Impiego di un array di sensori di gas e di tecniche gascromatografiche per lo studio di patologie e forme cellulari attraverso l'analisi di composti volatili rilasciati dai fluidi biologici

The present thesis describes the potentials that the volatile organic compounds (VOCs) have in diagnostics as well as the results achieved by using innovative analytical systems (such as SPME-GC/MS spectrometer and electronic nose instruments) to reveal pathologies, inflammatory processes, metabolic disorders, infections and degenerative cellular processes, also occurring in the early stages. Therefore, in collaboration with both clinicians and research groups of medicine and biology, chemistry and electronic engineering, three different experiments were carried out and here described. The first one was related to the application of both a homemade electronic nose (Department of Electronic Engineering of “Tor Vergata” University), based quartz crystal microbalances (QCM) differently coated with metal porphyrins (synthesized in the Laboratory of Chemistry of “Tor Vergata” University), and a SPME-GC/MS spectrometer to investigate the pattern of the volatile compounds of synovial fluids coming from several patients suffering from two different knee‟s rheumatic diseases (“Tor Vergata” General Hospital, Medicine Department). In this case a greater abundance of volatile compounds in OA than RA. The biomarkers for differential diagnosis between OA and RA are still defective. Through the analysis of the head space of the synovial fluid by NE, good discrimination was obtained between the different pathologies considered the results indicate that the VOC mixture in the synovial fluid of patients with OA is different from that of patients with RA. The second one involved a similar equipment, whereas the electronic nose contained an increased number of sensors, to investigate VOCs from living mice (i.e. breath, skin, urine, faeces) infected with erythrocytes containing different strains of plasmodium (Higher Health Institute, ISS). The results by Plasmodium berghei infection alters the profile of VOCs released, NE analysis of the entire murine volatiloma has led to a good discrimination between a group of healthy mice and one of malaria-affected rats. The GC/MS was detected by a set of VOCs whose concentration was statistically different between infected and uninfected mice. The last one provided an intriguing investigation, using the same instrumentation, on the pattern of volatile compounds from stem cell (specifically Induced Pluripotent Stem cell) in the different stages of differentiation (Department of Genetics). In each application, a suitable measurement protocol was arranged. All the results were treated with statistical analysis and multicomponent analysis. The results support the hypothesis that the volatile fraction of the metabolic profile changes along the differentiation process as a reflection of the variations occurring in the cells. The GC/MS shows a number of compounds that can discriminate between the various stages of differentiation. The NE shows good ability to discriminate between different cellular stages, from pluripotency to differentiated cells.