Biobased and biodegradable films exhibiting circularly polarized room temperature phosphorescence.

There is interest in developing sustainable materials displaying circularly polarized room-temperature phosphorescence, which have been scarcely reported. Here, we introduce biobased thin films exhibiting circularly polarized luminescence with simultaneous room-temperature phosphorescence. For this purpose, phosphorescence-active lignosulfonate biomolecules are co-assembled with cellulose nanocrystals in a chiral construct. The lignosulfonate is shown to capture the chirality generated by cellulose nanocrystals within the films, emitting circularly polarized phosphorescence with a 0.21 dissymmetry factor and 103 ms phosphorescence lifetime. By contrast with most organic phosphorescence materials, this chiral-phosphorescent system possesses phosphorescence stability, with no significant recession under extreme chemical environments. Meanwhile, the luminescent films resist water and humid environments but are fully biodegradable (16 days) in soil conditions. The introduced bio-based, environmentally-friendly circularly polarized phosphorescence system is expected to open many opportunities, as demonstrated here for information processing and anti-counterfeiting.

3D bioprinting by reinforced bioink based on photocurable interpenetrating networks for cartilage tissue engineering.

Cartilage has a limited ability to repair itself, highlighting the urgent need for suitable materials for cartilage regeneration. Achieving a balance between cell survival environment and hydrogel crosslinking density is crucial for photosensitive cell-laden cartilage repair materials to achieve both high strength and good cell viability. Here, an interpenetrating hydrogel consisted of methacrylate gelatin (GelMA) and glycidyl methacrylate silk fibroin (SG) was introduced. Compared to GelMA hydrogel, GelMA/SG had desired mechanical properties, with achieving up to 5 times of compression modulus and 6 times of compression failure energy. Meanwhile, the chondrocytes inside GelMA/SG exhibited great viability which was over 90 %. GelMA/SG as a bioink had favorable printability for digital light processing (DLP) bioprinting. The mesh DLP-printed scaffolds with high precision were created and GelMA/SG had a better shape retention ability than GelMA. Moreover, GelMA/SG cell-laden scaffolds had high strength while chondrocytes proliferated significantly in vitro culture. They were implanted under the skin of nude mice to evaluate ectopic chondrogenesis in vivo. The GelMA/SG cell-laden scaffolds indicated little deformation and high expression of collagen type II and glycosaminoglycans, which was advantageous for cartilage regeneration. The scaffold and its fabrication strategy provide potential solutions for clinical cartilage repair problems in the future.

Enhanced effects of antagomiR-3074-3p-conjugated PEI-AuNPs on the odontogenic differentiation by targeting FKBP9.

The odontogenic differentiation of dental pulp stem cells (DPSCs), which is vital for tooth regeneration, was regulated by various functional molecules. In recent years, a growing body of research has shown that miRNAs play a crucial role in the odontogenic differentiation of human dental pulp stem cells (hDPSCs). However, the mechanisms by which miRNAs regulated odontogenic differentiation of hDPSCs remained unclear, and the application of miRNAs in reparative dentin formation in vivo was also rare. In this study, we first discovered that miR-3074-3p had an inhibitory effect on odontogenic differentiation of hDPSCs and antagomiR-3074-3p-conjugated PEI-AuNPs effectively promoted odontogenic differentiation of hDPSCs in vitro. AntagomiR-3074-3p-conjugated PEI-AuNPs was further applied to the rat pulp-capping model and showed the increased formation of restorative dentin. In addition, the results of lentivirus transfection in vitro suggested that FKBP9 acted as the key target of miR-3074-3p in regulating the odontogenic differentiation of hDPSCs. These findings might provide a new strategy and candidate target for dentin restoration and tooth regeneration.

MiRNA 24-3p-rich exosomes functionalized DEGMA-modified hyaluronic acid hydrogels for corneal epithelial healing.

The damage of corneal epithelium may lead to the formation of irreversible corneal opacities and even blindness. The migration rate of corneal epithelial cells directly affects corneal repair. Here, we explored ocu-microRNA 24-3p (miRNA 24-3p) that can promote rabbit corneal epithelial cells migration and cornea repair. Exosomes, an excellent transport carrier, were exacted from adipose derived mesenchymal stem cells for loading with miRNA 24-3p to prepare miRNA 24-3p-rich exosomes (Exos-miRNA 24-3p). It can accelerate corneal epithelial migration in vitro and in vivo. For application in cornea alkali burns, we further modified hyaluronic acid with di(ethylene glycol) monomethyl ether methacrylate (DEGMA) to obtain a thermosensitive hydrogel, also reported a thermosensitive DEGMA-modified hyaluronic acid hydrogel (THH) for the controlled release of Exos-miRNA 24-3p. It formed a highly uniform and clear thin layer on the ocular surface to resist clearance from blinking and extended the drug-ocular-epithelium contact time. The use of THH-3/Exos-miRNA 24-3p for 28 days after alkali burn injury accelerated corneal epithelial defect healing and epithelial maturation. It also reduced corneal stromal fibrosis and macrophage activation. MiRNA 24-3p-rich exosomes functionalized DEGMA-modified hyaluronic acid hydrogel as a multilevel delivery strategy has a potential use for cell-free therapy of corneal epithelial regeneration.

Microstructure and Mechanical Properties of Y4Zr3O12-Added Fe-13.5Cr-2W Oxide-Dispersion-Strengthened Steels, Containing High Contents of C and N, Prepared by Mechanical Alloying and Two-Step Spark Plasma Sintering.

Oxide-dispersion-strengthened (ODS) steel is considered as a promising candidate structural material for nuclear applications. In this study, the microstructure and mechanical properties of Y4Zr3O12-added Fe-13.5Cr-2W ODS steels, containing high contents of C and N, prepared by mechanical alloying (MA) and two-step spark plasma sintering (SPS), were investigated. The results showed that pure Y4Zr3O12 powders, with a grain size of 3.5 nm, were well prepared with NH3·H2O addition by the sol-gel method in advance, in order to avoid the formation of some coarse or undesired oxides. W was completely dissolved into the matrix after 48 h of ball milling at 300 rpm, and the main elements were uniformly distributed on the surface of the milled powders. The unexpected face-centered cubic (FCC, γ)/body-centered cubic (BCC, α) dual-phase structure of the sintered specimens, could be explained by the unexpectedly high contents of C and N from the raw powder production process, fast-sintering characteristic of SPS, and inhibitory effect of W on the diffusion of C. The experimental results were approximately consistent with the simulation results from the Thermo Calc software. The temperature combination of 800 °C and 1100 °C during the SPS process, provided a relatively more homogeneous microstructure, while the combination of 750 °C and 1150 °C, provided the highest ultimate tensile strength (UTS), of 1038 MPa, with the highest uniform elongation (UE), of 6.2%. M23C6, Cr2O3, M2(C,N), and other precipitates, were mainly distributed at grain boundaries, especially at the triple junctions, which led to Cr depletion at grain boundaries.

Simultaneous removal of Pb2+, Cu2+ and Cd2+ ions from wastewater using hierarchical porous polyacrylic acid grafted with lignin.

In PAA-g-lignin, phase separation, caused by the difference in expansion properties between lignin and polyacrylic acid, is used to build a porous hydrogel. In this study, PAA-g-APL was produced by grafting polyacrylic acid with acid-pretreated alkali lignin. Acid-pretreated alkali lignin acts as a hierarchical pore-forming agent that enhances the simultaneous adsorption capacities for Pb2+, Cu2+ and Cd2+ ions from wastewater. Notably, PAA-g-APL acted as a selective adsorbent for Pb2+ ions has an excellent selective removal coefficient α (20.22) in contaminated wastewater contained Cu2+ ions. Its molar partition coefficient for Pb2+ ions (68 %) is higher than that for either Cu2+ ions (28.6 %) or Cd2+ ions (3.4 %). At equilibrium, the total adsorption capacities of PAA-g-APL for Pb2+, Cu2+ and Cd2+ were 1.076 mmol g-1, 0.3233 mmol g-1 and 0.059 mmol g-1, respectively. The experimental kinetic data fitted well to a pseudo-second order model and to an intra-particle-diffusion model. The Freundlich isotherm model gave the best fit with the experimental equilibrium data. The ΔG° for PAA-g-APL is < 0, indicating that the adsorption of heavy metal ions is a spontaneous process. This study provides a highly promising candidate for the treatment of wastewater contaminated with a mixture of heavy metals.