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G‐quadruplexes (G4s), non‐canonical nucleic acid secondary structure, regulate many biological functions and are considered potential molecular targets for cancer therapeutics. However, due to the lack of analytical methods, the regulating mechanism of monogenic G4s is still unclear. Here, we developed a Module Assembled Multifunctional Probes Assay (MAMPA) for visualizing endogenous G4s in individual genes in single cells. Two modular probes separately recognize G4 structures and the adjacent RNA sequences, and the module assembly enables imaging of G4s in an individual RNA with high specificity. Through imaging G4s in several individual genes, we found that G4s were steadily occupied by G4 Binding Proteins (G4BPs) in various mRNAs in every cell line and defined "Occupied G4 Ratio". We demonstrated MAMPA was suitable for most experimental situations and found that Occupied G4 Ratios had the potential to become a new parameter for the study of G4s in living cells. [ABSTRACT FROM AUTHOR]

Stroke is a lethal cerebral disease with severe sequelae and high mortality. Microglia, the main immune cell in the cerebrum, possess therapeutic potential for strokes as its specific anti‐inflammatory phenotype can reduce inflammation and promote neuron regeneration. However, the on‐demand anti‐inflammatory polarization of microglia at the stroke site is uncontrollable for therapeutic application. Here, we develop a platelet hybrid microglia platform which can specifically polarize to the anti‐inflammatory phenotype by ultrasound irradiation for targeted cerebrum repair after stroke. The engineered microglia have strong adherence to the injured cerebral vessels with platelet membrane fusion and realize on‐demand anti‐inflammatory polarization with ultrasound‐responsive IL‐4 liposome decoration. The intravenously injected microglia platform showed anti‐inflammatory polarization at the stroke site with insonation, and accelerated the M2‐type polarization of endogenous microglia for long‐term stroke recovery. Satisfied prognoses were achieved with reduced apoptosis, promoted neurogenesis, and functional recovery, indicating the implications of the microglia platform for stroke therapy. [ABSTRACT FROM AUTHOR]