“Bio-switch Chip” Based on Nanostructured Conducting Polymer and Entrapped Enzyme

We report a switchable biochip strategy where enzymes were entrapped in conducting polymer layers and the enzymatic reaction of the entrapped enzymes was controlled in real-time via electrical stimuli on the polymer layers. This device is named here as a “bio-switch chip” (BSC). We fabricated BSC structures using polypyrrole (Ppy) with entrapped glucose oxidase (GOx) and demonstrated the switching of glucose oxidation reaction in real-time. We found that the introduction of a negative bias voltage on the BSC structure resulted in the enhanced glucose oxidation reaction by more than 20 times than that without a bias voltage. Moreover, because the BSC structures could be fabricated on specific regions, we could control the enzymatic reaction on specific regions. In view of the fact that enzymes enable very useful and versatile biochemical reactions, the ability to control the enzymatic reactions via conventional electrical signals could open up various applications in the area of biochips and other biochemical industries

Controlling Surface Structure and Primary Particle Size to Enhance Performance and Reduce Gas Evolution in Lithium- and Manganese-Rich Layered Oxide Cathodes

Practical application of lithium- and manganese-rich layered oxide cathodes has been hindered despite their high performance and low cost owing to high gas evolution accompanying capacity loss even in a conservative voltage window. Here, we control the surface structure and primary particle size of lithium- and manganese-rich layered oxide cathodes not only to enhance the electrochemical performance but also to reduce gas evolution. Sulfur-coated Fm3̅m/R3̅m double reduced surface layers and Mo doping dramatically reduce gas evolution, which entails the improvement of electrochemical performance. With the optimization, we prove that it is competitive enough to conventional high-nickel cathodes in the aspects of gas evolution as well as electrochemical performance in the conservative voltage window of 2.5–4.4 V. Our findings provide invaluable insights on the improvement of electrochemical performance and gas evolution properties in lithium- and manganese-rich layered oxide cathodes