Role of surfactant in the formation of zein/Tween-20 nanoparticles studied by fluorescence and circular dichroism

Preparation and Characterization of Rutin–Loaded Zein–Carboxymethyl Starch Nanoparticles

In this work, rutin (RT)–loaded zein–carboxymethyl starch (CMS) nanoparticles were successfully prepared by the antisolvent precipitation method. The effect of CMS on composite nanoparticles at different concentrations was studied. When the ratio of zein–RT–CMS was 10:1:30, the encapsulation efficiency (EE) was the highest, reaching 73.5%. At this ratio, the size of the composite nanoparticles was 196.47 nm, and the PDI was 0.13, showing excellent dispersibility. The results of fluorescence spectroscopy, FTIR, XRD, and CD showed that electrostatic interaction, hydrogen bonding, and hydrophobic interaction were the main driving forces for the formation of nanoparticles. It can be seen from the FE–SEM images that the zein–RT–CMS nanoparticles were spherical. With the increase in the CMS concentration, the particles gradually embedded in the cross–linked network of CMS (10:1:50). After RT was loaded on zein–CMS nanoparticles, the thermal stability and pH stability of RT were improved. The results showed that zein–CMS was an excellent encapsulation material for bioactive substances.

Increased selectivity of sodium deoxycholate to around Tryptophan213 in bovine serum albumin upon micellization as revealed by singular value decomposition for excitation emission matrix

In the present study, we investigated the effect of bile salts (sodium deoxycholate, NaDC) on the conformation of a globular protein (bovine serum albumin, BSA). The two Tryptophan (Trp) residues of BSA and the fluorescence energy of NaDC are in a three-way relationship, and singular value decomposition (SVD) was used to separate each element in the fluorescence spectra. SVD was used to separate the elements in the fluorescence spectra. SVD showed that NaDC had a particularly large effect on the microenvironment around Trp213 and that micellar NaDC enhanced the selectivity for Trp213. In addition, the Stern-Volmer plots of the warfarin (WAR) specific domain (domain I) and ketoprofen (KP) specific domain (domain II) in the presence and absence of NaDC showed that the effect of NaDC was selective for domain II, where Trp213 is located. These results indicate that NaDC induces a localized and selective conformational change in BSA, and that the selectivity varies depending on the aggregation state of NaDC.

Zein as a versatile biopolymer: different shapes for different biomedical applications

In recent years, the interest regarding the use of proteins as renewable resources has deeply intensified. The strongest impact of these biomaterials is clear in the field of smart medicines and biomedical engineering. Zein, a vegetal protein extracted from corn, is a suitable biomaterial for all the above-mentioned purposes due to its biodegradability and biocompatibility. The controlled drug delivery of small molecules, fabrication of bioactive membranes, and 3D assembly of scaffold for tissue regeneration are just some of the topics now being extensively investigated and reported in the literature. Herein, we review the recent literature on zein as a biopolymer and its applications in the biomedical world, focusing on the different shapes and sizes through which it can be manipulated.

Zein a versatile biomaterial in the biomedical field. Easy to chemically functionalize with good emulsification properties, can be employed in drug delivery, fabrication of bioactive membranes and 3D scaffolds for tissue regeneration.

Spectroscopic Investigation into the Binding of Ferulic Acid with Sodium Deoxycholate: Hydrophobic Force Versus Hydrogen Bonding

The binding of ferulic acid (FA) with sodium deoxycholate (NaDC) has been investigated using fluorescence and absorption measurements. The fluorescence probe technique of pyrene reveals that the presence of FA favors the micellization of NaDC, leading to the decreased critical micelle concentrations for the formation of NaDC micelles. As NaDC molecules change gradually from monomers via primary micelles into secondary micelles, the intensities of absorption and fluorescence spectra of FA increase at low NaDC concentrations, but decrease suddenly at intermediate NaDC concentrations, and finally increase again at high NaDC concentrations. These results corroborated well with FA fluorescence lifetime data suggesting that the aryl ring of FA hydrophobically binds to the convex surface of NaDC monomers, whereas the hydrogen bonding between FA and NaDC is significantly involved in NaDC primary micelles, which is gradually overcome by the hydrophobic interaction between FA and NaDC secondary micelles. The absorption and fluorescence spectra as well as the binding constant value of FA indicate the strong binding of FA in the large hydrophobic core of NaDC secondary micelles. At low FA concentrations, the measurement of FA anisotropy suggests that FA can increase the packing order of hydrophobic surfaces in NaDC secondary micelles, whereas the high amount of FA can greatly disrupt the packing structure of NaDC secondary micelles which is ascribed to the formation of FA dimers. The spectroscopic experiments outlined here present the binding events of FA with NaDC monomers and primary and secondary micelles, which are significantly related with the hydrophobic force and hydrogen bonding as well as the unique structural characteristics of bile salt.

Fabrication of curcumin-zein-ethyl cellulose composite nanoparticles using antisolvent co-precipitation method

The stable colloidal nano-dispersion of curcumin (CU) loaded zein-ethyl cellulose (ZN-EC) as three hydrophobic agent in water was prepared using two step antisolvent co-precipitation method. The EC coated NPs were prepared by adding EC in ethyl acetate to the ZN-CU NPs at a concentration ratio of 1: 3.5 w/v. The prepared colloidal suspension of ZN-EC showed high physical stability during storage time. The particle diameters and zeta potential values of ZN-CU and ZN-CU-EC colloidal suspensions were 140 ± 12 nm, 38 ± 2 mV and 179 ± 12 nm, 12 ± 2 mV, respectively. Based on Scanning electron microscopy (SEM) images, participation of EC on the surface of ZN-CU particles could reduce the sticky appearance of particles. Encapsulation efficiency of CU in NPs did not improve after precipitation of EC, but the stability of NPs against pH changes, increased and release rate of CU from NPs at different pH values (3-8) were significantly reduced in comparison of ZN-CU NPs. The EC coated NPs showed the excessive protection for CU antioxidant activity during storage. In conclusion, the prepared NPs, with high physical stability, have good potential for encapsulation and delivery of CU to colon region.

Interfacial Engineering of Pickering Emulsion Co-Stabilized by Zein Nanoparticles and Tween 20: Effects of the Particle Size on the Interfacial Concentration of Gallic Acid and the Oxidative Stability

Lipid oxidation is still one of the major food-safety issues associated with the emulsion-based food systems. Engineering the interfacial region is an effective way to improve the oxidative stability of emulsion. Herein, a novel Pickering emulsion with strong oxidative stability was prepared by using zein nanoparticles and Tween 20 as stabilizers (ZPE). The modulation effects of the particle size on the distribution of gallic acid (GA) and the oxidative stability of ZPE were investigated. In the absence of GA, Pickering emulsions stabilized with different sizes of zein nanoparticles showed similar oxidative stability, and the physical barrier effect took the dominant role in retarding lipid oxidation. Moreover, in the presence of GA, ZPE stabilized by zein nanoparticles with the averaged particle size of 130 nm performed stronger oxidation than those stabilized by zein nanoparticles of 70 and 220 nm. Our study revealed that the interfacial concentration of GA (GA_I) was tuned by zein nanoparticles due to the interaction between them, but the difference in the binding affinity between GA and zein nanoparticles was not the dominant factor regulating the (GA_I). It was the interfacial content of zein nanoparticles (Γ), which was affected by the particle size, modulated the (GA_I) and further dominated the oxidative stability of ZPEs. The present study suggested that the potential of thickening the interfacial layer to prevent lipid oxidation was limited, increasing the interfacial concentration of antioxidant by interfacial engineering offered a more efficient alternative.

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

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

Interaction behaviors and structural characteristics of zein/NaTC nanoparticles

Bile salts are biosurfactants distributed in the human gastrointestinal tract, which can significantly influence the structure and functions of orally administrated components.