A coaxial nanocable textured by a cerium oxide shell and carbon core for sensing nitric oxide.

A corn-like CeO2/C coaxial cable textured by a cerium oxide shell and a carbon core was designed to sense NO. The carbon core possesses high electrical conductivity, and the CeO2 surface delivers excellent electrocatalytic activity. The sensor, typically operated at 0.8 V (vs. Ag/AgCl), exhibits a detection limit of 1.7 nM, which is 4-times lower than that of CeO2 nanotubes based one (at S/N = 3). It also displays wide linear response (up to 83 µM), a sensitivity of 0.81 µA µM-1 cm-2, and fast response (2 s). These values are highly competitive to that of a CeO2 tube (0.92 µA µM-1 cm-2 and 2 s). The sensor was used to quantify NO that is released by Aspergillus flavus. Graphical abstractSchematic representation of corn-like CeO2/C which can more sensitively and effectively detect NO released from A. flavus than when using CeO2 nanotubes, benefitting from its unique coaxial cable structure.

Involvement of O2·- release in zearalenone-induced hormesis of intestinal porcine enterocytes: An electrochemical sensor-based analysis.

Relationship between mycotoxin-induced hormesis and reactive oxygen species (ROS) has not been systematically investigated due to the lack of an effective analysis method. To monitor cellular release and intracellular level of O2·-, carboxymethyl cellulose-Mn3(PO4)2 nanocomposite was synthesized to fabricate an electrochemical biosensor, which selectively detects O2·- over the range of 57.50 nM âˆ¼ 2.95 µM (R2 = 0.99) with the sensitivity of 78.67 µA µM-1 cm-2 and the detection limit of 8.47 nM. Transient exposure to zearalenone (ZEA) induces the enhancement on cell viability, immediate O2·- release from cells, and reduction of intracellular O2·- level. After post-treatment culture, intracellular O2·- initially increases to a high level and then decreases to the normal level. Concurrently, the ZEA-induced hormesis disappears. Based on the findings, we propose a mechanism, involving the ROS release, increase of succinate dehydrogenase activity and recovery of intracellular ROS, to explain the occurrence and disappearance of hormesis in intestinal porcine enterocytes.

A Tissue-Like Soft All-Hydrogel Battery.

To develop wearable and implantable bioelectronics accommodating the dynamic and uneven biological tissues and reducing undesired immune responses, it is critical to adopt batteries with matched mechanical properties with tissues as power sources. However, the batteries available cannot reach the softness of tissues due to the high Young's moduli of components (e.g., metals, carbon materials, conductive polymers, or composite materials). The fabrication of tissue-like soft batteries thus remains a challenge. Here, the first ultrasoft batteries totally based on hydrogels are reported. The ultrasoft batteries exhibit Young's moduli of 80 kPa, perfectly matching skin and organs (e.g., heart). The high specific capacities of 82 mAh g-1 in all-hydrogel lithium-ion batteries and 370 mAh g-1 in all-hydrogel zinc-ion batteries at a current density of 0.5 A g-1 are achieved. Both high stability and biocompatibility of the all-hydrogel batteries have been demonstrated upon the applications of wearable and implantable. This work illuminates a pathway for designing power sources for wearable and implantable electronics with matched mechanical properties.

Electrochemical analysis of specific catalase activity during development of Aspergillus flavus and its correlation with aflatoxin B1 production.

Aflatoxin B1 (AFB1) contamination causes huge economic losses. To explore the correlation between catalase (CAT) and AFB1 production during fungal development, we fabricated an electrochemical CAT-activity sensor by measuring residual H2O2 after enzymatic degradation. The sensor made by palladium nanoparticles/carbonized bacterial cellulose nanocomposites exhibits a linear range over 0.5-3.5 U/mL and a detection limit of 0.434 U/mL. Both dry weight and CAT activity of mycelia continuously increase. But, the latter shows a greater increase than the former after three days. Specific CAT activity in crude enzyme extract of A. flavus was quantified. It maintains at ~25.00 U/mg for 3 days and enhances to 28.91 and 45.30 U/mg, respectively, on days 4 and 5. AFB1 production follows the same trend. On days 4 and 5, AFB1 concentration reaches 201.35 and 767.9 ng/mL, respectively. The positive correlation between specific CAT activity and AFB1 production suggests that CAT is involved in AFB1 biosynthesis.