Ti3C2 MXene-based aptasensor for sensitive and simultaneous detection of two diabetes biomarkers

The simultaneous detection of multiple diabetes markers is important for the diagnosis and typing of diabetes because of the complex causes of diabetes. Two-dimensional titanium carbide (MXene), an emerging material, has great potential for biomedical sensing, in addition to its electrical applications. In this study, a fluorescence resonance energy transfer (FRET) aptasensor with high sensitivity and specificity was constructed using monolayer Ti3C2 MXene for the simultaneous detection of insulin and visceral adipose tissue-derived serotonin (vaspin). Fluorescein-labeled insulin binding aptamers (IBAs) and Cy7-labeled vaspin-binding aptamers (VBAs) were attached to Ti3C2, and their fluorescence was effectively quenched by FRET between the fluorescein and Ti3C2. Insulin and vaspin were preferentially bound to IBA and VBA for a higher affinity. This process led to the subsequent shedding of fluorescein from Ti3C2, resulting in fluorescence recovery. The high fluorescence quenching efficiency and broad wavelength absorption of Ti3C2 MXene enabled the quenching of two different, wide spectrum fluorescence at two different wavelengths, thus enabling the simultaneous detection of both insulin and vaspin. The aptasensor was highly sensitive, with a low detection limit of 36 pM for insulin and 45 pM for vaspin. Importantly, this Ti3C2-based aptasensor can precisely detect insulin and vaspin in human serum and diagnose a specific type of diabetes and identify its cause to facilitate subsequent treatment. The above results indicate that the Ti3C2-based aptasensor has promising applications in the clinical diagnosis and typing of diabetes mellitus.