Search

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 30min), 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 200nm 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., (Copyright © 2017 Elsevier Inc. All rights reserved.)

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., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The toxicity associated with concentrated synthetic surfactants and the poor stability at gastrointestinal condition are two major constraints for practical applications of solid lipid nanoparticles (SLN) as oral delivery vehicles. In this study, a synthetic surfactant-free and cross-linker-free method was developed to fabricate effective, safe, and ultra-stable lipid-polymer hybrid nanoparticles (LPN). Bovine serum albumin (BSA) and dextran varying in molecular weights were first conjugated through Maillard reaction and the conjugates were exploited to emulsify solid lipid by a solvent diffusion and sonication method. The multilayer structure was formed by self-assembly of BSA-dextran micelles to envelope solid lipid via a pH- and heating-induced facile process with simultaneous surface deposition of pectin. The efficiency of different BSA-dextran conjugates was systematically studied to prepare LPN with the smallest size, the most homogeneous distribution and the greatest stability. The molecular interactions were characterized by Fourier transform infrared and fluorescence spectroscopies. Both nano spray drying and freeze-drying methods were tested to produce spherical and uniform pectin-coated LPN powders that were able to re-assemble nanoscale structure when redispersed in water. The results demonstrated the promise of a synthetic surfactant- and cross-linker-free technique to prepare highly stable pectin-coated LPN from all natural biomaterials as potential oral delivery vehicles.

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 112.2nm and 122.9kcps. 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., (Copyright © 2016 Elsevier B.V. All rights reserved.)

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., (Copyright © 2016 Elsevier B.V. All rights reserved.)

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., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The highly efficient enrichment of particles in microfluidics is of great significance in various biochemical studies. Here, a Polydimethylsiloxane (PDMS) membrane structure with small holes is proposed to promote the spinning of droplets in the acoustic microfluidic system. A finite element method (FEM) model based on the moving mesh method is established to analyze the streamline and particle motion in the droplet. The spinning and the dynamic deformation of the droplet are considered comprehensively. Results show that the deformation and spinning of the droplet can promote the enrichment of particles, and the deformation of the droplet is the key reason for the enrichment of nanoparticles. By analyzing the spatial streamline inside the droplet, it is found that the particles will be enriched at a certain height from the bottom of the droplet, which is confirmed in the experiment and to date has not been reported before. Furthermore, the acoustic microfluidic system is manufactured, tested and applied to the enrichment of 100 nm particles. The fluorescence intensity of the enriched particles can be used to characterize the concentration of the sample, indicating that the system is expected to be applied to the enrichment detection of biological particles such as extracellular vesicles. [Display omitted] • A moving mesh mode is proposed to analyze the spinning deformation of droplets. • PDMS film is applied to fix droplets and promote their spinning. • Droplets spinning deformation is the key reason for nanoparticles enriched. • Enrichment detection can be realized by the acoustic microfluidic system. [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]