Stable and pH-Sensitive Protein Nanogels Made by Self-Assembly of Heat Denatured Soy Protein

In this study, we examined the possibility of preparing stable soy protein nanogels by simply heating homogeneous soy protein dispersion. The protein nanogels formed were characterized by <i>z</i>-average hydrodynamic diameter, polydispersity index, turbidity, ζ-potential, morphology, and their stability to pH and ionic strength change. Soy protein dispersion (1% w/v) was homogeneous around pH 5.9 where it had the lowest polydispersity index (∼0.1). Stable and spherical nanogels were formed by heating soy protein dispersion at pH 5.9 under 95 °C. They sustained constantly low polydispersity index (∼0.1) in the investigated pH range of 6.06–7.0 and 2.6–3.0. The nanogels were pH-sensitive and would swell with pH change. They were stable at 0–200 mM NaCl concentration. Denaturation of soy glycinin was the prerequisite for the formation of stable nanogels. Soy protein nanogels had a core–shell structure with basic polypeptides and β subunits interacting together as the hydrophobic core; and acid polypeptides, α′, and α subunits locating outside the core as hydrophilic shell. The inner structure of soy protein nanogels was mainly stabilized by disulfide bonds cross-linked network and hydrophobic interaction. Soy protein nanogels made in this study would be useful as functional ingredients in biotechnological, pharmaceutical, and food industries

Exploiting Salt Induced Microphase Separation To Form Soy Protein Microcapsules or Microgels in Aqueous Solution

Self-assembly of native glycinin at room temperature was investigated as a function of the pH and the NaCl concentration. Microphase separation leading to the formation of dense protein microdomains was observed by confocal laser scanning microscopy. Depending on the conditions, the microdomains coalesced into a continuous protein rich phase or associated into large clusters. Addition of β-conglycinin inhibited phase separation and reduced the pH range in which it occurred. Microdomains of glycinin that were formed in the presence of 0.1 M NaCl transformed into hollow stable cross-linked microcapsules when heated above 60 °C with diameters between 3 and 30 μm depending on the protein concentration and a shell thickness between 1.0 and 1.4 μm. The microcapsules were stable to dilution in salt free water, whereas microdomains formed at room temperature redispersed. Microdomains formed in mixtures with β-conglycinin did not transform into microcapsules, but they became stable cross-linked homogeneous microgels

Ionic Strength and pH Responsive Permeability of Soy Glycinin Microcapsules

Recently, hollow protein microcapsules have been made simply by heating the microphase separated soy glycinin microdomains. However, the properties (e.g., mechanical properties and permeability) that relate to the application of these microcapsules are unknown. In this study, the permeability of the soy glycinin microcapsules was investigated by confocal laser scanning microscopy (CLSM), as influenced by ionic strength and pH using fluorescein isothiocyanate-dextran (FITC-dextran). The glycinin microcapsules kept the integrity between pH 1 and 11.5, swelled when pH was below 3 or above pH 11, dissociated at pH above 11.5 and deswelled slightly at pH 1. When the pH increased above 11, the permeability of the microcapsule significantly increased. Remarkably, when the pH was below the isoelectric point of glycinin (≈pH 5), FITC-dextran spontaneously accumulated inside the microcapsule with a significantly higher concentration than that in bulk solution, as evidenced by the strong intensity increase of fluorescence. This unique feature significantly increased the loading amount of FITC-dextran. The permeability of microcapsules was also increased by adding salt but less significant than by adjusting pH. The surface of the microcapsules became coarser when the permeability increased, which was revealed by scanning electron microscopy. These results show that soy glycinin has a great potential to be used as a wall material to fabricate hollow microcapsules that could find applications in biomedicine and food industry

O₃ induced NRF2 activation in human keratinocytes and MIX 1 and MIX 2 pre-treatment for 24 h potentiated this effect.

<p>Immuno-cytochemistry of keratinocytes showing localization of NRF2 (red) and Keap1 after O₃ exposure for 1 h. Images are merged and representative of at least 100 cells viewed in each experiments (n = 5). Nuclei (blue) were stained with DAPI. Original magnification X 630. Immunoreactivity of NRF2 and Keap1 was semi-quantified as area of both signals into nucleus respect to cytoplasm, by using Image J sophtware. Data are expressed in arbitrary units (averages of five experiments ± SEM, *<i>p</i> < 0.05 vs C (nuclear expression); °<i>p</i> < 0.05 vs C (cytoplasm expression)).</p

Cytotoxicity measured by using LDH release at T0 (A) and T24 (B) in human keratinocytes exposed to O₃ pre-treated with/without MIXs.

<p>Triton X represents 100% of LDH release. Data are expressed as percentage of Triton X-100 (averages of five experiments ± SEM, *<i>p</i> < 0.05 vs control; #<i>p</i> < 0.05 vs O3).</p

O₃ induced ROS formation in human keratinocytes and MIX 1 and MIX 2 pre-treatment prevented this effect.

<p>ROS production was measured by fluorimetry with DCFH-DA staining. Data are expressed in RFU (averages of five experiments ± SEM, *<i>p</i> < 0.05 vs control; #<i>p</i> < 0.05 vs O3).</p

Constructing a 3D Ion Transport Channel-Based CNF Composite Film with an Intercalated Structure for Superior Performance Flexible Supercapacitors

The weak stiffness, huge thickness, and low specific capacitance of commonly utilized flexible supercapacitors hinder their great electrochemical performance. Learning from a biomimetic interface strategy, we design flexible film electrodes based on functional intercalated structures with excellent electrochemical properties and mechanical flexibility. A composite film with high strength and flexibility is created using graphene (reduced graphene oxide (rGO)) as the plane layer, layered double metal hydroxide (LDH) as the support layer, and cellulose nanofiber (CNF) as the connection agent and flexible agent. The interlayer height can be adjusted by the ion concentration. The highly interconnected network enables excellent electron and ion transport channels, facilitating rapid ion diffusion and redox reactions. Moreover, the high flexibility and mechanical properties of the film achieve multiple folding and bending. The CNF-rGO-NiCoLDH film electrode exhibits high capacitance performance (3620.5 mF cm–2 at 2 mA cm–2), excellent mechanical properties, and high flexibility. Notably, flexible all-solid assembled CNF-rGO-NiCoLDH//rGO has an extremely high area energy density of 53.5 mWh cm–2 at a power density of 1071.2 mW cm–2, along with cycling stability of 89.8% retention after 10 000 charge–discharge cycles. This work provides a perspective for designing high-performance energy storage materials for flexible electronics and wearable devices

MIX 1 and MIX 2 pre-treatment prevents the decrease in cell proliferation 24 hr after O₃ exposure.

<p>Data are expressed as percentage of control (averages of five experiments ± SEM, *<i>p</i> < 0.05 vs control; #<i>p</i> < 0.05 vs O₃.</p

Primer sequences and PCR condition.

<p>Data calculated by Bio-Rad CFX Manager Software (Bio-Rad).</p><p>Primer sequences and PCR condition.</p