BPS2026 - Nanopore-based identification and discrimination of a gut-hormone biomarker family in human serum

In the following decades, we can expect to see a higher incidence of diseases. Two primary reasons are the rise in pollution and the global increase in the median age. Thus, early diagnosis is crucial to enable timely and appropriate treatment. Variations in peptide biomarker concentrations are associated with numerous diseases. Besides its different levels, the same peptide can undergo post-translational modification, resulting in a distinct physiological response. Current clinical methods are not powerful enough to detect and quantify these variations. A small biomarker family was investigated by aerolysin nanopore sensing. Immunoenzymatic assays lack specificity in distinguishing between a single PTM that differs between the two molecules here analyzed. Moreover, bulk methods such as MS do not permit measurement of bodily fluids without prior sample preparation. We characterized the dynamics of these two molecules in native conditions. We found that the experimental conditions could distinguish them by trapping and preventing translocation, as well as ensuring a highly resolutive signal. We then performed measurements at a final human serum concentration of 20% v/v using a hybrid lipid-block membrane. Finally, to obtain a good identification score, we employed a machine learning tool. We have got a double confirmation in detecting and discriminating among these subtle PTMs in a complex biofluid, such as human serum. These results pave the way for a trustworthy discrimination and quantification of these potential biomarkers. Moreover, this has been possible without prior sample filtration or pretreatment—except for the standard procedure to obtain serum.