Construction of an autofluorescence interference-free phosphorescence biosensor for the specific detection of TK1 mRNA.

The anti-interference ability of biosensors is critical for detection in biological samples. Fluorescence-based sensors are subject to interference from self-luminescent substances in biological matrices. Therefore, phosphorescent sensors stand out among biosensors due to their lack of self-luminescence background. In this study, a phosphorescent sensor was constructed, which can accurately detect thymidine kinase 1 (TK1) mRNA in biological samples and avoid autofluorescence interference. When there is no target, polydopamine (PDA) is used as the phosphorescence resonance energy transfer (PRET) acceptor to quench the phosphorescence of the persistently luminescent (PL) nanomaterial. When there is a target, the DNA modified by the PL nanomaterial is replaced by the hairpin H and removed away from the PDA, resulting in a rebound in phosphorescence. The phosphorescent sensor exhibits a good linear relationship in the TK1 mRNA concentration range of 0–200 nM, and the detection limit was 1.74 nM. The sensor fabricated in this study can effectively avoid interference from spontaneous fluorescence in complex biological samples, and sensitively and precisely detect TK1 mRNA in serum samples, providing a powerful tool to more accurately detect biomarkers in biological samples. When there is no target, polydopamine (PDA) is used as the acceptor of phosphorescence resonance energy transfer (PRET) to quench the phosphorescence of persistent luminescent nanomaterials (PL). When the target is present, the DNA modified by PL will be replaced by the hairpin H and away from the PDA, resulting in a rebound in phosphorescence. [Display omitted] • Avoid the interference of background fluorescence in complex biological samples. • Phosphorescence biosensor for specific detection of tumor marker TK1 mRNA. • A low detection line of 1.74 nM and a wide detection range were obtained. [ABSTRACT FROM AUTHOR]