About this Research Topic
Metabolomics deal with the study of small molecules produced by an organism, providing valuable information on its state under specific conditions at a specific point in time. Whole blood, serum, and plasma are well-established specimens in clinical and environmental studies aiming to discover new biomarkers linked to several pathologies, or to identify the impairment of metabolic cycles due to the effect of external agents. However, their sampling requires the presence of specialized personnel, as it is invasive and could adversely affect the participation of volunteers to the study. Nowadays, unconventional biological matrices such as saliva, tears, breath, sweat, and dried blood spots can be collected in a non-invasive manner and have thus attracted increasing attention in the field of metabolomics. The analysis of cell-derived extracellular vesicles (EVs), which are involved in the development of different pathologies, has also played an emerging role in the field. Moreover, since metabolites represent the final response to environmental stress, matrices such as external fish mucus, whose metabolome remains largely unexplored, could also be exploited to assess the effects of concerning contaminants on an organism.
From a practical point of view, these unconventional matrices bring with them, besides undoubtedly interesting features, challenging issues mainly related to: the absence of standardized collection protocols, the absolute quantity of collected material, as well as the lack of standardized reference materials and normalization methods for the quantified analytes. In addition, despite recent advancements in mass spectrometry and nuclear magnetic resonance, limitations still need to be addressed, such as the requirements of derivatization methods for GC/MS, or the poorer sensitivity of NMR compared to mass spectrometry. Furthermore, integration with the other –omics techniques is fundamental to providing a global view of mechanisms and pathways involved in normal physiological processes and in the development of diseases, as well as the combination of metabolomics and software dedicated to identifying cellular pathways.
The aim of this Research Topic is to collect recent, innovative, and promising analytical research, whose goal is to expand metabolomics investigations to non-canonical biological matrices. We welcome submissions of Original Research, Review, Mini-Review, and Perspective articles in areas including, but not limited to:
• Advanced targeted and untargeted chromatographic, mass-spectrometric and nuclear magnetic resonance techniques applied in metabolomics studies.
• The applicability of alternative biological matrices (e.g. extracellular vescicles, saliva, and breath) to assess the exposure to emerging contaminants or to define novel biomarkers.
• Innovative sampling strategies to address the challenges of the existing ones with the aim to define standardized collection protocols.
• Development of new point-of-care devices for the health monitoring by means of non-conventional fluids.
• Integrative approaches between metabolomic and other –omics sciences.
• The integration of chemometric tools and specialized databases to increase the number of identified metabolites.
Keywords: metabolomics, unconventional matrices, biomarkers, point-of-care devices, sensors
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