Centipede-Mimetic DNA Nanomachines with Circular Sensing Modules for Spatial Monitoring of Extracellular Metabolites

Dynamic monitoring of small-molecule metabolites in extracellular microenvironments is crucial for deciphering their roles as pathological regulators in disease progression. Despite their promise, DNA-based nanosensors remain constrained by insufficient sensitivity, structural instability, and poor signal output thresholds in spatially resolved extracellular biomarker imaging. Herein, we report a centipede-mimetic DNA nanomachine (CMNM) featuring (1) topologically engineered circular sensing modules that enhance nuclease stability and target recognition sensitivity and (2) a multibranched DNA nanowire scaffold with a morphology like a centipede, self-assembled by membrane-anchoring aptamers, enabling high-density sensor confinement at living cell surfaces via multivalent interactions. By reprogramming the recognition domains of the circular sensing modules, the CMNM enables spatial imaging of extracellular ATP and H⁺ in tumor cell environments and, notably, achieves the first DNA nanodevice-based visualization of extracellular lactate. This biomimetic and modular design strategy offers a versatile platform for expanding to a broader range of metabolic targets, paving the way for mechanistic studies of metabolic diseases and the development of precision diagnostic and therapeutic tools.