New tools for single‐cell interrogation enable deeper understanding of cellular heterogeneity and associated cellular behaviors and functions. Information of RNA expression in single cell could contribute to our knowledge of the genetic regulatory circuits and molecular mechanism of disease development. Although significant progresses have been made for intracellular RNA analysis, existing methods have a trade‐off between operational complexity and practical feasibility. We address this challenge by combining the ionic current rectification property of nanopipette reactor with duplex‐specific nuclease‐assisted hybridization chain reaction for signal amplification to realize a simple and practical intracellular nanosensor with minimal invasiveness, which enables single‐cell collection and electrochemical detection of intracellular RNA with cell‐context preservation. Systematic studies on differentiation of oncogenic miR‐10b expression levels in non‐malignant breast cells, metastatic breast cancer cells as well as non‐metastatic breast cancer cells were then realized by this nanotool accompanied by assessment of different drugs effects. This work has unveiled the ability of electrochemistry to probe intracellular RNA and opened new opportunities to study the gene expression and heterogeneous complexity under physiological conditions down to single‐cell level.

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This work reports the synthesis of dual functional molecularly imprinted polymer (MIP)-modified organometal lead halide perovskite (CH3NH3PbI3) and its application for photoelectrochemical (PEC) bioanalysis of salicylic acid (SA). Specifically, the CH3NH3PbI3 was encapsulated into the MIPs via a simple thermal polymerization process on the indium tin oxide (ITO) glass, and the as-obtained MIPs/CH3NH3PbI3/ITO electrode was characterized by various techniques, which revealed that the MIPs could not only stabilize CH3NH3PbI3 but also improve the electron–hole separation efficiency of CH3NH3PbI3 under light illumination. In the detection of model analyte SA, the PEC sensor, with numerous amounts of recognition sites to SA, exhibited desirable performance in terms of good sensitivity, selectivity, stability, and feasibility for real sample analysis. This work not only featured the use of MIPs/CH3NH3PbI3 for PEC detection of SA but also provided a new horizon for the design and implementation of functional polymers/perovskite materials in the field of PEC sensors and biosensors.

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