Controlled formation and stabilization of nanosized colloidal suspensions by combination of soy protein and biosurfactant stevioside as stabilizers

Suspension of micro- and nanoplastic test materials: Liquid compatibility, (bio)surfactants, toxicity and environmental relevance

Micro- and nanoplastics have been detected in environmental compartments from the highest mountains to the deepest seas. They have been shown to be present at almost all trophic levels, and within humans they have been detected in numerous organs and human stool. Whilst their ubiquitous nature is indisputable, little is known about the health risks they may present. Much current research is focussed on the production of test materials with which to perform the necessary health studies. An important aspect of this is the correct storage and suspension of the materials to ensure they remain stable both chemically and with regards to size and shape. In this review, we look at the chemical stability of nine common polymers in a range of liquids; first with the use of commercial compatibility charts and then with a more quantitative approach using Hansen solubility parameters. We then look at stability with regards to particle agglomeration, whether and how stable compositions can be predicted, and which dispersants can be added to increase stability. Finally, we discuss the role of bio-surfactants and the eco-corona and how these may offer a route to both better stability and environmental relevance.

Effects of ultrasonic pretreatment of soybean protein isolate on the binding efficiency, structural changes, and bioavailability of a protein-luteolin nanodelivery system

The combination of protein and flavonoids can ameliorate the problems of poor solubility and stability of flavonoids in utilization. In this study, soybean protein isolate pretreated by ultrasonication was selected as the embedding wall material, which was combined with luteolin to form a soybean protein isolate-luteolin nanodelivery system. The complexation effect and structural changes of soybean protein isolate (SPI) and ultrasonic pretreatment (100 W, 200 W, 300 W, 400 W and 500 W) of soybean protein isolate with luteolin (LUT) were compared, as well as the changes in digestion characteristics and antioxidant activity in vitro. The results showed that proper ultrasonic pretreatment increased the encapsulation efficacy, loading amount and solubility to 89.72%, 2.51 μg/mg and 90.56%. Appropriate ultrasonic pretreatment could make the particle size and the absolute value of ζ-potential of SPI-LUT nanodelivery system decrease and increase respectively. The FTIR and fluorescence results show that appropriate ultrasonic pretreatment could reduce α-helix, β-sheet and random coil, increase β-turn, and enhance fluorescence quenching. The thermodynamic evaluation results indicate that the ΔG < 0, ΔH > 0 and ΔS > 0, so the interaction of LUT with the protein was spontaneous and mostly governed by hydrophobic interactions. The XRD results show that the LUT was amorphous and completely wrapped by SPI. The DSC results showed that ultrasonic pretreatment could improve the thermal stability of SPI-LUT nanodelivery system to 112.66 ± 1.69 °C. Digestion and antioxidant analysis showed that appropriate ultrasonic pretreatment increased the LUT release rate and DPPH clearance rate of SPI-LUT nanodelivery system to 89.40 % and 55.63 % respectively. This study is a preliminary source for the construction of an SPI nanodelivery system with ultrasound pretreatment and the deep processing and utilization of fat-soluble active substances.

Study on physicochemical characteristics of lutein nanoemulsions stabilized by chickpea protein isolate-stevioside complex

BACKGROUND

Chickpea protein isolate (CPI) originating from chickpeas has the advantages of facilitating the stability of food emulsions. Stevioside (STE) exhibits a notable surface activity and can improve the water solubility of numerous hydrophobic nutrients. STE and protein mixtures show great potential as emulsions stabilizers. The present study aimed to prepare a novel nanoemulsion for encapsulating lutein (LUT) by ultrasonic homogenization using chickpea protein isolate-stevioside complex (CPI-STE) as a stabilizer and also to investigate the physicochemical characteristics.

RESULTS

The results obtained showed that different preparation conditions demonstrated significant influences on the physicochemical properties of CPI-STE-LUT nanoemulsions. Under the optimal condition, the average particle size of CPI-STE-LUT nanoemulsions was 195.1 nm, and the emulsifying and encapsulation efficiencies of lutein were 91.04% and 87.56%, respectively. CPI-STE-LUT nanoemulsions stabilized by CPI-STE could significantly increase the emulsifying and encapsulation efficiencies of lutein compared to that stabilized by CPI. Fourier transform infrared spectroscopy revealed that hydrogen bond was the main binding force of CPI and lutein, and there was a covalent bond between the two molecules. Furthermore, the stability of CPI-STE-LUT nanoemulsions in gastrointestinal phase was higher than that of CPI-LUT nanoemulsions, which could load lutein more effectively and be more resistant to digestive enzymes.

CONCLUSION

The present study reports the physicochemical characterization of CPI-STE-LUT nanoemulsions for the first time. CPI-STE-LUT nanoemulsions were characterized by a small average particle size lower than 200 nm, as well as high emulsifying and encapsulation efficiencies, and good stability. © 2021 Society of Chemical Industry.

pH-Responsive Pickering high internal phase emulsions stabilized by Waterborne polyurethane

HYPOTHESIS

Waterborne polyurethane (WPU) is a common colloidal dispersion that can aggregate in the aqueous phase to form nanoparticles with hydrophobic polyurethane chains as the core and hydrophilic ionic groups as the shell. Considering their structure and pH-responsive functional groups, WPU nanoparticles could be ideal particulate emulsifiers for preparing pH-responsive Pickering high internal phase emulsions (HIPEs).

EXPERIMENTS

A series of anionic WPU with different content of 2,2-bis(hydroxymethyl)propionic acid (DMPA) side chains were synthesized via a polyaddition reaction. The DMPA content, size, ζ-potential, and interfacial behaviors of WPU were then investigated. Furthermore, the effects of particle concentration, internal phase fraction (ϕ), oil type, and pH values on the Pickering HIPEs' morphology, stability, and rheological behaviors were systematically studied. Finally, we demonstrated the emulsification-demulsification process of WPU-stabilized Pickering HIPEs and discussed its mechanism.

FINDINGS

Oil-in-water (O/W) Pickering HIPEs with tailored morphology and excellent pH-responsiveness were prepared from anionic WPU nanoparticles. The WPU concentration, ϕ, and oil type had a large impact on the formation and mean droplet size of the WPU-stabilized emulsions. Rheology analysis demonstrated that the strictly limited movement of droplets endowed the WPU-stabilized HIPEs with high stability, shear sensitivity, and excellent thixotropic recovery. By simply changing the aqueous-phase pH value, the WPU-stabilized HIPEs could undergo more than ten emulsification-demulsification cycles, as the physical and interfacial properties of WPU nanoparticles were pH-dependent. The excellent performance of the WPU-stabilized pH-responsive Pickering HIPEs exhibited their potential practical applications, such as for oil transportation and recovery, emulsion polymerization, and heterogeneous catalysis.

(Carboxymethyl-stevioside)-coated magnetic dots for enhanced magnetic hyperthermia and improved glioblastoma treatment

The use of different types of biomaterials as surfactant moities has a defined role in magnetic hyperthermia-mediated cancer therapy (MHCT). In this work, we present carboxymethyl-stevioside (CMS)-modified magnetic dots (MDs) as efficient magnetic hyperthermia agents for glioma therapy. The synthesized MDs with CMS biosurfactant coating exhibited significant water stability that resulted in a remarkable specific absorption rate of 209.25 W/g on application of alternating magnetic field of strength 359 kHz and 188 Oe. The MDs further demonstrated significant anti-migratory and anti-invasive effect on glioma C6 cells by inhibiting the gene expression of matrix metalloproteinases-2 and -9. The effect of immediate and long term hyperthermia treatment was then evaluated after repetitive exposure to hyperthermia, in terms of glioma cell viability, the effect of treatment on cell morphology, the cell cycle distribution and oxidative stress generation. The results obtained suggest the promising potential of CMS-modified nano-heaters for excellent magnetic hyperthermia-mediated glioma therapy.

Study on the bioavailability of stevioside-encapsulized lutein and its mechanism

This study aims to develop novel lutein nanoparticles encapsulized by stevioside (LUT-STE, 165 ± 2 nm average particles size) and systematically evaluate its bioavailability. Multiple spectroscopy and NMR analyses showed lutein and stevioside could interact through hydrogen bonds, CHπ interaction and van der Waals forces. Molecular docking simulation showed lutein was well distributed in the hydrophobic cavity of stevioside. Analyzed by Caco-2 cellular models, the transported amount of LUT-STE was 2.39 times that of lutein in 120 min with a P_app (B → A)/P_app (A → B) value of 0.63 ± 0.04. Nystatin and dynasore significantly reduced the cellular uptake of LUT-STE by 41.3% and 57.7%, respectively. Compared with free lutein, LUT-STE increased the C_max in mice plasma by 5.01-fold and promoted the accumulation in multiple organs. LUT-STE promoted the protein expressions of CD36, NPC1L1 and PPARγ in both cell and animal models. In conclusion, stevioside entrapment significantly promote the bioavailability of lutein through multiple transmembrane pathways.

pH-Driven formation of soy peptide nanoparticles from insoluble peptide aggregates and their application for hydrophobic active cargo delivery

The insoluble soy peptide aggregates formed upon proteolysis are generally considered as "ready to be discarded", which placed additional burden on related industries. In this study, with the aim of promoting sustainable utilization of these large aggregates, novel soy peptide-based nanoparticles (SPN) were successfully fabricated from these aggregates via a controlled pH-shifting method, and the obtained SPN exhibited good storage stability and antioxidant activity. Furthermore, the pH-shifting process also provided a driven force for loading and delivering curcumin, which significantly improved its water solubility (up to 10⁵ folds), storage and simulated gastric-intestinal digestive stability, as well as in vitro bioavailability and antioxidant activity. These results indicated that controlled pH-shifting could be an effective and facile method to trigger the assembly of insoluble aggregates into functional peptide nanoparticles for the delivery of bioactive cargoes, which provided a new strategy for the sustainable and high-value application of these low-value peptide byproducts.

Formation, Physicochemical Stability, and Redispersibility of Curcumin-Loaded Rhamnolipid Nanoparticles Using the pH-Driven Method

The aim of the present work was to fabricate the curcumin-loaded rhamnolipid nanoparticles using the pH-driven method to enhance the physicochemical stability and redispersibility of curcumin. The mixture of curcumin and rhamnolipid could be spontaneously assembled into the curcumin-loaded rhamnolipid nanoparticles with a small size (107 nm) and negative charge (-45.5 mV). Curcumin molecules could bind to rhamnolipid molecules through hydrophobic effects and hydrogen bonds. The effect of different mass ratios of rhamnolipid and curcumin (1:2, 1:1, 2:1, 4:1, 6:1, and 8:1) on the functional property of the curcumin-loaded rhamnolipid nanoparticles was investigated. With the rise of rhamnolipid and curcumin mass ratio, the encapsulation efficiency of curcumin in the nanoparticles was increased from 44.59% to 81.12% and the loading capacity of curcumin was elevated from 10.14% to 31.67%. When the mass ratio of rhamnolipid and curcumin was 4:1, the curcumin-loaded rhamnolipid nanoparticles exhibited better physical stability, pH stability, and redispersibility. Moreover, the nanoparticles could effectively protect curcumin against the photodegradation and thermal degradation. Therefore, the rhamnolipid nanoparticles have the potential to be applied as a nanodelivery system for bioactive molecules in functional foods.

Addition of Selected Plant-Derived Proteins as Modifiers of Inulin Hydrogels Properties

The aim of the study was to determine the effects of pea and soy protein addition (1, 3, 6 g/100 g) on inulin hydrogels properties. Inulin hydrogels (20 g/100 g) were obtained by thermal induction. It was stated that tested plant protein might be used as a modifier of inulin hydrogels properties. The addition of pea and soy protein to inulin hydrogels resulted in networks with more a compact and homogeneous structure. The increase of the protein concentration caused the structure of the hydrogels to get smoother, more cohesive, and less granular. Pea and soy protein addition (3-6 g/100 g) to hydrogels allowed to obtain higher values of yield stress, texture (firmness, adhesiveness) and spreadability parameters. At a protein concentration of 6 g/100 g, the firmness of inulin hydrogels was seven times higher for those with pea protein (1.87 N) and ten times higher for those with soy protein (2.60 N) compering to the control hydrogel (0.24 N). The transmission profiles of hydrogels with incorporated 6 g/100 g of soy proteins showed the slowest motion of the particles, which indicates the highest stability of gel. As the concentration of protein addition increased, a reduction in the lightness was observed.

Globular protein stabilized nanoparticles for delivery of disulfiram: fabrication, characterization, in vitro toxicity, and cellular uptake

Disulfiram (DSF), an FDA-approved anti-alcoholic drug, has recently shown that it possesses anti-cancer effects. However, DSF is hydrophobic in nature with less stability. Therefore, new approaches are required for the effective delivery of DSF to treat cancers. Herein, we prepared DSF loaded soy protein isolate (SPI) nanosuspension (Ns) for enhancing the anti-cancer delivery of DSF. The optimized DSF-SPI-Ns had an average particle size of 164.28 ± 2.07 nm with a narrow size distribution of 0.217 ± 0.035 and zeta potential around −22.30 ± 2.11 mV, respectively. The highest drug loading and entrapment efficiency achieved was 5.516 ± 1.98%, and 91.61 ± 1.15%, respectively. The surface morphology of Ns was revealed by TEM, and the FTIR DSC, PXRD, and TGA were used for physicochemical characterization. Further, fluorescence spectroscopy and molecular docking studies were carried out to understand the interactions between (SPI and DSF) and binding sites of DSF on the surface of SPI, respectively. In vitro release studies showed a sustained release pattern and followed a Fickian diffusion release from the Ns. The in vitro cytotoxicity of SPI indicated the excellent biocompatibility, and DSF-SPI-Ns were found to be more cytotoxic compared to the free DSF solution. Moreover, the cellular uptake studies also indicated the effective delivery of the formulation to the cancer cells. Results of the current study suggested that the SPI coated Ns might be a promising drug delivery system for hydrophobic DSF, and the potential application of SPI as a coating/stabilizing agent for the delivery of hydrophobic/hydrophilic cancer therapeutics.

Disulfiram (DSF), an FDA-approved anti-alcoholic drug, has recently shown that it possesses anti-cancer effects.

Biosurfactants, natural alternatives to synthetic surfactants: Physicochemical properties and applications

Biosurfactants comprise a wide array of amphiphilic molecules synthesized by plants, animals, and microbes. The synthesis route dictates their molecular characteristics, leading to broad structural diversity and ensuing functional properties. We focus here on low molecular weight (LMW) and high molecular weight (HMW) biosurfactants of microbial origin. These are environmentally safe and biodegradable, making them attractive candidates for applications spanning cosmetics to oil recovery. Biosurfactants spontaneously adsorb at various interfaces and self-assemble in aqueous solution, resulting in useful physicochemical properties such as decreased surface and interfacial tension, low critical micellization concentrations (CMCs), and ability to solubilize hydrophobic compounds. This review highlights the relationships between biosurfactant molecular composition, structure, and their interfacial behavior. It also describes how environmental factors such as temperature, pH, and ionic strength can impact physicochemical properties and self-assembly behavior of biosurfactant-containing solutions and dispersions. Comparison between biosurfactants and their synthetic counterparts are drawn to illustrate differences in their structure-property relationships and potential benefits. Knowledge of biosurfactant properties organized along these lines is useful for those seeking to formulate so-called green or natural products with novel and useful properties.

Development of a Sono-Assembled, Bifunctional Soy Peptide Nanoparticle for Cellular Delivery of Hydrophobic Active Cargoes

Soy proteins are prone to aggregate upon proteolysis, hindering their sustainable development in food processing. Here, a continuous work on the large insoluble peptide aggregates was carried out, aiming to develop a new type of soy peptide-based nanoparticle (SPN) for active cargo delivery. Sono-assembled SPN in spherical appearance and core-shell structure maintained by noncovalent interactions was successfully fabricated, exhibiting small particle size (103.95 nm) in a homogeneous distribution state (PDI = 0.18). Curcumin as a model cargo was efficiently encapsulated into SPN upon sonication, showing high water dispersity (129.6 mg/L, 10⁴ higher than its water solubility) and storage stability. Additionally, the pepsin-resistant SPN contributed to the controlled release of curcumin at the intestinal phase and thus significantly improved the bioaccessibility. Encapsulated curcumin was effective in protecting glutamate-induced toxicity in PC12 cells, where the matrix SPN can simultaneously reduce lipid peroxidation and elevate antioxidant enzymes levels, innovatively demonstrating its bifunctionality during cellular delivery.

Enhanced colloidal stability, solubility and rapid dissolution of resveratrol by nanocomplexation with soy protein isolate

The polyphenolic compound resveratrol has received significant attention due to its many pharmacological actions such as anti-cancer, anti-inflammatory, antioxidant and antimicrobial activities. However, poor solubility and stability are major impediments for resveratrol's clinical effectiveness. In this work we have encapsulated resveratrol into soy protein isolate nanoparticles using a simple rotary evaporation technique. Resveratrol-loaded nanoparticles were around 100nm in diameter and negatively charged. Nano-encapsulated resveratrol was found to be in amorphous form and showed more than two times higher solubility with significantly increased dissolution when compared to free resveratrol. Finally, an in-vitro NF-κB inhibition assay revealed that encapsulated resveratrol was stable and retained bioactivity. This new formulation of resveratrol has the potential to boost the clinical effectiveness of this drug and could be utilised for other poorly soluble hydrophobic drugs.