The field of optical sensors has been a growing research area over the last three decades. A wide range of books and review articles has been published by experts in the field who have highlighted the advantages of optical sensing over other transduction methods. Fluorescence is by far the method most often applied and comes in a variety of schemes. Nowadays, one of the most common approaches in the field of optical biosensors is to combine the high sensitivity of fluorescence detection in combination with the high selectivity provided by ligand-binding proteins. In this chapter we deal with reviewing our recent results on the implementation of fluorescence-based sensors for monitoring environmentally hazardous gas molecules (e.g. nitric oxide, hydrogen sulfide). Reflectivity-based sensors, fluorescence correlation spectroscopy-based (FCS) systems, and sensors relying on the enhanced fluorescence emission on silver island films (SIFs) coupled to the total internal reflection fluorescence mode (TIRF) for the detection of gliadin and other prolamines considered toxic for celiac patients are also discussed herein.

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In this work, we investigate the mode of interaction of a family of fluorescent zinc complexes with HS − and H 2 S. Different experiments, performed by diverse spectroscopic techniques, provide evidence that HS − binds the zinc center of all the complexes under investigation. Treatment with neutral H 2 S exhibits a markedly different reactivity which indicates selectivity for HS − over H 2 S of the systems under investigation. Striking color changes, visible to the naked eye, occur when treating the systems with HS − or by an H 2 S flow. Accordingly, also the fluorescence is modulated by the presence of HS − , with the possible formation of multiple adducts. The results highlight the potential of the devised systems to be implemented as HS − / H 2 S colorimetric and fluorescent sensors. Bioimaging experiments indicate the potential of using this class of compounds as probes for the detection of H 2 S in living cells.

The aim of the present review is to highlight the most recent achievements in different fields of application of salen-based zinc and aluminum complexes. More specifically this article focuses on...

Vanadium compounds can exert anticancer effects, partly due to inhibition of tyrosine phosphatases. Here, we report the effect of N,N'-ethylenebis (pyridoxylideneiminato) vanadium (IV) complex (Pyr2 enV(IV)), that induced 93% and 57% of cell mortality in A375 (human melanoma) and A549 (human lung carcinoma) cells, respectively; the mortality was <24% in other cancer cell lines and in human normal epidermal keratinocytes, lung cells and peripheral blood mononuclear cells. The mechanism of Pyr2 enV(IV) effect relied on apoptosis induction; this was triggered by ROS increase, followed by mitochondrial membrane depolarization. Indeed, the addition of N-acetyl cysteine to cell cultures abated Pyr2 enV(IV)-induced apoptosis. These results disclose the pro-apoptotic activity of Pyr2 enV(IV) and its mechanism, relying on intracellular ROS increase.