RESUMEN

With global enforcement of plastic bans and restrictions, the biodegradable plastic, e.g., polylactic acid (PLA), has been extensively employed as a primary substitute for traditional petroleum-based plastics. However, the growing problem associated with PLA waste accumulation is posing grand environmental challenges. In addition, although PLA has the degrading property under natural conditions, the degradation process takes too long and the degradation products cannot be recycled. In this context, enzymatic degradation of PLA arouses great attention in scientific communities. This study aims at selecting the most cost-effective protease from various enzymes and optimizing the enzymolysis conditions towards the degradation of PLA. We will demonstrate that under an optimal temperature of 45 °C, a pH vale of 11, and an enzyme concentration of 0.6 mg mL-1, the protease K would achieve a remarkable degradation efficiency (> 99 %) for PLA films within just 50 min. Finally, molecular dynamics (MD) simulation and molecular docking studies reveal the mechanism behind the protease-induced PLA degradation, providing a promising direction for waste treatment and resource utilization for future biodegradable plastics.

Asunto(s)

RESUMEN

Liver disease is one of the serious threats to human life and health. Three-dimensional (3D) liver models, which simulate the structure and function of natural liver tissue in vitro, have become a common demand in medical, scientific and pharmaceutical fields nowadays. However, the complex cellular composition and multi-scale spatial arrangement of liver tissue make it extremely challenging to construct liver models in vitro. According to HepaRG preference and printing strategy, the formulation of bioink system with opposite charge is optimized. The sodium alginate-based bioink 1 and dipeptide-based bioink 2 are used to ensure structural integrity and provide flexible designability, respectively. The HepaRG/HUVECs/LX-2-laden liver organoids with biomimetic lobule structure are fabricated by a multicellular 3D droplet-based bioprinting strategy, to mimic the cell heterogeneity, spatial structure and extracellular matrix (ECM) features. The liver organoids can maintain structural integrity and multicellular distribution within the printed lobule-like structure after 7 days of culture. Compared with the 2D monolayer culture, the constructed 3D organoids show high cell viability, ALB secretion and urea synthesis levels. This study provides a droplet-based and layer-by-layer 3D bioprinting strategy for in vitro construction of liver organoids with biomimetic lobule structure, giving meaningful insights in the fields of new drugs, disease modelling, and tissue regeneration.

Asunto(s)

RESUMEN

By tuning the amount of the Se precursors during the synthesis, orthorhombic PdSe2, cubic Pd17Se15, and monoclinic Pd7Se2 nanoparticles are synthesized, which show phase-dependent electrocatalysis for the ethanol oxidation reaction. This work advances the controllable synthesis of transition metal selenides and inspires their applications in electrocatalysis.

RESUMEN

The cation-exchange strategy has shown great potential to create a large variety of inorganic nanostructures. We herein report the cation-exchange reactions between CdSe nanocrystals and Pd2+ cations in different solvent environments and identify three features not sufficiently noticed before: (i) the exchange between Cd2+ and Pd2+ cations could be fully achieved in both aqueous and organic solvents and is also independent of its parent CdSe crystal structures; (ii) the exchange between Cd2+ and Pd2+ cations in aqueous solvent results in amorphous Pd-Se exchanged products, while in organic solvent, it leads to a cubic Pd17Se15 phase; and (iii) the exchanged Pd17Se15 product exhibits better electrocatalysis for ethanol oxidation reaction in an alkaline medium relative to its amorphous counterpart and the commercial Pd/C catalyst.

RESUMEN

Single atoms are superior electrocatalysts having high atomic utilization and amazing activity for water oxidation and splitting. Herein, this work reports a thermal reduction method to introduce high-valence iridium (Ir) single atoms into bimetal phosphide (FeNiP) nanoparticles toward high-efficiency oxygen evolution reaction (OER) and overall water splitting. The presence of high-valence single Ir atoms (Ir4+ ) and their synergistic interaction with Ni3+ species as well as the disproportionation of Ni3+ assisted by Fe collectively contribute to the exceptional OER performance. In specific, at appropriate Ir/Ni and Fe/Ni ratios, the as-prepared Ir-doped FeNiP (Ir25 -Fe16 Ni100 P64 ) nanoparticles at a mass loading of only 35 µg cm-2 show the overpotential as low as 232 mV at 10 mA cm-2 and activity as high as 1.86 A mg-1 at 1.5 V versus RHE for OER in 1.0 m KOH. Computational simulations confirm the vital role of high-valence Ir to weaken the adsorption of OER intermediates, favorable for accelerating OER kinetics. Impressively, a Pt/C||Ir25 -Fe16 Ni100 P64 two-electrode alkaline electrolyzer affords a current density of 10 mA cm-2 at a low cell voltage of 1.42 V, along with satisfied stability. An AA battery with a nominal voltage of 1.5 V can drive overall water splitting with obvious bubbles released.

RESUMEN

The functionalization of self-assembled peptide hydrogel is of great importance to broaden its applications in the field of biomedicine. In this work, conductive hydrogel is fabricated by introducing conductive polymer polyaniline into peptide self-assembled hydrogel. Compared with pure peptide formed hydrogel, the conductive hydrogel exhibits enhanced conductivity, mechanical property and stability. In addition, the hydrogel is tested to be of great injectability and 3D bio-printability and could support the viability of encapsulated cells that are sensitive to electrical signals. It should have great application prospects in the preparation of tissue engineering scaffolds.

RESUMEN

Chlorophyll loss is a major problem during green vegetable storage. However, the molecular mechanism is still unclear. In this study, a 21 days of storage experiments showed chlorophyll content was higher in light-stored Chinese cabbage (Brassica chinensis L.) leaves than those in dark-stored samples. Transcriptome analyses were performed on these samples to determine the effects of light. Among 311 differentially expressed genes (DEGs), early light-induced protein 1 (ELIP1) was identified as the main control gene for chlorophyll synthesis. Tissues and subcellular localization indicated that ELIP1 was localized in the nucleus. Motifs structure analyses, chromatin immunoprecipitation (ChIP) assays, luciferase reporter assays, and overexpression experiments demonstrated that ELIP1 regulated the expressions of genomes uncoupled 4 (GUN4), Glutamyl-tRNA reductase family protein (HEMA1), and Mg-protoporphyrin IX methyltransferase (CHLM) by binding to G-box-like motifs and affected chlorophyll biosynthesis during the storage of Chinese cabbage. It is a possible common tetrapyrrole biosynthetic pathway for chlorophylls, hemes, and bilin pigments in photosynthetic organisms. Our research also revealed that white light can be used as a regulatory factor to improve the storage ability and extent shelf life of Chinese cabbage.

Asunto(s)