Facile Dissolution of Zein Using a Common Solvent Dimethyl Sulfoxide

Aligned Ion Conduction Pathway of Polyrotaxane-Based Electrolyte with Dispersed Hydrophobic Chains for Solid-State Lithium-Oxygen Batteries

A critical challenge hindering the practical application of lithium-oxygen batteries (LOBs) is the inevitable problems associated with liquid electrolytes, such as evaporation and safety problems. Our study addresses these problems by proposing a modified polyrotaxane (mPR)-based solid polymer electrolyte (SPE) design that simultaneously mitigates solvent-related problems and improves conductivity. mPR-SPE exhibits high ion conductivity (2.8 × 10-3 S cm-1 at 25 °C) through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain dispersion. Integrating this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 cycles. In situ Raman spectroscopy reveals the presence of an LiO2 intermediate alongside Li2O2 during oxygen reactions. Ex situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture, as demonstrated by the air permeability tests. The present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

Mechanically Robust Cellulose-Based Piezoelectric Elastomer Formed by Slidable Polyrotaxane Cross-Linker

Cellulose has great potential in the field of piezoelectricity owing to its high crystallinity; however, it exhibits low processability and poor mechanical robustness. In this study, to enhance the applicability of cellulose-based piezoelectric materials, a robust cellulose-based piezoelectric elastomer with excellent piezoelectric properties was developed by cross-linking cellulose with polyrotaxane (PR). The effects of cross-linking on the mechanical properties and crystalline structures of the resulting elastomers were investigated. The ferroelectric and piezoelectric properties were evaluated from their polarization hysteresis loops and voltage generation characteristics. eHPC25PR75 exhibited 2.7 times higher toughness (20.4 MJ m-3) than eHPC100 (7.57 MJ m-3). It also shows a power density 4.2 times higher (1.34 μW cm-2) than eHPC100 (0.321 μW cm-2). As a result, eHPC25PR75 demonstrated piezosensitivity to mechanical vibrations in a variety of devices that require mechanical robustness. These results can inform the design and development of high-performance piezoelectric devices.

Solubility and conformational characterization of rice glutelin after high temperature treatment

Enhancing the solubility of rice glutelin in neutral aqueous solution is the prerequisite for the development of rice protein drinks and ingredients. Herein, glutelin was first dissolved in an aqueous solution of pH 12, and then heated at 121 °C for 20 min. The results showed that the solubility of glutelin increased from 2.55 mg/mL to 20.7 mg/mL at pH 7. The size of glutelin aggregates at pH 7 decreased from 900 nm to 400 nm after high temperature treatment (HTT), which was confirmed by atomic force microscopy. The results of small angle X-ray scattering showed that HTT induced the conformational unfolding of glutelin, and the protein in the aggregate was rod like shape as well as the mean square rotation radius decreased from 64.9 to 54.8 Å. Furthermore, Raman spectrum results also agree with the unfolding of glutelin conformation, which was mainly reflected in the changes of tyrosine and tryptophan residues, as well as the decreasing of α-helix content and increasing of β-sheet content. After being freeze-dried, HTT glutelin has a re-solubilization capacity of 15.48 mg/mL in pH 7 aqueous solution, which was superior to that of spray dried glutelin powder (pH 7, 9.19 mg/mL).

Self-assembled zein organogels as in situ forming implant drug delivery system and 3D printing ink

Recently, biomedical applications of organogels have been increasing; however, there is a demand for bio-based polymers. Here, we report self-assembled zein organogels in N-methyl pyrrolidone (NMP), Dimethyl sulfoxide (DMSO), and glycerol formal (GF). The gel formation was driven by the solvent's polarity and the hydrogen bonding component of Hansen Solubility Parameters was important in promoting gelation. Gels exhibited shear-thinning and thixotropic properties. Furthermore, water-induced self-assembly of zein allows mechanically robust in situ implant formation by solvent exchange. Ciprofloxacin was incorporated as a model drug and sustained release depending upon the solvent exchange rate was observed. In situ implants in agarose gel retained antibacterial efficacy against S. aureus for more than 14 days. Zein-based organogels were further applied as 3D printing ink and it was found that zein gel in DMSO had superior printability than gels prepared in NMP and GF. Using three solvents to prepare organogels can enable the encapsulation of various drugs and facilitate the preparation of composite gels with other biocompatible polymers. These organogel systems can further be used for developing 3D printed drug delivery systems or scaffolds for tissue engineering.

Assessing protein digestibility in allergenicity risk assessment: A comparison of in silico and high throughput in vitro gastric digestion assays

The susceptibility of a novel food protein to digestion in the pepsin resistance test is widely used to inform the allergenicity risk assessment process. However, it does not model the variation in the intragastric environment found in vivo. Consequently a 96-well plate format in vitro gastric digestion protocol has been developed with a high and low pepsin activity test executed at pH 1.2, 2.5, 5.5 and 6.5. It was used to analyse seven allergens (from milk, egg, peach and peanut) and two non-allergens (cytochrome c and zein). Digestion was monitored using SDS-PAGE and densitometry. In silico predictions were not confirmed experimentally for most of the proteins studied. Proteins were ranked according to half-life and showed susceptibility to digestion was related to the stability of protein structure and protein solubility rather than allergenicity per se. Highly digestible proteins, such as β-casein and Ara h 1, generated abundant resistant fragments Mr > 3.5 kDa in the low pepsin activity test which could be immunologically significant within the context of allergenicity risk assessment for susceptible groups such as infants. The high- and low pepsin activity tests used in this study provided complementary data to support allergenicity risk assessment and used only 10 mg protein.

Dual-Drug Delivery via Zein In Situ Forming Implants Augmented with Titanium-Doped Bioactive Glass for Bone Regeneration: Preparation, In Vitro Characterization, and In Vivo Evaluation

In situ forming implants (IFIs) are non-surgical approach using biodegradable polymers to treat bone fractures. The study aimed at preparing dual-drug-loaded IFIs to deliver pitavastatin (osteogenic drug) and tedizolid (antibiotic) using zein as the implant matrix via solvent-induced phase inversion method. At first, several investigations were done on pitavastatin-loaded zein IFIs, where three concentrations of zein were used (10, 20, and 30% w/v). IFIs were evaluated for their solidification time, rheological properties, injectability, and in vitro release. IFIs containing bioactive glass nanoparticles were prepared by the addition of non-doped bioactive glass nanoparticles (BGT0; 1, 3, 5, and 10% w/v) or titanium-doped bioactive glass nanoparticles (BGT5; 1% w/v) to the selected concentration of zein (30% w/v) and then evaluated. The optimized dual-medicated implant (D-ZIFI 1) containing pitavastatin, tedizolid, sodium hyaluronate (3% w/v), and BGT5 (1% w/v) was prepared and compared to IFI lacking both sodium hyaluronate and BGT5 (D-ZIFI 2). D-ZIFI 1 and 2 sustained the release profiles of both drugs for 28 days. SEM images proved the interconnected porous structure of D-ZIFI 1 due to sodium hyaluronate. In vivo studies on surgically induced bone defects in Sprague-Dawley rats signified the proper accelerated bone healing ability of D-ZIFI 1 over D-ZIFI 2. Results presented D-ZIFI 1 as a promising, effective, non-surgical approach for bone healing.

Optimization of Anisotropic Crystalline Structure of Molecular Necklace-like Polyrotaxane for Tough Piezoelectric Elastomer

While piezoelectric materials are applied in various fields, they generally exhibit poor mechanical toughness. To increase the applicability of these, their mechanical properties need to be improved. In this study, a tough piezoelectric polyrotaxane (PRX) elastomer was developed by blending PRX samples of two different lengths, formed using 10K and 35K poly(ethylene glycol), to align dipole moments for optimization of the piezoelectricity characteristics. The effects of the blending ratio on the crystalline structure of the obtained PRX elastomer were investigated by X-ray diffraction analysis and transmission electron microscopy. In addition, the ferroelectric and piezoelectric properties of the PRX elastomer were evaluated based on its polarization hysteresis loop and voltage generation characteristics, respectively. The PRX elastomer formed by using a ratio of 3:1 (ePR10k₇₅35k₂₅) exhibited a long-range-ordered anisotropic crystalline structure, resulting in a large polarization (P_r) value. As a result, ePR10k₇₅35k₂₅ showed greatly enhanced piezosensitivity against the mechanical vibrations generated by respiratory signals.