Electrochemical Determination of Superoxide Based on CytochromecImmobilized on DDAB‐Modified Powder Microelectrode

Real-time monitoring of phenazines excretion in Pseudomonas aeruginosa microbial fuel cell anode using cavity microelectrodes

Phenazines are a kind of metabolites that can mediate extracellular Pseudomonas aeruginosa (P. aeruginosa) cells in microbial fuel cells (MFCs). However, it is still not clear that whether and how the excretion profile of phenazines is affected by the operating MFC. Here, we report a real time analysis approach based on a cavity microelectrode electrochemical sensor to investigate the phenazines excretion behavior of P. aeruginosa during MFC operation. The phenazine concentration increases at first 72 h, reaches a plateau and decreases after 120 h and also shows local dependent variation. It is dependent on the MFC current generation profile but also affect by the biofilm formation. Accordingly, a mechanism about phenazines excretion in MFC anode and the phenazines mediated extracellular electron transfer of the P. aeruginosa anode is proposed. This work provides a novel strategy for self-mediated extracellular electron transfer analysis in the operating MFCs.

Amperometric enzyme sensor to check the total antioxidant capacity of several mixed berries. Comparison with two other spectrophotometric and fluorimetric methods

The aim of this research was to test the correctness of response of a superoxide dismutase amperometric biosensor used for the purpose of measuring and ranking the total antioxidant capacity of several systematically analysed mixed berries. Several methods are described in the literature for determining antioxidant capacity, each culminating in the construction of an antioxidant capacity scale and each using its own unit of measurement. It was therefore endeavoured to correlate and compare the results obtained using the present amperometric biosensor method with those resulting from two other different methods for determining the total antioxidant capacity selected from among those more frequently cited in the literature. The purpose was to establish a methodological approach consisting in the simultaneous application of different methods that it would be possible to use to obtain an accurate estimation of the total antioxidant capacity of different mixed berries and the food products containing them. Testing was therefore extended to also cover jams, yoghurts and juices containing mixed berries.

Determination of the antioxidants' ability to scavenge free radicals using biosensors

Free radicals are highly reactive molecules generated during cellular metabolism. However, their overproduction results in oxidative stress, a deleterious process that can damage cell structures, including lipids and membranes, proteins and DNA. Antioxidants respond to this problem, scavenging free radicals. This chapter critically reviews the electrochemical biosensors developed for the evaluation of the antioxidant capacity of specific compounds. Due to the ability of these devices to perform simple, fast and reliable analysis, they are promising biotools for the assessment ofantioxidant properties.