Protective effects of degraded Bletilla striata polysaccharides against UVB-induced oxidative stress in skin.

The Bletilla striata polysaccharides (BSP) extracted through alkali-assisted method exhibit significant antioxidant activity, but its bioaccessibility was inadequate due to its tightly filamentous reticulation structure and high molecular weight. The anti-photoaging and anti-melanogenesis effects of degraded BSP (DBSPs) against UVB-induced oxidative stress on the skin were investigated. The molecular weights of the DBSPs were reduced to 153.94 kDa, 66.96 kDa, and 15.54 kDa from an initial value of 298.82 kDa. The degradation treatment altered the branched chain structure of the DBSPs, while the backbone structure, triple-helix structure, and crystallinity remained. DBSPs with a lower molecular weight exhibit better in vitro antioxidant activity. DBSPs did not show cytotoxicity to HSF cells but inhibited B16F10 cell proliferation. The addition of DBSPs protected HSF and B16F10 cells from oxidative stress and reduced ROS levels, B16F10 melanin content, and B16F10 tyrosinase activity after UVB damage, but DBSP-10 particles were slightly less effective due to aggregation. In contrast, DBSP-5 demonstrated effectiveness in reducing MDA levels in cells stressed by oxidative stress, increased total antioxidant capacity, and inhibited melanogenesis in B16F10, suggesting that DBSP-5 has potential as a topical therapeutic agent for the treatment of skin diseases associated with oxidative stress.

Proteomic analysis of exosomal proteins associated with bone healing speed in a rat tibial fracture model.

This study investigates the impact of exosomes on bone fracture healing in a rat tibial model, distinguishing between fast and slow healing processes. Bone healing and protein expression were assessed through X-ray examinations, hematoxylin and eosin staining, and immunohistochemical staining. Exosomes were isolated, characterized and subjected to liquid chromatography-mass spectrometry for protein analysis. Molecular differences were explored using differentially expressed protein analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment and protein-protein interaction networks. Differential bone healing patterns and protein expressions were observed between the control and model groups. Exosomes were successfully isolated and characterized, revealing 2004 identified proteins, including distinct expression profiles. Notably, ribosomal proteins, ferritin and beta-actin emerged as pivotal players in bone fracture healing. This study unveils dynamic changes in bone healing and underscores the role of exosomes in the process. Identified proteins and pathways offer valuable insights for developing innovative therapeutic strategies for bone healing.

Highly efficient visible light photocatalytic reduction of CO2 to hydrocarbon fuels by Cu-nanoparticle decorated graphene oxide.

The production of renewable solar fuel through CO2 photoreduction, namely artificial photosynthesis, has gained tremendous attention in recent times due to the limited availability of fossil-fuel resources and global climate change caused by rising anthropogenic CO2 in the atmosphere. In this study, graphene oxide (GO) decorated with copper nanoparticles (Cu-NPs), hereafter referred to as Cu/GO, has been used to enhance photocatalytic CO2 reduction under visible-light. A rapid one-pot microwave process was used to prepare the Cu/GO hybrids with various Cu contents. The attributes of metallic copper nanoparticles (∼4-5 nm in size) in the GO hybrid are shown to significantly enhance the photocatalytic activity of GO, primarily through the suppression of electron-hole pair recombination, further reduction of GO's bandgap, and modification of its work function. X-ray photoemission spectroscopy studies indicate a charge transfer from GO to Cu. A strong interaction is observed between the metal content of the Cu/GO hybrids and the rates of formation and selectivity of the products. A factor of greater than 60 times enhancement in CO2 to fuel catalytic efficiency has been demonstrated using Cu/GO-2 (10 wt % Cu) compared with that using pristine GO.