SLNs that were GI-stable and re-dispersible in water after spray drying. This study provides insight into the preparation of natural biopolymer-emulsified SLNs as a potential food-grade oral delivery system for lipophilic bioactives. [ABSTRACT FROM AUTHOR]

Exploitation of lipid nanoparticles for oral delivery of nutrients and drugs is limited by their poor stability under gastrointestinal tract and low loading capacity, unless a high concentration of synthetic surfactants is formulated. The main objective of present study is to design a series of new formulations for solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) that are suitable for potential oral delivery applications, using natural biopolymers, i.e. sodium caseinate (NaCas) as emulsifier and pectin as coating, with minimal addition of a synthetic surfactant, Tween 80. Effects of pectin coating, concentration of Tween 80, thermal treatment (80 °C for 30 min), as well as two chemical cross-linkers on the particulate characteristics, stability, encapsulation efficiency, controlled release and drying feasibility were comprehensively investigated. The intermolecular interactions and cross-linking reactions were studied using Fourier transform infrared spectroscopy. Tween 80 at 0.15% (w/v) together with 0.15% (w/v) NaCas was proved effective to obtain stable cross-linked pectin-coated SLN (PSLN) under 200 nm with high loading capacity for curcumin, while NLC prepared under the same condition failed to pass storage stability test. The 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/ N- hydroxysuccinimide (EDC/NHS) cross-linked PSLN exhibited superior characteristics than glutaradehyde (GA) cross-linked PSLN, especially for the stability and controlled release under simulated gastrointestinal conditions, with curcumin studied as a model compound. The feasibility of both nano spray drying and freeze-drying technologies were both investigated to transform of colloidal lipid nanoparticles into dry powders. Our results demonstrated a novel strategy to prepare small and homogenous SLN with exceptional GI stability and high loading capacity as a potential oral delivery system. [ABSTRACT FROM AUTHOR]

The formation of protein-polysaccharide complex nanoparticles was investigated using caseinate (NaCas), zein, and three polysaccharides, i.e. pectin, carboxymethyl cellulose (CMC) and gum arabic. Their complexation behavior was examined by dynamic light scattering, Fourier transform infrared and fluorescence spectroscopy. Chemical cross-linker, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide, were exploited to covalently bridge proteins and polysaccharide to improve the stability of complex nanoparticles in simulated gastrointestinal (GI) fluids. Curcumin was studied as a model lipophilic nutrient to explore the encapsulation and delivery applications. The polysaccharide type significantly affected the cross-linking efficiency which led to distinctive physical stability under simulated GI conditions and completely different morphology of powders obtained by nano spray drying, as well as their redispersibility in water. Compared to gum arabic, pectin and CMC were more favorable to form cross-linked nanoparticles with smaller size (160–210 nm), uniform distribution, spherical shape, higher encapsulation efficiency (up to 80%), slower release and much improved antioxidant activity, as well as exceptional redispersibility after drying. Our study suggested that chemical cross-linking process and selection of polysaccharide should be considered when developing desirable protein-polysaccharide complex nanoparticles that could maintain their integrity under simulated GI conditions for oral delivery applications. [ABSTRACT FROM AUTHOR]

In this study, pectin was used as coating material to form zein/caseinate/pectin complex nanoparticles through pH adjustment and heating treatment for potential oral delivery applications. The preparation conditions were studied by applying heating treatment at different pHs, either the isoelectric point of zein (pH 6.2) or caseinate (pH 4.6), or consecutively at both pHs. The particulate characteristics, including particle size, polydispersity index, and zeta potential were monitored for complex nanoparticles formed under different preparation conditions. The complex nanoparticles generally exhibited particle size smaller than 200 nm with narrow distribution, spherical shape, and strong negative charge. Fourier transform infrared and fluorescence spectroscopy revealed that hydrophobic interactions and hydrogen bonds were involved in the formation of complex nanoparticles, in addition to electrostatic interactions. Fresh colloidal dispersion and freeze-dried powders varied in their morphology, depending on their preparation conditions. Our results suggested that heating pH and sequence significantly affected the morphology of complex nanoparticles, and pectin coating exerted stabilization effect under simulated gastrointestinal conditions. The present study provides insight into the formation of protein/polysaccharide complex nanoparticles under different preparation conditions. [ABSTRACT FROM AUTHOR]

In this work, a new and novel organic solvent-free and synthetic surfactant-free method was reported to fabricate stable solid lipid nanoparticles (SLNs) from stearic acid, sodium caseinate (NaCas) and pectin, as well as water. Melted stearic acid was directly emulsified into an aqueous phase containing NaCas and pectin, followed by pH adjustment and thermal treatment to induce the formation of a compact and dense polymeric coating which stabilized SLNs. The preparation procedures and formulations were comprehensively optimized. The inter- and intra-molecular interactions among three ingredients were characterized by fluorescence and Fourier transform infrared spectroscopies. The stability of as-prepared SLNs was evaluated under simulated gastrointestinal conditions, and compared with traditional SLNs prepared with organic solvents. Our results revealed that the SLNs prepared from this organic solvent-free method had superior physicochemical properties over the traditional SLNs, including smaller size and better stability. Furthermore, redispersible SLNs powders were obtained by nano spray drying, but only the SLNs prepared by organic solvent-free method had sub-micron scale, uniform and spherical morphology. The organic solvent-free preparation method was proved to be a promising approach to prepare stable and uniform SLNs for potential oral delivery applications. [ABSTRACT FROM AUTHOR]

In this study, pectin was applied as a carbohydrate-based coating to improve physicochemical stability of sodium caseinate/zein (CZ) complex protein nanoparticles. Pectin coating was achieved via a pH- and heating-induced facile electrostatic adsorption process. The effect of pectin coating was tested on two different nanoparticle structures, i.e. solid and hollow CZ nanoparticles. The inter- and intra-molecular interactions between proteins and pectin were characterized by Fourier transform infrared and fluorescence spectroscopy. Pectin coating significantly improved the stability of nanoparticles under gastrointestinal conditions, showing minimal change in particle size and polydispersity. Our results showed that pectin coating not only significantly increased the capability of protein nanoparticles to encapsulate curcumin and but also provided sustained release under gastrointestinal conditions. Pectin-coated CZ nanoparticles demonstrated exceptional stability by maintaining their morphology before and after freeze-drying. Therefore, pectin coating is an effective strategy to potentially realize practical applications of protein nanoparticles as oral delivery vehicles. [ABSTRACT FROM AUTHOR]

Sodium carbonate was proposed as a sacrifice template and tannic acid was used as a natural cross-linker to prepare hollow zein nanoparticles (HZN/T). The formulation of nanoparticles, including the amount of water, zein and sodium carbonate, were optimized by surface response methodology (Box-Behnken design). The optimized HZN/T exhibited a small dimension of 87.93 nm with a PDI of only 0.105 and a zeta potential of −39.70 mV, indicating the nanoparticles were homogenous and formed stable colloidal dispersion. Then curcumin was used as a model lipophilic nutrient to explore the encapsulation and delivery potentials of HZN/T, in comparison with hollow zein nanoparticles without tannic acid (HZN/NT) and solid zein nanoparticles with tannic acid (SZN/T) prepared under the same conditions. Generally, the encapsulation efficiency of HZN/T or HZN/NT was significantly higher than that of SZN/T. Interestingly, encapsulation of curcumin dramatically increased particle size of SZN/T by 50 nm, while it did not induce any expansion of the dimension of HZN/T due to its hollow structure. The molecular interactions between curcumin and zein nanoparticles were investigated by Fourier transform infrared spectroscopy and fluorescent spectrophotometer. The in vitro stability and release profile of nanoparticles were evaluated under the simulated gastrointestinal conditions. Although all types of zein nanoparticles showed a sustained release of curcumin, cross-linking via tannic acid played an important role to make zein nanoparticles more resistant against simulated intestinal digestion. Therefore, compared with traditional SZN/T, the HZN/T developed in this study has promising features as a potential oral delivery system for lipophilic nutrients/drugs. [ABSTRACT FROM AUTHOR]

Solid lipid nanoparticles (SLNs) are regarded as promising carriers to improve the safety and effectiveness of delivery for drugs and nutrients, however, the clinic applications for oral administration are limited by their poor stability in gastrointestinal conditions. In this study, surface modification was explored to confer new physicochemical properties to SLNs and thus achieve enhanced functionalities. Novel SLNs with biopolymeric double layer (DL) coating using two natural biopolymers, i.e. caseinate (NaCas) and pectin, were prepared to encapsulate and deliver curcumin, a lipophilic bioactive compound studied as a model drug/nutrient. The DL coating was chemically cross-linked by creating covalent bonds between NaCas and pectin, using two different cross-linkers, i.e. glutaraldehyde (GA) and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-Hydroxysuccinimide (EDC/NHS). Prior to cross-linking, the mean particle size, polydispersity index and zeta potential of DL-SLNs were 300–330 nm, 0.25–0.30, −45–40 mV, respectively. It was found that cross-linking with GA had a more prominent effect on particle size and polydispersity index than EDC/NHS. The cross-linking process significantly improved physicochemical properties of DL-SLNs, resulting in higher encapsulation efficiency and loading capacity, better stability and slower release profile in simulated gastrointestinal conditions. Particularly, an optimal zero-order release kinetic was observed for EDC/NHS crosslinked DL-SLNs. The electron microscopy revealed that both cross-linked DL-SLNs exhibited spherical shape with homogeneous size and smooth surface. Encapsulation of curcumin in SLNs dramatically enhanced its antioxidant activity in aqueous condition. The cross-linking process further helped spray drying of SLNs by forming homogenous powder particles. These results indicated that coating with cross-linked polymers could significantly improve the physicochemical properties of SLNs and expand their potentials as oral delivery systems for lipophilic nutrients and drugs. [ABSTRACT FROM AUTHOR]

In this work, nanotechnology was applied to formulate a novel functional drink from all natural food ingredients and a complete formulation of nutrients, including both hydrophilic and hydrophobic vitamins as well as mineral salts, was developed. Peppermint oil dissolved in propylene glycol together with fat-soluble vitamins was first emulsified in aqueous phase with sodium caseinate as natural emulsifier to obtain nanoemulsion. Then sodium caseinate was coated with pectin to form nanocomplex particles, via electro-deposition induced by pH adjustment and heating treatment. The formulations were systematically optimized in terms of various physicochemical properties, including particle size, polydispersity index, and zeta potential. The optimal formulations, which were prepared at pH 4.5, exhibited the particle size around 250 nm with PDI < 0.25, and the zeta potential of −22 mV. The functional drink was able to retain the antioxidant activity of encapsulated nutrients during storage at both refrigeration and room temperature for up to 15 days. The functional drink was also spray dried to obtain powders with excellent redispersibility in water. The present study suggest that this nanotechnology-enabled formulation is able to simultaneously incorporate both hydrophilic and hydrophobic nutrients as well as mineral salts in a single product with great potential of health-promoting benefits. [ABSTRACT FROM AUTHOR]

Polyelectrolyte complex (PEC) nanoparticles between chitosan (CS) and biomacromolecules offer better physicochemical properties as delivery vehicles for nutrients than other CS-based nanoparticles. Our major objective was to fabricate PEC nanoparticles between water soluble gallic acid-chitosan conjugate (GA-CS) and gum arabic. The optimal fabrication method, physicochemical characteristics and stability were investigated. Furthermore, we also evaluated the effects of nano spray drying technology on the morphology and redispersibility of nanoparticle powders using Buchi B-90 Nano Spray Dryer. Results showed that the mass ratio between GA-CS and gum arabic and the preparation pH had significant contributions in determining the particle size and count rate of the nanoparticles, with the ratio of 3:1 and pH 5.0 being the optimal conditions that resulted in 112.2 nm and 122.9 kcps. The polyethylene glycol (PEG) played a vital role in forming the well-separated spray dried nanoparticles. The most homogeneous nanoparticles with the smoothest surface were obtained when the mass ratio of GA-CS and PEG was 1:0.5. In addition, the GA-CS/gum arabic spray dried nanoparticles exhibited excellent water-redispersibiliy compared to native CS/gum arabic nanoparticles. Our results demonstrated GA-CS/gum arabic nanoparticles were successfully fabricated with promising physicochemical properties and great potential for their applications in food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Solid lipid nanoparticles (SLNs) have gained tremendous attraction as carriers for controlled drug delivery. Despite numerous advances in the field, one long-standing historical challenge for their practical applications remains unmet: redispersibility after drying. In this work, a novel design of SLNs using a layer-by-layer (LbL) technique was developed and the formulations were optimized by surface response methodology (Box-Behnken design). To the best of our knowledge, this is the first study reporting the fabrication of SLNs from all natural ingredients in the absence of any synthetic surfactants or coatings. The SLNs were prepared by a combined solvent-diffusion and hot homogenization method, with soy lecithin as natural emulsifier (first layer), followed by the subsequent coating with sodium caseinate (second layer) and pectin (third layer), both of which are natural food biopolymers. The adsorption of pectin coating onto caseinate was reinforced by hydrophobic and electrostatic interactions induced by a pH-driven process along with thermal treatment. The innovative nano spray drying technology was further explored to obtain ultra-fine powders of SLNs. Compared to uncoated or single-layer coated SLNs powders, which showed severe aggregation after spray drying, the well-separated particles with spherical shape and smooth surface were obtained for layer-by-layer (LbL) SLNs, which were redispersible into water without variation of dimension, shape and morphology. The SLNs were characterized by Fourier transform infrared and high-performance differential scanning calorimetry for their physical properties. The LbL-coated SLNs based on all natural ingredients have promising features for future applications as drug delivery systems, overcoming the major obstacles in conventional spray drying and redispersing SLNs-based formulations. [ABSTRACT FROM AUTHOR]

In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20–30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. [ABSTRACT FROM AUTHOR]

Development of delivery systems from natural protein/polysaccharide complexes is of particularly interests for applications in food, pharmaceutics and biomedicine. In this study, novel nanogels smaller than 60 nm were prepared from egg yolk low density lipoprotein (LDL) and pectin complexation via a pH- and heat-induced facile process. The nanostructure of egg yolk LDL was elucidated for the first time under different pH conditions and its complexation with pectin was comprehensively investigated. Under optimized condition, the prepared nanogels had a diameter of 58 nm and zeta potential of −41 mV, with spherical shape, smooth surface, and homogeneous size distribution, as evidenced by dynamic light scattering, scanning and transmission electron microscopes. The Fourier transform infra-red spectrum revealed that hydrophobic and electrostatic interactions were the driving forces to form nanogels. The innovative Nano Spray Drying technology was studied and optimized to obtain nano-size powder of nanogels which exhibited excellent re-dispersibility in water, overcoming the drying challenge (irreversible gelation) of egg yolk LDL and greatly expanding its practical applications. Curcumin was adopted as a model compound to investigate the drug delivery potential of LDL/pectin nanogels. The mass ratio of curcumin/LDL played an essential role in determining the particle size and encapsulation efficiency. The LDL/pectin nanogels had excellent stability under simulated gastrointestinal conditions with the presence of digestive enzymes and enabled controlled release of curcumin. The novel LDL/pectin nanogels have promising features for oral delivery of nutrients and drugs. [ABSTRACT FROM AUTHOR]

In this study, we designed a series of hybrid peptides based on pep5-TAT (P-05), comprising antitumor segment (pep5), endosomal escape segment ((LLHH) 3) and cell penetrating/membrane disrupting segment (TAT, R 9 , sC18 2). These peptides exhibited remarkable antitumor activity towards tumor cells (HepG2, A549). Among them, the IC 50 values of peptide P-09 were 4.0 and 4.8 times lower than those of P-05 in HepG2 and A549 cells, respectively. It was proved that P-09 could enter tumor cells through endocytosis and direct penetration and induce the apoptosis and necrosis. The antitumor effects were attributed to the synergistic effect of membrane disruption and proteasome inhibition, which occurred during and after the cellular entry, respectively. The whole process was accompanied by excessive ROS production. In vivo , P-09 exhibited enhanced ability to inhibit the growth of HepG2 subcutaneous tumor xenografts than P-05 in nude mice. In brief, this work provided valuable insights into the design of peptide-based antitumor agents with synergistic antitumor effects. [Display omitted] • New pep5-based antitumor peptides with synergistic antitumor effect were designed and synthesized. • The synergistic antitumor effect resulted from the membrane disruption and the proteasome inhibition. • P-09 could selectively enter tumor cells and effectively induce the apoptosis and necrosis. • Introducing endosomal-escape segment into ATP-CPP offered an alternative direction for ATPs design. [ABSTRACT FROM AUTHOR]

This study successfully fabricated double-layer superhydrophobic coatings possessing good thermal and mechanical stability for cellulose-based substrates using natural and edible ingredients by a simple and low-cost casting and spray-coating technique. The first layer of the coatings was prepared by spray-coating the surfactant-free beeswax or camellia wax emulsion for providing high surface roughness and low surface energy to the coatings. Wax concentration (5, 10, and 20 mg/ml) and spray coating time (5, 10, 20, 30 s) were investigated on coating density and superhydrophobicity. The underneath second layer composed of zein particles (ZP)/cellulose nanofiber (CNF) or precipitated calcium carbonate (PCC)/CNF with different thickness (0.1, 0.3, 0.5, and 0.7 mm), was prepared by casting. The prepared coatings had micro/submicron-scale structure surface morphology. A variety of liquid foods could freely roll on the coated filter paper surfaces in spherical without leaving a trace. The introduction of PCC/CNF as the second layer significantly (P < 0.05) increased the thermal and cold stability of the superhydrophobic coatings. The apparent contact angle of PCC/CNF coatings remained to be above 150° after 30 min heating under 80 °C or 24 h cold storage under −20 °C. The mechanical stability of the two-layer coatings with PCC/CNF was also improved significantly (P < 0.05) compared with wax only single-layer coating during abrasion test. Superhydrophobic coatings prepared with beeswax showed more homogenous morphology compared to candelilla wax due to lower melting point of beeswax. The developed thermo- and abrasion-resistant edible superhydrophobic coatings can potentially be employed for a broad range of applications in food packaging. [Display omitted] • Double-layer superhydrophobic coatings were prepared via a two-step casting and spray coating method. • Zein/pectin (ZP) or precipitated calcium carbonate (PCC) were introduced as supporting layer for wax coating. • Cellulose nanofibers were used as binder to retain ZP or PCC on surface of fiber paper substrate. • Double-layer superhydrophobic coatings with PCC/CNF had excellent thermal, cold and mechanical stability. • A variety of liquid foods can roll off the double-layer superhydrophobic coatings without trace. [ABSTRACT FROM AUTHOR]

• Celluloses were extracted from apple and kale pomace by chemical treatments. • Cellulose yield from kale pomace was significantly lower than that of apple pomace. • Excessive bleaching with 2–3 % NaClO could cause severe oxidation damage to cellulose. • Moderate bleaching with 1–1.5 % NaClO and at 80 °C improved quality of cellulose. • Cellulose from apple pomace formed into films with good mechanical strength and transparency. Celluloses from apple and kale pomaces were extracted through sequentially chemical treatments, characterized, and evaluated for the film forming property. Since bleaching step is critical to cellulose quality, bleaching conditions including concentration of bleaching agent (NaClO) (0.5–3 %), temperature (60−80 °C) and time (1−2 h) were optimized. NaClO concentration and temperature exhibited significant impact on the quality of celluloses. Excessive bleaching conditions caused severe oxidation of celluloses and significantly reduced their dimension. The optimum bleaching conditions for apple pomace were identified as 1–1.5 % NaClO at 80 °C for 1 h, resulting in cellulose yield of 7.9 %, water retention value of 2.96, and whiteness index of 72.36. Morphological analysis of optimum apple pomace-celluloses revealed their long-shaped structure with 500−750 μm in length and 20−25 μm in width. The prepared cellulose films had high transparency and good mechanical strength. This study provided new insight in converting fruit processing byproducts into high quality celluloses. [ABSTRACT FROM AUTHOR]

In this study, the innovative and multifunctional nanoparticles–hydrogel nanocomposites made with chitosan hydrogel beads and solid lipid–polymer hybrid nanoparticles (SLPN) were prepared through conjugation between SLPN and chitosan beads. The SLPNs were first fabricated via coating the bovine serum albumin (BSA)-emulsified solid lipid nanoparticles with oxidized dextran. The aldehyde groups of the oxidized dextran on the surface of the SLPN enabled an in situ conjugation with the chitosan beads through the Schiff base linkage. The obtained nano-on-beads composite exhibited a spherical shape with a homogeneous size distribution. The successful conjugation of SLPN on the chitosan beads was confirmed by a Fourier transform infrared spectroscopy and a scanning electron microscope. The effects of the beads dosage (50, 100, 200, and 300 beads) and the incubation duration (30, 60, 90, 120, and 150 min) on the conjugation efficiency of SLPN onto the beads were comprehensively optimized. The optimal formulations were found to be a 200 bead dosage, with 30–90 min incubation duration groups. The optimal formulations were then used to encapsulate thymol, an antibacterial agent, which was studied as a model compound. After encapsulation, the thymol exhibited sustained release profiles in the phosphate buffer saline. The as-prepared nanoparticles–hydrogel nanocomposites reported in this proof-of-concept study hold promising features as a controlled-release antibacterial approach for improving food safety. [ABSTRACT FROM AUTHOR]

Abstract Alginate hydrogel beads have been extensively investigated as drug delivery systems due to promising gastric environment stability. In the present study, alginate hydrogel beads were prepared with Ca2+ or Fe3+ to serve as the loading vehicles for egg yolk low density lipoprotein (LDL)/pectin nanogels. Scanning electron microscope was carried out to confirm the successful incorporation of nanogels into the beads. The FT-IR spectra and swelling ratio analyses proved that incorporation of nanogels did not affect the physicochemical properties of the hydrogel beads. The developed hydrogel beads exhibited pH dependent release of curcumin pre-encapsulated in nanogels, with significant retention of curcumin in gastric condition compared to curcumin encapsulated in nanogels or alginate beads alone. Hydrogel beads prepared with low viscous alginate and Ca2+ showed limited swelling property and more sustained release of curcumin in simulated gastrointestinal conditions, compared to the beads prepared with high viscous alginate and Fe3+. Gradual dissociation of nanogels from the beads during incubation in simulated intestinal fluid was studied with transmission electron microscope. Our study demonstrated the promising potential of alginate beads as a carrier to protect LDL-based nanogels from destabilization in gastric condition, thus expanding their applications as oral delivery system. Highlights • Egg yolk LDL/pectin nanogels were incorporated into alginate hydrogel beads • Incorporation of nanogels into beads was affected by the types of cation and alginate used to prepare beads • LDL/pectin nanogels exhibited enhanced stability against aggregation during preparation of and loading into the beads • Incorporation of nanogels did not alter the physicochemical properties of beads. • Sustained kinetic release in simulated gastrointestinal fluids was achieved and verified by TEM. [ABSTRACT FROM AUTHOR]

In this work, egg yolk high density lipoprotein (HDL) was first extracted and solubilized with a salt-free method. The freshly purified egg yolk HDL was characterized for its physicochemical properties and its delivery potentials for hydrophobic bioactives were also investigated. Native chitosan (NACS) and its amphiphilic derivative (stearic acid conjugated chitosan, SACS) were adopted to fabricate polyelectrolyte nanocomplexes with egg yolk HDL and the fabrication as well as formulation of nanocomplexes were optimized. HDL/SACS and HDL/NACS nanocomplexes had a diameter of 75 nm and 97 nm, respectively. Gastrointestinal stability tests suggested that the nanocomplexes were more stable in gastric phase than in the intestinal condition with the presence of digestive enzymes (pepsin and pancreatin). Curcumin was selected as a model hydrophobic compound to assess the encapsulation and delivery potentials of HDL-based nanocomplexes. HDL/SACS nanocomplexes showed better encapsulation property than HDL/NACS nanocomplexes due to enhanced hydrophobic interactions, which was confirmed by fluorescence and surface hydrophobicity tests. The HDL/SACS nanocomplexes also exhibited slower sustained release of curcumin in simulgated GI tract, indicating the promising features as nanoscale oral delivery vehicles for hydrophobic phytochemicals. [ABSTRACT FROM AUTHOR]

Three food polymers, zein, sodium caseinate (NaCas) and pectin were exploited as the matrix to formulate colloidal complex nanoparticles for encapsulation of eugenol. A heat- and pH-induced complexation process was optimized via polymer concentrations, loading percentage of eugenol, as well as pH conditions, to obtain small, homogeneous, and stable complex nanoparticles. The particulate properties were significantly affected by pH condition during heating process, and the smallest and most homogeneous complex nanoparticles were obtained when heated at pH 6.6, the isoelectric point of zein. NaCas played an important role to achieve desirable stability during storage and spray drying. Fourier transform infrared spectroscopy indicated that hydrophobic and electrostatic interactions were driving forces to form complex structure. The innovative nano spray drying was tested to transform colloidal nanoparticles to fine powder particles, enabling the long-term storage in powder form and thus a greater potential to the applications in food industry. Under optimal preparation condition and formulation, eugenol-loaded complex nanoparticles with a size of 140 nm, spherical shape and uniform size distribution were obtained and their structure was verified by both scanning and transmission electron microscopies. [ABSTRACT FROM AUTHOR]

Egg yolk low density lipoprotein (LDL)/polysaccharide nanogels are newly explored as oral delivery systems with promising encapsulation potentials. Nonetheless, the stability of nanogels against aggregation in gastrointestinal tract remains a challenge. Therefore, chemical crosslinking by 1-ethyl-3-(3-dimethylaminopropyl) and carbodiimide/N-hydroxysuccinimide (EDC/NHS) was adopted to improve the gastrointestinal stability of nanogels. Compared to original uncrosslinked nanogels, crosslinking did not change particle size, polydispersity index (PDI) and morphology, but it reduced surface charge of nanogels. The nano spray dried LDL/CMC/EDC nanogels had relatively poor surface structure with agglomerations. The FT-IR spectra confirmed the formation of new peptide bonds, which significantly improved stability of nanogels under simulated gastrointestinal conditions. Fluorescence spectra evidenced that non-polar microenvironment for curcumin embedded in nanogels was strengthened, which therefore enhanced encapsulation efficiency. Moreover, curcumin exhibited sustained release profile from crosslinked nanogels in simulated gastrointestinal fluids. Overall, our study provided a promising strategy to enhance the stability of LDL-based nanogels in digestive conditions. [ABSTRACT FROM AUTHOR]

Five polysaccharides, pectin, carboxymethyl cellulose (CMC), gum arabic, carrageenan and alginate, were studied to form complex nanogels with egg yolk low density lipoprotein (LDL). All nanogels were smaller than 85 nm with high negative zeta potential, while LDL/carrageenan and LDL/alginate nanogels exhibited more heterogeneous size distribution. Fourier transform infrared spectrum suggested that hydrogen bonds, hydrophobic and electrostatic interactions were involved to form nanogels. Overall, significant expansion of nanogels was observed after encapsulation of curcumin, being studied as a model lipophilic nutrient. Fluorescence spectra evidenced that LDL provided non-polar microenvironment for curcumin and polysaccharides played an important role in the encapsulation process. All nanogels showed sustained release of curcumin under simulated gastrointestinal conditions. Furthermore, nanoscale, smooth and spherical ultrafine dry powders of nanogels were obtained by innovative nano spray drying technology. Our study indicated that LDL/polysaccharides may serve as potential oral delivery systems for lipophilic nutrients. [ABSTRACT FROM AUTHOR]

Phytoglycogen (PG) is a plant-based carbohydrate nanoparticle comprising of highly branched glucose monomers. In this study, we have compared three commonly used methods varying in the removal process of proteins and lipids, and developed a novel extraction/purification approach to obtain highly purified PG nanoparticles via a simple, easy, cost-efficient process combining dehulling, pH adjustment, and thermal treatment. The resulting four PG samples were subject to comprehensive characterizations, including colloidal and particulate properties, purify measurement and morphological observation. PG nanoparticles obtained from the new approach had a uniform particle size of 75 nm with less than 1% of protein impurity and more than 98.8% polysaccharide content, for which the purity was significantly higher than the other three conventional methods. In addition, the stability in simulated gastrointestinal fluids was tested for the first time and a rapid digestion behavior of PG nanoparticles under intestinal condition with the presence of pancreatin was revealed. Image 10406 • Four methods were compared to extract phytoglycogen nanoparticles (PG NPs). • Dehulling, pH adjustment and thermal coagulation were critical for high purity. • PG NPs had small size (75 nm) and low polydispersity index (<0.2). • PG NPs had exceptional colloidal stability in a wide range of pHs. • PG NPs were digested rapidly in simulated intestinal fluid with pancreatin. [ABSTRACT FROM AUTHOR]

[Display omitted] • The structured porous hydrogel scaffolds were fabricated by 3D printing. • The porous structure is more conducive to the activity and proliferation of cells in the hydrogel. • The porous structure promotes the expression of osteogenesis-related genes of BMSCs in hydrogel scaffolds. • Structured porous hydrogels produce more mineralization in vivo. Hydrogel is a suitable material for three-dimensional cell culture, and is rich in water content and can better simulate a natural extracellular matrix. However, the relatively compact pores in the interior often inhibit the growth and differentiation of containing cells. Additionally, the impact of the pore structure on the differentiation of cells remains to be unknown. In this work, porous hydrogel scaffolds with medium pore sizes (100–1000 μm) were prepared using 3D printing technology, and the hydrogel scaffolds without pores and non-printed hydrogel scaffolds were designed as control to investigate the effect of 3D printed porous structures on osteogenic differentiation of BMSCs within hydrogel scaffolds, both in vitro and in vivo. The pore structure of 3D printed structured porous scaffold was explicitly inspected by SEM. The water content and expansion rate of hydrogel did not change, despite its porous structure. The BMSCs were evenly distributed across the porous scaffold and maintained high activity, thus benefiting from the sufficient circulation and diffusion of oxygen and nutrients due to the regular pores. In vitro , the osteogenic differentiation of BMSCs in the structured porous hydrogels was more prominent compared to the non-porous groups. Moreover, the mineralization of the hydrogel scaffolds was also enhanced. After ectopic implantation in the posterior gluteal muscle punch, the structured porous hydrogel exhibited relatively good mineralization and ectopic osteogenesis by the three-dimensional reconstruction of micro-CT, collagen staining, and immunological analysis. The 3D printing-based approach provides a facile strategy for the preparation of hydrogels with intermediate pore structures. This can promote the viability and osteogenic differentiation of BMSCs in hydrogel scaffolds. [ABSTRACT FROM AUTHOR]

Phytoglycogen (PG) is a carbohydrate biomaterial with naturally occurring dendrimer-like nanostructures. Being a hyperbranched α-D-glucan, PG holds promising potential to encapsulate bioactive compounds, but on the other hand it is highly susceptible to digestive degradations, limiting its applications as oral delivery vehicles for bioactive compounds. In this study, we exploited chemical modification, i.e. carboxymethylation, to turn PG into a polyelectrolyte (CMPG) with abundant surface carboxylic groups carrying negative charge. Sodium caseinate (NaCas), an amphiphilic protein molecule, was studied to form nanocomplex with CMPG via a pH- and heating-induced complexation. The fabrication of CMPG/NaCas nanocomplex was optimized based on biopolymer concentrations, mass ratios, pH conditions and heating temperatures. Heating the CMPG/NaCas mixture at mass ratio of 2:1, pH 4.6 (isoelectric point of NaCas), and 60 °C for 1 h was the optimal preparation condition to form nanocomplex. Both Fourier transform infrared and fluorescence spectroscopies revealed that the driving forces to form nanocomplex were primarily electrostatic interactions and hydrogen bonding, with limited contributions from hydrophobic interactions. Spherical nanoparticles with a size of 65 nm and uniform size distribution were characterized by dynamic light scattering and visualized by transmission electron microscopy. The colloidal stability under simulated gastrointestinal conditions was greatly improved after the formation of nanocomplex. CMPG/NaCas nanocomplex was capable to encapsulate curcumin with a sustained release profile under simulated gastrointestinal conditions. Nevertheless, heating process was found to have a negative impact on the encapsulation capability of nanocomplex for curcumin, due to highly hydrophilic nature of CMPG. Image 1 • Carboxymethylated phytoglycogen was prepared with a smaller particle size. • Electrostatic interactions were the driving force to form nanocomplex with caseinate. • Nanocomplex demonstrated good stability under simulated gastrointestinal conditions. • Heating negatively affected the encapsulation capability of nanocomplex for curcumin. [ABSTRACT FROM AUTHOR]