Influence of sodium chloride content in electrolyte solution on electrochemical impedance measurements of human dentin

Sweet Drinks as Fuels for an Alkaline Fuel Cell with Nonprecious Catalysts

Sugar has the potential to create enough energy to power mobile electronics. Various sugar-powered fuel cells have been reported, however, most of them used pure glucose as substrate and enzymes/noble metals as catalysts. In this work, an alkaline fuel cell with cheap catalysts were constructed, and different sweet drinks were used as fuels for power generation. The influence of different substrates on the electrochemical performance was characterized under the controlled conditions. Our experimental results showed that the fuel cell fueled with carbonated soft drinks had the best performance under the conditions of 99.95 g/L chemical oxygen demand and 3M KOH. The power densities of the fuel cell fueled with different substrates decreased in the order of Pepsi (33.41 W/m2) > Sprite (28.38 W/m2) > apple juice (20.63 W/m2) > Coca (16.31 W/m2) > pear juice (15.31 W/m2) > orange juice (12.75 W/m2), which was consistent with linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) analysis. This is the first report on alkaline fuel cell (AFC) performance using different sweet drinks as substrate. These values are more than 10 times higher than those of reported microbial fuel cells. Our findings demonstrated that sweet drinks fueled alkaline fuel cells can be a promising energy source for low-power electronics.

Hemostasis-On-a-Chip: Impedance Spectroscopy Meets Microfluidics for Hemostasis Evaluation

In the case of vascular injury, a complex process (of clotting) starts, involving mainly platelets and coagulation factors. This process in healthy humans is known as hemostasis, but when it is deregulated (thrombosis), it can be the cause of important cardiovascular diseases. Nowadays, the aging of the population and unhealthy lifestyles increase the impact of thrombosis, and therefore there is a need for tools to provide a better understanding of the hemostasis mechanisms, as well as more cost-effective diagnosis and control devices. This study proposes a novel microflow chamber, with interchangeable biomimetic surfaces to evaluate global hemostasis, using reduced amounts of blood sample and reagents, and also a minimized time required to do the test. To validate the performance of this novel device, a study on the new oral anticoagulant Apixaban (APIX) has been performed and compared to previous conventional techniques. The test shows an excellent agreement, while the amount of the required sample has been reduced (only 100 µL is used), and the amount of reagent as well. An imprinted electrode embedded in the chamber in order to measure the impedance during the coagulation process. This approach distinguishes the impedance behavior of plasma poor in platelets (PPP) and plasma rich in platelets (PRP) for the first time.