Alla ricerca di sonde selettive per il rilevamento della mucina: uno studio spettroscopico

Over the years, fluorescent probes have gained increasing attention because of their advantages of label free and fluorescent properties. Particularly, the fluorogenic and chromogenic probes, which undergo a change in their spectroscopic properties, such as a colour shift or an enhancement in fluorescence emission (turn on) in response to specific biological target (e.g., proteins) find promising application both in elucidating mechanisms of biological processes but also as potential biomarkers in medical diagnosis and biological imaging at the molecular, cellular and organism level. In this study the focus was addressed on the search of a selective probe for mucin glycoprotein because of its key role as human biomarker. Dye-protein interaction was studied in aqueous media by means of UV–Vis and fluorescence spectroscopies. The turn on and selectivity of the dyes with mucin are evaluated in relation to other human proteins (albumin, transferrin, fibrinogen, trypsin, pepsin, and a generic protease). The most promising dye was used to probe mucin both in diluted deproteinized human serum and in diluted pure human serum spiked with mucin. Almost all the analysed dyes show good affinity for mucin with some variability. The effect (turn on) generally consists of an enhancement in fluorescence emission up to 25/30-fold upon the addition of mucin and 3/9-fold with albumin. In addition, very interesting is a dye that showed a selective responsive to mucin by means of a clear colour change not occurring with albumin. The obtained results represent a step forward for the understanding of how dye-protein interaction takes place. They provide useful information for the design of more effective and selective probes for the development of specific spectroscopic assays exploiting their simplicity, convenience, non-invasive monitoring capability and applicability to biological samples.