A gas pressure and colorimetric signal dual-mode strategy for sensitive detection of spermine using ssDNA-coated Au@Pt nanoparticles as the probe.

The naturally occurring spermine (Spm), as one of the many cationic polyamines, plays a key role in biological processes and is involved in a variety of diseases. The very similar structures among biogenic polyamines present a major challenge to achieve discriminative testing among them. In this contribution, using arbitrary ssDNA-coated Au@PtNPs as the probe, we demonstrated that a dual-mode strategy via a gas pressure and colorimetric signal readout can be used for the sensitive and specific detection of Spm, due to the target-responsive aggregation of the Au@PtNPs leading to the inhibition of the catalyzed gas-generation reaction and the colorimetric change of the Au@PtNP solution. The proposed pressure-based signaling strategy has a detection limit of 9.6 nM, and can be used not only in the laboratory but also in the point-of-care setting. Meanwhile, the colorimetric assay displays the advantage of being easily discerned with the naked eye. Compared with the traditional methods of chromatography and capillary electrophoresis combined with chemical derivatization, the strategy described here would provide a convenient new alternative for the specific detection of Spm in biological samples.