Establishing an RNA sensor with high sensitivity and dynamic range utilizing a signal amplifier platform.

Precise control of gene expression in a cell-state-specific manner is essential for effective therapeutic interventions in complex and dynamic disease microenvironments. Traditional targeting strategies that rely on surface markers or cell type-specific promoters often assume static cellular identities, limiting effectiveness in contexts such as cancer and inflammation, where cell states are highly heterogeneous and dynamic. RNA sensors, such as RADAR (RNA sensing using Adenosine Deaminases Acting on RNA), provide a modular, programmable, and non-integrating platform for classifying cell states. However, it is also characterized by low sensitivity and dynamic range, which limits its applications in detecting low-abundance transcripts. In this work, we integrate RADAR sensors with a signal amplification circuit to enhance sensitivity and dynamic range. We demonstrate that this combined RADAR-amplifier platform enables real-time monitoring of subtle changes in the abundance of endogenous transcripts under physiological conditions. Our results demonstrate the utility of this platform for fundamental biological studies and the development of precision therapeutic strategies.