Novel Spatially Asymmetric Copper Bismuthate-Mediated Augmentation of Energy Conversion to Realize "Three-Step" Tumor Suppression.

The generally undesirable bandgap and electron-hole complexation of inorganic sonosensitizers limit the efficiency of reactive oxygen species (ROS) generation, affecting the effectiveness of sonodynamic therapy (SDT). Comparatively, the novel polyvinylpyrrolidone-modified copper bismuthate (PCBO) sonosensitizers are manufactured for a "three-step" SDT promotion. In brief, first, the strong hybridization between Bi 6s and O 2p orbitals in PCBO narrows the bandgap (1.83 eV), facilitating the rapid transfer of charge carriers. Additionally, nonequivalent [CuO4]6- layers reduce crystal symmetry, confer PCBO unique piezoelectricity, and improve electron-hole separation under ultrasonic (US) excitation. This allows PCBO to convert US energy into chemical energy to produce ROS, achieving the accumulation of abundant ROS, resulting in apoptosis and tumor suppression. Concurrently, PCBO also acts as a glutathione scavenger to reduce tumor antioxidant capacity and improve efficacy. To the best of authors understanding, this study reveals PCBO as an innovative piezoelectric sonosensitizer and provides a meaningful paradigm for designing energy conversion strategies for tumor suppression.

Root iron plaque alleviates cadmium toxicity to rice (Oryza sativa) seedlings.

Iron plaque (IP) on root surface can enhance the tolerance of plants to environmental stresses. However, it remains unclear the impact of Fe2+ on cadmium (Cd) toxicity to rice (Oryza sativa) seedlings. In this study, the effects of different Fe2+ and Cd2+ concentration combinations on rice growth were examined hydroponically. Results indicated that Fe2+ concentration up to 3.2 mM did not damage rice roots while induced IP formation obviously. Cd2+ of 10 µM repressed rice growth significantly, while the addition of 0.2 mM Fe2+ to 10 µM Cd2+ solution (Cd+Fe) did not damage rice roots, indicating that Fe2+ could ameliorate Cd toxicity to rice seedlings. Microstructure analysis showed Cd+Fe treatment induced the formation of IP with dense and intricate network structure, Cd adsorption on the root surface was reduced significantly. Cd concentration of rice roots and shoots and Cd translocation from roots to shoots with Fe+Cd treatment were reduced by 34.1%, 36.0% and 20.1%, respectively, in comparison to a single Cd treatment. Noteworthy, the removal of IP resulted in a larger loss of root biomass under Cd treatment. In addition, Cd+Fe treatment increased the activities of root superoxide dismutase and catalase by 105.5% and 177.4%, and decreased H2O2 and O2·- accumulation of rice roots by 56.9% and 35.9%, and recovered Cd-triggered electrolyte leakage obviously, when compared with a single Cd treatment. The results from this experiment indicated that the formed dense IP on rice roots decreased Cd absorption and reactive oxygen species accumulation, and Fe2+ supply alleviated Cd toxicity to rice seedlings.

Drying-submergence alternation enhanced crystalline ratio and varied surface properties of iron plaque on rice (Oryza sativa) roots.

Iron plaque (IP) is valuable in nutrient management and contaminant tolerance for rice (Oryza sativa) because it can adsorb various nutrients and toxic ions. Crystalline ratio (CR) can be defined as the proportion of crystalline iron (CI) to total IP to describe IP crystallinity. Although the knowledge on IP has abounded, the information on the relationship among its formation condition, surface properties, and CR remains insufficient. In this study, quartz sand-soil cultivation with rice was conducted to explore the effect of drying-submergence alternation (DSA) on CI, amorphous iron (AI), CR, root oxidizing capacity (ROC), and surface properties of IP with different treatment durations and at different stages. Fourteen-day DSA treatment increased CI to 2.20 times of that after continuous submergence (CS) but decreased AI to 72.3% of that after CS. Correspondingly, CR was raised to 6.89% from 4.08%. Remarkably, CR of IP after DSA ending in submergence and ending in drying was 6.89% and 4.23%, respectively. In addition, ROC after 14-day DSA was enhanced to twice of that after CS. Results from scanning electronic microscope suggested that 14-day DSA induced thinner sheets with finer particles in IP compared to that after CS. Results from X-ray diffraction revealed that IP contained higher proportions of goethite, lepidocrocite, magnetite, and hematite after DSA than those after CS. Variable charge and surface area of IP after DSA were only 26.5% and 32.0% of those after CS, respectively. Together, our results indicated that proper strength DSA promoted ROC and transformation from AI to CI, and consequently increased CR of IP, while it changed its surface properties.