Site-specific cleavage-based fluorescence sensing strategy for imaging thioredoxin reductase in living cells and tissues

Thioredoxin reductase (TrxR) is a pivotal biomarker and therapeutic target, monitoring its expression levels with good accuracy and sensitivity in cells or tissues is of great significance for clinical disease diagnosis and prognosis studies. Herin, we first develop a novel TrxR fluorescence sensing strategy based on the nucleic acid site-specific cleavage (NASC) mechanism, which highlights the benefits of prominent selectivity and high sensitivity. Notably, our NASC-based sensing strategy shows the limit of detection (LOD) is over two orders of magnitude lower than other site-specific cleavage-based approaches. Our proposed method has demonstrated the successful application in determining the TrxR level of in living cell and tissue, highlighting its potential for analyzing TrxR in clinical samples. The results convincingly illustrated that the NASC strategy stands as a highly promising molecular instrument for unraveling the physiological roles of TrxR within living organisms.