Application of Nanoparticles in Human Nutrition: A Review

Nanotechnology in human nutrition represents an innovative advance in increasing the bioavailability and efficiency of bioactive compounds. This work delves into the multifaceted dietary contributions of nanoparticles (NPs) and their utilization for improving nutrient absorption and ensuring food safety. NPs exhibit exceptional solubility, a significant surface-to-volume ratio, and diameters ranging from 1 to 100 nm, rendering them invaluable for applications such as tissue engineering and drug delivery, as well as elevating food quality. The encapsulation of vitamins, minerals, and antioxidants within NPs introduces an innovative approach to counteract nutritional instabilities and low solubility, promoting human health. Nanoencapsulation methods have included the production of nanocomposites, nanofibers, and nanoemulsions to benefit the delivery of bioactive food compounds. Nutrition-based nanotechnology and nanoceuticals are examined for their economic viability and potential to increase nutrient absorption. Although the advancement of nanotechnology in food demonstrates promising results, some limitations and concerns related to safety and regulation need to be widely discussed in future research. Thus, the potential of nanotechnology could open new paths for applications and significant advances in food, benefiting human nutrition.

Development and cytotoxicity evaluation of multiple nanoemulsions for oral co-delivery of 5-fluorouracil and short chain triglycerides for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world, but current chemotherapy options are limited due to adverse effects and low oral bioavailability of drugs. In this study, we investigated the obtainment parameters and composition of new multiple nanoemulsions (MN) based on microemulsions for oral co-delivery of 5-fluorouracil (5FU) and short-chain triglycerides (SCT, either tributyrin or tripropionin). The area of microemulsion formation was increased from 14% to 38% when monocaprylin was mixed with tricaprylin as oil phase. Addition of SCT reduced this value to 24-26%. Using sodium alginate aqueous dispersion as internal aqueous phase (to avoid phase inversion) did not further affected the area but increased microemulsion viscosity by 1.5-fold. To obtain the MN, selected microemulsions were diluted in an external aqueous phase; droplet size was 500 nm and stability improved using polyoxyethylene (den Besten et al., 2013) oleyl ether at 1-2.5% as surfactant in the external phase and a dilution ratio of 1:1 (v/v). 5FU in vitro release could be better described by the Korsmeyer-Peppas model. No pronounced changes in droplet size were observed when selected MNs were incubated in buffers mimicking gastrointestinal fluids. The 5FU cytotoxicity in monolayer cell lines presenting various mutations was influenced by its incorporation in the nanocarrier, presence of SCT and cell mutation status. The MNs selected reduced the viability of tumor spheroids (employed as 3D tumor models) by 2.2-fold compared to 5FU solution and did not affect the survival of the G. mellonella, suggesting effectiveness and safety.

Updated insight into the characterization of nano-emulsions

INTRODUCTION

In most of the studies, nano-emulsion characterization is limited to their size distribution and zeta potential. In this review, we present an updated insight of the characterization methods of nano-emulsions, including new or unconventional experimental approaches to explore in depth the nano-emulsion properties.

AREA COVERED

We propose an overview of all the main techniques used to characterize nano-emulsions, including the most classical ones, up to in vitro, ex vivo and in vivo evaluation. Innovative approaches are then presented in the second part of the review that presents innovative, experimental techniques less known in the field of nano-emulsion such as the nanoparticle tracking analysis, small-angle X-ray scattering, Raman spectroscopy, and nuclear magnetic resonance. Finally, in the last part we discuss the use of lipophilic fluorescent probes and imaging techniques as an emerging tool to understand the nano-emulsion droplet stability, surface decoration, release mechanisms, and in vivo fate.

EXPERT OPINION

This review is mostly intended for a broad readership and provides key tools regarding the choice of the approach to characterize nano-emulsions. Innovative and uncommon methods will be precious to disclose the information potentially reachable behind a formulation of nano-emulsions, not always known in first intention and with conventional methods.

Impact of Recombined Milk Systems on Gastrointestinal Fate of Curcumin Nanoemulsion

Milk powder is an important ingredient in various foods and pediatric formulations. The textural and digestion properties of the formulations depend on the preheat treatment of the milk powder during manufacture. Thus, it is interesting to know how these modifications can influence on the release of fortified bioactive compounds during digestion with a milk matrix. In this study, a curcumin nanoemulsion was incorporated into milks reconstituted from low-heat, medium-heat and high-heat skim milk powders (SMPs) and the milks were subjected to semi dynamic in vitro digestion. All the recombined milk systems formed a curd under gastric conditions, which reduced the gastric emptying of protein and curcumin-loaded oil droplets. Because of the formation of heat-induced casein/whey protein complexes, the open fragmented curd formed by the high-heat-treated reconstituted powder resulted in higher protein and oil droplets emptying to the intestine and higher curcumin bioaccessibility. This study provides useful information for how protein ingredients can govern the fate of added health-promoting compounds during digestion.

In vitro Bioaccessibility and Intestinal Absorption of Selected Bioactive Compounds in Terminalia ferdinandiana

Terminalia ferdinandiana (or Kakadu plum), a native Australian fruit with potential health benefits, contains bioactive compounds such as ellagic acid (EA), ascorbic acid (AA) and calcium, and antinutrients such as oxalic acid (OA). However, few is known about the biological fate of these compounds following ingestion; therefore, the aim of this study was to evaluate in vitro bioaccessibility and intestinal absorption of T. ferdinandiana compounds using the INFOGEST static digestion model and Caco-2-HT29-MTX-E12 intestinal absorption model. No significant changes (p > 0.05) were observed in total AA content throughout in vitro digestion, whereas bioaccessibility of EA, OA, and calcium increased significantly from 33, 72, and 67% in the gastric phase to 48, 98, and 90% in the intestinal phase, respectively. The intestinal absorption study revealed variable rates of movement across the cell barrier. Findings reveal novel and important insights for the prediction of in vivo bioavailability of selected T. ferdinandiana compounds.

Anti-aging properties of phytoconstituents and phyto-nanoemulsions and their application in managing aging-related diseases

Aging is spontaneous and inevitable process in all living beings. It is a complex natural phenomenon that manifests as a gradual decline of physiological functions and homeostasis. Aging inevitably leads to age-associated injuries, diseases, and eventually death. The research on aging-associated diseases aimed at delaying, preventing or even reversing the aging process are of great significance for healthy aging and also for scientific progress. Numerous plant-derived compounds have anti-aging effects, but their therapeutic potential is limited due to their short shelf-life and low bioavailability. As the novel delivery system, nanoemulsion can effectively improve this defect. Nanoemulsions enhance the delivery of drugs to the target site, maintain the plasma concentration for a longer period, and minimize adverse reaction and side effects. This review describes the importance of nanoemulsions for the delivery of phyto-derived compounds and highlights the importance of nanoemulsions in the treatment of aging-related diseases. It also covers the methods of preparation, fate and safety of nanoemulsions, which will provide valuable information for the development of new strategies in treatment of aging-related diseases.

Optimizing the Process Design of Oil-in-Water Nanoemulsion for Delivering Poorly Soluble Cannabidiol Oil

Process approaches and intensification technological processes are integrated parts of available devices, which have a positive effect on the parameters of the obtained products. Nanoemulsions as delivery carriers are becoming more popular and there is a real need to increase the possibilities of formulation designing and engineering. Therefore, preparations of oil-in-water nanoemulsion with encapsulated cannabidiol (CBD) as oil phase were carried out in two ways: sonication method and two-stage high-pressure homogenization. The provided analysis showed spherical morphology and much larger sizes and polydispersity of nanoemulsions obtained by the sonication approach. The size of nanodroplets was from 216 nm up to 1418 nm for sonication, whereas for homogenization 128–880 nm. Additionally, it was observed that a proportionally higher percentage of surfactin resulted in a higher value of the Zeta potential. The formulations were found to be stable for at least 30 days. The in vitro experiments performed on human skin cell lines (HaCaT keratinocytes and normal dermal NHDF fibroblasts), and in vivo topical tests on probants established the biocompatibility of nanoemulsions with CBD. The last stage exhibits reduced discoloration and a higher degree of hydration by the selected systems with CBD and, thus indicating this nanoformulation as useful in cosmetics applications.

Hormesis-Inducing Essential Oil Nanodelivery System Protects Plants against Broad Host-Range Necrotrophs

Botrytis cinerea, a broad host-range necrotrophic (BHN) phytopathogen, establishes compatible interactions with hosts by deploying multigene infection strategies, rendering simply inherited resistance ineffective to fight off this pathogen. Since essential oils (EOs) serve as intermediators during phytobiome communication, we hypothesize that they have the potential to enhance the quantitative disease resistance against BHN by eliciting the adaptive stress response (hormesis) in plants. However, using EOs is challenging due to their poor solubility in water. Nanoemulsification of EOs enhances not only the solubility of EOs but also their potency and stability. Here, we demonstrate the potential use of essential oil nanoemulsions (EONEs) to control infections caused by BHN. Using basic engineering principles of nanocarrier design, we demonstrate the efficacy of a robust EONEs design for controlling B. cinerea infection in a model plant, Arabidopsis thaliana. Our nanoemulsion delivery system significantly enhanced the disease resistance of the host by reducing the necrotic area by up to 50% compared to untreated plants. RNA-seq analysis indicated that successful treatments upregulated autophagy, ROS scavenging, and activation of the jasmonic acid signaling pathway.

Nanocomposite sponges for enhancing intestinal residence time following oral administration

In this work, nanocomposites that combine mucopenetrating and mucoadhesive properties in a single system are proposed as innovative strategy to increase drug residence time in the intestine following oral administration. To this aim, novel mucoadhesive chitosan (CH) sponges loaded with mucopenetrating nanoemulsions (NE) were developed via freeze-casting technique. The NE mucopenetration ability was determined studying the surface affinity and thermodynamic binding of the nanosystem with mucins. The ability of nanoparticles to penetrate across a preformed mucins layer was validated by 3D-time laps Confocal Laser Scanning Microscopy imaging. Microscopy observations (Scanning Electron Microscopy and Optical Microscopy) showed that NE participated in the structure of the sponge affecting its stability and in vitro release kinetics. When incubated with HCT 116 and Caco-2 cell lines, the NE proved to be cytocompatible over a wide concentration range. Finally, the in vivo biodistribution of the nanocomposite was evaluated after oral gavage in healthy mice. The intestinal retention of NE was highly enhanced when loaded in the sponge compared to the NE suspension. Overall, our results demonstrated that the developed nanocomposite sponge is a promising system for sustained drug intestinal delivery.

Advances in edible nanoemulsions: Digestion, bioavailability, and potential toxicity

The design, fabrication, and application of edible nanoemulsions for the encapsulation and delivery of bioactive agents has been a highly active research field over the past decade or so. In particular, they have been widely used for the encapsulation and delivery of hydrophobic bioactive substances, such as hydrophobic drugs, lipids, vitamins, and phytochemicals. A great deal of progress has been made in creating stable edible nanoemulsions that can increase the stability and efficacy of these bioactive agents. This article highlights some of the most important recent advances within this area, including increasing the water-dispersibility of bioactives, protecting bioactives from chemical degradation during storage, increasing the bioavailability of bioactives after ingestion, and targeting the release of bioactives within the gastrointestinal tract. Moreover, it highlights progress that is being made in creating plant-based edible nanoemulsions. Finally, the potential toxicity of edible nanoemulsions is considered.

Eugenol loaded chitosan nanoemulsion for food protection and inhibition of Aflatoxin B1 synthesizing genes based on molecular docking

The present investigation entails the fabrication and characterization of nanometric emulsion of eugenol (Nm-eugenol) encompassed into chitosan for assessing bio-efficacy in terms of in vitro antifungal actions, antiaflatoxigenic potential, and in situ preservative efficacy against Aspergillus flavus infestation and aflatoxin B₁ (AFB₁) mediated loss of dietary minerals, lipid triglycerides and alterations in composition of important macronutrients in stored rice. Nm-eugenol characterized by SEM, XRD, and FTIR exhibited biphasic burst release of eugenol. Reduction in ergosterol and methylglyoxal (AFB₁-inducer) content after Nm-eugenol fumigation depicted biochemical mechanism of antifungal and antiaflatoxigenic activities. In silico 3D homology docking of eugenol with Ver-1 gene validated molecular mechanism of AFB₁ inhibition. Further, significant protection of rice seeds from fungi, AFB₁ contamination and preservation against loss of rice minerals, macronutrients and lipids during storage suggested deployment of chitosan as a biocompatible wall material for eugenol encapsulation and application as novel green preservative for food protection.

Bergamot essential oil nanoemulsions: antimicrobial and cytotoxic activity

Bergamot essential oil (BEO) is well-known for its food preservation activity, as well as anticancer efficacy. However, the poor BEO water solubility and deriving low bioaccessibility have limited its wider applications. The incorporation in nanoemulsions of BEO and its refined fractions was investigated to enhance its dispersibility in water to promote its antimicrobial activity, tested against Escherichia coli, Lactobacillus delbrueckii, and Saccharomyces cerevisiae, and its cytotoxicity already at low concentrations. Different nanoemulsion formulations were tested based on food-grade ingredients, which were characterized in terms of hydrodynamic diameter and polydispersity index, and physical stability. The antimicrobial activity against all the tested micro-organisms was observed to be higher for BEO in its initial composition, than the light fraction, richer in d-limonene, ß-pinene, and γ-terpinene, or the heavy fraction, richer in linalyl acetate and linalool. Remarkably, the use of BEO nanoemulsions notably enhanced the antimicrobial activity for all the tested oils. BEO exhibited also a measurable cytotoxic activity against Caco-2 cells, which was also enhanced by the use of the different nanoemulsions tested, in comparison with free oil, which discourages the direct use of BEO nanoemulsions as a food preservative. Conversely, BEO nanoemulsions might find use in therapeutic applications as anticarcinogenic agents.

Depletion-Induced Flocculation of Concentrated Emulsions Probed by Photon Density Wave Spectroscopy

Stable, creaming-free oil in water emulsions with high volume fractions of oil (ϕ = 0.05-0.40, density matched to water) and polysorbate 80 as an emulsifier were characterized without dilution by Photon Density Wave spectroscopy measuring light absorption and scattering behavior, the latter serving as the basis for droplet size distribution analysis. The emulsion with ϕ = 0.10 was used to investigate flocculation processes induced by xanthan as a semi-flexible linear nonabsorbing polymer. Different time regimes in the development of the reduced scattering coefficient μ_s' could be identified. First, a rapid, temperature-dependent change in μ_s' during the depletion process was observed. Second, the further decrease of μ_s' follows a power law in analogy to a spinodal demixing behavior, as described by the Cahn-Hilliard theory.

Hierarchically structured phase separated biopolymer hydrogels create tailorable delayed burst release during gastrointestinal digestion

The on demand delivery of novel peptide actives, traditional pharmaceuticals, nutrients and/or vitamins is a ever present challenge due to the digestive and metabolic degradation of the active and the delivery vehicle. Biodegradable biopolymer hydrogels have long held promise as candidates for creating tailored release profiles due to the ability to control gel porosity. The present study describes the creation of novel hierarchical biopolymer hydrogels for the controlled release of lipids/lipophilic actives pharmaceutical ingredients (APIs), and mathematically describes the mechanisms that affect the timing of release. The creation of phase separated protein/polysaccharide core (6.6 wt% gelatin, 40 wt% Oil in water emulsion) shell structures (7 g/L xanthan with 70-140 g/L β-lactoglobulin) altered enzyme mass transport processes. This core shell structure enabled the creation of a tailorable burst release of API during gastrointestinal digestion where there is a delay in the onset of release, without affecting the kinetics of release. The timing of the delay could be readily programmed (with release of between 60 and 240 min) by controlling either the thickness or protein concentration (between 70 g/L and 140 g/L β-lactoglobulin) of the outer mixed biopolymer hydrogel shell (7 g/L xanthan with 70-140 g/L β-lactoglobulin). Enzyme diffusion measurements demonstrated that surface erosion was the main degradation mechanism. A kinetic model was created to describe the delayed burst release behaviour of APIs encapsulated within the core, and successfully predicted the influence of shell thickness and shell protein density on the timing of gastro-intestinal release (in vitro). Our work highlights the creation of a novel family of core-shell hydrogel oral dosage forms capable of programmable delivery of lipids/lipophilic APIs. These findings could have considerable implications for the delivery of peptides, poorly soluble drugs, or the programmed delivery of lipids within the gastrointestinal tract.

Stabilization of Dispersed Oil Droplets in Nanoemulsions by Synergistic Effects of the Gemini Surfactant, PHPA Polymer, and Silica Nanoparticle

Nanoemulsion systems comprising n-heptane (oleic component), stabilized by the {gemini surfactant (14-6-14 GS) + polymer [partially hydrolyzed poly-acrylamide (PHPA)] + silica (SiO₂) nanoparticle} shell and dispersed in aqueous phase, were synthesized by ultrasonication (high-energy method). Influence of ultrasonication time on nanoemulsion kinetics was investigated to predict the saturation droplet diameter. Morphological analysis by transmission electron cryomicroscopy imaging showed that oleic phase appears as uniformly dispersed spherical droplets in 14-6-14 GS-stabilized nanoemulsion, which on PHPA addition changes into a network structure consisting of larger oil droplets. 14-6-14 + PHPA + SiO₂ nanoemulsion systems show more effective packing arrangement with irregular-shaped (nonspherical) droplets. Dynamic light scattering studies identified droplet size distribution profiles in the range 4.2-25.4 nm for the surfactant-stabilized nanoemulsion, 125.9-358.8 nm for the surfactant-polymer nanoemulsion, and 88.4-222.3 nm for the surfactant-polymer-nanoparticle-based nanoemulsion in optimal dosage(s). Statistical analyses were performed using normal, log-normal, and Cauchy-Lorentz distribution functions. A modified form of Hinze theory was employed to model droplet behavior in analyzed nanoemulsion systems. Zeta potential values of nanoemulsions were studied at different time intervals to determine kinetic stability as well as corroborate Hinze model findings. In summary, this article aims at investigating nanoemulsion droplet stability by thorough examination of electrostatic repulsive barrier and steric hindrance effects.

The delivery of sensitive food bioactive ingredients: Absorption mechanisms, influencing factors, encapsulation techniques and evaluation models

Food-sourced bioactive compounds have drawn much attention due to their health benefits such as anti-oxidant, anti-cancer, anti-diabetes and cardiovascular disease-preventing functions. However, the poor solubility, low stability and limited bioavailability of sensitive bioactive compounds greatly limited their application in food industry. Therefore, numbers of carriers were developed for improving their dispersibility, stability and bioavailability. This review addresses the digestion and absorption mechanisms of bioactive compounds in epithelial cells based on several well-known in vitro and in vivo models. Factors such as environmental stimuli, stomach conditions and mucus barrier influencing the utilization efficacy of the bioactive compounds are discussed. Delivery systems with enhanced utilization efficacy, such as complex coacervates, cross-linked polysaccharides, self-assembled micro-/nano-particles and Pickering emulsions are compared. It is a comprehensive multidisciplinary review which provides useful guidelines for application of bioactive compounds in food industry.

Effects of interesterified lipid design on the short/medium chain fatty acid hydrolysis rate and extent (in vitro)

Short/medium chain fatty acids have well known health effects such as gut immune regulation and ketogenesis.

Enhanced delivery of lipophilic bioactives using emulsions: a review of major factors affecting vitamin, nutraceutical, and lipid bioaccessibility

Many researchers are currently developing emulsion-based delivery systems to increase the bioavailability of lipophilic bioactive agents, such as oil-soluble vitamins, nutraceuticals, and lipids. Oil-in-water emulsions can be specifically designed to improve the bioavailability of these bioactives by altering their composition and structural organization. This article reviews recent progress in understanding the impact of emulsion properties on the bioaccessibility of lipophilic bioactive agents, including oil phase composition, aqueous phase composition, droplet size, emulsifier type, lipid physical state, and droplet aggregation state. This knowledge can be used to design emulsions that can enhance the bioavailability and efficacy of encapsulated hydrophobic bioactives.